企业项目实战k8s篇（八）ConfigMap配置管理_将文件型configmap传递给pod的环境变量-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_42003848/article/details/119255709

本文详细介绍了Kubernetes中的ConfigMap资源，包括它的用途、创建方法（字面量、文件、目录、yaml文件）以及如何在Pod中通过环境变量、命令行参数和挂载为Volume来使用ConfigMap。ConfigMap主要用于存储配置数据，解耦配置文件与镜像，提高可移植性和可复用性。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

一.ConfigMap简介

Configmap用于保存配置数据，以键值对形式存储。

configMap 资源提供了向 Pod 注入配置数据的方法。

旨在让镜像和配置文件解耦，以便实现镜像的可移植性和可复用性。

典型的使用场景：

填充环境变量的值
设置容器内的命令行参数
填充卷的配置文件

二.ConfigMap创建

创建ConfigMap的方式有4种：

使用字面值创建
使用文件创建
使用目录创建
编写configmap的yaml文件创建

1.使用字面值创建

kubectl create configmap my-config --from-literal=key1=config1 --from-literal=key2=config2

[root@server1 ingress]# kubectl create configmap my-config --from-literal=key1=config1 --from-literal=key2=config2
configmap/my-config created
[root@server1 ingress]# kubectl  get cm
NAME               DATA   AGE
kube-root-ca.crt   1      5d18h
my-config          2      5s
[root@server1 ingress]# kubectl  describe  cm my-config 
Name:         my-config
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====

key1:
----

config1

key2:
----

config2
Events:  <none>

2.文件创建

kubectl create configmap my-config-2 --from-file=/etc/resolv.conf

[root@server1 ingress]#  kubectl create configmap my-config-2 --from-file=/etc/resolv.conf
configmap/my-config-2 created
[root@server1 ingress]# kubectl  get cm
NAME               DATA   AGE
kube-root-ca.crt   1      5d18h
my-config          2      98s
my-config-2        1      13s
[root@server1 ingress]# kubectl  describe  cm my-config-2 
Name:         my-config-2
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====

resolv.conf:
----

nameserver 114.114.114.114

Events:  <none>

3.使用目录创建

 kubectl create configmap my-config-3 --from-file=test

[root@server1 ~]# cd configmap/
[root@server1 configmap]# ls
[root@server1 configmap]# mkdir test
[root@server1 configmap]# cp /etc/passwd test/
[root@server1 configmap]# cp /etc/fstab  test/
[root@server1 configmap]# ls test/
fstab  passwd
[root@server1 configmap]# kubectl create configmap my-config-3 --from-file=test
configmap/my-config-3 created
[root@server1 configmap]# kubectl  get cm
NAME               DATA   AGE
kube-root-ca.crt   1      5d18h
my-config          2      3m33s
my-config-2        1      2m8s
my-config-3        2      10s
[root@server1 configmap]# kubectl  describe  cm my-config-3
Name:         my-config-3
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====

fstab:
----

#

# /etc/fstab

# Created by anaconda on Mon Jun 21 22:30:15 2021

#

# Accessible filesystems, by reference, are maintained under '/dev/disk'

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

#
/dev/mapper/rhel-root   /                       xfs     defaults        0 0
UUID=13a4a38f-65aa-49d3-adb5-a62bb3bc065a /boot                   xfs     defaults        0 0
#/dev/mapper/rhel-swap   swap                    swap    defaults        0 0

passwd:
----

root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:998:User for polkitd:/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
chrony:x:998:996::/var/lib/chrony:/sbin/nologin
rpc:x:32:32:Rpcbind Daemon:/var/lib/rpcbind:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin

Events:  <none>

4.编写configmap的yaml文件

[root@server1 configmap]# cat cm1.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: cm1-config
data:
  db_host: "172.25.3.250"
  db_port: "3306"

[root@server1 configmap]# kubectl  apply -f  cm1.yml 
configmap/cm1-config created
[root@server1 configmap]# kubectl  get cm
NAME               DATA   AGE
cm1-config         2      7s
kube-root-ca.crt   1      5d18h
my-config          2      5m54s
my-config-2        1      4m29s
my-config-3        2      2m31s
[root@server1 configmap]# kubectl  describe  cm cm1-config 
Name:         cm1-config
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====

db_port:
----

3306

db_host:
----

172.25.3.250
Events:  <none>

三.ConfigMap使用

如何使用configmap：

通过环境变量的方式直接传递给pod
通过在pod的命令行下运行的方式
作为volume的方式挂载到pod内

1.通过环境变量的方式直接传递给pod

指定key名称

[root@server1 configmap]# cat pod.yml 
apiVersion: v1
kind: Pod
metadata:
  name: pod1
spec:
  containers:
    - name: pod1
      image: busyboxplus
      command: ["/bin/sh", "-c", "env"]
      env:
        - name: key1
          valueFrom:
            configMapKeyRef:
              name: cm1-config
              key: db_host
        - name: key2
          valueFrom:
            configMapKeyRef:
              name: cm1-config
              key: db_port
  restartPolicy: Never


[root@server1 configmap]# kubectl  apply  -f pod.yml 
pod/pod1 configured
[root@server1 configmap]# kubectl  logs  pod1 
key1=172.25.3.250
key2=3306

使用默认名称

[root@server1 configmap]# cat pod2.yml 
apiVersion: v1
kind: Pod
metadata:
  name: pod2
spec:
  containers:
    - name: pod2
      image: busyboxplus
      command: ["/bin/sh", "-c", "env"]
      envFrom:
        - configMapRef:
            name: cm1-config
  restartPolicy: Never

[root@server1 configmap]# vim pod2.yml 
[root@server1 configmap]# kubectl  apply  -f pod2.yml 
pod/pod2 created
[root@server1 configmap]# kubectl  logs  pod2 
db_port=3306
db_host=172.25.3.250

2.通过在pod的命令行下运行的方式

[root@server1 configmap]# cat pod3.yml 
apiVersion: v1
kind: Pod
metadata:
  name: pod3
spec:
  containers:
    - name: pod3
      image: nginx
      #command: ["/bin/sh", "-c", "cat /config/db_host"]
      volumeMounts:
      - name: config-volume
        mountPath: /config
  volumes:
    - name: config-volume
      configMap:
        name: cm1-config
  #restartPolicy: Never

[root@server1 configmap]# vim pod3.yml
[root@server1 configmap]# kubectl  apply  -f pod3.yml 
pod/pod3 created
[root@server1 configmap]# kubectl  logs  pod3
172.25.3.250

3.作为volume的方式挂载到pod内

添加配置文件到cm

[root@server1 configmap]# vim nginx.conf
[root@server1 configmap]# kubectl create configmap nginxconf --from-file=nginx.conf
configmap/nginxconf created

[root@server1 configmap]# kubectl  get cm
NAME               DATA   AGE
cm1-config         2      28m
kube-root-ca.crt   1      5d18h
nginxconf          1      8s

cm文件内容

[root@server1 configmap]# cat nginx.yml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx
          volumeMounts:
          - name: config-volume
            mountPath: /etc/nginx/conf.d
      volumes:
        - name: config-volume
          configMap:
            name: nginxconf

创建pod，获取端口访问

[root@server1 configmap]# kubectl  apply  -f nginx.yml 
deployment.apps/my-nginx created
[root@server1 configmap]# kubectl  get pod
NAME                                READY   STATUS      RESTARTS   AGE
my-nginx-b9b58dbdf-9ww5n            1/1     Running     0          7s

[root@server1 configmap]# kubectl  get pod -o wide
NAME                                READY   STATUS      RESTARTS   AGE    IP              NODE      NOMINATED NODE   READINESS GATES
my-nginx-b9b58dbdf-9ww5n            1/1     Running     0          30s    10.244.179.81   server2   <none>           <none>

[root@server1 configmap]# curl 10.244.179.81
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>

编辑cm 访问端口8080，测试端口未切换

[root@server1 configmap]# kubectl  edit cm nginxconf 
configmap/nginxconf edited
[root@server1 configmap]# curl 10.244.179.81:8080
curl: (7) Failed connect to 10.244.179.81:8080; Connection refused
[root@server1 configmap]# curl 10.244.179.81
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>

执行热切命令，查看新ip访问，访问端口切换成功

[root@server1 configmap]# kubectl patch deployments.apps my-nginx --patch '{"spec": {"template": {"metadata": {"annotations": {"version/config": "20200219"}}}}}'
deployment.apps/my-nginx patched
[root@server1 configmap]# kubectl  get pod -o wide
NAME                                READY   STATUS        RESTARTS   AGE     IP              NODE      NOMINATED NODE   READINESS GATES
my-nginx-6b67dc79c9-zrbcz           1/1     Running       0          10s     10.244.22.17    server4   <none>           <none>
my-nginx-b9b58dbdf-9ww5n            0/1     Terminating   0          2m20s   10.244.179.81   server2   <none>           <none>

[root@server1 configmap]# curl 10.244.22.17 
curl: (7) Failed connect to 10.244.22.17:80; Connection refused
[root@server1 configmap]# curl 10.244.22.17:8080
[root@server1 configmap]# curl 10.244.22.17:8080
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    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 href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>