Various tools can be used to connect to Elastic Compute Service (ECS) instances, such as Workbench, Virtual Network Computing (VNC), and third-party client tools. To select an appropriate tool to connect to your instance, consider the operating system of your instance, the operating system of your on-premises machine, and the operations that you want to perform.
Connection methods
You can use the connection tools provided by Alibaba Cloud or third-party client tools to connect to ECS instances.
Connection tools provided by Alibaba Cloud: You can log on to the ECS console to use the tools.
Third-party client tools: To use a third-party client tool, you must install the tool on-premises.
Connection tool | Connection method | |
Connection tools provided by Alibaba Cloud | Workbench You can use Workbench to connect to instances in the ECS console. | |
Session Manager Before you can use Session Manager, you must install a version of Cloud Assistant Agent that supports Session Manager. | ||
Alibaba Cloud Client You must install Alibaba Cloud Client on-premises. | ||
VNC You can use VNC to connect to instances in the ECS console. | ||
Third-party client tools such as PuTTY, Xshell, and SecureCRT You must install the client tools on-premises. | ||
All third-party client tools used to connect to instances require that instances to which you want to connect have public IP addresses or elastic IP addresses (EIPs).
After a Windows instance is created, it takes 2 to 3 minutes to initialize the operating system. Do not restart the instance while it is being initialized. After a non-I/O optimized Windows instance is created, it takes 10 minutes to initialize the operating system. Do not connect to the instance while it is being initialized.
Scenarios for which connection tools are suitable
VNC and Workbench are suitable for different scenarios and can be used to perform different operations on instances that are in specific lifecycle states.
VNC: can be used to connect to instances that are not in the Stopped lifecycle state.
Workbench: can be used to connect to only instances that are in the Running lifecycle state and in the OK or Impaired health state.
Operating system status | Scenario | VNC | Workbench |
Starting | Access instances that reside in the classic network. | Supported. | Unsupported. |
View and interrupt Linux boot processes. For example, you can interrupt a Linux boot process to modify the Grand Unified Bootloader (GRUB) menu. | Supported. Only the reboot command is supported. When you restart an instance in the ECS console, the VNC connection to the instance is disconnected. | Unsupported. | |
View and interrupt Windows boot processes. For example, you can interrupt a Windows boot process by booting into safe mode. | Supported. Only the reboot command is supported. When you restart an instance in the ECS console, the VNC connection to the instance is disconnected. | Unsupported. | |
Use with a GUI. | Supported. | Supported. | |
Running | Use with a GUI. | Supported. | Supported. |
Use public IP addresses to access instances that reside in the classic network. | Supported. | Supported. | |
Use private IP addresses to access instances that reside in the classic network. | Supported. | Supported. | |
Use public IP addresses to access instances that reside in virtual private clouds (VPCs). | Supported. | Supported. | |
Use private IP addresses to access instances that reside in VPCs. | Supported. | Supported. | |
Stopping | View Linux shutdown processes. | Supported. | Unsupported. |
Stopped | None. | Unsupported. | Unsupported. |
Comparison of connection tools
The following table compares the advantages of Workbench, VNC, Session Manager, Alibaba Cloud Client, and third-party client tools.
Item | Workbench | Session management | Alibaba Cloud Client | VNC | Third-party client tool |
Supported instance operating systems | Workbench can be used to connect to both Linux and Windows instances. | Session Manager can be used to connect to both Linux and Windows instances. | Alibaba Cloud Client can be used to connect to both Linux and Windows instances. | VNC can be used to connect to both Linux and Windows instances. | Typically, third-party client tools can be used to connect to Linux or Windows instances. |
Allocation of public IP addresses or EIPs to instances | Optional. Workbench can be used to connect to instances by using the private IP addresses of the instances. | Optional. Session Manager can be used to connect to instances by using various credentials such as AccessKey pairs and Security Token Service (STS) tokens. | Optional. Alibaba Cloud Client can be used to connect to instances by using various credentials such as AccessKey pairs and STS tokens. | Optional. VNC can be used to troubleshoot network configuration exceptions, such as firewalls being enabled by mistake. | Required. |
Enabling services such as SSH on Linux instances | Required. | Optional. Session Manager can be used to troubleshoot SSH service exceptions, such as sshd being disabled. | Optional. Alibaba Cloud Client can be used to troubleshoot SSH service exceptions, such as sshd being disabled. | Optional. VNC can be used to troubleshoot SSH service exceptions, such as sshd being disabled. | Required. |
Logons by using the ECS console | Supported. | Not supported. A version of Cloud Assistant Agent that supports Session Manager must be installed. | Not supported. Alibaba Cloud Client must be installed. | Supported. | Not supported. The on-premises client must be installed. |
Simultaneous logons by multiple operating system users to a single instance | Supported. | Supported. | Supported. | Unsupported. | Depends on the client tool. |
Ease of interaction | Workbench supports copying and pasting text. | Session Manager supports copying and pasting text. | Alibaba Cloud Client supports copying and pasting text. | Not supported. To copy or paste text, use the feature for copying long commands. | Depends on the client tool. |
Visibility into Linux system file resources | Supported. | Unsupported. | Unsupported. | Unsupported. | Depends on the client tool. |
Permissions to control and modify hardware | Unsupported. | Unsupported. | Unsupported. | Supported. VNC can be used to manage resources such as basic Input output system (BIOS) and troubleshoot exceptions such as system startup failures. | Unsupported. |
Configurability of terminal settings such as usernames, passwords, and keys | Supported, but depends on the capabilities that Workbench provides. | Supported, but depends on the capabilities that the client tool provides. | Supported, but depends on the capabilities that the client tool provides. | Unsupported. | Supported, but detailed capabilities vary based on the client tool. |
Security | Workbench provides access encryption. Workbench provides the screen recording feature that allows you to audit commands and operations. | Session Manager establishes persistent WebSocket connections based on the Web Socket Secure (WSS) protocol. The WSS protocol encrypts the persistent WebSocket connections by using the SSL protocol to ensure data security. | Alibaba Cloud Client can be used to connect to ECS instances and elastic container instances without the need to provide passwords or public IP addresses. | VNC does not provide access encryption. You can only set VNC passwords to ensure that secure VNC connections are established to instances. | Depends on the client tool. |