rookout-k8s-operator

Rookout's k8s operator

Main operator goals

• Patch deployments with init container that loads rookout agent
• Inject pod metadata into containers to be collected by the SDK

Supported Runtimes

• Java (version >= 8)

Supported k8s resources

• Deployment (pod resources which not part of deployment not affected by the operator)

How to install the operator on a cluster ?

# install the operator
kubectl apply -f ./config/samples/deployment.yaml

# deploy operator's configuration
kubectl apply -f ./config/samples/rookout_v1alpha1_rookout.yaml

# test deployment
kubectl logs deployment.apps/rookout-controller-manager -n rookout -c manager

# uinstall
kubectl delete -f ./config/samples/deployment.yaml
kubectl delete -f ./config/samples/rookout_v1alpha1_rookout.yaml

The following log line shows that the operator is ready to patch deployments

time="2021-01-20T17:49:10Z" level=info msg="operator configuration updated"

How a successful deployment patch looks in the logs ?

time="2021-01-20T17:49:27Z" level=info msg="adding rookout agent to container <CONTAINER> of deployment <DEPLOYMENT> in <NAMESPACE> namespace"
time="2021-01-20T17:49:27Z" level=info msg="deployment <DEPLOYMENT> patched successfully"

Development

Code structure

• Project's initial structure created by operator-sdk init
• Operator's entry point : /controllers/rookout_controller.go
• Operator Resource API : /api/v1alpha1/rookout_types.go

Repo local setup

• Install operator sdk: brew install operator-sdk
• Init repo: make all

How to run and test on a cluster

• Move to a dev cluster
• Run make build-and-deploy
• It should create an operator on rookout namespace

Known issues

• Can't inject to PID=1 on linux alpine with openjdk < 14
• Java 7 requires Suns's tools.jar

References

• Basic operator tutorial - here
• Inspired by this blog post
• Inspired by prometheus-jmx-exporter-operator
• Controller watches - we use them to get notified on pods events