I have a very simple Spring Boot Helloworld application that displays Hello World! message using a REST API.
I would like to deploy that application on my Ubuntu node which has MicroK8s installed.
Steps Followed:
I am able to build that image using ./mvnw k8s:build command and can also see the image using docker images command but not able to deploy it on MicroK8s cluster using ./mvnw k8s:resource and ./mvnw k8s:deploy commands
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.3.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>helloworld</artifactId>
<version>0.0.2-SNAPSHOT</version>
<name>helloworld</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>11</java.version>
<spring-boot.build-image.imageName>chandeln/${project.artifactId}:${project.version}</spring-boot.build-image.imageName>
<jkube.generator.name>${spring-boot.build-image.imageName}</jkube.generator.name>
<docker.skip.tag>true</docker.skip.tag>
<jkube.enricher.jkube-service.type>NodePort</jkube.enricher.jkube-service.type>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.eclipse.jkube</groupId>
<artifactId>kubernetes-maven-plugin</artifactId>
<version>1.0.2</version>
</plugin>
</plugins>
</build>
</project>HelloworldController.java
@RestController
public class HelloworldController {
@GetMapping("/")
public String hello() {
return "Hello World!";
}
}
On my Ubuntu machine I have MicroK8s installed.
microk8s status --wait-ready
microk8s is running
high-availability: no
datastore master nodes: <my-ubuntu-machine-public-ip>:19001
datastore standby nodes: none
addons:
enabled:
dashboard # The Kubernetes dashboard
dns # CoreDNS
ha-cluster # Configure high availability on the current node
ingress # Ingress controller for external access
metrics-server # K8s Metrics Server for API access to service metrics
disabled:
ambassador # Ambassador API Gateway and Ingress
cilium # SDN, fast with full network policy
fluentd # Elasticsearch-Fluentd-Kibana logging and monitoring
gpu # Automatic enablement of Nvidia CUDA
helm # Helm 2 - the package manager for Kubernetes
helm3 # Helm 3 - Kubernetes package manager
host-access # Allow Pods connecting to Host services smoothly
istio # Core Istio service mesh services
jaeger # Kubernetes Jaeger operator with its simple config
knative # The Knative framework on Kubernetes.
kubeflow # Kubeflow for easy ML deployments
linkerd # Linkerd is a service mesh for Kubernetes and other frameworks
metallb # Loadbalancer for your Kubernetes cluster
multus # Multus CNI enables attaching multiple network interfaces to pods
prometheus # Prometheus operator for monitoring and logging
rbac # Role-Based Access Control for authorisation
registry # Private image registry exposed on localhost:32000
storage # Storage class; allocates storage from host directorykubectl cluster-info
Kubernetes master is running at https://127.0.0.1:16443
Metrics-server is running at https://127.0.0.1:16443/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy
CoreDNS is running at https://127.0.0.1:16443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxykubectl get all
NAME READY STATUS RESTARTS AGE
pod/microbot-5f5499d479-t2cdz 1/1 Running 1 31d
pod/microbot-5f5499d479-r6d57 1/1 Running 3 31d
pod/microbot-5f5499d479-7zztm 1/1 Running 3 31d
pod/nginx-6799fc88d8-9sf5j 1/1 Running 5 31d
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.152.183.1 <none> 443/TCP 31d
service/microbot-service NodePort 10.152.183.184 <none> 81:31587/TCP 31d
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/microbot 3/3 3 3 31d
deployment.apps/nginx 1/1 1 1 31d
NAME DESIRED CURRENT READY AGE
replicaset.apps/microbot-5f5499d479 3 3 3 31d
replicaset.apps/nginx-6799fc88d8 1 1 1 31d./mvnw k8s:build
Docker image built successfully. See below.
docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
chandeln/helloworld 0.0.2-SNAPSHOT dc061ea2b469 17 minutes ago 509MB
chandeln/helloworld latest dc061ea2b469 17 minutes ago 509MB./mvnw k8s:resource
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------------< com.example:helloworld >-----------------------
[INFO] Building helloworld 0.0.2-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- kubernetes-maven-plugin:1.0.2:resource (default-cli) @ helloworld ---
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] k8s: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc: Name or service not known
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[INFO] k8s: Running generator spring-boot
[INFO] k8s: spring-boot: Using Docker image quay.io/jkube/jkube-java-binary-s2i:0.0.8 as base / builder
[INFO] k8s: Using resource templates from /home/admin/apps/helloworld/src/main/jkube
[INFO] k8s: jkube-controller: Adding a default Deployment
[INFO] k8s: jkube-service: Adding a default service 'helloworld' with ports [8080]
[INFO] k8s: jkube-healthcheck-spring-boot: Adding readiness probe on port 8080, path='/actuator/health', scheme='HTTP', with initial delay 10 seconds
[INFO] k8s: jkube-healthcheck-spring-boot: Adding liveness probe on port 8080, path='/actuator/health', scheme='HTTP', with initial delay 180 seconds
[INFO] k8s: jkube-revision-history: Adding revision history limit to 2
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10.701 s
[INFO] Finished at: 2020-12-24T03:01:08Z
[INFO] ------------------------------------------------------------------------./mvnw k8s:deploy
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.3.3.RELEASE)
2020-12-24 03:18:13.492 INFO 1828768 --- [ main] c.e.h.HelloworldApplicationTests : Starting HelloworldApplicationTests on tools-server.kanaaritech.com with PID 1828768 (started by admin in /home/admin/apps/helloworld)
2020-12-24 03:18:13.494 INFO 1828768 --- [ main] c.e.h.HelloworldApplicationTests : The following profiles are active: tools
2020-12-24 03:18:24.499 INFO 1828768 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2020-12-24 03:18:27.959 INFO 1828768 --- [ main] o.s.b.a.e.web.EndpointLinksResolver : Exposing 2 endpoint(s) beneath base path '/actuator'
2020-12-24 03:18:28.684 INFO 1828768 --- [ main] c.e.h.HelloworldApplicationTests : Started HelloworldApplicationTests in 15.912 seconds (JVM running for 18.923)
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 20.012 s - in com.example.helloworld.HelloworldApplicationTests
2020-12-24 03:18:31.927 INFO 1828768 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO]
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ helloworld ---
[INFO] Building jar: /home/admin/apps/helloworld/target/helloworld-0.0.2-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:2.3.3.RELEASE:repackage (repackage) @ helloworld ---
[INFO] Replacing main artifact with repackaged archive
[INFO]
[INFO] --- maven-install-plugin:2.5.2:install (default-install) @ helloworld ---
[INFO] Installing /home/admin/apps/helloworld/target/helloworld-0.0.2-SNAPSHOT.jar to /home/admin/.m2/repository/com/example/helloworld/0.0.2-SNAPSHOT/helloworld-0.0.2-SNAPSHOT.jar
[INFO] Installing /home/admin/apps/helloworld/pom.xml to /home/admin/.m2/repository/com/example/helloworld/0.0.2-SNAPSHOT/helloworld-0.0.2-SNAPSHOT.pom
[INFO]
[INFO] <<< kubernetes-maven-plugin:1.0.2:deploy (default-cli) < install @ helloworld <<<
[INFO]
[INFO]
[INFO] --- kubernetes-maven-plugin:1.0.2:deploy (default-cli) @ helloworld ---
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] k8s: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc: Name or service not known
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] k8s: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[ERROR] k8s: Could not connect to kubernetes cluster!
[ERROR] k8s: Connection error: %s: java.net.UnknownHostException: kubernetes.default.svc
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 38.670 s
[INFO] Finished at: 2020-12-24T03:18:42Z
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.eclipse.jkube:kubernetes-maven-plugin:1.0.2:deploy (default-cli) on project helloworld: Execution default-cli of goal org.eclipse.jkube:kubernetes-maven-plugin:1.0.2:deploy failed: Could not connect to kubernetes cluster. Have you started a cluster via `mvn jkube:cluster-start` or connected to a remote cluster via `kubectl`? Error: java.net.UnknownHostException: kubernetes.default.svc: An error has occurred. Unknown host kubernetes.default.svc -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionExceptionInformation about Eclipse JKube (successor of Jib plugin) plugin can be found here.
MicroK8s has his own packaged version of kubectl that by default it's accessed through MicroK8s including its configuration.
microk8s kubectl
In order that JKube knows about your MicroK8s cluster you will need to export the configuration microk8s config and put it on your kubeconfig file ~/.kube/config
cd $HOME
mkdir .kube
cd .kube
microk8s config > config