Kubernetes resource object introduction and common commands (V) - (configmap)

One 、ConfitMap

config set , Extract application configuration .

ConfigMap Save in kubernetes Of etcd in .

ConfigMap Can be file Mount directly to Pod Inside , Different from the previous article PV&PVC mount Catalog .

establish ConfigMap

• Command line mode

[[email protected] ~]# vi redis.conf
[[email protected] ~]# cat redis.conf 
appendonly yes
[[email protected] ~]# kubectl create cm redis-conf --from-file=redis.conf
configmap/redis.conf created
[[email protected] ~]#

First of all, there is redis.conf file , Then make the document ConfigMap.

• yaml The way ,redis-conf.yml

apiVersion: v1
data:
  redis.conf: |
    appendonly yes
kind: ConfigMap
metadata:
  name: redis-conf
  namespace: default

data Is all the real data ,key： The default is file name ,value： Content of profile

[[email protected] ~]# kubectl apply -f redis-conf.yml 
configmap/redis-conf created
[[email protected] ~]#

see ConfigMap

[[email protected] ~]# kubectl get cm
NAME               DATA   AGE
kube-root-ca.crt   1      2d1h
redis-conf         1      53s
[[email protected] ~]# 

Expand ： see redis-conf Of yaml file

kubectl get cm redis-conf -oyaml

establish pod

redis.yml

apiVersion: v1
kind: Pod
metadata:
  name: redis
spec:
  containers:
  - name: redis
    image: redis
    command:
      - redis-server
      - "/redis-master/redis.conf"  # refer to redis Position inside the container 
    ports:
    - containerPort: 6379
    volumeMounts:
    - mountPath: /data
      name: data
    - mountPath: /redis-master
      name: config
  volumes:
    - name: data
      emptyDir: {}
    - name: config
      configMap:
        name: redis-conf
        items:
        - key: redis.conf
          path: redis.conf

explain ： One ConfigMap The file may have multiple configurations ,items Will traverse each configuration ,key Define which configuration to take here ,path Indicates which file in the container the content of the extracted configuration file is placed .

Refer to the diagram below ：

[[email protected] ~]# kubectl apply -f redis.yml 
pod/redis created 

#  Go inside the container to verify 
[[email protected] ~]# kubectl exec -it redis -c redis -- /bin/bash
[email protected]:/data# cd /redis-master/
[email protected]:/redis-master# ls
redis.conf
[email protected]:/redis-master# cat redis.conf 
appendonly yes
[email protected]:/redis-master#

modify ConfigMap

[[email protected] ~]# kubectl edit cm redis-conf
configmap/redis-conf edited
[[email protected] ~]#

Added a line of configuration requirepass 123456.

[[email protected] ~]# kubectl exec -it redis -c redis -- /bin/bash
[email protected]:/data# cd /redis-master/
[email protected]:/redis-master# ls
redis.conf
[email protected]:/redis-master# cat redis.conf 
appendonly yes
requirepass 123456
[email protected]:/redis-master# 

ConfigMap Automatically updated .

Key points ： The automatic update here is just the file following inside the container ConfigMap To change , But it may not really take effect , It mainly depends on whether the application has hot deployment capability , Applications without hot deployment capability need to be restarted to take effect .

Delete ConfigMap

kubectl delete cm redis-conf

Two 、Secret

Secret Object types are used to hold sensitive information , For example, password 、OAuth Token and SSH secret key . Put this information in secret Put the middle ratio in Pod The definition of or Container mirror More secure and flexible in .

establish Secret

#  Command format 
kubectl create secret docker-registry regcred \
  --docker-server=< Your mirror warehouse server > \
  --docker-username=< Your username > \
  --docker-password=< Your password > \
  --docker-email=< Your email address >

see Secret

[[email protected] ~]# kubectl get secret
NAME                  TYPE                                  DATA   AGE
default-token-ssmvn   kubernetes.io/service-account-token   3      2d2h
jiangnan              kubernetes.io/dockerconfigjson        1      2m6s
[[email protected] ~]# 

Delete Secret

[[email protected] ~]# kubectl delete secret jiangnan
secret "jiangnan" deleted
[[email protected] ~]#