Deploy on Kubernetes with Helm
Helm is a tool that helps define, install and upgrade complex applications on Kubernetes clusters.
In this post, we will use the Wildfly chart from https://github.com/wildfly/wildfly-charts/ to deploy a simple Wildfly application:
-
Create a simple Java application
-
Use the wildfly-maven-plugin’s
imagegoal to create a Docker image straight from Maven -
Push that image in a container registry (eg quay.io or ghcr.io)
-
Use Helm to deploy that image in a Kubernetes cluster (e.g. using kind)
Note: for the purpose of this article we will use 'kind' as a tool for running local Kubernetes cluster (see more about kind).
Prerequisites
Create a simple Java application
We will use the helloworld WildFly quickstart as an example:
$ git clone https://github.com/wildfly/quickstart
$ cd quickstart/helloworldInstall Helm and have access to a Kubernetes cluster.
Please refer to Installing Helm page to install Helm in your environment.
We will use kind as our Kubernetes cluster.
Install Helm Repository for WildFly Chart
The wildfly Chart can be installed from the https://docs.wildfly.org/wildfly-charts/ repository
$ helm repo add wildfly https://docs.wildfly.org/wildfly-charts/
"wildfly" has been added to your repositories
$ helm search repo wildfly
NAME CHART VERSION APP VERSION DESCRIPTION
wildfly/wildfly 2.3.1 Build and Deploy WildFly applications on OpenShift
wildfly/wildfly-common 2.1.0 A library chart for WildFly-based applicationsMake sure your application pom contains the wildfly-maven-plugin plugin
In our helloworld quickstart the wildfly-maven-plugin plugin is already present under the 'openshift' profile. Add it if you don’t have it in your pom.xml.
<profiles>
...
<profile>
<id>openshift</id>
<build>
<plugins>
<plugin>
<groupId>org.wildfly.plugins</groupId>
<artifactId>wildfly-maven-plugin</artifactId>
<version>${version.wildfly.maven.plugin}</version>
<configuration>
<feature-packs>
<feature-pack>
<location>org.wildfly:wildfly-galleon-pack:${version.server}</location>
</feature-pack>
<feature-pack>
<location>org.wildfly.cloud:wildfly-cloud-galleon-pack:${version.cloud.fp}</location>
</feature-pack>
</feature-packs>
<layers>
<layer>cloud-server</layer>
</layers>
<filename>${project.artifactId}-${project.version}.war</filename>
</configuration>
<executions>
<execution>
<goals>
<goal>package</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
...
</profiles>Build the docker image with the wildfly-maven-plugin plugin
Note: In this example we use 'docker', but 'podman' works as well.
$ mvn package wildfly:image -Popenshift
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------< org.wildfly.quickstarts:helloworld >-----------------
[INFO] Building Quickstart: helloworld 29.0.0.Alpha1-SNAPSHOT
[INFO] --------------------------------[ war ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ helloworld ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /home/msappegr/workspace/test/helloworld/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ helloworld ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 2 source files to /home/msappegr/workspace/test/helloworld/target/classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ helloworld ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ helloworld ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 2 source files to /home/msappegr/workspace/test/helloworld/target/test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ helloworld ---
[INFO]
[INFO] --- maven-war-plugin:3.2.3:war (default-war) @ helloworld ---
[INFO] Packaging webapp
[INFO] Assembling webapp [helloworld] in [/home/msappegr/workspace/test/helloworld/target/helloworld-29.0.0.Alpha1-SNAPSHOT]
[INFO] Processing war project
[INFO] Copying webapp resources [/home/msappegr/workspace/test/helloworld/src/main/webapp]
[INFO] Webapp assembled in [38 msecs]
[INFO] Building war: /home/msappegr/workspace/test/helloworld/target/helloworld-29.0.0.Alpha1-SNAPSHOT.war
[INFO]
[INFO] --- wildfly-maven-plugin:4.1.0.Final:package (default) @ helloworld ---
[INFO] Provisioning server in /home/msappegr/workspace/test/helloworld/target/server
[INFO] Resolving feature-packs
[INFO] Installing packages
[INFO] Resolving artifacts
[INFO] Generating configurations
Jul 07, 2023 5:10:53 PM org.wildfly.core.embedded.LoggerContext$JBossLoggingModuleLogger greeting
INFO: JBoss Modules version 2.1.0.Final
Jul 07, 2023 5:10:54 PM org.jboss.msc.service.ServiceContainerImpl <clinit>
INFO: JBoss MSC version 1.5.0.Final
Jul 07, 2023 5:10:54 PM org.jboss.threads.Version <clinit>
INFO: JBoss Threads version 2.4.0.Final
Jul 07, 2023 5:10:54 PM org.jboss.as.server.ApplicationServerService start
INFO: WFLYSRV0049: WildFly Full 28.0.1.Final (WildFly Core 20.0.2.Final) starting
Jul 07, 2023 5:10:54 PM org.jboss.as.patching.installation.InstallationManagerService start
INFO: WFLYPAT0050: WildFly Full cumulative patch ID is: base, one-off patches include: none
Jul 07, 2023 5:10:54 PM org.jboss.as.server.suspend.SuspendController resume
INFO: WFLYSRV0212: Resuming server
Jul 07, 2023 5:10:54 PM org.jboss.as.server.BootstrapListener printBootStatisticsMessage
INFO: WFLYSRV0025: WildFly Full 28.0.1.Final (WildFly Core 20.0.2.Final) started in 868ms - Started 29 of 32 services (3 services are lazy, passive or on-demand) - Server configuration file in use: standalone.xml
Jul 07, 2023 5:10:55 PM org.wildfly.security.Version <clinit>
INFO: ELY00001: WildFly Elytron version 2.1.0.Final
Jul 07, 2023 5:10:56 PM org.jboss.as.server.ApplicationServerService stop
INFO: WFLYSRV0050: WildFly Full 28.0.1.Final (WildFly Core 20.0.2.Final) stopped in 4ms
[INFO] Copy deployment /home/msappegr/workspace/test/helloworld/target/helloworld-29.0.0.Alpha1-SNAPSHOT.war to /home/msappegr/workspace/test/helloworld/target/server/standalone/deployments/helloworld-29.0.0.Alpha1-SNAPSHOT.war
[INFO]
[INFO] --- wildfly-maven-plugin:4.1.0.Final:image (default-cli) @ helloworld ---
[INFO] A server already exists in /home/msappegr/workspace/test/helloworld/target/server, skipping image of org.wildfly.quickstarts:helloworld
[INFO] Generating Dockerfile /home/msappegr/workspace/test/helloworld/target/Dockerfile from base image quay.io/wildfly/wildfly-runtime:latest
[INFO] Building application image helloworld:latest using docker.
[INFO] Executing the following command to build application image: 'docker build -t helloworld:latest .'
[INFO] #1 [internal] load build definition from Dockerfile
[INFO] #1 transferring dockerfile: 351B done
[INFO] #1 DONE 0.0s
[INFO]
[INFO] #2 [internal] load .dockerignore
[INFO] #2 transferring context: 2B done
[INFO] #2 DONE 0.0s
[INFO]
[INFO] #3 [internal] load metadata for quay.io/wildfly/wildfly-runtime:latest
[INFO] #3 DONE 0.7s
[INFO]
[INFO] #4 [1/4] FROM quay.io/wildfly/wildfly-runtime:latest@sha256:841dcb723e1dd55c86c5762a19f190967c7f5382c2b1896ab34e033091b2d1b1
[INFO] #4 DONE 0.0s
[INFO]
[INFO] #5 [internal] load build context
[INFO] #5 transferring context: 148.55MB 0.8s done
[INFO] #5 DONE 0.8s
[INFO]
[INFO] #4 [1/4] FROM quay.io/wildfly/wildfly-runtime:latest@sha256:841dcb723e1dd55c86c5762a19f190967c7f5382c2b1896ab34e033091b2d1b1
[INFO] #4 CACHED
[INFO]
[INFO] #6 [2/4] COPY --chown=jboss:root server /opt/server
[INFO] #6 DONE 0.5s
[INFO]
[INFO] #7 [3/4] RUN chmod -R ug+rwX /opt/server
[INFO] #7 DONE 2.0s
[INFO]
[INFO] #8 [4/4] COPY --chown=jboss:root helloworld-29.0.0.Alpha1-SNAPSHOT.war /opt/server/standalone/deployments/helloworld-29.0.0.Alpha1-SNAPSHOT.war
[INFO] #8 DONE 0.1s
[INFO]
[INFO] #9 exporting to image
[INFO] #9 exporting layers
[INFO] #9 exporting layers 0.8s done
[INFO] #9 writing image sha256:cb47ca7e7baccc74e877087f98659509e14d70c91030d0234245ffaa481f7cbc done
[INFO] #9 naming to docker.io/library/helloworld:latest done
[INFO] #9 DONE 0.8s
[INFO] Successfully built application image helloworld:latest
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 17.841 s
[INFO] Finished at: 2023-07-07T17:11:05+02:00
[INFO] ------------------------------------------------------------------------And then make sure you have it in your docker images
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
helloworld latest 6d404b584da2 32 seconds ago 686MBPush the just created image to a container registry (e.g. quay.io, ghcr.io or hub.docker.com)
In this article we will use Quay.io as a container registry. If you don’t have an account you can start a free trial on https://quay.io/ or create an account on dockerhub.
-
Login to your container registry (see how to get started here)
-
Tag the new image with the proper format 'quay.io/username/reponame'
Note: make sure to replace the 'username' (your account username) and the 'reponame' (your image name) accordingly!
If you use ghcr.io you have to change 'quay.io/username/reponame' with ghcr.io/NAMESPACE/IMAGE_NAME
If you use hub.docker.com you have to change 'quay.io/username/reponame' with username/image_name
$ docker login quay.io
$ docker tag helloworld quay.io/username/helloworldCheck that your image has been tagged:
$ docker images
helloworld latest 6d404b584da2 56 minutes ago 686MB
quay.io/username/helloworld latest 6d404b584da2 56 minutes ago 686MBPush the image in your registry:
$ docker push quay.io/username/helloworld
Using default tag: latest
The push refers to repository [quay.io/username/helloworld]
ad91a69a4efb: Pushed
f454069ae0d4: Pushed
b21a08aa50a4: Pushed
4fc9e93f9cc1: Pushed
55ea6d5a354e: Pushed
latest: digest: sha256:1d72e7b4f8dd75414a2b1dc8da3505906b0211ac6962e871b84f2c8ead43cb3a size: 1377Now your image is available in your container registry (in my case it is available at https://quay.io/repository/rh_ee_msappegr/helloworld)
Note: make sure your registry is public in order to pull it from the cluster. Otherwise you will need to create a docker-registry secret .
Create the YAML value file under the charts folder
In our example the charts folder already exists under quickstart/helloworld/charts, so move to that directory and create a file named values.yaml
$ cd charts
$ touch values.yamland paste the following inside the values.yaml
image:
name: quay.io/rh_ee_msappegr/helloworld # change it with the image you have just pushed
build:
enabled: false # The build part is not needed since we have already built our application with the wildfly-maven-plugin plugin
deploy:
route:
enabled: false # the route can be enabled, but only for OpenShift clustersDeploy the Application on Kubernetes
Once the wildfly Chart is added, we can install a Helm release by using the helm install command with the name of the release as well as a YAML configuration file that contains all the settings to build and deploy the application:
$ helm install helloworld-app \
wildfly/wildfly \
-f charts/values.yaml
NAME: helloworld-app
LAST DEPLOYED: Wed Jun 14 18:45:38 2023
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
To follow the deployment of your application, run:
$ kubectl get deployment helloworld-app -wAs you can read above, the output of the helm install command contains instructions to follow the installation of the application.
We can watch its deployment by running:
$ kubectl get deployment helloworld-app -w
NAME READY UP-TO-DATE AVAILABLE AGE
helloworld-app 1/1 1 1 30sThe application is now available and we can query it (you might need to wait some seconds to see our application up and running).
In order to reach your application from the browser you could port-forward port 8080 to your host:
$ kubectl port-forward $(oc get pod -l app.kubernetes.io/instance=helloworld-app -o name) 8080:8080
Forwarding from 127.0.0.1:8080 -> 8080
...Note: If your application has a different name you can retrieve your pod name by executing:
$ kubectl get pod
Then in the output you will see your pod name.
Using the 'pod name' execute:
$ kubectl port-forward your_pod_name 8080:8080
Now open your browser and browse URL 'localhost:8080', your application will respond: Hello World!
Alternately you can curl it from your terminal:
$ curl localhost:8080
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Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
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<!-- Plain HTML page that kicks us into the app -->
<html>
<head>
<meta http-equiv="Refresh" content="0; URL=HelloWorld">
</head>
</html>The application is up and running.
Conclusion
It is possible to run your application with very simple steps.
All that is necessary is to:
-
have the wildfly-maven-plugin plugin in your root pom
-
generate your image and to push it to your registry
-
install the helm chart
More about Helm Chart
More documentation about it can be found at wildfly Chart documentation.
More information
-
Helm - The package manager for Kubernetes
