lp:~paelzer/cloud-utils

Author: Christian Ehrhardt 
Author Date: 2021-01-08 08:29:35 UTC

test: retry delpart that is flaky on arm64

Recently these tests got flaky on autopkgtest infrastructure [1] failing
most runs. It turned out that on slow machines this test can hit a race
of delpart trying to remove the partition slightly too early and fails
like:
   delpart: failed to remove partition: Device or resource busy

I was unable to find the root cause why this now is more racy than in
the past but wanted to extend the test with a retry logic to ensure we
only catch non timing related issues.

Tests ahve shown that ~14% of the runs fail, but 0% with the retry
logic. Also none of the cases was retried twice, so the 5 retries I
added should be enough to make it rather stable.

This does not add any delay if there is no issue in the first place.

[1]: https://autopkgtest.ubuntu.com/packages/c/cloud-utils/hirsute/arm64

Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>