Kubernetes Operator

Kubernetes Operator to manage Tomcat deployments

• Learning Quarkus
• Learning Kubernetes Operator development
• Learning Kotlin

Works with java >= 11. In case you have other projects running a different java version please use ASDF with Java plugin.

$ asdf install java openjdk-14.0.1
$ asdf global java openjdk-14.0.1

Problems

I found 3 issues when dealing with Kotlin data classes:

• Data classes representing CustomResource definitions should be explicitly registered for reflection using @RegisterForReflection annotation.
• A default constructor or default values for all arguments is required (this is required while deserializing kubernetes events into objects)
• Quarkus native build doesn't recognize the generic typed arguments in the CustomResource, so we need to explicitly provide initialization for the spec and status classes by overriding initSpec() and initStatus() respectively.

A final Data class representing a CustomResource will look like:

@RegisterForReflection
@Group("tomcat.operator.io")
@Version("v1")
class Tomcat(var spec: TomcatSpec = TomcatSpec(), var status: TomcatStatus = TomcatStatus()) : CustomResource<TomcatSpec, TomcatStatus>(), Namespaced {

    override fun initSpec(): TomcatSpec {
        return TomcatSpec()
    }

    override fun initStatus(): TomcatStatus {
        return TomcatStatus()
    }
}

Native build

Official documentation

Install GraalVM

https://www.graalvm.org/docs/getting-started/#install-graalvm

Tutorial for Macc

Export environment variables:

export GRAALVM_HOME=$HOME/Library/Java/JavaVirtualMachines/<graalvm-dir>/Contents/Home
export PATH=$GRAALVM_HOME/bin:$PATH

Install native-image

gu install native-image

Software Notarization

If you are using macOS Catalina and later you may need to remove the quarantine attribute from the bits before you can use them. To do this, run the following:

sudo xattr -r -d com.apple.quarantine $HOME/Library/Java/JavaVirtualMachines/<graalvm-dir>

Build

• Build native executable

./mvnw package -Pnative

• Creating a Linux executable without GraalVM installed

./mvnw package -Pnative -Dquarkus.native.container-build=true

By default Quarkus automatically detects the container runtime. If you want to explicitely select the container runtime, you can do it with:

# Docker
./mvnw package -Pnative -Dquarkus.native.container-build=true -Dquarkus.native.container-runtime=docker
# Podman
./mvnw package -Pnative -Dquarkus.native.container-build=true -Dquarkus.native.container-runtime=podman

• Creating a container

By far the easiest way to create a container-image from your Quarkus application is to leverage one of the container-image extensions.

If one of those extensions is present, then creating a container image for the native executable is essentially a matter of executing a single command:

./mvnw package -Pnative -Dquarkus.native.container-build=true -Dquarkus.container-image.build=true

quarkus.native.container-build=true allows for creating a Linux executable without GraalVM being installed (and is only necessary if you don’t have GraalVM installed locally or your local operating system is not Linux)

quarkus.native.container-build=true allows for creating a Linux executable without GraalVM being installed (and is only necessary if you don’t have GraalVM installed locally or your local operating system is not Linux)

Test native build

• Running native executable directly

./tomcat-operator-1.0.0-SNAPSHOT-runner