This topic provides answers to frequently asked questions about Elastic Compute Service (ECS) instances.

How do I check which instance resources are available for purchase within a specific region or zone?

You can go to the ECS Instance Types Available for Each Region page to view the instance types available in each region.

What do I do if resources are sold out when I attempt to purchase an instance within a specific region or zone?

If the resources for a specific instance type are sold out when you attempt to purchase an instance of that instance type within a specific region or zone, take one of the following measures:
  • Select another region.
  • Select another zone.
  • Select another instance type.

If the resources that you want to purchase are still unavailable after you take the preceding measures, try again later. Instance resources are dynamic. Resources that are insufficient are replenished by Alibaba Cloud as quickly as possible.

You can also use the arrival notice feature to receive notifications when resources become available.

How do I select an instance type that is suitable for my business?

Consider the following factors when you select an instance type. For more information about how to select an instance type, see Best practices for instance type selection.

  • Your business needs
  • Your website type
  • The average number of page views per day on your website
  • The size of your homepage
  • The data capacity of your website

How long does it take to create an ECS instance?

It takes a minute or two to create an ECS instance.
  • You can immediately connect to a Linux instance after it is created. For more information, see Connect to an ECS instance.
  • After a Windows instance is created, you must use Sysprep to initialize the operating system before you can connect to the instance. Do not restart the instance while its operating system is being initialized. After the operating system is initialized, you can connect to the instance. For more information, see Connect to an ECS instance. The amount of time required to initialize the operating system is determined by the type of the instance.
    • For an I/O optimized Windows instance, it takes 2 to 3 minutes to initialize the operating system.
    • For a non-I/O optimized Windows instance, it takes 10 minutes to initialize the operating system.
Note If an error occurs while the instance is being created, submit a ticket.

I paid for an instance but no instance was created. Why?

If resources within the specified zone are insufficient to create an instance of your selected instance type, the instance cannot be created. A refund is automatically credited to your account. If you do not receive a refund within half an hour, submit a ticket.

You can go to the ECS Instance Types Available for Each Region page to view the instance types available in each region.

Why does a purchased instance have a memory size different than that defined in the instance type?

The memory size defined in each instance type is the total amount of memory, which includes the amount of memory occupied by the system, such as the BIOS reserved memory and memory overheads of running the kernel and hypervisor. As a result, the size of available memory on your instance is smaller than the memory size defined in the instance type. Different instance families may use different technology stacks, which causes the percentage of memory occupied by the system to vary slightly.

What are enterprise-level instances? What are shared instances?

Enterprise-level instances belong to a series of instance families released by Alibaba Cloud in September 2016. Enterprise-level instances provide high performance, consistent computing power, and balanced network performance. Enterprise-level instances have exclusive and consistent computing, storage, and network resources, and are suitable for enterprise scenarios that require high business stability.

Shared instances belong to a series of instance families that are intended for individuals or small and medium-sized websites. Shared instances share resources, in contrast with enterprise-level instances that each have their own resources exclusively. As a result, shared instances do not provide consistent computing performance, but cost less.

What are the differences between enterprise-level and shared instances?

Enterprise-level instances use a CPU-bound scheduling scheme. Each vCPU is bound to a CPU hyperthread. Instances do not compete for CPU resources and do provide consistent computing performance as guaranteed in the service-level agreement (SLA).

Shared instances use a CPU-unbound scheduling scheme. Each vCPU is randomly allocated to an idle CPU hyperthread. vCPUs of different instances compete for CPU resources, which causes computing performance to fluctuate when traffic loads are heavy. Shared instances can guarantee availability but cannot guarantee the performance that may be required in the SLA.

Which instance families are enterprise-level instance families? Which instance families are shared instance families?

Among the instance families that are available for purchase, t6, t5, s6, n4, mn4, xn4, and e4 are shared instance families, and the rest are enterprise-level instance families.

In what business scenarios do I need to purchase enterprise-level instances?

For business scenarios to which different enterprise-level instances are applicable, see Instance families and Best practices for instance type selection.

How is the network performance of enterprise-level instances?

The network performance of enterprise-level instances depends on their specifications. The higher their specifications are, the higher network performance the instances can deliver. For more information about the network performance of different instance specifications, see Instance families.

Which disk categories do enterprise-level instances support?

For information about the disk categories that enterprise-level instances support, see Disk categories.

Which image types do enterprise-level instances support?

For information about the public images that enterprise-level instances support, see Overview.

You can also import custom images. For more information, see Import custom images.

What are the limits on changing the instance types of enterprise-level instances?

For information about the limits on changing the instance types of enterprise-level instances, see Instance families that support instance type changes.

Can I change a shared instance into an enterprise-level instance?

Yes, you can change a shared instance into an enterprise-level instance. For more information, see Instance families that support instance type changes.

What characteristics do persistent memory-optimized instances have?

Persistent memory-optimized instances use high-capacity persistent memory, and provide slower access and higher data durability than the instances that use regular memory do. When persistent memory-optimized instances are stopped or restarted, data in their persistent memory is not lost. Persistent memory can be used as memory or local SSDs.
  • When persistent memory is used as memory, you can move some data from regular memory to persistent memory, such as non-hot data that does not require high-speed storage access. Persistent memory offers large capacity at a low price per GiB and can help reduce the total cost of ownership (TCO) per GiB of memory.
  • Persistent memory can be used as local SSDs to deliver ultra-high performance and offer a read/write latency as low as 400 nanoseconds. You can use persistent memory for core application databases that require consistent response time. You can also replace cache disks with persistent memory to achieve higher IOPS, higher bandwidth, and lower latency and improve the business performance of an entire cluster.

What requirements do persistent memory-optimized instances have for operating systems?

The following image versions can be used on persistent memory-optimized instances:
  • Alibaba Cloud Linux 2
  • CentOS 7.6 or later
  • Ubuntu 18.10 or later
  • SUSE Linux 12 SP4 or later

Alibaba Cloud provides support for Alibaba Cloud Linux 2. Alibaba Cloud Linux 2 integrates tools for scenarios to which persistent memory is applicable to work out of the box. In some scenarios such as those in which Redis applications are used, Alibaba Cloud Linux 2 outperforms community-supported Linux distributions by 20% in terms of performance.

After I purchase a persistent memory-optimized instance, how do I configure its persistent memory as memory?

You can use tools to configure the persistent memory as memory. For more information, see Configure the usage mode of persistent memory.

When persistent memory is being used as memory on a persistent memory-optimized instance, can I deploy and run Redis applications on the instance?

You can significantly reduce the TCO per GiB of memory for Redis applications by running them on persistent memory-optimized instances. To ensure performance, you must modify the Redis applications by stratifying their data and storing the data in different places. You can store non-hot data in persistent memory and hot data in regular memory.

To reduce your modification costs, Alibaba Cloud provides re6p instance types exclusively for Redis applications. You can run several commands to deploy Redis applications on re6p instances. For more information, see Deploy Redis applications on re6p instances.
Note When you purchase persistent memory-optimized instances, select instance types named in the ecs.re6p-redis.<nx>large format.

I already have a Redis cluster based on regular memory and want to migrate business from this cluster to persistent memory-optimized instances. How do I do this? What items do I need to take note of?

You must ensure business consistency and data reliability while you are migrating business from the Redis cluster to persistent memory-optimized instances. We recommend that you first purchase a single persistent memory-optimized instance and test it with a small amount of required business to check whether the basic performance and capacity model of the instance meet your business requirements. If the basic performance and capacity model of the instance meet your business requirements, you can scale out to more persistent memory-optimized instances and take over business from the entire Redis cluster.

Can I deploy and run a parameter server (PS) architecture on persistent memory-optimized instances whose persistent memory is used as memory?

Server nodes in a PS architecture store all training parameters of training clusters, traditionally in their memory. These parameters consume a large amount of memory and are expensive to store. When you run a PS architecture on persistent memory-optimized instances whose persistent memory is used as memory, we recommend that you store all parameters in persistent memory and only hash tables in regular memory. This way, you can significantly reduce the TCO of training clusters.

You can modify the applications to suit your business requirements, or submit a ticket to contact Alibaba Cloud for technical support.

After I purchase a persistent memory-optimized instance, how do I configure its persistent memory as local SSDs?

You can use tools to configure the persistent memory as local SSDs. For more information, see Configure the usage mode of persistent memory.

To which applications are local SSDs that can deliver higher performance applicable?

To optimize performance or costs for I/O-intensive applications, you can select persistent memory-optimized instances. You can use persistent memory-optimized instances to solve common issues such as the following ones:
  • The latency of single SQL queries is high, and SQL queries require a more consistent response time.
  • It takes too long to load resources on frontend game servers, heavily loaded databases, and heavily loaded web servers.
  • You purchased large cloud disks or local disks for their high IOPS and bandwidth but now have unused capacity that causes unnecessary costs.
You can use persistent memory-optimized instances in typical I/O-intensive scenarios such as the following ones:
  • Redis and other NoSQL databases such as Cassandra and MongoDB
  • Structured databases such as MySQL
  • I/O-intensive applications such as e-commerce, online games, and media applications
  • Search with Elasticsearch
  • Live video streaming, instant messaging, and room-based online games that require persistent connections
  • High-performance relational databases and online transaction processing (OLTP) systems

Can I deploy Redis or MySQL applications on persistent memory-optimized instances whose persistent memory is used as local SSDs? Do the applications need to be modified in the same manner as they do when persistent memory is used as memory?

Yes, you can deploy Redis and MySQL applications on persistent memory-optimized instances whose persistent memory is used as local SSDs. You do not need to modify these applications before they can identify the persistent memory as standard SSDs.

How is the performance of persistent memory used as local SSDs, compared with local NVMe SSDs and cloud disks?

The following table describes the performance comparison between local NVMe SSDs, enhanced SSDs (ESSDs), and persistent memory that is used as local SSDs.
Note The performance levels (PLs) in the following table are only for reference. If you want to obtain details of a single test, the results of your own tests prevail.
Item Persistent memory of 128 GiB NVMe SSD of 1,788 GiB PL1 ESSD of 800 GiB
Read bandwidth 8-10 GB/s 2-3 GB/s 0.2-0.3 GB/s
Read/write bandwidth 8-10 GB/s 1-2 GB/s 0.2-0.3 GB/s
Write bandwidth 4-6 GB/s 1-2 GB/s 0.2-0.3 GB/s
Read IOPS 1,000,000 500,000 20,000-30,000
Read/write IOPS 1,000,000 300,000 20,000-30,000
Write IOPS 1,000,000 300,000 20,000-30,000
Read latency 300-400 nanoseconds 100,000 nanoseconds 250,000 nanoseconds
Write latency 300-400 nanoseconds 20,000 nanoseconds 150,000 nanoseconds
You can perform the following steps to test the performance of the persistent memory when it is used as local SSDs:
  1. Configure persistent memory as local SSDs and attach it to instances.

    For more information, see Configure the usage mode of persistent memory.

  2. Use disk performance test tools to test the performance of the persistent memory as local SSDs.

    For information about how to use fio to test disk performance in Linux, see the "Commands used to test the performance of local disks" section of the Test the performance of Elastic Block Storage devices topic.

How reliable is persistent memory?

The reliability of data stored in persistent memory depends on the reliability of persistent memory devices and the physical servers to which these devices are attached. This increases risks of single points of failure. To ensure the reliability of application data, we recommend that you implement data redundancy at the application layer and use cloud disks for long-term data storage.

When persistent memory-optimized instances are released, data stored in their persistent memory is automatically cleared. We recommend that you back up data before you release the instances. It takes longer to release persistent memory-optimized instances than to release other types of instances.

After the NVIDIA driver was installed on an instance, nvidia-smi did not work and an error message was returned indicating that the NVIDIA driver had not been installed. Why?

Problem description: The mismatch between the kernel and kernel-devel package versions resulted in a driver compilation error when the driver was installed from the .rpm file.

Solution: Check the kernel version and download the corresponding kernel-devel package version. Then, run the rpm –qa | grep kernel command on the instance to check whether the kernel-devel package version matches the kernel version. Make sure that they match and then install the driver again.

Why does Windows Graphics not support DirectX-based features?

Problem description: On Windows instances where the installed GPU driver has taken effect, Windows Remote Desktop Protocol (RDP) may not support DirectX- or OpenGL-based applications.

Solution: Install the VNC service and client or use other protocols that support these applications, such as PC over IP (PCoIP) and XenDesktop HDX 3D.

Do GPU-accelerated instances support Android emulators?

No, GPU-accelerated instances do not support Android emulators.

Can I change the configurations of GPU-accelerated instances?

You cannot change the configurations of the following GPU-accelerated instances:
  • GPU-accelerated instances equipped with local storage
  • vGPU-accelerated instances

For information about the GPU-accelerated instance families that support instance type changes, see Instance families that support instance type changes.

Do pay-as-you-go GPU-accelerated instances support the economical mode?

Instance families such as gn5 that are equipped with local storage do not support the economical mode. For more information, see No Fees for Stopped Instances (VPC-Connected).

How do I view GPU monitoring data?

You can log on to the CloudMonitor console or call the DescribeMetricList operation to view GPU monitoring data. For more information, see GPU monitoring.

What are the differences between ECS bare metal instances, traditional cloud hosts (virtual machines), and traditional physical machines?

For information about the differences, see Overview.

How is the network performance of ECS bare metal instances?

The network performance of ECS bare metal instances depends on their specifications. The higher their specifications are, the higher network performance the instances can deliver. For more information about the network performance of different ECS bare metal instance types, see Instance families.

Which disk categories do ECS bare metal instances support? How many data disks can be attached to a single ECS bare metal instance?

ECS bare metal instances support ultra disks, standard SSDs, and enhanced SSDs (ESSDs). Up to 16 data disks can be attached to a single ECS bare metal instance.

Can the configurations of ECS bare metal instances be upgraded or downgraded? Do the instances support failover?

The configurations of ECS bare metal instances cannot be upgraded or downgraded. The instances do support failover. When the physical machine that hosts an ECS bare metal instance fails, the instance is failed over. Data is retained in the data disks of the instance.

How do I create an SCC instance?

You can create an SCC instance in one of the following ways:
  • If you only want to use the remote direct memory access (RDMA) feature, log on to the ECS console and create an SCC instance. For more information, see Create an SCC instance.
  • If you want to use the HPC scheduler and the cluster resizing feature in addition to RDMA, log on to the E-HPC console, create an SCC, and then create an SCC instance.

How are SCC instances billed?

SCC instances can be billed on a weekly, monthly, or yearly subscription basis.

How do I create an SCC by using E-HPC?

You can log on to the E-HPC console or call the CreateCluster operation to create an SCC.

How do I use SCC RDMA?

If you select an image that is customized for SCC and supports RDMA RoCE drivers and OFED stacks when you create an SCC instance, you can use SCC RDMA by virtue of the IB verbs API or implement RDMA-based communication by using the MPI.

Which instance types support preemptible instances?

Instance types that support pay-as-you-go instances also support preemptible instances. If a preemptible instance of a specific instance type cannot be created due to insufficient resources, try another instance type.

In which regions can I create preemptible instances?

Preemptible instances can be created within all Alibaba Cloud regions. If preemptible instances cannot be created within a specific region due to insufficient resources, try another region.

When I attempt to purchase an ECS instance, the Preemptible Instance option is unavailable on the instance buy page. Why?

The availability of the Preemptible Instance option depends on your ECS usage. The Preemptible Instance option is available only to authorized users.

How do I bid for a preemptible instance?

To create a preemptible instance, you must specify a maximum hourly price to bid for spare resources of an instance type. If the spot price (current market price per hour) of the instance type does not exceed your specified maximum hourly price, the preemptible instance that you request is created and billed based on the spot price. For more information, see Create a preemptible instance.

What is the relationship between the user-defined maximum hourly price and the spot price of a preemptible instance?

If the spot price does not exceed the user-defined maximum hourly price, the preemptible instance is created and billed based on the spot price. After a preemptible instance is created, it enters a protection period during which it cannot be automatically released due to insufficient resources or fluctuations in the spot price.

After the protection period ends, the system checks the spot price and resource availability of the instance type every 5 minutes. If the spot price exceeds the user-defined maximum hourly price or if resources for the instance type are insufficient, the preemptible instance that is in the Running state is released.

Can I view the spot price of an instance type when I purchase a preemptible instance?

Yes, when you create a preemptible instance in the ECS console, you can view the spot price and price history of each selected instance type. The total instance price includes fees for the instance type, storage, and bandwidth and is displayed in the lower part of the instance buy page. The instance type fee is the spot price of the selected instance type.

Can I view the price history of a preemptible instance type? How?

Yes, you can select an instance type to view its price history when you attempt to create a preemptible instance in the ECS console. You can also call the DescribeSpotPriceHistory operation to view the price history of a preemptible instance type.

How many preemptible instances can be purchased by a single account?

vCPU-based quotas apply to preemptible instances within each account, whereas instance count-based quotas do not. When you create a preemptible instance, you can view the available vCPU-based quota after you select an instance type. For more information, see the "Instance limits" section of the Limits topic.

How do I increase my vCPU-based quotas?

To increase your vCPU-based quotas, submit a ticket.

Can preemptible instances be converted into subscription instances?

No, preemptible instances cannot be converted into subscription instances.

Can the instance type of a preemptible instance be changed?

No, the instance types of preemptible instances cannot be changed.

A preemptible instance cannot meet my requirements. How do I upgrade it to a higher-specification instance type at a low cost?

The instance types of preemptible instances cannot be changed. We recommend that you create a custom image based on the system disk of your preemptible instance and then use the custom image to create a preemptible instance of a higher-specification instance type. For more information, see Create a custom image from a snapshot and Create an ECS instance by using a custom image.

If I select Use Automatic Bid (SpotAsPriceGo) when I create a preemptible instance, will the created instance be automatically released due to insufficient resources?

When you select Use Automatic Bid (SpotAsPriceGo), the spot price is used as the bid price and can raise as high as the pay-as-you-go price for the selected instance type. This ensures that the created preemptible instance will not be automatically released due to fluctuations in the spot price. However, the instance may still be automatically released due to insufficient resources for the instance type.

If I set the maximum hourly price to the pay-as-you-go price for the selected instance type when I create a preemptible instance, may the instance be automatically released?

You can set the maximum hourly price to the pay-as-you-go price for your selected instance when you create a preemptible instance. This ensures that the created instance will not be automatically released due to fluctuations in the spot price. However, the instance may still be automatically released due to insufficient resources for the instance type.

Can I cancel or reschedule the automatic release of a preemptible instance?

Yes, you can cancel or reschedule the automatic release of your preemptible instance at any time.

I do not have overdue payments in my account. Why have my preemptible instances been released?

After the protection period of a preemptible instance ends, if the spot price exceeds the user-defined maximum hourly price or if resources are insufficient, the instance is automatically released.

How are release rates on the instance buy page calculated? Why are most of them in the range of 0% to 3%?

Release rates vary based on zones and instance types. The one-day release rate of an instance type within a zone is calculated based on the following formula: One-day number of released preemptible instances/One-day total number of preemptible instances. Most release rates are in the range of 0% to 3% as expected. Alibaba Cloud continues their efforts to reduce release rates and ensure higher availability of your preemptible instances.

Am I notified when my preemptible instances are about to be released? How am I notified?

Yes, you are notified when your preemptible instances are about to be released. When your preemptible instance needs to be released due to a spot price change or insufficient resources, the instance first enters the To Be Released state and is automatically released in 5 minutes.

You can use CloudMonitor to subscribe to notifications for interrupted preemptible instances. For more information, see Set event notifications.

To check whether an instance is in the To Be Released state, you can view the instance metadata, or call the DescribeInstances operation and view the returned OperationLocks data. For more information, see Overview of ECS instance metadata and DescribeInstances.

Can the data of a preemptible instance be automatically retained when the instance is released?

No, the data of a preemptible instance cannot be automatically retained when the instance is released. When a preemptible instance is no longer needed, we recommend that you create snapshots to back up your data and environment and then release the instance. You can purchase new preemptible instances at any time. For more information, see Create a snapshot for a disk.

How do I retain the public IP address of a preemptible instance when the instance is released?

When a preemptible instance is released, its public IP address is reclaimed. If you want to retain the IP address, we recommend that you use Elastic IP Address (EIP). For more information, see EIPs.

You can convert the public IP address into an EIP. For more information, see Convert the public IP address of a VPC-type instance to an EIP and Convert the static public IP address of an ECS instance in a classic network to an EIP.

To what resources are the prices of preemptible instances applicable?

The prices of preemptible instances are applicable only to instance types. You are charged for other resources such as system disks, data disks, and network bandwidth at the same prices as those of pay-as-you-go instances.

Why do preemptible instances of the same instance type and region vary widely in spot prices across different zones?

Price differences are caused by resource inventory differences. Each zone corresponds to different data centers. Within each region, data centers for zones may vary in construction conditions, capacity, sales, and deployment policies. Resource inventories for each instance type may also vary across different zones. The spot prices of preemptible instances fluctuate with supply and demand changes and therefore are different across zones.

May the spot price of a preemptible instance exceed the pay-as-you-go price?

No, the spot price of a preemptible instance can be up to but cannot exceed the pay-as-you-go price. You do not need to worry about being charged more for a preemptible instance than for a pay-as-you-go instance with the same configurations.

For the first hour after a preemptible instance is created, am I charged at a price that fluctuates with the spot price?

No, the hourly price of the first instance hour for a preemptible instance is set at the beginning of the hour and remains in effect for the whole hour.

Do I continue to be charged for preemptible instances after they are stopped?

Yes, you continue to be charged for your preemptible instances after they are stopped. When a preemptible instance is no longer needed, we recommend that you create snapshots to back up your data and environment and then release the instance. You can purchase new preemptible instances at any time.
Note You continue to be charged for preemptible instances after you stop them by using the ECS console or by calling the StopInstance operation.

Which is more cost-effective: a preemptible instance with a protection period or a preemptible instance without a protection period?

Preemptible instances without a protection period are more cost-effective and have a discount of about 10% off compared with preemptible instances with a protection period.

Is the release rate of preemptible instances without a protection period higher than that of preemptible instances with a protection period?

You can check the release rate of each instance type on the instance buy page in the ECS console regardless of whether you attempt to create preemptible instances with or without a protection period. For each instance type, the release rate is determined by the bidding policy and the supply-demand relationships of resources. release-rate

Are preemptible instances without a protection period prioritized for release over those with a protection period?

No, preemptible instances without a protection period are not prioritized for release over those with a protection period.

If I have created a preemptible instance without a protection period, do subsequently created preemptible instances also not have a protection period?

No, preemptible instances are created without a protection period only if you choose not to configure a protection period for them. By default, each preemptible instance is created with a protection period of 1 hour.
Note You can configure a protection period for preemptible instances only when you create them.

If a preemptible instance does not have a protection period, do I still receive a notification 5 minutes in advance before the instance is released?

Yes, you still receive a notification 5 minutes in advance before a preemptible instance is released even if it does not have a protection period.

Are fewer resources provided for preemptible instances with a protection period than for those without a protection period?

No, the same amount of resources are provided for preemptible instances with and without a protection period.

Can I convert between preemptible instances with and without a protection period?

No, you cannot convert between preemptible instances with and without a protection period. By default, each preemptible instance is created with a protection period of 1 hour. You can configure a protection period for preemptible instances only when you create them. The protection period settings of preemptible instances cannot be changed after the instances are created.

What are reserved instances?

Reserved instances automatically match pay-as-you-go instances (excluding preemptible instances) within your account to provide a billing discount. Reserved instances can also be used to reserve instance resources. A combination of reserved instances and pay-as-you-go instances provides higher cost-effectiveness and a higher degree of flexibility as compared with subscription instances.

Do reserved instances provide reserved resources?

Zonal reserved instances provide reserved resources, but regional reserved instances do not.

What operating systems do reserved instances support?

Reserved instances support both Windows and Linux. For example, you can purchase a reserved Linux instance, and this reserved instance can be applied to pay-as-you-go Linux instances that match its attributes regardless of the image type (public images, custom images, shared images, or Alibaba Cloud Marketplace images).

To apply a reserved instance to pay-as-you-go instances created from Bring Your Own License (BYOL) images, submit a ticket.

Which instance families do reserved instances support?

Reserved instances support the following instance families:
  • General purpose instance families: g7, g6e, g6, g5, g5ne, and sn2ne
  • Compute optimized instance families: c7, c6e, c6, c5, ic5, and sn1ne
  • Memory optimized instance families: r7, r6e, r6, r5, re6, re4, and se1ne
  • Big data instance family: d2s
  • Instance families with local SSDs: i2 and i2g
  • Instance families with high clock speeds: hfc6, hfc5, hfg6, hfg5, and hfr6
  • GPU-accelerated compute optimized instance families: gn6i, gn6e, and gn6v
  • ECS Bare Metal Instance families: ebmc6, ebmg6, ebmr6, ebmhfc6, ebmhfg6, and ebmhfr6
  • Burstable instance families: t6 and t5

Can reserved instances be applied to preemptible instances?

No, reserved instances cannot be applied to preemptible instances.

Can the instance families of reserved instances be changed?

No, the instance families of reserved instances cannot be changed.

To what scenarios are zonal reserved instances applicable?

We recommend that you purchase zonal reserved instances when you have clear requirements to reserve resources.

To what scenarios are regional reserved instances applicable?

We recommend that you purchase regional reserved instances if you want to have a higher degree of zone flexibility or instance size flexibility.

How is the zone flexibility of reserved instances applied?

Only regional reserved instances provide zone flexibility. Example:

Assume that you are running the following pay-as-you-go instance:

One ecs.c5.xlarge Linux instance in Qingdao Zone B. This instance is named C5PAYG-b.

Assume that you have purchased the following reserved instance:

One regional ecs.c5.xlarge reserved instance in the China (Qingdao) region. This instance is named C5RI.

C5RI is matched to C5PAYG-b.

You release C5PAYG-b and start another pay-as-you-go Linux instance of the same instance type named C5PAYG-c in Qingdao Zone C. C5RI is then matched to C5PAYG-c.

How is the instance size flexibility of reserved instances applied?

Only regional reserved instances provide instance size flexibility. Example:

Assume that you have one regional ecs.g5.4xlarge reserved instance. It can be applied to one ecs.g5.4xlarge pay-as-you-go instance, two ecs.g5.2xlarge pay-as-you-go instances, or four ecs.g5.xlarge pay-as-you-go instances.

Assume that you have a one-year regional ecs.g5.xlarge reserved instance. It can be applied to offset the bills of an ecs.g5.xlarge pay-as-you-go instance or 50% of the bills of an ecs.g5.2xlarge pay-as-you-go instance by hour for one year.

Do zonal reserved instances provide instance size flexibility?

No, zonal reserved instances do not provide instance size flexibility. A zonal reserved instance can be applied only to pay-as-you-go instances of the same instance type as it.

Do zonal reserved instances provide zone flexibility?

No, zonal reserved instances do not provide zone flexibility. A zonal reserved instance can be applied only to pay-as-you-go instances in the same zone as it.

Can a zonal reserved instance be changed into a regional one?

Yes, a zonal reserved instance can be changed into a regional one. The scope of a reserved instance can be changed in the following ways:

  • From a zone to a region
  • From a region to a zone
  • From one zone to another within the same region for a zonal reserved instance

Can the scope of a reserved instance be changed from one region to another?

No, the scope of a reserved instance cannot be changed from one region to another. For example, assume that you have a zonal reserved instance scoped to Hangzhou Zone B. You can change the instance scope to another zone within the China (Hangzhou) region or change the instance into a regional reserved instance scoped to the China (Hangzhou) region. However, you cannot change the scope of the instance to a zone of another region or change the instance into a regional reserved instance scoped to another region.

Can reserved instances be used across accounts?

No, reserved instances cannot be used across accounts.

Can reserved instances be used to cover the storage and network usage charges of pay-as-you-go instances?

No, reserved instances cannot be used to cover the storage or network usage charges of pay-as-you-go instances. Reserved instances are applied to cover the charges for vCPUs and memory of pay-as-you-go instances. For pay-as-you-go Windows instances, reserved instances can also cover image charges.

Can I configure a reserved instance to be applied to a specified pay-as-you-go instance?

No, you cannot configure a reserved instance to be applied to a specified pay-as-you-go instance. When multiple pay-as-you-go instances match the attributes of a reserved instance, the reserved instance is applied based on the optimized matching scheme.

How are reserved instances billed?

Reserved instances are billed separately and support the All Upfront, Partial Upfront, and No Upfront payment options.

The term of a reserved instance begins at the time when the instance is purchased. You are charged based on the payment option that you selected regardless of whether the reserved instance is matched to pay-as-you-go instances. The All Upfront option is most cost-effective.

When does a reserved instance take effect after it is purchased?

A reserved instance takes effect and is billed starting on the hour when the reserved instance is purchased. The reserved instance expires at 00:00:00 on the day after its term end date. For example, assume that you purchase a reserved instance with a one-year term at 13:45:00 on February 26, 2019. The reserved instance takes effect and is billed starting from 13:00:00 on February 26, 2019. The reserved instance expires at 00:00:00 on February 27, 2020. If you already have eligible pay-as-you-go instances when you purchase a reserved instance, the reserved instance is applied to offset the bills generated by the pay-as-you-go instances starting from the hour of 13:00 to 14:00 on February 26, 2019 until the reserved instance expires.

After I modify, split, or merge a reserved instance, when does the operation take effect?

When reserved instances are modified, split, or merged, new reserved instances are generated and the original ones become invalid. The new reserved instances take effect and the original ones become invalid. Both occur on the hours of the modification, splitting, or merging operations. For example, assume that you split one ecs.g5.2xlarge zonal reserved instance RI1 into two zonal ecs.g5.xlarge reserved instances RI2 and RI3 at 13:45:00 on February 26, 2019. At 13:00:00 on February 26, 2019, RI1 becomes invalid and RI2 and RI3 take effect. Starting from 13:00:00 on February 26, 2019, the instance type eligible for resource reservation and billing discounts is ecs.g5.xlarge, not ecs.g5.2xlarge any more. If RI2 and RI3 are matched to pay-as-you-go instances immediately after they take effect, RI2 and RI3 are also applied to offset the hourly bills of ecs.g5.xlarge pay-as-you-go instances starting from 13:00:00 on February 26, 2019.

Why is the No Upfront payment option not displayed on the buy page?

The availability of this option depends on your ECS usage.

Can the payment option of a reserved instance be changed?

No, the payment options of reserved instances cannot be changed.

Can reserved instances be resold?

No, reserved instances cannot be resold.

Can I use reserved instances to cover the image charges of pay-as-you-go Windows instances?

Yes, reserved instances can be applied to cover the image charges of pay-as-you-go Windows instances. This is because reserved Windows instances already include Windows image fees.

Can reserved instances be applied to cover the image charges of pay-as-you-go Linux instances?

No, reserved instances cannot be applied to cover the image charges of pay-as-you-go Linux instances.

Are the consumption details of reserved instances refreshed every hour?

Yes, the consumption details of reserved instances are refreshed every hour.

Can a reserved instance be applied to more than one pay-as-you-go instance at the same time?

Yes, a reserved instance can be applied to more than one pay-as-you-go instance at the same time. The reserved instance checks for eligible pay-as-you-go bills on an hourly basis and deducts fees based on its computing power.
Note The computing power and term of each reserved instance are fixed. You cannot increase the computing power of a reserved instance by shortening its term.
You have a reserved instance with the following attributes:
  • Instance type: c5.large
  • Instances: 1 (indicating that the reserved instance can match one pay-as-you-go instance of the specified instance type)
  • Term: one year
The following examples demonstrate how the reserved instance is applied based on the pay-as-you-go instances that exist:
  • Assume that six c5.large pay-as-you-go instances exist for 1 hour each. Each of these pay-as-you-go instances consumes 1 hour of computing power equal to that delivered by the c5.large reserved instance every hour. The reserved instance is randomly applied to one of the pay-as-you-go instances. You cannot configure the reserved instance to be applied to all six pay-as-you-go instances by shortening the term of the reserved instance to two months.
  • Assume that six c5.large pay-as-you-go instances exist for 10 minutes each. The six instances consume 10 minutes of computing power each and in total consume the amount of computing power that the c5.large reserved instance can deliver every hour. The reserved instance is applied to all six pay-as-you-go instances.
  • Assume that six c5.large pay-as-you-go instances exist for 15 minutes each. The six instances consume 15 minutes of computing power each, in total exceeding the amount of computing power that the c5.large reserved instance can deliver every hour. The reserved instance is randomly applied to the pay-as-you-go instances to offset the charges for 1 hour of computing power.

Does a VNC management terminal allow multiple users to log on simultaneously?

No, a VNC management terminal allows a single user to log on at a time.

What do I do if I forget the remote connection password?

You can reset your remote connection password. For more information, see Change the VNC password.

Why am I unable to connect to a VNC management terminal even after I reset my remote connection password?

If the instance to which you are connecting is not I/O optimized, you must restart the instance by using the ECS console or by calling the RebootInstance operation for the new password to take effect.
Note If you restart the instance from within the instance, the new password does not take effect.

I was prompted with an authentication failure when I attempted to connect to a VNC management terminal. What do I do?

Authentication fails if the password that you entered is incorrect. Perform the following troubleshooting operations:
  1. Enter the correct remote connection password.
  2. If you forget your password, you can reset it and try again. For more information, see Change the VNC password.
    Note If the instance to which you are connecting is not I/O optimized, you must restart the instance by using the ECS console or by calling the RebootInstance operation for the new password to take effect.

What do I do if a black screen appears while I am connected to a VNC management terminal?

A black screen indicates that the instance is in sleep mode. Perform the following operations based on your operating system:
  • For a Linux instance, click your mouse or press any key to activate the instance.
  • For a Windows instance, choose Send Remote Call > CTRL+ALT+DELETE in the upper-left corner to go to the logon page.

What do I do if a VNC management terminal cannot be accessed?

You can use a browser to access the VNC management terminal for troubleshooting. For example, you can use Google Chrome to access the VNC management terminal, and press the F12 key to open the developer tools panel. Then, click the Console tab and identify errors based on the information displayed.

Why am I unable to use Internet Explorer 8.0 to access a VNC management terminal?

VNC management terminals support Internet Explorer 10 and later.

We recommend that you use Google Chrome because it is most compatible with the Alibaba Cloud Management Console.

When I use Firefox to access a VNC management terminal, an error message is returned indicating that a secure connection cannot be established. What do I do?

This problem occurs if the encryption algorithm used by your version of Firefox is different from that used by the VNC management terminal.

We recommend that you use Google Chrome because it is most compatible with the Alibaba Cloud Management Console.

How do I connect to a Linux instance?

Linux instances support Secure Shell (SSH) for connection. You can use one of the following methods to connect to a Linux instance:

What are the default username and password used to connect to the operating system of an ECS instance?

The default username varies per operating system type.
  • For a Windows instance, the default username is administrator.
  • For a Linux instance, the default username is root.
The password used to connect to the operating system of an instance is set by yourself when you create the instance. For more information, see Create an instance by using the wizard. If you forget the password, you can reset it. For more information, see Reset the logon password of an instance.
Note This password is used to connect to the instance operating system, not to VNC management terminals.

How do I adjust the desktop resolution of a Windows instance?

You can use one of the following methods to adjust the desktop resolution of a Windows instance:
  • Connect to the instance by using a VNC management terminal and adjust the desktop resolution on the instance.

    The following example demonstrates how to adjust the desktop resolution of an instance that runs a Windows Server 2019 Datacenter 64-bit operating system:

    1. Connect to the instance by using a VNC management terminal in the ECS console. For more information, see Connect to a Windows instance by using password authentication.
    2. On the Windows desktop, right-click a blank area and select Display settings.
    3. In the Scale and layout section, adjust the resolution.
  • Use the Remote Desktop Connection (RDC) tool on your computer.
    You cannot adjust the desktop resolution of a Windows instance after you connect to the instance from your computer by using RDC. You must adjust the display settings in RDC on your computer, and then connect to the instance by using RDC to apply the new display settings to the instance. windows

Why do two cursors appear after I log on to a Windows instance by using a VNC management terminal?

If two cursors appear when you use a VNC management terminal to log on to a Windows instance of the g7, c7, or r7 instance family, perform the following steps to modify mouse settings:
  1. Modify mouse settings in Control Panel.
    1. Open Control Panel, set View by to Small icons, and then click Mouse. small-icon
    2. In the Mouse Properties dialog box, click the Pointer Options tab, clear Enhance pointer precision, and then click OK. cancel-accuracyenhance
  2. Modify mouse settings in the registry.
    Note If two cursors do not appear in the user logon interface, skip this step.
    1. Open Registry Editor.
    2. In the left-side hierarchy tree, click HKEY_USERS and choose Edit > Find in the top navigation bar. start-search
    3. In the Find dialog box, enter MouseSpeed and click Find Next. search-mousespeed
    4. Double-click MouseSpeed. In the Edit String dialog box, set Valid data to 0 and click OK. modify-mousespeed
  3. Use a VNC management terminal to log on to the Windows instance again.

What do I do if a Data Plane Development Kit (DPDK) application cannot be deployed on an ECS instance?

We recommend that you deploy DPDK applications on g5ne instances. For more information about the g5ne instance types, see Instance families.

If you deploy a DPDK application on an instance of a sixth-generation (such as g6, c6, or r6) instance family or later, an exception may occur when the DPDK application runs. For example, when you use Pktgen-DPDK to test the packet forwarding rate of an instance, the igb_uio port to which the network interface controllers (NICs) are bound may not be detected and the following error is reported:
EAL: eal_parse_sysfs_value(): cannot open sysfs value /sys/bus/pci/devices/0000:00:06.0/uio/uio0/portio/port0/start
We recommend that you use one of the following methods to solve the problem:
  • Upgrade DPDK to DPDK Release 21.05 or later. This method is applicable to x86-based instances. For more information about DPDK versions, visit the official DPDK website.
  • Replace UIO drivers with VFIO drivers. This method is applicable to both x86-based instances and ARM-based instances. For more information, see Replace UIO drivers with VFIO drivers.

Can I upgrade the instance types and other configurations of subscription instances?

Yes, you can upgrade the instance types and other configurations of subscription instances. For more information, see Upgrade the instance types of subscription instances.

Can I upgrade the instance types and other configurations of pay-as-you-go instances?

Yes, but you must stop pay-as-you-go instances before you can upgrade their instance types and other configurations. You can upgrade the instance types and other configurations of pay-as-you-go instances by following the instructions in Change the instance type of a pay-as-you-go instance or by calling the ModifyInstanceSpec operation.

How long does it take to upgrade the configurations of an instance?

  • Subscription instances do not need to be stopped for their instance types to be upgraded. It takes about 15 minutes to upgrade the instance type of a subscription instance.
  • Pay-as-you-go instances must be stopped for their instance types to be upgraded. It also takes about 15 minutes to upgrade the instance type of a pay-as-you-go instance.
  • You can upgrade the bandwidths of instances without stopping the instances. The upgrade process takes about 5 minutes.

How is the fee for an instance configuration upgrade calculated?

The fee and its calculation method are displayed in the ECS console when you upgrade the instance type or other configurations of an instance. You can also view the billing details on the Account Overview page.

Are my cloud service configurations affected if I upgrade the configurations of ECS instances?

Pay-as-you-go instances must be stopped before their configurations can be upgraded. After you upgrade the configurations of a subscription instance, you must restart the instance for the new configurations to take effect. The upgrade operation interrupts the services that run on the instance for a short period of time. We recommend that you upgrade the configurations of instances during off-peak hours. Instances can seamlessly resume services after upgrades without the need to reconfigure environments.

How do I upgrade ECS resources?

For information about how to upgrade ECS resources, see Overview of instance upgrade and downgrade.
  • ECS instances, except those that use local storage, can have their CPU and memory resources scaled and their bandwidths upgraded while the instances are running. You can also downgrade the configurations of ECS instances.
  • Up to 16 data disks can be attached to each ECS instance. You can extend cloud disks. Cloud disks cannot be shrunk after they are extended.
  • The bandwidth of each ECS instance is measured in Mbit/s and can range from 0 Mbit/s to 200 Mbit/s. You can modify the bandwidth or change the billing method for network usage.

I have upgraded the configurations of an instance but no changes have taken effect. Why?

After you upgrade the configurations of an instance, you must restart the instance by using the ECS console or by calling an API operation for the new configurations to take effect.

What do I do if I cannot access a website that runs on an ECS instance?

For information about how to solve this problem,see You cannot access websites that run on ECS instances.

If the problem persists, submit a ticket.

My ECS instance was stuck in the Starting state, and AliyunService was disabled or deleted. What do I do?

Problem description: After an ECS instance was started, it remained in the Starting state for an extended period of time and then automatically stopped. You logged on to the instance and found that AliyunService was deleted or disabled in the system services.

Solution:
  • If AliyunService was disabled, perform the following operations:
    1. Change the state of AliyunService to automatic.
    2. Restart the instance.
  • If AliyunService was deleted, perform the following operations:
    1. Run the following command to add AliyunService to the instance:
      sc create AliyunService type= "own" start= "auto" binPath= "C:\Program Files\AliyunService\AliyunService.exe -d" tag= "no" DisplayName= "AliyunService"
      Note Make sure that you leave a space after each equal sign (=).
    2. Find the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\AliyunService, and change c:\Program Files\AliyunService\AliyunService.exe -d to "c:\Program Files\AliyunService\AliyunService.exe" -d.
    3. Restart the instance.

How do I use f1 instances?

After you create an f1 instance, Alibaba Cloud shares an FPGA development image to you. Only CentOS 7u2 images are supported. The FPGA development image includes the complete Intel Quartus development suite and the f1 instance constraint files to provide a complete cloud development environment.

Note You can go to the ECS Instance Types Available for Each Region page to view the instance types available in each region.
Basic procedure to use an f1 instance:
  1. After the development phase is complete, you can generate an intermediate QAR file during the compilation stage and upload the file to an Object Storage Service (OSS) bucket. Currently, this file can be uploaded only to an OSS bucket within the China (Hangzhou) region. Then, you can call an API operation to register the QAR file information with Alibaba Cloud.

    We recommend that you use the free Intel Quartus development suite to complete development, compilation, and simulation operations on the cloud.

  2. Alibaba Cloud verifies your registration request about the QAR file and sends you an email that includes an FPGA image ID if your request is determined as valid.
  3. To deploy the image, you can call an API operation with the f1 instance ID and FPGA image ID specified to associate the instance with the image.

    You can initiate the association operation in all scenarios where ECS API is available.

    • If the f1 instance has never been associated with an FPGA image, initiate the association operation.
    • If the f1 instance was previously associated with an FPGA image and had the image loaded, erase the FPGA image from the f1 instance before you initiate the association operation.
  4. After you associate the FPGA image with the instance, call an API operation to load the image.

    You must initiate the load operation from the f1 instance. Then, the underlying service of Alibaba Cloud burns the associated FPGA image to the corresponding FPGA on the instance.

If you want to restore the f1 instance to its initial state, call an API operation to erase the burned FPGA image from the f1 instance.

For more information about how to manage f1 instances, see the following topics:

How do I use FTP tools in macOS to upload files?

Method 1: Use the Terminal of macOS to upload files

Open the Terminal in macOS or iTerm2 for Mac (click here to download iTerm2). Make sure that you select the correct destination path.

  1. Connect to the FTP server.
  2. Access the destination directory. In Windows, use the working directory as the destination directory. In Linux, switch to the htdocs directory and use it as the destination directory.
  3. Run the put command to upload files.

Method 2: Use a third-party tool to upload files

  1. Download Yummy FTP.
  2. Install Yummy FTP.
  3. Enter the server IP address, username, and password. Set Protocol to Standard (FTP). Set Port to 21 or a different port number that you are using, and leave the SSH key field unselected.
  4. Click Connect.
  5. In the right-side pane, select the destination directory. In Windows, use the current working directory. In Linux, select the htdocs directory. In the left-side pane, select files. Then, click the Upload icon to upload the files.
    If you attempt to install Yummy FTP and are prompted with a message similar to "Your security preferences only allow the installation of applications from the Mac App Store and authorized developers", perform the following steps:
    1. Choose System Preference > Security and Privacy.
    2. Click the security lock in the lower-left corner of the window and enter the administrator password.
    3. Set Allow apps download from to Anywhere.

    Then, you can use Yummy FTP to upload files.

If you have further questions, submit a ticket.

How do I apply for an ICP filing for my domain name after I purchase an ECS instance?

For each ECS instance, you can apply for a limited number of ICP filing service identification numbers. For more information, see Prepare and check the instance and access information.

An ECS instance cannot load the kernel to start. What do I do?

Problem description: The system does not respond when you select an option from the GRUB menu on system startup. After you have mounted the LiveCD image to the ECS instance, you can log on to the instance and confirm that the file system permissions are correct and that the message logs show no exceptions.

Cause: The system has been attacked by ransomware.

Solution: Back up your data and re-initialize the system.

For more information, see Recover from ransomware attacks.

How do I change the logon password from within an instance?

For information about how to change the logon password from within an instance, see Change the logon password of an instance by connecting to the instance.

Why am I unable to add sound or video cards to ECS instances?

Alibaba Cloud ECS instances are not multimedia servers and do not provide sound or video card components. Sound or video cards cannot be added to ECS instances.

Can I transfer the unused time of an ECS instance to another ECS instance?

No, the unused time of an ECS instance cannot be transferred to other ECS instances. If you want both higher flexibility and cost-effectiveness, we recommend that you use a combination of reserved instances and pay-as-you-go instances. For more information, see Overview.

Do ECS instances provide databases by default?

No, ECS instances do not provide databases by default. To use database services, perform one of the following operations:
  • Deploy your own database.
  • Purchase RDS instances in the ApsaraDB RDS console.
  • Use a database image provided in Alibaba Cloud Marketplace.

Can I build a database on an ECS instance?

Yes, you can install database software and configure a database environment on an ECS instance. You can also separately purchase RDS instances in the ApsaraDB RDS console.

Do ECS instances support Oracle databases?

Yes, ECS instances support Oracle databases. Before you install an Oracle database, we recommend that you perform a performance stress test on the ECS instance to ensure that the instance can satisfy the read and write requirements of the database.

Are public and private IP addresses independent? Can I specify or add IP addresses?

In the classic network, public and private IP addresses are independent of each other. Private IP addresses in the classic network are used for communication between ECS instances and between ECS instances and OSS buckets or RDS instances. If the public bandwidth of an ECS instance is 0 Mbit/s, no public IP address is assigned to the instance. In normal cases, public and private IP addresses in the classic network do not change. You cannot specify, select, or add IP addresses in the classic network.

In VPCs, NAT gateways map public IP addresses to private IP addresses. You can add IP addresses by specifying or automatically assigning secondary private IP addresses to elastic network interfaces (ENIs).

Can load balancing be implemented for a single ECS instance?

Both Linux and Windows ECS instances can be load-balanced. Make sure that the configurations of ECS instances used as web servers meet the requirements for website code to run. Load balancing can be implemented for as few as one ECS instance. However, we recommend you implement load balancing for two or more ECS instances within an account.

Can I change the region of an ECS instance that I purchased?

No, the regions of purchased ECS instances cannot be changed. To change the region of an ECS instance, you can use the ACS-ECS-CloneInstancesAcrossRegion public template provided by Operation Orchestration Service (OOS) to copy the instance to another region. The new and original instances have identical disk data but different IP addresses.

Can I adjust the partition size of a purchased disk?

For system security and stability purposes, system disks cannot be repartitioned on Windows or Linux instances. If you use a third-party tool to repartition system disks, unknown exceptions such as system failures and data loss may occur.

If you repartition a data disk, data may be lost. We recommend that you do not repartition data disks.

How do I replace the automatically assigned public IP address of an ECS instance with an EIP?

To replace the automatically assigned public IP address of an ECS instance with an EIP, make sure that the instance uses the pay-by-bandwidth billing method for network usage and that you have purchased an EIP. Then, use one of the following methods to replace the public IP address with the EIP:

How do I view subscription ECS instances in all regions within my account?

You can go to the Renewal page to view subscription ECS instances within all regions within your account.
  1. Log on to the ECS console.
  2. In the top navigation bar, choose Expenses > Renewal Management.

When can I force stop an ECS instance? What are the consequences?

If an instance cannot be stopped by a proper shutdown procedure, you can force stop the instance. A forced stop is equivalent to disconnecting the power from the instance, and can result in loss of unsaved data.

Why am I unable to reactivate my ECS instance?

You may be unable to reactivate an ECS instance due to one of the following reasons:
  • You have overdue payments in your account. Pay the outstanding bills and try again.
  • The system is busy. Try again later.
  • Resources of the specified instance type are sold out.
    Note You can go to the ECS Instance Types Available for Each Region page to view the instance types available in each region.

Why has an ECS instance with release protection enabled been automatically released from a scaling group?

Auto Scaling can automatically release an ECS instance created by a scale-out event even if you have enabled release protection for the instance by using the ECS console or by calling the ModifyInstanceAttribute operation.

To prevent the ECS instance from being automatically released, you must change its state to Protected in the Auto Scaling console. For more information, see Put an ECS instance into the Protected state.

How do I test the packet forwarding rate of an instance?

For information about how to test the packet forwarding rate of an instance, see the "Use Netperf to test network performance" section of the Test network performance topic. For information about how to test the packet forwarding rate of a g7, c7, or r7 instance, see Use Pktgen to test the network performance of ECS instances.

What is the AliVulfix process in an ECS instance?

The AliVulfix process is an Alibaba Cloud Security program that scans ECS instances for vulnerabilities.

How do I protect ECS instances against attacks?

ECS instances use Alibaba Cloud Security to defend against DDoS attacks. CloudMonitor deployed on ECS instances can automatically detect network attacks and scrub suspicious traffic. Alibaba Cloud implements blackhole filtering to protect ECS instances against high-volume attacks. To strengthen security protection, we recommend that you install security software and disable ports that are not commonly used.

What security services does Alibaba Cloud provide?

Alibaba Cloud Security is backed by the robust data analysis capabilities of the cloud computing platform of Alibaba Cloud to provide a comprehensive set of security services such as security vulnerability detection, website trojan detection, host intrusion detection, and anti-DDoS protection.

For information about more security services, visit the Alibaba Cloud Security Services page.

I have already renewed an expired Linux instance but I am still unable to access the website hosted on it. What do I do?

Problem description: A Linux ECS instance is in the Stopped state after it has expired. After you have renewed and restarted the instance, you still cannot access the website hosted on it.

Problem description: This may be because the website service has not been started.

Solution:
  1. Connect to the instance and run the following command to check whether the website service has been started:
    # netstat -nltp //Check whether port 80 on the instance is being listened on.
  2. If no information about port 80 is displayed in the command output, the website service has not been started. Run a command to manually start the website service and relevant services.

    In Linux, websites are typically developed based on PHP and MySQL.

    • In Apache, you need only to start the website service and MySQL.
      #/etc/init.d/httpd start          //Start the website service. This command is applicable to Apache.
      #/etc/init.d/mysqld start         //Start MySQL.
    • In NGINX, you must start the website service, PHP, and MySQL.
      #/etc/init.d/nginx start          //Start the website service. This command is applicable to NGINX.
      #/etc/init.d/php-fpm start        //Start PHP.
      #/etc/init.d/mysqld start         //Start MySQL.
  3. Check again whether the website service has been started.
    #netstat -nltp //Check whether port 80 on the instance is being listened on.
  4. After the website service has been started, access the website again.

If the problem persists, submit a ticket.

How do I activate a Windows ECS instance within a VPC?

To activate a Windows ECS instance within a VPC, you must use a specific Key Management Service (KMS) domain name. For more information, see Activate the VPC-Connected Windows instances using KMS servers.

How do I query, partition, and format the disks of a Linux instance?

You can run the df –h command to check the capacity and usage of disks, and run the fdisk –l command to view disk information. For information about how to partition and format the disks of Linux instances, see Format a data disk for a Linux instance.

How do I upload files to a Linux instance?

You can use the FTP service to upload files to a Linux instance.

How do I change the owner and owner group of directories and files on a Linux instance?

If the file or directory permissions are not correctly configured on the web server, a 403 error is reported when you access a website hosted on the instance. Before you adjust a file or directory, you must identify the identity under which the file or directory process is running.

You can run the ps and grep commands to query the identities under which processes are running.

You can run the ls –l command to query the owners and owner groups of files and directories.

To change the owners and groups, run the chown command. For example, you can run the chown -R www.www /alidata/www/phpwind/ command to change the owners and groups of all files and directories under the /alidata/www/phpwind directory to the www account.

How do I update the software repository for Linux instances?

You can use an automatic tool to update the software repository for Linux instances. For more information, see Use scripts to automatically update software repositories in Linux instances.

What limits apply to the transfer and change of public IP addresses of ECS instances?

The following limits apply to the transfer and change of public IP addresses of ECS instances:
  • ECS instances in the classic network
    • You cannot transfer public IP addresses across accounts.
    • The public IP address of an instance can be changed within 6 hours after the instance is created, and can be changed up to three times. For more information, see Change the public IP address of an ECS instance.
    • If Anti-DDoS Pro is deployed, you can change the IP address of an instance up to 10 times by using the Anti-DDoS Pro console. For more information, see Change ECS IP in Anti-DDoS Pro User Guide.
  • ECS instances within VPCs
    • You cannot transfer public IP addresses or EIPs across accounts.
    • If no public IP address is assigned to your instance, you can associate an EIP with the instance. You can replace the public IP address of your instance with an EIP.
    • If you assign a public IP address to your instance while you create the instance, take note of the following limits:

If you have further questions, submit a ticket.

Can I access amazon.com from my ECS instance?

You can access amazon.com from your ECS instance if the instance can properly connect to the Internet.

Why am I unable to access a website hosted outside mainland China after I log on to my ECS instance?

Websites hosted outside mainland China can be accessed by your ECS instance only when the websites comply with the laws, regulations, and regulatory requirements of the country or region where your instance is located. Make sure that your ECS instance can properly connect to the Internet and that the website complies with the preceding laws, regulations, and regulatory requirements.

I cannot purchase more pay-as-you-go instances. What do I do?

If you have reached the maximum number of pay-as-you-go instances that you can purchase, you cannot purchase more pay-as-you-go instances. For more information, see the "Instance limits" section of the Limits topic. You can log on to the ECS console and click Privileges on the Overview page to view your resource quotas. For more information, see View quotas (old version).

How can I view the resource quota?

For more information about how to view the limits and quotas of resources, see Limits.

After a pay-as-you-go instance is stopped manually or due to an overdue payment, am I still charged for it?

Stopped due to an overdue payment: When a payment becomes overdue in your account, your pay-as-you-go instance is automatically stopped and billing for the instance stops. Instances do not always remain in the Stopped state after they are stopped due to overdue payments. For more information, see Pay-as-you-go.

Manually stopped: You can use the ECS console or call the StopInstance operation to stop a running pay-as-you-go instance. When the instance is stopped, it enters the Stopped state. How stopped pay-as-you-go instances are billed depends on their network types.
  • VPC: You can enable the economical mode for pay-as-you-go instances within VPCs.
    • After the economical mode is enabled, billing for pay-as-you-go instances begins when they are created, and billing for some instance resources stops when the instances enter the Stopped state and resumes when the instances are started. When a pay-as-you-go instance enters the Stopped state, the economical mode stops the billing only for the vCPUs, memory, and public IP address of the instance. Other resources such as disks and EIP of the instance continue to be billed. For more information, see No Fees for Stopped Instances (VPC-Connected).
    • After the economical mode is disabled, billing for pay-as-you-go instances continues when they enter the Stopped state.
  • Classic network: Pay-as-you-go instances in the classic network are billed regardless of whether they are in the Stopped state.

What do I do if an order cannot be placed to change the billing method of an instance from pay-as-you-go to subscription?

You may be unable to place the order due to one of the following reasons:
  • The instance is in a state that does not support changes to the billing method. For example, you have an unpaid order for the instance.
  • Changes to the billing method are not allowed due to an upcoming scheduled automatic release.
  • Changes to the billing method are not allowed because the instance information has been changed.
  • A previous order to change the billing method of the instance has not been paid.

If one of the preceding errors is reported, adjust the instance accordingly.

How long after an order is paid does it take to change the billing method of an instance from pay-as-you-go to subscription?

The billing method of your instance is changed after the order is paid. It can take up to 4 seconds to change the billing method of 20 instances. After the change is complete, you can see that the billing method of your instance has been changed to Subscription in the ECS console.

What do I do if the billing method of an instance cannot be changed from pay-as-you-go to subscription?

Submit a ticket.

When I change the billing method of an instance from pay-as-you-go to subscription, does the billing method for network usage of the instance also change?

No, the billing method for network usage of the instance does not change. Only the billing method of instances and disks can be changed from pay-as-you-go to subscription. For information about how to change the billing method for network usage, see Overview of instance upgrade and downgrade.

I have an unpaid order to change the billing method of an instance from pay-as-you-go to subscription. If I upgrade the configurations of the instance, is the order still valid?

An order is created when you change the billing method of your instance from pay-as-you-go to subscription. You must pay for the order to complete the change. If you upgrade the configurations of the instance before the order is paid, the order payment cannot be completed because the instance components are different and the original order no longer matches. If you still want to change the billing method of your instance, you must cancel the unpaid order and place a new order.

What do I do if the billing method of an instance cannot be changed from subscription to pay-as-you-go?

You may be unable to change the billing method of an instance from subscription to pay-as-you-go due to one of the following reasons:

  • The instance is in a state that does not support changes to the billing method. For example, you have an unpaid order for the instance.
  • The instance is in the Expired state.
  • Changes to the billing method are not allowed because the instance information has been changed. For example, the bandwidth of the instance has been temporarily upgraded.

If one of the preceding errors is reported, adjust the instance accordingly. If the problem persists, submit a ticket.

When I attempt to change the billing method of a disk in an instance, an error message is returned indicating that I have already changed the billing method three times. What does this mean?

Each ECS instance can have its configurations downgraded up to three times. Downgrade operations include downgrades of instance specifications, bandwidth downgrades, and the change of the disk billing method from subscription to pay-as-you-go.

Why am I unable to change a pay-as-you-go instance into a subscription one?

The pay-as-you-go instance whose billing method you want to change must meet the following requirements:
  • The instance type of the instance is not retired. For more information, see Retired instance types.
  • The instance is not a preemptible instance.
  • No unpaid orders related to the instance exist.

    If unpaid orders related to the instance exist, you must pay for the orders or cancel the orders before you change the billing method of the instance.

  • Automatic release time is not configured for the instance.

    If automatic release time is set for the instance, you must disable the automatic release configuration before you change the billing method. For more information, see Disable automatic release.

  • The instance is in the Running or Stopped state.

    Example: An order to change the billing method was placed while the ECS instance is in the Running or Stopped state. However, the instance status changes before the payment was attempted. The order fails and the billing method does not change. You can go to the Billing Management console and pay for the order when the instance is in the Running or Stopped state again.

How do I view the expiration time of a subscription instance?

You can log on to the ECS console and go to the Instances page to view the expiration time of your subscription instance in the Billing Method column.

Note If the Billing Method column is not displayed, click the icon in the upper-right corner. In the Column Filters dialog box, select Billing Method and click OK.