You can use Cloud Assistant commands to perform routine tasks for ECS instances. These tasks include running automated O&M scripts, polling the processes, resetting user passwords, installing or uninstalling software, updating applications, and installing patches. Command types can be bat or PowerShell for Windows instances, or shell for Linux instances. You can also specify custom parameters as variables.

Background information

  • You can keep a maximum of 100 Cloud Assistant commands within an Alibaba Cloud region. The service quota of commands may increase based on your ECS usage.
    Note You can also call the DescribeAccountAttributes operation and set the AttributeName.N parameter to max-axt-command-count to query the maximum number of Cloud Assistant commands that you can retain within a region.
  • A command cannot exceed 16 KB in size after it is encoded in Base64.
  • A maximum of 20 custom parameters can be specified in a Cloud Assistant command.
  • When you create a command, you must check whether the syntax, logic, and algorithm of the command are correct.

    For example, assume that you have created the /backup directory (mkdir /backup) in the instance, you can run the following shell commands to archive a file in this directory: 

    #! /bin/bash 
OF=/backup/my-backup-$(date +%Y%m%d).tgz
tar -cf $OF {{file}}
    Note In this example, {{file}} is a custom parameter. When you run the commands, you can set this custom parameter to the name of the file to be archived, such as /app/usrcredential. Custom parameters can be used in scenarios of dynamic values and multi-purpose values. We recommend that you specify custom parameters for data that is security-sensitive or changes based on the environment, such as AccessKey pairs, instance IDs, authorization codes, time parameters, and critical system files.

Procedure in the console

  1. Log on to the ECS console and navigate to the Cloud Assistant page.
  2. In the top navigation bar, select a region.
  3. Click Create or Run Command.
  4. In the Command Information section, configure the corresponding parameters.
    The following table describes the parameters.
    Parameter Description
    Command Source The source of the command.
    • New Command: Create a command.
    • Existing Command: Select a command from the existing ones.
    Command Name The name of the command.
    Command Type The type of the command.
    • For Linux instances, select Shell.
    • For Windows instances, select Bat or PowerShell.
    Command The content of the command. You can enter or paste the command content.

    For more information about shell commands, see View instance configurations.

    Use Parameters The option that specifies whether to enable parameters.

    If you turn on Use Parameters, you can specify custom parameters in the {{key}} format in the Command field.

    Command Parameters The values of the custom parameters specified in the Command field in the {{key}} format.

    This parameter is available only when Use Parameters is turned on.

    Save Command The option that specifies whether to save the command.
    Command Description The description of the command. We recommend that you enter information such as the purpose of the command to facilitate subsequent management and maintenance.
    Execution Path The custom execution path of the command. The following list provides default execution paths for instances that have different operating systems:
    • For Linux instances, the default execution path is the /home directory of the root user.
    • For Windows instances, the default execution path is the directory where the process of the Cloud Assistant client is located, such as C:\ProgramData\aliyun\assist\$(version).
    Timeout Period The timeout period for the command to run instances. If the command times out, Cloud Assistant forcibly stops the execution process.

    Unit: seconds. Default value: 60. Minimum value: 10. If you set Timeout Period to a value less than 10 seconds, the system changes the value to 10 seconds to ensure that the execution succeeds.

  5. In the Select Instances section, select the instances on which you want to run the command.
  6. Click Save.

Procedure by using Alibaba Cloud CLI

  • Sample request:

    Call the CreateCommand operation to create a Cloud Assistant command named test. The command content is echo 123 and is encoded as a Base64-encoded plaintext. If the instances on which the command will be run are Windows instances, set Type to RunBatScript or RunPowershellScript. 

    aliyun ecs CreateCommand --RegionId TheRegionId --CommandContent ZWNobyAxMjM= --Type RunShellScript --Name test --Description test --output cols=CommandId
  • Sample response: 
    CommandId
---------
c-hz0b8osxk8a***

What to do next

Run commands

Note If you turn on Use Parameters when you create the command, enter the parameter values in the Command Parameters field.