無法使用 jkube 插件在 MicroK8s 集群上部署 Spring Boot Helloworld 應用程序

Question

我有一個非常簡單的Spring Boot Helloworld 應用程序，它顯示Hello World! 使用REST API的消息。

我想在安裝了MicroK8s的Ubuntu節點上部署該應用程序。

遵循的步驟：

1. git 克隆project_repo_url_here
2. 使用./mvnw k8s:build構建鏡像
3. 使用./mvnw k8s:resource應用資源
4. 使用./mvnw k8s:deploy部署應用程序

我可以使用./mvnw k8s:build命令構建該映像，還可以使用docker images命令查看該映像，但無法使用./mvnw k8s:resource和./mvnw k8s:deploy命令將其部署在MicroK8s集群上

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!";
    }

}

在我的Ubuntu機器上，我安裝了MicroK8s 。

microk8s 狀態——等待就緒

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 directory

kubectl 集群信息

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/proxy

kubectl 得到所有

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:構建

Docker 鏡像構建成功。 見下文。

docker 圖片

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:資源

[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:部署

 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: 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/PluginExecutionException

關於 Eclipse JKube（Jib 插件的繼任者）插件的信息可以在這里找到。

https://www.eclipse.org/jkube/docs/kubernetes-maven-plugin

Answer 1

MicroK8s有他自己的kubectl打包版本，默認情況下它是通過MicroK8s訪問的，包括它的配置。

microk8s kubectl

為了讓JKube了解您的MicroK8s集群，您需要導出配置microk8s config並將其放在您的 kubeconfig 文件~/.kube/config

cd $HOME
mkdir .kube
cd .kube
microk8s config > config

參考： https://microk8s.io/docs/working-with-kubectl