k8s configmap 详解
一、概述
ConfigMap是k8s的一个配置管理组件，可以将配置以key-value的形式传递，通常用来保存不需要加密的配置信息，加密信息则需用到Secret，主要用来应对以下场景：
-
生成为容器内的环境变量；
-
设置容器启动命令的启动参数（需设置为环境变量）
-
以Volume的形式挂载为容器内部的文件或目录。
二、创建configmap
- 从普通文件创建
1: 创建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内容
[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:
Annotations:
Data
====
local.repo:
----
[local]
name=local repo from http
baseurl=http://192.168.10.162:7080
enabled=1
gpgcheck=0
BinaryData
====
Events:
- 从目录创建cm
1:创建对应的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:
Annotations:
Data
====
hello.txt:
----
hello
world.txt:
----
world
BinaryData
====
Events:
[root@node1 ~]#
- 自定义数据源
类似和从文件创建一样，多了一个key的定义
[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:
Annotations:
Data
====
test-cm-define:
----
[local]
name=local repo from http
baseurl=http://192.168.10.162:7080
enabled=1
gpgcheck=0
BinaryData
====
Events:
[root@node1 ~]#
- 从字符集创建
[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:
Annotations:
Data
====
edge:
----
30
name:
----
www
BinaryData
====
Events:
[root@node1 ~]#
- 从yaml创建
1：编辑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:
Annotations:
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:
[root@node1 ~]#
三、configmap应用
- 以volume形式挂载
1：编辑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：启动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：进入pod查看挂载内容
[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#
- 以环境变量的形式使用cm
1:创建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：启动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:/#
- 以启动参数传入
一下以nginx 为例
1：首选查看nginx镜像的启动参数
[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启动，编辑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：启动pod，查看启动日志
[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
nginx-cmd 1/1 Running 0 15s 10.233.96.36 node2
nginx-env 1/1 Running 0 70m 10.233.92.33 node3
[root@node1 ~]# curl 10.233.96.36
Welcome to nginx!
Welcome to nginx!
If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.
For online documentation and support please refer to
nginx.org.
Commercial support is available at
nginx.com.
Thank you for using nginx.
4：**创建cm，指定参数**
[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：编辑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：启动pod测试
[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
[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：测试业务正常
[root@node1 ~]# curl 10.233.90.20
Welcome to nginx!
Welcome to nginx!
If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.
For online documentation and support please refer to
nginx.org.
Commercial support is available at
nginx.com.
Thank you for using nginx.
- 使用某一个cm的key作为volume挂载
1:创建一个多个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：编辑yaml 使用此cm的某一个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 ###指定单独的key
path: loca.repo ###挂载路径
3：启动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#