Arvados

The LocalKeepBlobBuffersPerVCPU config is not exported, so (unless we change that) we can't use that directly to decide what to check.

But we can check presence/absence of the ARVADOS_KEEP_SERVICES environment variable in the container. This is actually more direct: that env var is how clients decide whether to ask controller for the list of keep services, which is the thing that relies on internal client detection.

Tested on tordo.

New -check-container flag comes with a log message to reveal whether/why internal client detection is being checked.

example tordo-xvhdp-ef7j5lgegd3y5gd

2025-11-20T17:59:37.977435590Z level=info msg=" 60: checking internal/external client detection" 
2025-11-20T17:59:38.000439681Z level=info msg=" ... controller returned only non-proxy services, this host is treated as \"internal\"" 
2025-11-20T17:59:38.000449092Z level=info msg=" ... ARVADOS_KEEP_SERVICES is set, container connectivity does not rely on being treated as \"internal\"" 

23317-internal-client-check @ c83fb143e3852a410130f138bf17322333eb5f0c -- developer-run-tests: #4953

Tom Clegg wrote in #note-3:

23317-internal-client-check @ c83fb143e3852a410130f138bf17322333eb5f0c -- developer-run-tests: #4953

Assuming tests pass this LGTM. Thanks for explaining the implementation change, that makes sense and works for me.