一.简单说明

我们在运行一个mysql服务时，mysql服务有两类重要的数据，一个是存储的数据、另一个是存储的配置文件。存储数据这里我们可以使用挂载PVC来实现持久化存储，配置文件这里我们如果实现和容器的解耦，可以采用configmap来实现。

二.ConfigMap介绍

2.1 ConfigMap作用和使用场景

ConfigMap用于保存配置数据，以键值对的形式存储

ConfigMap资源提供了向Pod注入配置数据的方法

ConfigMap旨在让镜像与配置文件解耦，以实现镜像的可移植性和可复用性。

填充环境变量的值

填充卷的配置文件

2.2 ConfigMap的创建

这里有以下几种创建方式：

使用字面值创建kubectl create configmap my-configmap --from-literal=key1=1 --from-literal=key2=2

[root@k8s001 ~]# kubectl get cm my-configmap -o yaml

apiVersion: v1

data:

key1: "1"

key2: "2"

kind: ConfigMap

metadata:

creationTimestamp: "2020-08-11T03:54:00Z"

name: my-configmap

namespace: default

resourceVersion: "4745970"

selfLink: /api/v1/namespaces/default/configmaps/my-configmap

uid: 4a277575-db86-11ea-bb5f-6c4b9005d934

使用文件创建[root@k8s001 ~]# cat configmap-file

10.10.2.2 k8s001

[root@k8s001 ~]# kubectl create cm my-configmap-file --from-file=configmap-file

configmap/my-configmap-file created

[root@k8s001 ~]# kubectl get cm my-configmap-file -o yaml

apiVersion: v1

data:

configmap-file: |

10.10.2.2 k8s001

kind: ConfigMap

metadata:

creationTimestamp: "2020-08-11T03:58:23Z"

name: my-configmap-file

namespace: default

resourceVersion: "4747102"

selfLink: /api/v1/namespaces/default/configmaps/my-configmap-file

uid: e6c966b8-db86-11ea-bb5f-6c4b9005d934

使用目录创建[root@k8s001 ~]# mkdir configmap-dir

[root@k8s001 ~]# cp configmap-file ./configmap-dir/

[root@k8s001 ~]# kubectl create cm myconfigmap-dir --from-file=configmap-dir

configmap/myconfigmap-dir created

[root@k8s001 ~]# kubectl get cm myconfigmap-dir -o yaml

apiVersion: v1

data:

configmap-file: |

10.10.2.2 k8s001

kind: ConfigMap

metadata:

creationTimestamp: "2020-08-11T04:01:51Z"

name: myconfigmap-dir

namespace: default

resourceVersion: "4748006"

selfLink: /api/v1/namespaces/default/configmaps/myconfigmap-dir

uid: 62fde3bb-db87-11ea-ab20-6c4b9005ca34

编写ConfigMap的yaml文件来创建[root@k8s001 ~]# cat configmap_mysql.yaml

apiVersion: v1

kind: ConfigMap

metadata:

name: mysql-config

namespace: business

data:

mysqld.cnf: |-

[mysqld]

pid-file= /var/run/mysqld/mysqld.pid

socket = /var/run/mysqld/mysqld.sock

datadir= /var/lib/mysql

symbolic-links = 0

max_allowed_packet = 50M

character_set_server = utf8

collation_server = utf8_general_ci

group_concat_max_len = 102400

[client]

default_character_set = utf8

2.3 如何使用ConfigMap

可以通过环境变量的形式直接传递给Pod

---

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

name: wf-mysql

spec:

containers:

- image: mysql:5.7

imagePullPolicy: IfNotPresent

name: mysql

env:

- name: MYSQL_ROOT_PASSWORD

valueFrom:

configMapKeyRef:

name: mysql-credentials

key: rootpw

- name: MYSQL_USER

valueFrom:

configMapKeyRef:

name: mysql-credentials

key: user

- name: MYSQL_PASSWORD

valueFrom:

configMapKeyRef:

name: mysql-credentials

key: password

通过在Pod的命令行下运行命令方式

[k8s001 ~]# cat busybox.yaml

---

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

name: wf-mysql

spec:

containers:

- image: busybox

imagePullPolicy: IfNotPresent

command: ["/bin/sh", "-c", "echo ${test_env}"]

name: busybox

envFrom:

- configMapRef:

name: configmap-test

restartPolicy: Always

作为volume的方式挂载到Pod内

---

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

name: wf-mysql

spec:

containers:

- image: mysql:5.7

imagePullPolicy: IfNotPresent

name: mysql

env:

- name: MYSQL_ROOT_PASSWORD

valueFrom:

secretKeyRef:

name: mysql-credentials

key: rootpw

- name: MYSQL_USER

valueFrom:

secretKeyRef:

name: mysql-credentials

key: user

- name: MYSQL_PASSWORD

valueFrom:

secretKeyRef:

name: mysql-credentials

key: password

ports:

- containerPort: 3306

name: mysql

volumeMounts:

- name: config-volume

mountPath: /etc/mysql/mysql.conf.d

volumes:

- name: config-volume

configMap:

name: mysql-config