一、概述

ConfigMap是k8s的一個(gè)配置管理組件，可以將配置以key-value的形式傳遞，通常用來(lái)保存不需要加密的配置信息，加密信息則需用到Secret，主要用來(lái)應(yīng)對(duì)以下場(chǎng)景：

• 生成為容器內(nèi)的環(huán)境變量；

• 設(shè)置容器啟動(dòng)命令的啟動(dòng)參數(shù)（需設(shè)置為環(huán)境變量）

• 以Volume的形式掛載為容器內(nèi)部的文件或目錄。文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-494011.html

二、創(chuàng)建configmap

• 從普通文件創(chuàng)建

1: 創(chuàng)建configmap
[root@node1 ~]# 
[root@node1 ~]# kubectl create ns configmap
namespace/configmap created
[root@node1 ~]# 
[root@node1 ~]# kubectl create cm test-config --from-file=/root/local.repo -n configmap
configmap/test-config created

2：查看configmap內(nèi)容
[root@node1 ~]# kubectl get cm -n configmap
NAME               DATA   AGE
kube-root-ca.crt   1      41s
test-config        1      39s
[root@node1 ~]# kubectl describe  cm test-config -n configmap
Name:         test-config
Namespace:    configmap
Labels:       <none>
Annotations:  <none>

Data
====
local.repo:
----
[local]
name=local repo from http
baseurl=http://192.168.10.162:7080
enabled=1
gpgcheck=0



BinaryData
====

Events:  <none>

• 從目錄創(chuàng)建cm

1:創(chuàng)建對(duì)應(yīng)的cm信息
[root@node1 ~]# mkdir config
[root@node1 ~]# echo hello > config/hello.txt
[root@node1 ~]# echo world > config/world.txt
[root@node1 ~]# 
[root@node1 ~]# kubectl create cm test-config-dir --from-file=/root/config -n configmap
configmap/test-config-dir created
[root@node1 ~]# 

2：查看cm
[root@node1 ~]# kubectl get cm -n configmap
NAME               DATA   AGE
kube-root-ca.crt   1      3m58s
test-config        1      3m56s
test-config-dir    2      66s
[root@node1 ~]# 
[root@node1 ~]# kubectl describe  cm test-config-dir -n configmap
Name:         test-config-dir
Namespace:    configmap
Labels:       <none>
Annotations:  <none>

Data
====
hello.txt:
----
hello

world.txt:
----
world


BinaryData
====

Events:  <none>
[root@node1 ~]# 

• 自定義數(shù)據(jù)源

類(lèi)似和從文件創(chuàng)建一樣，多了一個(gè)key的定義
[root@node1 ~]# kubectl create configmap cm-data --from-file=test-cm-define=/etc/yum.repos.d/local.repo  -n configmap
configmap/cm-data created
[root@node1 ~]# 
[root@node1 ~]# kubectl get cm -n configmap
NAME               DATA   AGE
cm-data            1      31s
kube-root-ca.crt   1      14m
test-config        1      14m
test-config-dir    2      11m
[root@node1 ~]# kubectl describe  cm cm-data -n configmap
Name:         cm-data
Namespace:    configmap
Labels:       <none>
Annotations:  <none>

Data
====
test-cm-define:
----
[local]
name=local repo from http
baseurl=http://192.168.10.162:7080
enabled=1
gpgcheck=0



BinaryData
====

Events:  <none>
[root@node1 ~]# 

• 從字符集創(chuàng)建

[root@node1 ~]# kubectl create cm test-cm-zifu --from-literal=name=www --from-literal=edge=30 -n configmap
configmap/test-cm-zifu created
[root@node1 ~]# kubectl get cm -n configmap
NAME               DATA   AGE
cm-data            1      4m43s
kube-root-ca.crt   1      18m
test-cm-zifu       2      2s
test-config        1      18m
test-config-dir    2      16m
[root@node1 ~]# kubectl describe  cm test-cm-zifu -n configmap
Name:         test-cm-zifu
Namespace:    configmap
Labels:       <none>
Annotations:  <none>

Data
====
edge:
----
30
name:
----
www

BinaryData
====

Events:  <none>
[root@node1 ~]# 

• 從yaml創(chuàng)建

1：編輯yaml文件

---
apiVersion: v1
data:
  customization.cnf: |-
    [mysqld]
    datadir = /mariadb_data
    lower_case_table_names = 1
    sql-mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
    character-set-server=utf8
    [client]
    default-character-set=utf8
kind: ConfigMap
metadata:
  name: mysql-config
  namespace: configmap
  
[root@node1 ~]# kubectl apply -f  configmap.yaml 
configmap/mysql-config created
[root@node1 ~]# kubectl get cm -n configmap
NAME               DATA   AGE
cm-data            1      9m24s
kube-root-ca.crt   1      23m
mysql-config       1      2s
test-cm-zifu       2      4m43s
test-config        1      23m
test-config-dir    2      20m
[root@node1 ~]# kubectl describe  cm mysql-config -n configmap
Name:         mysql-config
Namespace:    configmap
Labels:       <none>
Annotations:  <none>

Data
====
customization.cnf:
----
[mysqld]
datadir = /mariadb_data
lower_case_table_names = 1
sql-mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
character-set-server=utf8
[client]
default-character-set=utf8

BinaryData
====

Events:  <none>
[root@node1 ~]# 

三、configmap應(yīng)用

• 以volume形式掛載

1：編輯podyaml文件
---
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  namespace: configmap                                                                                                                                                     
spec:
  containers:
  - name: nginx
    image: docker.io/library/nginx:latest
    imagePullPolicy: IfNotPresent
    volumeMounts:
    - name:  mysql-config
      mountPath: /etc/config
  volumes:
  - name: mysql-config
    configMap:
      name: mysql-config

2：?jiǎn)?dòng)pod
[root@node1 ~]# kubectl apply -f  pod.yaml 
pod/nginx created
[root@node1 ~]# kubectl get po -n configmap
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          7s

3：進(jìn)入pod查看掛載內(nèi)容
[root@node1 ~]# kubectl exec -it nginx bash -n configmap
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@nginx:/# cd etc/config/
root@nginx:/etc/config# ls
customization.cnf
root@nginx:/etc/config# cat customization.cnf 
[mysqld]
datadir = /mariadb_data
lower_case_table_names = 1
sql-mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
character-set-server=utf8
[client]
default-character-set=utf8root@nginx:/etc/config# 

• 以環(huán)境變量的形式使用cm

1:創(chuàng)建cm
[root@node1 ~]# kubectl create cm cm-zifu --from-literal=testname=www --from-literal=testedge=30 -n configmap
configmap/cm-zifu created

2：pod使用
---        
apiVersion: v1
kind: Pod  
metadata:  
  name: nginx-env
  namespace: configmap
spec:      
  containers:
  - name: nginx
    image: docker.io/library/nginx:latest
    imagePullPolicy: IfNotPresent
    env:   
    - name: testname
      valueFrom:
        configMapKeyRef:
          name: cm-zifu                                                                                                                                                    
          key: testname
    - name: testedge
      valueFrom:
        configMapKeyRef:
          name: cm-zifu
          key: testedge
          
 3：?jiǎn)?dòng)pod，查看env         
[root@node1 ~]# kubectl apply -f  pod.yaml 
pod/nginx-env created
[root@node1 ~]# kubectl get po -n configmap
NAME        READY   STATUS    RESTARTS   AGE
nginx       1/1     Running   0          16m
nginx-env   1/1     Running   0          5s
[root@node1 ~]# kubectl exec -it nginx-env bash -n configmap
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@nginx-env:/# env  | grep test
testedge=30
testname=www
root@nginx-env:/# 

• 以啟動(dòng)參數(shù)傳入

一下以nginx 為例
1：首選查看nginx鏡像的啟動(dòng)參數(shù)
[root@node1 ~]# crictl   inspecti docker.io/library/nginx:latest |more
        "Entrypoint": [
          "/docker-entrypoint.sh"
        ],
        "Cmd": [
          "nginx",
          "-g",
          "daemon off;"
        ],

2：先以正常的pod啟動(dòng)，編輯yaml文件
---  
apiVersion: v1
kind: Pod
metadata:
  name: nginx-cmd
  namespace: configmap
spec:
  containers:
  - name: nginx
    image: docker.io/library/nginx:latest
    imagePullPolicy: IfNotPresent
    command: ["/docker-entrypoint.sh"]
    args: ["nginx", "-g", "daemon off;"]
    
3：?jiǎn)?dòng)pod，查看啟動(dòng)日志
[root@node1 ~]# kubectl apply -f  pod.yaml 
pod/nginx-cmd created
[root@node1 ~]# 
[root@node1 ~]# 
[root@node1 ~]# kubectl logs nginx-cmd -n configmap
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2023/06/19 08:14:36 [notice] 1#1: using the "epoll" event method
2023/06/19 08:14:36 [notice] 1#1: nginx/1.21.6
2023/06/19 08:14:36 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2023/06/19 08:14:36 [notice] 1#1: OS: Linux 3.10.0-1160.6.1.el7.x86_64
2023/06/19 08:14:36 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/06/19 08:14:36 [notice] 1#1: start worker processes
2023/06/19 08:14:36 [notice] 1#1: start worker process 32
2023/06/19 08:14:36 [notice] 1#1: start worker process 33
2023/06/19 08:14:36 [notice] 1#1: start worker process 34
2023/06/19 08:14:36 [notice] 1#1: start worker process 35

[root@node1 ~]# kubectl get po -n configmap  -o wide 
NAME        READY   STATUS    RESTARTS   AGE   IP             NODE    NOMINATED NODE   READINESS GATES
nginx       1/1     Running   0          87m   10.233.96.28   node2   <none>           <none>
nginx-cmd   1/1     Running   0          15s   10.233.96.36   node2   <none>           <none>
nginx-env   1/1     Running   0          70m   10.233.92.33   node3   <none>           <none>
[root@node1 ~]# curl 10.233.96.36
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a >nginx.org</a>.<br/>
Commercial support is available at
<a >nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

4：**創(chuàng)建cm，指定參數(shù)**
[root@node1 ~]# kubectl create configmap nginx-cmd --from-literal=daemon="daemon off"  -n configmap
configmap/nginx-cmd created
[root@node1 ~]# kubectl get cm/nginx-cmd  -n configmap 
NAME        DATA   AGE
nginx-cmd   1      18s

5：編輯pod使用cm
---  
apiVersion: v1
kind: Pod
metadata:
  name: nginx-cmd
  namespace: configmap
spec:
  containers:
  - name: nginx
    image: docker.io/library/nginx:latest
    imagePullPolicy: IfNotPresent
    command: ["/docker-entrypoint.sh"]
    args: ["nginx", "-g", "$(daemon-cmd);"]                                                                                                                                
    env:
    - name: daemon-cmd
      valueFrom:
        configMapKeyRef:
          name:  nginx-cmd
          key: daemon
          
6：?jiǎn)?dòng)pod測(cè)試
[root@node1 ~]# kubectl apply -f  pod.yaml 
pod/nginx-cmd created
[root@node1 ~]# kubectl get po -n configmap -owide 
NAME        READY   STATUS    RESTARTS   AGE    IP             NODE    NOMINATED NODE   READINESS GATES
nginx-cmd   1/1     Running   0          2m5s   10.233.90.20   node1   <none>           <none>

[root@node1 ~]# kubectl logs nginx-cmd -n configmap
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2023/06/19 08:24:04 [notice] 1#1: using the "epoll" event method
2023/06/19 08:24:04 [notice] 1#1: nginx/1.21.6
2023/06/19 08:24:04 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6) 
2023/06/19 08:24:04 [notice] 1#1: OS: Linux 3.10.0-1160.6.1.el7.x86_64
2023/06/19 08:24:04 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/06/19 08:24:04 [notice] 1#1: start worker processes
2023/06/19 08:24:04 [notice] 1#1: start worker process 31
2023/06/19 08:24:04 [notice] 1#1: start worker process 32
2023/06/19 08:24:04 [notice] 1#1: start worker process 33
2023/06/19 08:24:04 [notice] 1#1: start worker process 34

7：測(cè)試業(yè)務(wù)正常
[root@node1 ~]# curl 10.233.90.20
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a >nginx.org</a>.<br/>
Commercial support is available at
<a >nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

• 使用某一個(gè)cm的key作為volume掛載

1:創(chuàng)建一個(gè)多個(gè)from-file的cm
kubectl create configmap multi-file --from-file=test-cm-define=/etc/yum.repos.d/local.repo --from-file=/root/cert.pem --from-file=/root/dashboard.yaml  -n configmap

2：編輯yaml 使用此cm的某一個(gè)key
---
apiVersion: v1
kind: Pod
metadata:
  name: nginx-key
  namespace: configmap
spec:
  containers:
  - name: nginx
    image: docker.io/library/nginx:latest
    imagePullPolicy: IfNotPresent
    volumeMounts:
    - name: localrepo
      mountPath: /etc/yum.repos.d
  volumes:
  - name: localrepo
    configMap:
      name: multi-file
      items:
      - key: test-cm-define     ###指定單獨(dú)的key
        path: loca.repo         ###掛載路徑
        
3：?jiǎn)?dòng)pod,查看
[root@node1 ~]# kubectl apply -f   pod-key.yaml 
pod/nginx-key created
[root@node1 ~]# kubectl exec -it  nginx-key  bash -n configmap
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@nginx-key:/# cd etc/yum.repos.d/
root@nginx-key:/etc/yum.repos.d# 
root@nginx-key:/etc/yum.repos.d# ls
loca.repo
root@nginx-key:/etc/yum.repos.d#

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