service/ci.md

@@ -306,6 +306,17 @@ this:
 
 See the [gitlab-ci.yml templates](#gitlab-ci-yml-templates) section for a discussion.
 
+### Job failed because the runner picked an i386 image
+
+Some jobs may fail to run due to tpo/tpa/team#41656 even though the CI
+configuration didn't request an `i386` and would be instead expected to run
+with an `amd64` image. This issue is tracked in tpo/tpa/team#41621.
+
+The workaround is to configure jobs to pull an architecture-specific version of
+their image (eg. `amd64/debian:stable`) instead of the multi-arch manifest (eg.
+`debian:stable`). Note that not all organizations provide such arch-specific
+versions.
+
 ## Disaster recovery
 
 Runners should be disposable: if a runner is destroyed, at most the