从 Azure 管道中的 `az vm run-command` 获取退出代码

Question

I'm running a rather hefty build in my Azure pipeline, which involves processing a large amount of data, and hence requires too much memory for my buildagent to handle. My approach is therefore to start up an linux VM, run the build there, and push up the resulting docker image to my container registry.

To achieve this, I'm using the Azure CLI task to issue commands to the VM (eg az vm start , az vm run-command... etc).

The problem I am facing is that az vm run-command "succeeds" even if the script that you run on the VM returns a nonzero status code. For example, this "bad" vm script:

az vm run-command invoke -g <group> -n <vmName> --command-id RunShellScript --scripts "cd /nonexistent/path"

returns the following response:

{
  "value": [
    {
      "code": "ProvisioningState/succeeded",
      "displayStatus": "Provisioning succeeded",
      "level": "Info",
      "message": "Enable succeeded: \n[stdout]\n\n[stderr]\n/var/lib/waagent/run-command/download/87/script.sh: 1: cd: can't cd to /nonexistent/path\n",
      "time": null
    }
  ]
}

So, the command succeeds, presumably because it succeeded in executing the script on the VM. The fact that the script actually failed on the VM is buried in the response "message"

I would like my Azure pipeline task to fail if the script on the VM returns a nonzero status code. How would I achieve that?

One idea would be to parse the response (somehow) and search the text under stderr - but that sounds like a real hassle, and I'm not sure even how to "access" the response within the task.

Answer 1

Have you enabled the option " Fail on Standard Error " on the Azure CLI task? If not, you can try to enable it and run the pipeline again to see if the error " cd: can't cd to /nonexistent/path " can make the task run failed.

If the task still is passed, the error " cd: can't cd to /nonexistent/path " should not be a Standard Error. In this situation, you may need to add more command lines in your script to monitor the output logs of the az command. Once there is any output message shows error, execute " exit 1 " to exit the script and return a Standard Error to make the task be failed.

Answer 2

I solved this by using the SSH pipeline task - this allowed me to connect to the VM via SSH, and run the given script on the machine "directly" via SSH.

This means from the context of the task, you get the status code from the script itself running on the VM. You also see any console output inside the task logs, which was obscured when using az vm run-command .

Here's an example:

  - task: SSH@0
    displayName: My VM script
    timeoutInMinutes: 10
    inputs:
      sshEndpoint: <sshConnectionName> 
      runOptions: inline
      inline: |
        echo "Write your script here" 

Not that the SSH connection needs to be set up as a service connection using the Azure pipelines UI. You reference the name of the service connection you set up in yaml.