29 名词解释 PodPreset

PodPreset

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。

开启PodPreset

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

示例

增加环境变量和存储卷的PodPreset

kind: PodPreset

apiVersion: settings.k8s.io/v1alpha1

metadata:

name: allow-database

namespace: myns

spec:

selector:

matchLabels:

role: frontend

env:

- name: DB_PORT

value: "6379"

volumeMounts:

- mountPath: /cache

name: cache-volume

volumes:

- name: cache-volume

emptyDir: {}

用户提交Pod

apiVersion: v1

kind: Pod

metadata:

name: website

labels:

app: website

role: frontend

spec:

containers:

- name: website

image: ecorp/website

ports:

- containerPort: 80

经过准入控制PodPreset后，Pod会自动增加环境变量和存储卷

apiVersion: v1

kind: Pod

metadata:

name: website

labels:

app: website

role: frontend

annotations:

podpreset.admission.kubernetes.io/allow-database: "resource version"

spec:

containers:

- name: website

image: ecorp/website

volumeMounts:

- mountPath: /cache

name: cache-volume

ports:

- containerPort: 80

env:

- name: DB_PORT

value: "6379"

volumes:

- name: cache-volume

emptyDir: {}

ConfigMap示例

ConfigMap

apiVersion: v1

kind: ConfigMap

metadata:

name: etcd-env-config

data:

number_of_members: "1"

initial_cluster_state: new

initial_cluster_token: DUMMY_ETCD_INITIAL_CLUSTER_TOKEN

discovery_token: DUMMY_ETCD_DISCOVERY_TOKEN

discovery_url: http://etcd_discovery:2379

etcdctl_peers: http://etcd:2379

duplicate_key: FROM_CONFIG_MAP

REPLACE_ME: "a value"

PodPreset

kind: PodPreset

apiVersion: settings.k8s.io/v1alpha1

metadata:

name: allow-database

namespace: myns

spec:

selector:

matchLabels:

role: frontend

env:

- name: DB_PORT

value: 6379

- name: duplicate_key

value: FROM_ENV

- name: expansion

value: $(REPLACE_ME)

envFrom:

- configMapRef:

name: etcd-env-config

volumeMounts:

- mountPath: /cache

name: cache-volume

- mountPath: /etc/app/config.json

readOnly: true

name: secret-volume

volumes:

- name: cache-volume

emptyDir: {}

- name: secret-volume

secretName: config-details

用户提交的Pod

apiVersion: v1

kind: Pod

metadata:

name: website

labels:

app: website

role: frontend

spec:

containers:

- name: website

image: ecorp/website

ports:

- containerPort: 80

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

apiVersion: v1

kind: Pod

metadata:

name: website

labels:

app: website

role: frontend

annotations:

podpreset.admission.kubernetes.io/allow-database: "resource version"

spec:

containers:

- name: website

image: ecorp/website

volumeMounts:

- mountPath: /cache

name: cache-volume

- mountPath: /etc/app/config.json

readOnly: true

name: secret-volume

ports:

- containerPort: 80

env:

- name: DB_PORT

value: "6379"

- name: duplicate_key

value: FROM_ENV

- name: expansion

value: $(REPLACE_ME)

envFrom:

- configMapRef:

name: etcd-env-config

volumes:

- name: cache-volume

emptyDir: {}

- name: secret-volume

secretName: config-details