Support a "check" feature to facilitate validation of requirements and dependencies (like Linkerd)

[controlpl4n3]

I have worked on several teams that have been very impressed with the linkerd check option and they appreciate having a list of system requirements confirmed before making any changes....
.... and those very same teams (every single one) refused to include a similar feature in their code.

I suspect that testkube could win adoption if it made it easier for devs to provide similar reality checks.
see https://linkerd.io/2.12/tasks/troubleshooting/ if you haven't used this feature before.

[vsukhin]

converted to an issue

[exu]

I like the idea!