DNS resolution failure on consumption compute.

[MathewWaltersRVU]

Please provide us with the following information:

This issue is a: (mark with an x)

• [x] bug report -> please search issues before submitting
• [ ] documentation issue or request
• [ ] regression (a behavior that used to work and stopped in a new release)

Issue description

When a DNS query encounters a ServerFail status code it will block DNS resolution for any hostname for ~20 seconds.

Steps to reproduce

1. On an Alpine/Ubuntu container, issue a DNS query that generates a ServerFail response
2. Attempt any other DNS query

Expected behavior [What you expected to happen.] DNS queries should continue to work

Actual behavior [What actually happened.] DNS queries fail

Additional context

I am raising this issue to track the resolution of the bug, as directed by Microsoft support.

The diagnosis from Microsoft:

There is a bug identified with the ACA consumption V2 backend compute service that has a DNS resolution issue when the DNS server returns a ServFail status code and will block new DNS query requests for the next about 20 seconds. The fix is being worked on and will start the deployment. The ETA of rollout to all the regions will be 1 month.

[simonjj]

Thank you for reporting this to us @MathewWaltersRVU. We have a fix deploying and it should be available in westus2 reaching other regions in the coming days.