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Developing Strimzi

This document gives a detailed breakdown of the various build processes and options for building Strimzi from source. For a quick start guide see the Getting Started document.

Build Pre-Requisites

To build this project you must first install several command line utilities and a Kubernetes or OpenShift cluster

Command line tools

  • make - Make build system
  • mvn (version 3.5 and above) - Maven CLI
  • helm - Helm Package Management System for Kubernetes
    • After installing Helm be sure to run helm init.
  • asciidoctor - Documentation generation.
    • Use gem to install latest version for your platform.
  • yq - YAML manipulation tool.
    • Warning: There are several different yq YAML projects in the wild. Use this one.
  • docker - Docker command line client

In order to use make these all need to be available in your $PATH.

Mac OS

The make build is using GNU versions of find and sed utilities and is not compatible with the BSD versions available on Mac OS. When using Mac OS, you have to install the GNU versions of find and sed. When using brew, you can do brew install gnu-sed findutils grep coreutils. This command will install the GNU versions as gcp, ggrep, gsed and gfind and our make build will automatically pick them up and use them.

The build requires bash version 4+ which is not shipped Mac OS but can be installed via homebrew. You can run brew install bash to install a compatible version of bash. If you wish to change the default shell to the updated bash run sudo bash -c 'echo /usr/local/bin/bash >> /etc/shells' and chsh -s /usr/local/bin/bash

Kubernetes or OpenShift Cluster

In order to run the integration tests and test any changes made to the operators you will need a functioning Kubernetes or OpenShift cluster. This can be a remote cluster or a local development cluster.

Minishift

In order to perform the operations necessary for the integration tests, your user must have the cluster administrator role assigned. For example, if your username is developer, you can add the cluster-admin role using the commands below:

oc login -u system:admin

oc adm policy add-cluster-role-to-user cluster-admin developer

oc login -u developer -p <password>
Minikube

The default minishift setup should allow the integration tests to be run without additional configuration changes.

Sometimes however, updates to minikube may prevent the test cluster context being correctly set. If you have errors due to oc commands being called on your minikube cluster then explicitly set the TEST_CLUSTER environment variable before running the make commands.

export TEST_CLUSTER=minikube

Make targets

Strimzi includes a Makefile with various Make targets to build the project.

Commonly used Make targets:

Note: If you are having trouble running any of the Make commands it may help to run mvn clean and then mvn install -DskipTests -DskipITs before running the commands again.

Building Docker images

The docker_build target will build the Docker images provided by the Strimzi project. You can build all Strimzi Docker images by calling make docker_build from the root of the Strimzi repository. Or you can build an individual Docker image by running make docker_build from the subdirectories with their respective Dockerfiles - e.g. kafka_base, kafka etc.

The docker_build target will always build the images under the strimzi organization. This is necessary in order to be able to reuse the base image you might have just built without modifying all Dockerfiles. The DOCKER_TAG environment variable configures the Docker tag to use (default is latest).

Tagging and pushing Docker images

Target docker_tag tags the Docker images built by the docker_build target. This target is automatically called as part of the docker_push target, but can be called separately if you wish to avoid pushing images to an external registry.

To configure the docker_tag and docker_push targets you can set following environment variables:

  • DOCKER_ORG configures the Docker organization for tagging/pushing the images (defaults to the value of the $USER environment variable)
  • DOCKER_TAG configured Docker tag (default is latest)
  • DOCKER_REGISTRY configures the Docker registry where the image will be pushed (default is docker.io)

Docker build options

When building the Docker images you can use an alternative JRE or use an alternate base image.

Alternative Docker image JRE

The docker images can be built with an alternative java version by setting the environment variable JAVA_VERSION. For example, to build docker images that have the java 11 JRE installed use JAVA_VERSION=11 make docker_build. If not present, JAVA_VERSION is defaulted to 1.8.0.

If JAVA_VERSION environment variable is set, a profile in the parent pom.xml will set the maven.compiler.source and maven.compiler.target properties.

Alternative docker command

The build assumes the docker command is available on your $PATH. You can set the DOCKER_CMD environment variable to use a different docker binary or an alternative implementation such as podman.

Alternative Docker base image

The docker images can be built with an alternative container OS version by adding the environment variable ALTERNATE_BASE. When this environment variable is set, for each component the build will look for a Dockerfile in the subdirectory named by ALTERNATE_BASE. For example, to build docker images based on alpine, use ALTERNATE_BASE=alpine make docker_build. Alternative docker images are an experimental feature not supported by the core Strimzi team.

Building Strimzi

The make all target can be used to trigger both the docker_build and the docker_push targets described above. This will build the Docker images, tag them and push them to the configured repository.

The build can be customised by:

Other build options:

Kafka versions

As part of the Docker image build several different versions of Kafka will be built, which can increase build times. Which Kafka versions are to be built are defined in the kafka-versions.yaml file. Unwanted versions can be commented out to speed up the build process.

Maven Settings

Running make invokes Maven for packaging Java based applications (that is, Cluster Operator, Topic Operator, etc). The mvn command can be customized by setting the MVN_ARGS environment variable when launching make all. For example, MVN_ARGS=-DskipTests make all can be used to avoid running the unit tests and adding -DskipIT will skip the integration tests.

Local build with push to Docker Hub

To build the images on your local machine and push them to the Docker Hub, log into Docker Hub with your account details. This sets the Hub as the docker push registry target.

docker login

By default the docker_push target will build the images under the strimzi organisation (e.g. strimzi/operator:latest) and attempt to push them to the strimzi repositories on the Docker Hub. Only certain users are approved to do this so you should push to your own Docker Hub organisation (account) instead. To do this, make sure that the DOCKER_ORG environment variable is set to the same value as your username on Docker Hub before running the make commands.

export DOCKER_ORG=docker_hub_username

When the Docker images are build then will now be labeled in the form: docker_hub_username/operator:latest in your local repository and pushed to your Docker Hub account under the same label.

In order to use these newly built images, you need to update the install/cluster-operator/050-Deployment-strimzi-cluster-operator.yml to obtain the images from your repositories on Docker Hub rather than the official Strimzi images. That can be done using the following command and replacing docker_hub_username with the relevant value:

sed -Ei -e 's#(image|value): strimzi/([a-z0-9-]+):latest#\1: docker_hub_username/\2:latest#' \
        -e 's#([0-9.]+)=strimzi/([a-zA-Z0-9-]+:[a-zA-Z0-9.-]+-kafka-[0-9.]+)#\1=docker_hub_username/\2#' \
        install/cluster-operator/050-Deployment-strimzi-cluster-operator.yaml

This will update 050-Deployment-strimzi-cluster-operator.yaml replacing all the image references (in image and value properties) with ones with the same name but with the repository changed.

Then you can deploy the Cluster Operator by running (for an OpenShift cluster):

oc create -f install/cluster-operator

Finally, you can deploy the cluster custom resource running:

oc create -f examples/kafka/kafka-ephemeral.yaml

Local build with push to Minishift Docker registry

When developing locally you might want to push the docker images to the docker repository running in your local OpenShift (minishift) cluster. This can be quicker than pushing to Docker Hub and works even without a network connection.

Assuming your OpenShift login is developer (a user with the cluster-admin role) and the project is myproject, you can push the images to OpenShift's Docker repo using the steps below:

  1. Make sure your cluster is running,

     oc cluster up

    By default, you should be logged in as developer (you can check this with oc whoami)

  2. Get the internal OpenShift docker registry address by running the command below:

     oc get services -n default

    172.30.1.1:5000 is the typical default IP and port of the Docker registry running in the cluster, however the command may above may return a different value.

  3. Log in to the Docker repo running in the local cluster:

     docker login -u developer -p $(oc whoami -t) 172.30.1.1:5000

    Note that we are using the developer OpenShift user and the token for the current (developer) login as the password.

  4. Now run the docker_push target to push the development images to that Docker repo. If you need to build/rebuild the Docker images as well, then run the all target instead:

     DOCKER_REGISTRY=172.30.1.1:5000 DOCKER_ORG=$(oc project -q) make docker_push

  5. In order to use the built images in a deployment, you need to update the install/cluster-operator/050-Deployment-strimzi-cluster-operator.yml to obtain the images from the registry at 172.30.1.1:5000, rather than from DockerHub. That can be done using the following command:

    sed -Ei -e 's#(image|value): strimzi/([a-z0-9-]+):latest#\1: 172.30.1.1:5000/myproject/\2:latest#' \
        -e 's#([0-9.]+)=strimzi/([a-zA-Z0-9-]+:[a-zA-Z0-9.-]+-kafka-[0-9.]+)#\1=172.30.1.1:5000/myproject/\2#' \
        install/cluster-operator/050-Deployment-strimzi-cluster-operator.yaml

    This will update 050-Deployment-strimzi-cluster-operator.yaml replacing all the image references (in image and value properties) with ones with the same name from 172.30.1.1:5000/myproject.

  6. Then you can deploy the Cluster Operator by running:

    oc create -f install/cluster-operator

  7. Finally, you can deploy the cluster custom resource by running:

    oc create -f examples/kafka/kafka-ephemeral.yaml

Local build on Minishift or Minikube

If you do not want to have the docker daemon running on your local development machine, you can build the container images in your minishift or minikube VM by setting your docker host to the address of the VM's daemon:

eval $(minishift docker-env)

or

eval $(minikube docker-env)

The images will then be built and stored in the cluster VM's local image store and then pushed to your configured Docker registry.

Skipping the registry push

You can avoid the docker_push step and sed commands above by configuring the Docker Host as above and then running:

make docker_build

make DOCKER_ORG=strimzi docker_tag

This labels your latest container build as strimzi/operator:latest and you can then deploy the standard CRDs without changing the image targets. However, this will only work if all instances of the imagePullPolicy: setting are set to IfNotPresent or Never. If not, then the cluster nodes will go to the upstream registry (Docker Hub by default) and pull the official images instead of using your freshly built image.

Helm Chart

The strimzi-kafka-operator Helm Chart can be installed directly from its source.

helm install ./helm-charts/strimzi-kafka-operator

The chart is also available in the release artifact as a tarball.

Running system tests

System tests has its own guide with more information. See Testing Guide document for more information.

DCO Signoff

The project requires that all commits are signed-off, indicating that you certify the changes with the developer certificate of origin (DCO) (https://developercertificate.org/). This can be done using git commit -s for each commit in your pull request. Alternatively, to signoff a bunch of commits you can use git rebase --signoff _your-branch_.

IDE build problems

The build also uses a Java annotation processor. Some IDEs (such as IntelliJ) don't, by default, run the annotation processor in their build process. You can run mvn clean install -DskipTests -DskipITs to run the annotation processor as part of the maven build and the IDE should then be able to use the generated classes. It is also possible to configure the IDE to run the annotation processor directly.