Kubeadm: Create a `kubeadm validate` command

[luxas]

Is this a BUG REPORT or FEATURE REQUEST?

Choose one: BUG REPORT or FEATURE REQUEST

FEATURE REQUEST

It would be really cool to have a kubeadm validate command!
This has been discussed a few times, but never brought to life.

Example commands/usage:

• kubeadm validate network: Would spin up an nginx Deployment or so to serve on port 80, then spin up an other busybox Pod to nslookup nginx && wget http://nginx. That only works if the network/dns is function is set up correctly and is really fast (<1min)
• kubeadm validate conformance: This command would download the right e2e binary and make that one run the Conformance suite against the cluster. IIRC that takes about an hour.
• kubeadm validate ???: There are lots of other interesting ideas that we could implement here, please come with suggestions!

@mikedanese @timothysc @lukemarsden @jbeda @roberthbailey were involved in this discussion IIRC

[luxas]

cc @kubernetes/sig-testing-feature-requests Do you have any cool ideas or thoughts?

[cheld]

in dashboard we get many issues that users cannot access dashboard, but actually the cluster setup or their environment is the cause. I think this would help a lot

@kubernetes/dashboard-maintainers do we have any additional ideas?

[spxtr]

Why kubeadm instead of kubectl or some other tool?

[luxas]

@spxtr kubectl is a tool to manage the API resources, etc.
kubeadm is more a tool to manage your cluster

[ozdanborne]

I agree with @spxtr. This sounds like an incredibly useful tool for any Kubernetes clusters - not just ones created by kubeadm.

Question @luxas: is kubeadm only meant to manage clusters it created?

[luxas]

Question @luxas: is kubeadm only meant to manage clusters it created?

@ozdanborne Not necessarily. kubeadm token can talk to any cluster. Generic functions like that work on any cluster.

But I still think there would be pushback to add such a command to kubectl, it really doesn't feel client-y enough to me. This is more a high-level feature than a client-thing. kubeadm is the higher-level tool here indeed and kubectl is the client that shouldn't build in such features.

As this evolves, I see it become a kubectl plugin though...

[cheld]

If feasible, I would suggest to leave the validation in kubeadm, but have an option to execute against any cluster. I would reference this tool then from the setup or trouble-shooting guides in Dashboard. This would be very nice...

[luxas]

@GheRivero volunteered to work on this :tada:
Feel free to ask here if you have any questions or post what implementation/design you have in mind.

[timothysc]

I think that should be a separation of concerns and we shouldn't conflate kubeadm, to quote unix philosophy:

• Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new "features".

• Expect the output of every program to become the input to another, as yet unknown, program.

I think setup is where kubeadm stops and validation is where another tool begins.

[luxas]

@timothysc I'm totally fine with that, should have thought about that in the first place ;)

Still, feel free to prototype this @GheRivero or whoever is working on this, it'd be a very cool project to check out :)

[timothysc]

There are ongoing efforts in the CNCF on conformance, and sig-testing around this topic. That may a better venue to vet this.