Developing kured

We love contributions to kured, no matter if you are helping out on Slack, reporting or triaging issues or contributing code to kured.

In any case, it will make sense to familiarise yourself with the main README to understand the different features and options, which is helpful for testing. The “building” section in particular makes sense if you are planning to contribute code.

Certificate of Origin

By contributing to this project you agree to the Developer Certificate of Origin (https://github.com/kubereboot/kured/blob/main/DCO). This document was created by the Linux Kernel community and is a simple statement that you, as a contributor, have the legal right to make the contribution.

We require all commits to be signed. By signing off with your signature, you certify that you wrote the patch or otherwise have the right to contribute the material by the rules of the https://github.com/kubereboot/kured/blob/main/DCO:

Signed-off-by: Jane Doe <jane.doe@example.com>

The signature must contain your real name (sorry, no pseudonyms or anonymous contributions) If your user.name and user.email are configured in your Git config, you can sign your commit automatically with git commit -s.

Kured Repositories

All Kured repositories are kept under https://github.com/kubereboot. To find the code and work on the individual pieces that make Kured, here is our overview:

Regular development activities

Prepare environment

Please run make bootstrap-tools once on a fresh repository clone to download several needed tools, e.g. GoReleaser.

Updating k8s support

Whenever we want to update e.g. the kubectl or client-go dependencies, some RBAC changes might be necessary too.

This is what it took to support Kubernetes 1.14: https://github.com/kubereboot/kured/pull/75

That the process can be more involved based on kubernetes changes. For example, k8s 1.10 changes to apps triggered the following commits:

b3f9ddf: Bump client-go for optimum k8s 1.10 compatibility bc3f28d: Move deployment manifest to apps/v1 908998a: Update RBAC permissions for kubectl v1.10.3 efbb0c3: Document version compatibility in release notes 5731b98: Add warning to Dockerfile re: upgrading kubectl

Search the git log for inspiration for your cases.

Please update our .github/workflows with the new k8s images, starting by the creation of a .github/kind-cluster-<version>.yaml, then updating our workflows with the new versions.

Once you updated everything, make sure you update the support matrix on the main README as well.

Updating other dependencies

Dependabot proposes changes in our go.mod/go.sum. Some of those changes are covered by CI testing, some are not.

Please make sure to test those not covered by CI (mostly the integration with other tools) manually before merging.

Review periodic jobs

We run periodic jobs (see also Automated testing section of this documentation). Those should be monitored for failures.

If a failure happen in periodics, something terribly wrong must have happened (or github is failing at the creation of a kind cluster). Please monitor those failures carefully.

Introducing new features

When you introduce a new feature, the kured team expects you to have tested your change thoroughly. If possible, include all the necessary testing in your change.

If your change involves a user facing change (change in flags of kured for example), please include expose your new feature in our default manifest (kured-ds.yaml), as a comment.

Our release manifests and helm charts are our stable interfaces. Any user facing changes will therefore have to wait for a release before being exposed to our users.

This also means that when you expose a new feature, you should create another PR for your changes in https://github.com/kubereboot/charts to make your feature available at the next kured version for helm users.

In the charts PR, you can directly bump the appVersion to the next minor version (you are introducing a new feature, which requires a bump of the minor number. For example, if current appVersion is 1.6.x, make sure you update your appVersion to 1.7.0). It allows us to have an easy view of what we land each release.

Do not hesitate to increase the test coverage for your feature, whether it’s unit testing to full functional testing (even using helm charts)

Increasing test coverage

We are welcoming any change to increase our test coverage. See also our github issues for the label testing.

Automated testing

Our CI is covered by github actions. You can see their contents in .github/workflows.

We currently run:

• go tests and lint
• shellcheck
• a check for dead links in our docs
• a security check against our base image (alpine)
• a deep functional test using our manifests on all supported k8s versions

To test your code manually, follow the section Manual testing.

Manual (release) testing

Before kured is released, we want to make sure it still works fine on the previous, current and next minor version of Kubernetes (with respect to the client-go & kubectl dependencies in use). For local testing e.g. minikube or kind can be sufficient. This will allow you to catch issues that might not have been tested in our CI, like integration with other tools, or your specific use case.

Deploy kured in your test scenario, make sure you pass the right image, update the e.g. period and reboot-days options, so you get immediate results, if you login to a node and run:

sudo touch /var/run/reboot-required

Example of golang testing

Please run make test. You should have golint installed.

Example of testing with minikube

A test-run with minikube could look like this:

# start minikube
minikube start --driver=kvm2 --kubernetes-version <k8s-release>

# build kured image and publish to registry accessible by minikube
make image minikube-publish

# edit kured-ds.yaml to
#   - point to new image
#   - change e.g. period and reboot-days option for immediate results

minikube kubectl -- apply -f kured-rbac.yaml
minikube kubectl -- apply -f kured-ds.yaml
minikube kubectl -- logs daemonset.apps/kured -n kube-system -f

# In separate terminal
minikube ssh
 sudo touch /var/run/reboot-required
minikube logs -f

Now check for the ‘Commanding reboot’ message and minikube going down.

Unfortunately as of today, you are going to run into https://github.com/kubernetes/minikube/issues/2874. This means that minikube won’t come back easily. You will need to start minikube again. Then you can check for the lock release.

Example of testing with kind

A test-run with kind could look like this:

# create kind cluster
kind create cluster --config .github/kind-cluster-<k8s-version>.yaml

# create reboot required files on pre-defined kind nodes
./tests/kind/create-reboot-sentinels.sh

# check if reboot is working fine
./tests/kind/follow-coordinated-reboot.sh

Publishing a new kured release

Prepare Documentation

Check that compatibility matrix is updated to the new version you want to release.

Create a tag on the repo

Before going further, we should freeze the code for a release, by tagging the code. The Github-Action should start a new job and push the new image to the registry.

Create the combined manifest

Now create the kured-<release>-dockerhub.yaml for e.g. 1.3.0:

VERSION=1.3.0
MANIFEST="kured-$VERSION-dockerhub.yaml"
make DH_ORG="kubereboot" VERSION="${VERSION}" manifest
cat kured-rbac.yaml > "$MANIFEST"
cat kured-ds.yaml >> "$MANIFEST"

Publish release artifacts

Now you can head to the Github UI, use the version number as tag and upload the kured-<release>-dockerhub.yaml file.

Please describe what’s new and noteworthy in the release notes, list the PRs that landed and give a shout-out to everyone who contributed.

Please also note down on which releases the upcoming kured release was tested on. (Check old release notes if you’re unsure.)