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2024 iThome 鐵人賽
DAY 15
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Kubernetes

當 Quarkus 想要騎乘駱駝並用8腳章魚掌控舵手 系列 第 15 篇

Quarkus 實現 Hot-reload 之 Downward API 與 RBAC - 續

16th鐵人賽 kubernetes camel quarkus java
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本篇主要學習目標是讓 Quarkus 的 Pod 透過 ServiceAccount 的 token 對 Kubernetes API 進行交互。

部署上一章節 YAML 檔案。

kubectl apply -f kubernetes/ServiceAccount.yaml
kubectl apply -f kubernetes/Deployment.yaml

查看部署結果

$ kubectl get all
NAME                                READY   STATUS    RESTARTS   AGE
pod/ithomerbaclab-f967c6ccc-5v9h8   0/1     Running   0          7s

NAME                       TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
service/kubernetes         ClusterIP   10.43.0.1      <none>        443/TCP   13d
service/gracefulshutdown   ClusterIP   10.43.100.69   <none>        80/TCP    6d13h
service/ithomerbaclab      ClusterIP   10.43.186.70   <none>        80/TCP    7s

NAME                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/ithomerbaclab   0/1     1            0           7s

NAME                                      DESIRED   CURRENT   READY   AGE
replicaset.apps/ithomerbaclab-f967c6ccc   1         1         0       7s

查看 ServiceAccount 是否建立。

$ kubectl get sa
NAME            SECRETS   AGE
default         0         12d
ithomerbaclab   0         107s

最重要的令牌

$ kubectl get secrets ithomerbaclab-token 
NAME                  TYPE                                  DATA   AGE
ithomerbaclab-token   kubernetes.io/service-account-token   3      2m29s
$ kubectl describe secrets ithomerbaclab-token 
Name:         ithomerbaclab-token
Namespace:    default
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: ithomerbaclab
              kubernetes.io/service-account.uid: 20469ebb-d0f3-4733-9ed4-1ca0b8980151

Type:  kubernetes.io/service-account-token

Data
====
token:      ...
ca.crt:     570 bytes
namespace:  7 bytes

對於 Quarkus 範例，有撰寫一隻 API GET /hello。

@Path("/hello")
public class HelloResource {

    @ConfigProperty(name = "greeting.message") 
    String message;

    @GET
    public String hello() {
        return message;
    }
}

測試該 API

$ kubectl port-forward services/ithomerbaclab 9090:80
$ curl http://localhost:9090/hello
ithome123

假設一個需求來了，需要變換環境變數。將 greeting.message 變成 "ithome-Day14"。

apiVersion: v1
kind: ConfigMap
metadata:
  name: ithomerbaclab
  namespace: default
data:
  application.yaml: |
    watch:
      dir:
        path: /home/jboss/config
    greeting:
      message: "ithome-Day14"
    k8s: 
      kubernetes:
        deployment:
          name: ${DEPLOYMENT_NAME}
        namespace: ${KUBERNETES_NAMESPACE}
        trust-certs: true
        api-server: "https://kubernetes.default.svc"
        token: ...
    quarkus:
      config:
        locations: /home/jboss/config/application.yaml

此時可以變更 YAML 重新佈署 ConfigMap 資源或是 kubectl edit 方式進行異動。接著從日誌就看到說其偵測到檔案變化後

File event: CREATE occurred on file ..2024_09_07_02_54_22.1199477851 at 1725677662483

，就進行重啟 Deployment 動作。

2024-09-07 02:54:23,075 INFO  [restart-replica] (Camel (camel-1) thread #2 - CamelFileWatchPoll) upgrade replica: ithomerbaclab

2024-09-07 02:54:23,089 INFO  [ith.cch.ser.KubernetesService] (Camel (camel-1) thread #2 - CamelFileWatchPoll) rollout deployment

$ kubectl logs -f ithomerbaclab-f967c6ccc-5v9h8
...
__  ____  __  _____   ___  __ ____  ______
 --/ __ \/ / / / _ | / _ \/ //_/ / / / __/
 -/ /_/ / /_/ / __ |/ , _/ ,< / /_/ /\ \
--\___\_\____/_/ |_/_/|_/_/|_|\____/___/
2024-09-07 02:52:59,594 INFO  [org.apa.cam.qua.cor.CamelBootstrapRecorder] (main) Apache Camel Quarkus 3.14.0 is starting
2024-09-07 02:52:59,595 INFO  [org.apa.cam.mai.MainSupport] (main) Apache Camel (Main) 4.7.0 is starting
2024-09-07 02:52:59,682 INFO  [org.apa.cam.sup.LifecycleStrategySupport] (main) Autowired property: kubernetesClient on component: kubernetes-deployments as exactly one instance of type: io.fabric8.kubernetes.client.KubernetesClient (io.fabric8.kubernetes.client.impl.KubernetesClientImpl) found in the registry
2024-09-07 02:52:59,689 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 4.7.0 (camel-1) is starting
2024-09-07 02:52:59,700 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Routes startup (total:3)
2024-09-07 02:52:59,700 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started route1 (direct://trigger)
2024-09-07 02:52:59,700 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started Watch File (file-watch:///home/jboss/config)
2024-09-07 02:52:59,701 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started restart-replica (direct://restart-replica)
2024-09-07 02:52:59,701 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 4.7.0 (camel-1) started in 11ms (build:0ms init:0ms start:11ms)
2024-09-07 02:52:59,754 INFO  [io.quarkus] (main) ithomerbaclab 1.0.0-SNAPSHOT on JVM (powered by Quarkus 3.14.1) started in 1.085s. Listening on: http://0.0.0.0:8080
2024-09-07 02:52:59,754 INFO  [io.quarkus] (main) Profile prod activated.
2024-09-07 02:52:59,754 INFO  [io.quarkus] (main) Installed features: [camel-bean, camel-core, camel-direct, camel-file-watch, camel-kubernetes, camel-log, camel-timer, cdi, config-yaml, kubernetes, kubernetes-client, rest, rest-jackson, smallrye-context-propagation, smallrye-health, vertx]
2024-09-07 02:54:22,488 INFO  [Watch File] (Camel (camel-1) thread #2 - CamelFileWatchPoll) File event: CREATE occurred on file ..2024_09_07_02_54_22.1199477851 at 1725677662483
2024-09-07 02:54:22,996 INFO  [restart-replica] (Camel (camel-1) thread #2 - CamelFileWatchPoll) upgrade replica: ithomerbaclab

2024-09-07 02:54:23,066 INFO  [ith.cch.ser.KubernetesService] (Camel (camel-1) thread #2 - CamelFileWatchPoll) rollout deployment
2024-09-07 02:54:23,067 INFO  [Watch File] (Camel (camel-1) thread #2 - CamelFileWatchPoll) File event: MODIFY occurred on file application.yaml at 1725677662484
2024-09-07 02:54:23,075 INFO  [restart-replica] (Camel (camel-1) thread #2 - CamelFileWatchPoll) upgrade replica: ithomerbaclab

2024-09-07 02:54:23,089 INFO  [ith.cch.ser.KubernetesService] (Camel (camel-1) thread #2 - CamelFileWatchPoll) rollout deployment
2024-09-07 02:54:43,515 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (Shutdown thread) Apache Camel 4.7.0 (camel-1) is shutting down (timeout:45s)
2024-09-07 02:54:43,519 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (Shutdown thread) Routes stopped (total:3)
2024-09-07 02:54:43,519 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (Shutdown thread)     Stopped restart-replica (direct://restart-replica)
2024-09-07 02:54:43,519 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (Shutdown thread)     Stopped Watch File (file-watch:///home/jboss/config)
2024-09-07 02:54:43,520 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (Shutdown thread)     Stopped route1 (direct://trigger)
2024-09-07 02:54:43,521 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (Shutdown thread) Apache Camel 4.7.0 (camel-1) shutdown in 6ms (uptime:1m43s)
2024-09-07 02:54:43,535 INFO  [io.quarkus] (Shutdown thread) ithomerbaclab stopped in 0.024s

從以下可以看到說，ReplicaSet 換了一個。ithomerbaclab-f967c6ccc 變成 ithomerbaclab-7bf85657bc。

$ kubectl get all
NAME                                 READY   STATUS    RESTARTS   AGE
pod/ithomerbaclab-7bf85657bc-fg9lw   1/1     Running   0          2m41s

NAME                       TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
service/kubernetes         ClusterIP   10.43.0.1      <none>        443/TCP   13d
service/gracefulshutdown   ClusterIP   10.43.100.69   <none>        80/TCP    6d13h
service/ithomerbaclab      ClusterIP   10.43.186.70   <none>        80/TCP    4m8s

NAME                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/ithomerbaclab   1/1     1            1           4m8s

NAME                                       DESIRED   CURRENT   READY   AGE
replicaset.apps/ithomerbaclab-7fb57c8457   0         0         0       2m41s
replicaset.apps/ithomerbaclab-7bf85657bc   1         1         1       2m41s
replicaset.apps/ithomerbaclab-f967c6ccc    0         0         0       4m8s

因此最後配置也隨之變化，透過 API 可以看到回復訊息。

$ curl http://localhost:9090/hello
ithome-Day14

總體來說，hot-reload 是可以自行實現，不過本範例還沒到很完整。考慮部屬多個 Quarkus 應用程式，如果都收到會重複觸發，而這又是另外要設計的場景。

如果 roleBinding 綁定權限不足會發生以下錯誤訊息，即 403 forbidden。


Caused by: io.fabric8.kubernetes.client.KubernetesClientException: Failure executing: GET at: https://kubernetes.default.svc/apis/apps/v1/namespaces/default/deployments/ithomerbaclab. Message: deployments.apps "ithomerbaclab" is forbidden: User "system:serviceaccount:default:ithomerbaclab" cannot get resource "deployments" in API group "apps" in the namespace "default". Received status: Status(apiVersion=v1, code=403, details=StatusDetails(causes=[], group=apps, kind=deployments, name=ithomerbaclab, retryAfterSeconds=null, uid=null, additionalProperties={}), kind=Status, message=deployments.apps "ithomerbaclab" is forbidden: User "system:serviceaccount:default:ithomerbaclab" cannot get resource "deployments" in API group "apps" in the namespace "default", metadata=ListMeta(_continue=null, remainingItemCount=null, resourceVer

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Quarkus 實現 Hot-reload 之 Downward API 與 RBAC
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當 Quarkus 想要騎乘駱駝並用8腳章魚掌控舵手 共 31 篇
  1. 27
    Argo CD - Application in any namespace
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    Argo CD - notification
  3. 29
    Argo rollouts - blue/green
  4. 30
    Argo CD - Git strategies
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