Version: v1.0

使用 Sidecar

在本章节中，我们会展示如何使用 sidecar trait 来收集日志。

查看 Sidecar 的使用手册

  1. $ kubectl vela show sidecar
  2. # Properties
  3. +---------+-----------------------------------------+-----------------------+----------+---------+
  4. |  NAME   |               DESCRIPTION               |         TYPE          | REQUIRED | DEFAULT |
  5. +---------+-----------------------------------------+-----------------------+----------+---------+
  6. | name    | Specify the name of sidecar container   | string                | true     |         |
  7. | cmd     | Specify the commands run in the sidecar | []string              | false    |         |
  8. | image   | Specify the image of sidecar container  | string                | true     |         |
  9. | volumes | Specify the shared volume path          | [[]volumes](#volumes) | false    |         |
  10. +---------+-----------------------------------------+-----------------------+----------+---------+
  15. ## volumes
  16. +-----------+-------------+--------+----------+---------+
  17. |   NAME    | DESCRIPTION |  TYPE  | REQUIRED | DEFAULT |
  18. +-----------+-------------+--------+----------+---------+
  19. | name      |             | string | true     |         |
  20. | path      |             | string | true     |         |
  21. +-----------+-------------+--------+----------+---------+

安装应用

应用的组件 log-gen-worker 和 sidecar 共享相同的日志数据目录。sidecar 会重新输出日志到标准输出中。

  1. # app.yaml
  2. apiVersion: core.oam.dev/v1beta1
  3. kind: Application
  4. metadata:
  5.   name: vela-app-with-sidecar
  6. spec:
  7.   components:
  8.     - name: log-gen-worker
  9.       type: worker
  10.       properties:
  11.         image: busybox
  12.         cmd:
  13.           - /bin/sh
  14.           - -c
  15.           - >
  16.             i=0;
  17.             while true;
  18.             do
  19.               echo "$i: $(date)" >> /var/log/date.log;
  20.               i=$((i+1));
  21.               sleep 1;
  22.             done
  23.         volumes:
  24.           - name: varlog
  25.             mountPath: /var/log
  26.             type: emptyDir
  27.       traits:
  28.         - type: sidecar
  29.           properties:
  30.             name: count-log
  31.             image: busybox
  32.             cmd: [ /bin/sh, -c, 'tail -n+1 -f /var/log/date.log']
  33.             volumes:
  34.               - name: varlog
  35.                 path: /var/log

安装这个应用

  1. kubectl apply -f app.yaml

检查应用生成的 workload

  1. $ kubectl get pod
  2. NAME                              READY   STATUS    RESTARTS   AGE
  3. log-gen-worker-76945f458b-k7n9k   2/2     Running   0          90s

查看 sidecar 的输出

  1. $ kubectl logs -f log-gen-worker-76945f458b-k7n9k count-log
  2. 0: Fri Apr 16 11:08:45 UTC 2021
  3. 1: Fri Apr 16 11:08:46 UTC 2021
  4. 2: Fri Apr 16 11:08:47 UTC 2021
  5. 3: Fri Apr 16 11:08:48 UTC 2021
  6. 4: Fri Apr 16 11:08:49 UTC 2021
  7. 5: Fri Apr 16 11:08:50 UTC 2021
  8. 6: Fri Apr 16 11:08:51 UTC 2021
  9. 7: Fri Apr 16 11:08:52 UTC 2021
  10. 8: Fri Apr 16 11:08:53 UTC 2021
  11. 9: Fri Apr 16 11:08:54 UTC 2021