PodPreset

发布于 2020-07-18 字数11836 浏览 888 评论 0
PodPreset 用来给指定标签的 Pod 注入额外的信息，如环境变量、存储卷等。这样，Pod 模板就不需要为每个 Pod 都显式设置重复的信息。

API 版本对照表

开启 PodPreset

• 开启 API settings.k8s.io/v1alpha1/podpreset
• 开启准入控制 PodPreset

  PodPreset 示例

  增加环境变量和存储卷的 PodPreset

1. kind: PodPreset
2. apiVersion: settings.k8s.io/v1alpha1
3. metadata:
4. name: allow-database
5. namespace: myns
6. spec:
7. selector:
8. matchLabels:
9. role: frontend
10. env:
11. - name: DB_PORT
12. value: "6379"
13. volumeMounts:
14. - mountPath: /cache
15. name: cache-volume
16. volumes:
17. - name: cache-volume
18. emptyDir: {}

用户提交 Pod

1. apiVersion: v1
2. kind: Pod
3. metadata:
4. name: website
5. labels:
6. app: website
7. role: frontend
8. spec:
9. containers:
10. - name: website
11. image: ecorp/website
12. ports:
13. - containerPort: 80

经过准入控制 PodPreset 后，Pod 会自动增加环境变量和存储卷

1. apiVersion: v1
2. kind: Pod
3. metadata:
4. name: website
5. labels:
6. app: website
7. role: frontend
8. annotations:
9. podpreset.admission.kubernetes.io/allow-database: "resource version"
10. spec:
11. containers:
12. - name: website
13. image: ecorp/website
14. volumeMounts:
15. - mountPath: /cache
16. name: cache-volume
17. ports:
18. - containerPort: 80
19. env:
20. - name: DB_PORT
21. value: "6379"
22. volumes:
23. - name: cache-volume

24. emptyDir: {}

    ConfigMap 示例

    ConfigMap

25. apiVersion: v1

26. kind: ConfigMap
27. metadata:
28. name: etcd-env-config
29. data:
30. number_of_members: "1"
31. initial_cluster_state: new
32. initial_cluster_token: DUMMY_ETCD_INITIAL_CLUSTER_TOKEN
33. discovery_token: DUMMY_ETCD_DISCOVERY_TOKEN
34. discovery_url: http://etcd_discovery:2379
35. etcdctl_peers: http://etcd:2379
36. duplicate_key: FROM_CONFIG_MAP
37. REPLACE_ME: "a value"

PodPreset

1. kind: PodPreset
2. apiVersion: settings.k8s.io/v1alpha1
3. metadata:
4. name: allow-database
5. namespace: myns
6. spec:
7. selector:
8. matchLabels:
9. role: frontend
10. env:
11. - name: DB_PORT
12. value: 6379
13. - name: duplicate_key
14. value: FROM_ENV
15. - name: expansion
16. value: $(REPLACE_ME)
17. envFrom:
18. - configMapRef:
19. name: etcd-env-config
20. volumeMounts:
21. - mountPath: /cache
22. name: cache-volume
23. - mountPath: /etc/app/config.json
24. readOnly: **true**
25. name: secret-volume
26. volumes:
27. - name: cache-volume
28. emptyDir: {}
29. - name: secret-volume
30. secretName: config-details

用户提交的 Pod

1. apiVersion: v1
2. kind: Pod
3. metadata:
4. name: website
5. labels:
6. app: website
7. role: frontend
8. spec:
9. containers:
10. - name: website
11. image: ecorp/website
12. ports:
13. - containerPort: 80

经过准入控制 PodPreset 后，Pod 会自动增加 ConfigMap 环境变量

1. apiVersion: v1
2. kind: Pod
3. metadata:
4. name: website
5. labels:
6. app: website
7. role: frontend
8. annotations:
9. podpreset.admission.kubernetes.io/allow-database: "resource version"
10. spec:
11. containers:
12. - name: website
13. image: ecorp/website
14. volumeMounts:
15. - mountPath: /cache
16. name: cache-volume
17. - mountPath: /etc/app/config.json
18. readOnly: **true**
19. name: secret-volume
20. ports:
21. - containerPort: 80
22. env:
23. - name: DB_PORT
24. value: "6379"
25. - name: duplicate_key
26. value: FROM_ENV
27. - name: expansion
28. value: $(REPLACE_ME)
29. envFrom:
30. - configMapRef:
31. name: etcd-env-config
32. volumes:
33. - name: cache-volume
34. emptyDir: {}
35. - name: secret-volume
36. secretName: config-details