Get health check path from readiness probe

[glindstedt]

This PR is not ready but I wanted to open it because I would like some feedback on the approach before continuing. I tried reusing as much as possible from ingress-gce, however I chose to copy GetProbe and getHTTPProbe from ingress-gce/controller/utils.go. This is because the GCETranslator that was the receiver needed a LoadBalancerController to initialize which seemed like unnecessary bloat. One possible solution would be to refactor the code in ingress-gce to make it easier to reuse so we could avoid code duplication. I haven't bothered with the tests yet since I'm not sure if this is the way you'd want to implement this.

I tested the implementation manually by running and it works ~with one exception, sometimes it seems like even though the cached informer has been synced it fails to get the correct path and defaults to /. I'm not yet sure if there's an issue with some race condition in the syncing or if the error is in this PR.~ EDIT: found the issue, I used the wrong HasSynced method when checking if the pod informer had synced

[k8s-ci-robot]

Hi @glindste. Thanks for your PR.

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[G-Harmon]

cc @nikhiljindal @csbell @bowei

[nikhiljindal]

/ok-to-test

Hey thanks a lot for the PR @glindste. Appreciate the contribution.

Regarding code duplication with ingress-gce, we are working with @bowei to reduce it. We have existing copied code here and want to get rid of it as soon as possible, but realize that requires refactoring in ingress-gce and then revendoring it here.

I am curious how you found this problem? Are you using kubemci?

[glindstedt]

@nikhiljindal I spent last week researching how to do multi cluster ingress. Kubernetes federation did not fit our usecase at all, we want individual control over the clusters and it doesn't mesh well with how we deploy things. I think I was digging around in the ingress-gce source code and found the gce-multi-cluster annotation which led me to kubemci, which seems to do exactly what we want.

Getting the health check path from the probe was pretty much the only missing feature before I could test how kubemci worked (neither our service or the default backend returns 200 on /) so I figured I'd give it a go.

[nikhiljindal]

Thats great @glindste! Are you going to use this with your GCP clusters?

We'd like to include you (and others) in our early access program if possible. Could you sign up for the EAP using this form? https://goo.gl/forms/RHg032DrRnnqF0by1 . We would love your feedback as you try out kubemci and would love to know what works and what doesnt. cc @mdelio

[glindstedt]

Thanks a lot for the feedback! :)

Yes if no major blocker comes up we'll probably use kubemci to set up the LB for our clusters, the alternative currently is managing the LB manually which we'd like to avoid. I've signed up for the EAP

[nikhiljindal]

Thanks for the changes @glindste This looks great. I have a few comments, mostly minor about being explicit about which code is copied and better error messages.

We should be good to merge once we resolve them. Thanks!

[coveralls]

Changes Unknown when pulling 7e1ba4c7da01a0a5bbf8d29dfd21fca9c47ca60b on glindste:hc-path-from-probe into on GoogleCloudPlatform:master.

[glindstedt]

@nikhiljindal I think I'm done now, please have a look if I addressed all your comments and if there's anything else I can fix. Thank you for the excellent review comments. Also, would you like me to squash the commits before merging?

[coveralls]

Changes Unknown when pulling faac038510d2b5bd4a941d85c4e6972506c26436 on glindste:hc-path-from-probe into on GoogleCloudPlatform:master.

[glindstedt]

I saw you'd fixed vet and fmt on master so I rebased and made sure they pass for this branch as well

[coveralls]

Changes Unknown when pulling bc005f37674b4f8bc0a42d35043c45b009720e9b on glindste:hc-path-from-probe into on GoogleCloudPlatform:master.

[nikhiljindal]

Yes, please squash the commits. You can also remove WIP from the PR title and commit message :)

[coveralls]

Changes Unknown when pulling f3b69812719c4315fa819bac89337d5d0dcd6f9b on glindste:hc-path-from-probe into on GoogleCloudPlatform:master.