CODEWITHSUNDEEP
azureazure-devopsazure-pipelinesazure-vm-scale-set
David Masters
David Masters

Reputation: 8295

Setting up file share for NuGet packages cache on Azure VM Scale Set with Azure DevOps self hosted agents

I have setup a VM Scale Set and configured it with Azure DevOps as an agent pool.

In order to prevent nuget packages being re-downloaded on every build, I have created a File Share with a storage account, and added a script extension to the scale set to mount the file share as drive Z when the VMs are created.

I've updated my NuGetCommand@2 as follows:

  - task: NuGetCommand@2
    displayName: 'Restore Packages'
    inputs:
      restoreSolution: '**/*.sln'
      restoreDirectory: 'Z:\NuGetCache'

But this now fails with the error:

##[error]The nuget command failed with exit code(1) and error(The user name or password is incorrect.

There are no private nuget sources used that require authentication, so I suspect the issue is perhaps the account that the agent runs under doesn't have access to the file share / mounted drive. But I don't know what the account name would be or how to grant access?

Upvotes: 0

Views: 103

Answers (1)

Ziyang Liu-MSFT
Ziyang Liu-MSFT

Reputation: 4957

I can reproduce the issue when the image of my VMSS is WindowsServer.

enter image description here

After investigation, I found the reason was that the custom script extension did not successfully connect the instance to the Azure file share. When I remote to the instance, I can see this:

enter image description here

For further investigation, I manually run the scripts (copied from file share connection page) used to connect to Azure file share, then the instance can connect to the file share successfully. However, the pipeline still can't access the file share.

According to Lifecycle of a Scale Set Agent,

The configuration script creates a local user named AzDevOps if the operating system is Windows Server or Linux.

And this account has been added into the Administrators group. I don't understand why the local account created from VMSS which is also Administrator can access it but AzDevOps can't. However, if the custom scripts are run by AzDevOps, then the pipeline can access the file share. You can use it as a workaround.

enter image description here

Workarounds:

Workaround1: Don't use the custom script extension in VMSS to mount the file share and run the scripts directly in the pipeline. For example,

# Add azure file share to the instance

- task: PowerShell@2
  inputs:
    filePath: 'fileshare.ps1'

- task: NuGetCommand@2
  inputs:
    command: 'restore'
    restoreSolution: 'mockagent/mockagent.sln'
    restoreDirectory: 'Z:\nuget'

Result:

enter image description here

Workaround2: Use custom image.

According to Create a scale set with custom image, software, or disk size,

To customize the permissions of the pipeline agent user, you can create a user named AzDevOps, and grant that user the permissions you require. This user will be created by the scaleset agent startup script if it doesn't already exist.

In the image, create AzDevOps account manually and use it to connect to Azure file share.

Upvotes: 0

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