|
| 1 | +# Flake Finder Fridays #0 |
| 2 | + |
| 3 | +February 5th 2021 ([Recording](https://youtu.be/Hqlm2h2AEvA)) |
| 4 | + |
| 5 | +## Introduction |
| 6 | + |
| 7 | +This is the first episode of Flake Finder Fridays with Dan Mangum and Rob |
| 8 | +Kielty. |
| 9 | + |
| 10 | +On the first friday of every month we will go through an issue that was logged |
| 11 | +for a failing or flaking test on the Kubernetes project. |
| 12 | + |
| 13 | +We will review the triage, root cause analysis, and problem resolution for a |
| 14 | +test related issue logged in the past four weeks. |
| 15 | + |
| 16 | +We intend to demo how CI works on the Kubernetes project and also how we |
| 17 | +collaborate across teams to resolve test maintenance issues. |
| 18 | + |
| 19 | +## Issue |
| 20 | +This is the issue that we are going to look at today ... |
| 21 | + |
| 22 | +[[Failing Test] ci-kubernetes-build-canary does not understand |
| 23 | +"--platform"](https://github.com/kubernetes/kubernetes/issues/98646) |
| 24 | + |
| 25 | +### Testgrid Dashboard |
| 26 | +[build-master-canary](https://testgrid.k8s.io/sig-release-master-informing#build-master-canary) |
| 27 | + |
| 28 | +### Breaking PRs |
| 29 | +- [Use buildx in favor of `FROM --platform` syntax |
| 30 | + ](https://github.com/kubernetes/kubernetes/pull/98529) |
| 31 | +- [Switch to `docker buildx` for conformance |
| 32 | + image](https://github.com/kubernetes/kubernetes/pull/98569) |
| 33 | + |
| 34 | +## Investigation |
| 35 | + |
| 36 | +1. Desire to move from Google-owned infrastructure to Kubernetes community |
| 37 | + infrastructure. Thus the introduction of a **canary** build job to test |
| 38 | + pushing building and pushing artifacts with new infrastructure. |
| 39 | +1. Desire to move off of `bootstrap.py` job (currently being used for canary |
| 40 | + job) to `krel` tooling. |
| 41 | +1. Separate job existed (`ci-kubernetes-build-no-bootstrap`) that was doing the |
| 42 | + same thing as the canary job, but with `krel` tooling. |
| 43 | +1. The `no-bootstrap` job was running smoothly, so [updated to use it for the |
| 44 | + canary job](https://github.com/kubernetes/test-infra/pull/20663). |
| 45 | +1. Right before the update, we [switched to using buildx for multi-arch |
| 46 | + images](https://github.com/kubernetes/kubernetes/pull/98529). |
| 47 | +1. Job started failing, which showed up in [some interesting |
| 48 | + ways](https://kubernetes.slack.com/archives/C09QZ4DQB/p1612269558032700). |
| 49 | +1. Triage begins! Issue |
| 50 | + [opened](https://github.com/kubernetes/kubernetes/issues/98646) and release |
| 51 | + management team is pinged in Slack. |
| 52 | +1. The `build-master` |
| 53 | + [job](https://testgrid.k8s.io/sig-release-master-blocking#build-master) was |
| 54 | + still passing though... interesting. |
| 55 | +1. Both are eventually calling `make release`, so environment must be different. |
| 56 | +1. Let's look inside! |
| 57 | + |
| 58 | + ``` |
| 59 | + docker run -it --entrypoint /bin/bash gcr.io/k8s-testimages/bootstrap:v20210130-12516b2 |
| 60 | + ``` |
| 61 | +
|
| 62 | + ``` |
| 63 | + docker run -it gcr.io/k8s-staging-releng/k8s-ci-builder:v20201128-v0.6.0-6-g6313f696-default /bin/bash |
| 64 | + ``` |
| 65 | +
|
| 66 | +1. A few directions we could go here: |
| 67 | + 1. Update the `k8s-ci-builder` image to you use newer version of Docker |
| 68 | + 1. Update the `k8s-ci-builder` image to ensure that |
| 69 | + `DOCKER_CLI_EXPERIMENTAL=enabled` is set |
| 70 | + 1. Update the `release.sh` script to set `DOCKER_CLI_EXPERIMENTAL=enabled` |
| 71 | +
|
| 72 | +1. Making the `release.sh` script more flexible serves the community better |
| 73 | + because it allows for building with more environments. Would also be good to |
| 74 | + update the `k8s-ci-builder` image for this specific case as well. |
| 75 | +1. And we get a new |
| 76 | + [failure](https://storage.googleapis.com/kubernetes-jenkins/logs/ci-kubernetes-build-canary/1356704759045689344/build-log.txt)! |
| 77 | +1. Let's see what is going on in those images again... |
| 78 | +1. Why would this cause an error in one but not the other if we have |
| 79 | + `DOCKER_CLI_EXPERIMENTAL=enabled`? |
| 80 | + ([this](https://github.com/docker/buildx/pull/403) is why) |
| 81 | +1. In the mean time we went ahead and [re-enabled the bootstrap |
| 82 | + job](https://github.com/kubernetes/test-infra/pull/20712) (consumers of those |
| 83 | + images need them!) |
| 84 | +1. Decided to [increase logging |
| 85 | + verbosity](https://github.com/kubernetes/kubernetes/pull/98568) on failures |
| 86 | + to see if that would give us a clue into what was going wrong (and to remove |
| 87 | + those annoying `quiet currently not implemented` warnings). |
| 88 | +1. Job turns green! But how? |
| 89 | +1. [Buildx](https://github.com/docker/buildx) is versioned separately than |
| 90 | + Docker itself. Turns out that the `--quiet` flag warning was [actually an |
| 91 | + error](https://github.com/docker/buildx/pull/403) until `v0.5.1` of Buildx. |
| 92 | +1. The `build-master` job was running with buildx `v0.5.1` while the `krel` job |
| 93 | + was running with `v0.4.2`. This meant the quiet flag was causing an error in |
| 94 | + the `krel` job, and removing it alleviated the error. |
| 95 | +1. Finished up by once again [removing the `bootstrap` |
| 96 | + job](https://github.com/kubernetes/test-infra/pull/20731). |
| 97 | +
|
| 98 | +### Fixes |
| 99 | +
|
| 100 | +- [Set DOCKER_CLI_EXPERIMENTAL=enabled for images using |
| 101 | + buildx](https://github.com/kubernetes/kubernetes/pull/98672) |
| 102 | +- [Make image build logs verbose if |
| 103 | + necessary](https://github.com/kubernetes/kubernetes/pull/98568) |
| 104 | +
|
| 105 | +### Test Infra |
| 106 | +
|
| 107 | +- [ci-kubernetes-build-canary: Migrate from bootstrap to |
| 108 | + krel](https://github.com/kubernetes/test-infra/pull/20663) |
| 109 | +- [releng: Re-enable a bootstrap build job for K8s |
| 110 | + Infra](https://github.com/kubernetes/test-infra/pull/20712) |
| 111 | +- [Revert "releng: Re-enable a bootstrap build job for K8s |
| 112 | + Infra"](https://github.com/kubernetes/test-infra/pull/20731) |
| 113 | +
|
| 114 | +### Slack Threads |
| 115 | +
|
| 116 | +- [kubeadm failing with |
| 117 | + ci/latest](https://kubernetes.slack.com/archives/C09QZ4DQB/p1612269558032700) |
| 118 | +
|
| 119 | +### Helpful Links |
| 120 | +
|
| 121 | +- [Docker Buildx |
| 122 | + Documentation](https://docs.docker.com/buildx/working-with-buildx/) |
| 123 | +- [What is Docker Buildkit and What can I use it |
| 124 | + for?](https://brianchristner.io/what-is-docker-buildkit/) |
| 125 | +- [Buildx --quiet error](https://github.com/docker/buildx/pull/403) |
| 126 | +
|
| 127 | +## Kubernetes Project Resources |
| 128 | +
|
| 129 | +Brand new to the project? |
| 130 | + - Start here: https://www.kubernetes.dev/ |
| 131 | +
|
| 132 | +Setup already and interested in maintaining tests? |
| 133 | + - Check out [this video](https://www.youtube.com/watch?v=Ewp8LNY_qTg) from |
| 134 | + Jordan Liggit who describes strategies and tactics to deflake flaking tests |
| 135 | + ([Jordan's show notes for that |
| 136 | + talk](https://gist.github.com/liggitt/6a3a2217fa5f846b52519acfc0ffece0)) |
| 137 | +
|
| 138 | +Here's how the CI Signal Team actively monitors CI during a release cycle: |
| 139 | + - [A Tour of CI on the Kubernetes |
| 140 | + Project](https://www.youtube.com/watch?v=bttEcArAjUw) |
| 141 | + - [Show notes](bit.ly/k8s-ci) |
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