Containerized Alpine Job Hangs on dotnet build-server shutdown --vbcscompiler

[ellahathaway]

This is a tracking issue describing a block related to the work in #4547.

Source-build builds hang when shutting down the VB/C# compiler build server via dotnet build-server shutdown or dotnet build-server shutdown --vbcscompiler. This hanging only occurs in a containerized job using an Alpine with Node image. The hang occurs regardless of whether the build is internal or public, and it does not repro outside of a containerized azure devops job.

Diagnostics so far:

• Our alpine images meet the requirements specified in the Azure DevOps documentation.
• Running dotnet exec VBCSCompiler.dll --shutdown succeeds, allowing immediate subsequent calls to dotnet build-server shutdown or dotnet build-server shutdown --vbcscompiler to finish. Note that if the server is started again, the build will hang when attempting to shutdown the server without dotnet exec VBCSCompiler.dll.
• There doesn't appear to be a process count limit on Alpine, as ulimit -u returns unlimited.
• Replicating the Azure DevOps container setup doesn't reproduce the issue. Note that the setup can't be entirely replicated locally due to internal volumes being configured by the pipeline task.

cc @jaredpar

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[ellahathaway]

The suggestion from an internal team is to post the issue on stack overflow, so I opened https://stackoverflow.microsoft.com/questions/436123.

I think it would still be helpful to have someone with more knowledge on the VB/C# compiler build server help to investigate the issue as well.

[ellahathaway]

Was able to get some workarounds to help unblock this. I will be implementing those today.

That said, the investigation is still ongoing. dotnet/sdk#45393 is needed to continue to investigation.