Review ECS security responsibilities, prohibited actions, and configuration guidelines to prevent data loss or account suspension.
Security responsibilities
Alibaba Cloud and customers share security responsibilities for ECS. See Shared security responsibility model of ECS.
General notes
After you create an ECS instance, only you have administrator access to it.
Prohibited actions — account and legal
| Action | Consequence |
|---|---|
| Reselling or sublicensing bandwidth without authorization | Instance stopped, locked, and released |
| Using instances for malicious, fraudulent, or illegal activities, e.g., click farming or fraudulent transactions | Account suspended or terminated |
Prohibited actions — instance configuration
| Action | Consequence |
|---|---|
| Uninstalling hardware drivers | Instance malfunction |
| Modifying the MAC addresses of NICs unless necessary | Disrupts network identity |
| Enabling SELinux | — |
Best practices — reliability
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Configure services to start automatically on boot to maintain continuity after failovers or restarts.
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Enable database auto-reconnection to prevent downtime during transient network interruptions.
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Do not upgrade the kernel or OS unless necessary. If required, follow Upgrade the operating system kernel of a Linux ECS instance.
License compatibility
Hardware-bound software licenses may become invalid after migration because the underlying hardware changes. Verify license portability before migrating instances that run licensed software.
Operating system requirements
Instances with 4 GiB or more of memory require a 64-bit OS. A 32-bit OS addresses a maximum of 4 GiB.
ECS supports the following 64-bit operating systems. Available versions are shown on the instance buy page.
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Alibaba Cloud Linux 64-bit
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CoreOS 64-bit
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CentOS 64-bit
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Debian 64-bit
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FreeBSD 64-bit
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openSUSE 64-bit
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SUSE Linux 64-bit
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Ubuntu 64-bit
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Red Hat 64-bit
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Windows 64-bit
Notes on Windows instances
Prohibited actions
| Action | Consequence |
|---|---|
Stopping Aliyun Assist Service or shutdownmon.exe |
Instance may fail to stop or restart from the ECS console |
| Modifying the hostname of the domain controller | — |
| Renaming, deleting, or disabling the administrator account | May prevent instance access |
Setup decisions (hard to reverse after creation)
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Virtual memory: Do not use virtual memory on instances with basic disks. Instances with ultra disks, standard SSDs, or ESSDs support virtual memory.
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Custom images from domain controllers: Avoid creating custom images from domain controller instances. Domain controller state can cause image-based instances to behave unexpectedly.
Data safety
When using the administrator account to resize disks, manage spanned volumes or the registry, or update the system, proceed with caution. Errors can result in data loss.
Capacity limits
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A 32-bit Windows operating system supports a maximum of 4 vCPUs.
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Hosting a website or web environment requires at least 2 GiB of memory. Instances with 1 vCPU and 1 GiB of memory do not support MySQL.
For image and OS notes, see Select an image.
Notes on Linux instances
Prohibited actions
| Action | Consequence |
|---|---|
Modifying /etc/issue |
Custom images created from the instance cannot detect the OS distribution, causing image-based instances to fail to start |
Modifying permissions on directories in the root partition — especially /etc, /sbin, /bin, /boot, /dev, /usr, and /lib |
May cause system errors or prevent startup |
| Renaming, deleting, or disabling the root account | May prevent instance access |
| Compiling or modifying the Linux kernel | May cause instability or failure |
Setup decisions (hard to reverse after creation)
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Swap partitions: Do not use swap partitions on instances with basic disks. Instances with ultra disks, standard SSDs, or ESSDs support swap partitions.
Data safety
When using root to run fio, mkfs, or fsck, or to resize disks, proceed with caution. Errors can result in data loss.
For image and OS notes, see Select an image.
Limitations
See Limits.