【Kubernetes】第二十二篇 - k8s 部署 MySQL 服务（secret、deployment、service）-Toy模板网

这篇具有很好参考价值的文章主要介绍了【Kubernetes】第二十二篇 - k8s 部署 MySQL 服务（secret、deployment、service）。希望对大家有所帮助。如果存在错误或未考虑完全的地方，请大家不吝赐教，您也可以点击"举报违法"按钮提交疑问。

一，前言

上一篇，介绍基于 k8s 项目部署流程设计；

本篇，介绍 MySQL 服务的部署；

二，部署 MySQL 服务

部署 MySQL

可以为指定 node 添加污点，专门用于 mysql 部署（当前只有一个节点，不考虑）；
为了保证mysql容器重启时数据不会丢失：创建 mysql 数据目录，用于存储 mysql 数据，实现 MySQL 数据的持久化；
创建 Secret 对象，向为 mysql 容器提供用户名、密码信息；
创建 mysql Deployment 配置文件，并创建 deploy 完成 pod 部署；
创建 mysql Service 配置文件，并创建 service 解决 ip 漂移问题，对外提供 pod 访问；
为 k8s-master 安装 mysql，使 k8s-master 能够使用 mysql 命令，测试数据库使用；

三，MySQL 数据的持久化

容器中的数据是需要保留的，否则容器重启就没了，需要创建数据目录，存储 MySQL 数据；

在本地创建 MySQL 数据文件夹，然后挂载到 MySQL 容器，实现 MySQL 数据的可以持久化

在 k8s-node 节点创建 MySQL 数据文件夹（此文件夹必须为空，否则导致 MySQL 启动失败；

// 创建数据目录文件夹（mysql 运行时的数据目录，约定好的）
[root@k8s-master ~]# mkdir /var/lib/mysql
[root@k8s-master ~]# ll /var/lib/mysql
总用量 0

创建一个新的文件夹：cicd

将所有的配置文件都放在这个cicd目录下

[root@k8s-master ~]# mkdir cicd
[root@k8s-master ~]# cd cicd/
[root@k8s-master cicd]#

四，创建 Secret 对象

通过 Secret 对象，将 MySQL 的用户名、密码传递到镜像中使用；

创建 Secret 对象：mysql-auth

// 创建 secret，generic：基于普通文本格式，--from-literal：从字面量创建
[root@k8s-master cicd]# kubectl create secret generic mysql-auth --from-literal=username=root --from-literal=password=123456
secret/mysql-auth created

[root@k8s-master cicd]# kubectl get secret mysql-auth
NAME                  TYPE                                  DATA   AGE
mysql-auth            Opaque                                2      17s

[root@k8s-master cicd]# kubectl get secret mysql-auth -o yaml
apiVersion: v1
data:
  password: MTIzNDU2
  username: cm9vdA==
kind: Secret
metadata:
  creationTimestamp: "2022-01-06T07:14:25Z"
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:
      f:data:
        .: {}
        f:password: {}
        f:username: {}
      f:type: {}
    manager: kubectl-create
    operation: Update
    time: "2022-01-06T07:14:25Z"
  name: mysql-auth
  namespace: default
  resourceVersion: "1934676"
  uid: c4a219d2-3754-4133-8484-9b4caa5a54cd
type: Opaque

[root@k8s-master cicd]# echo MTIzNDU2 | base64 -d
123456
[root@k8s-master cicd]# echo cm9vdA== | base64 -d
root

五，创建 Deployment

创建 mysql Deployment 配置文件，并创建 deploy 完成 pod 部署；

创建 deploy：deployment-cicd-mysql.yaml

[root@k8s-master cicd]# vi deployment-cicd-mysql.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: cicd-mysql
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cicd-mysql
  template:
    metadata:
      labels:
        app: cicd-mysql
    spec:
      containers:
      - name: cicd-mysql
        image: mysql:5.7
        imagePullPolicy: IfNotPresent #镜像拉取策略:如果不存在就拉取镜像
        args:
        - "--ignore-db-dir=lost+found"
        ports:
        - containerPort: 3306
        volumeMounts: #挂载数据卷
        - name: mysql-data
          mountPath: "/var/lib/mysql" #挂载到容器内的目录
        env: #环境变量
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-auth
              key: password #引用mysql-auth中的password值
      volumes: #数据卷
      - name: mysql-data
        hostPath: #宿主机路径
          path: /var/lib/mysql #宿主机的目录
          type: Directory 

备注：以下配置文档中有，但视频没用
      tolerations:
      - key: "mysql"
        operator: "Equal"
        value: "true"
        effect: "NoSchedule"

备注：

mysql 自带 root 用户，只设置 root 用户密码即可使用；

环境变量 env MYSQL_ROOT_PASSWORD 是在 mysql:5.7 的镜像中约定的；

mysql容器启动成功后，会读取到 MYSQL_ROOT_PASSWORD 并设置为密码；

如：docker run mysql:5.7 --env PASSWORD=123

生效配置

[root@k8s-master cicd]# kubectl apply -f deployment-cicd-mysql.yaml
deployment.apps/cicd-mysql created

[root@k8s-master cicd]# kubectl get pods
NAME                          READY   STATUS             RESTARTS   AGE
cicd-mysql-745975859b-kstnh   0/1     Pending            0          65s
pay-v1-6db6455b8-np2hw        1/1     Running            0          6h38m
user-v1-9f4d589cc-rdmnz       1/1     Running            0          24h
v4-57b4cf7fd9-zcl45           0/1     ImagePullBackOff   0          7d
v4-fb4cd75f5-bf2pf            0/1     ImagePullBackOff   0          2d17h

清理一下资源，删除 pay-v1、user-v1、v4 的 deploy

[root@k8s-master cicd]# kubectl delete deploy pay-v1 user-v1 v4
deployment.apps "pay-v1" deleted
deployment.apps "user-v1" deleted
deployment.apps "v4" deleted

[root@k8s-master cicd]# kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
cicd-mysql-745975859b-kstnh   0/1     Pending   0          4m8s

cicd-mysql-745975859b-kstnh 这个 pod 是 pending 状态

[root@k8s-master cicd]# kubectl describe pods cicd-mysql-745975859b-kstnh
Events:
  Type     Reason            Age                  From               Message
  ----     ------            ----                 ----               -------
  Warning  FailedScheduling  49s (x7 over 4m51s)  default-scheduler  0/2 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate, 1 node(s) had taint {pay-v1: true}, that the pod didn't tolerate.


kubectl logs cicd-mysql-6cbd4f95-g64hh

这是因为，k8s-node 服务器之前配置了 pay-v1: true，需要删除掉污点

// 查看污点
[root@k8s-master cicd]# kubectl describe node k8s-node
Taints:             pay-v1=true:NoSchedule

// 删除污点
[root@k8s-master cicd]# kubectl taint nodes k8s-node pay-v1-
node/k8s-node untainted

// 再次查看，没有污点了
[root@k8s-master cicd]# kubectl describe node k8s-node
Taints:             <none>

再看 pod 信息，已经在创建中了

[root@k8s-master cicd]# kubectl get pods
NAME                          READY   STATUS              RESTARTS   AGE
cicd-mysql-745975859b-kstnh   0/1     ContainerCreating   0          20m

但是有些问题，再看一下容器描述

[root@k8s-master cicd]# kubectl describe pods cicd-mysql-745975859b-kstnh
Events:
  Type     Reason            Age                    From               Message
  ----     ------            ----                   ----               -------
  Warning  FailedScheduling  6m58s (x20 over 24m)   default-scheduler  0/2 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate, 1 node(s) had taint {pay-v1: true}, that the pod didn't tolerate.
  Normal   Scheduled         6m36s                  default-scheduler  Successfully assigned default/cicd-mysql-745975859b-kstnh to k8s-node
  Warning  FailedMount       2m15s (x2 over 4m33s)  kubelet            Unable to attach or mount volumes: unmounted volumes=[mysql-data], unattached volumes=[mysql-data default-token-q4qxd]: timed out waiting for the condition
  Warning  FailedMount       24s (x11 over 6m35s)   kubelet            MountVolume.SetUp failed for volume "mysql-data" : hostPath type check failed: /var/lib/mysql is not a directory

原因是，pod 在 k8s-node 服务器上部署，但 k8s-node 服务器上并没有/var/lib/mysql目录

所以，需要在 k8s-node 服务器上创建/var/lib/mysql目录

[root@k8s-node ~]# mkdir /var/lib/mysql

删除 pod，再看新启动的 pod，已经正常 Running

（注意：1，不删除 pod 过一会儿也会正常 Running；2，删除 pod后，副本会重新创建）

[root@k8s-master deployment]# kubectl delete pod cicd-mysql-745975859b-kstnh
pod "cicd-mysql-745975859b-kstnh" deleted

[root@k8s-master deployment]# kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
cicd-mysql-745975859b-gpwzh   1/1     Running   0          10s

[root@k8s-master deployment]# kubectl describe pods cicd-mysql-745975859b-gpwzh
Events:
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Scheduled  29s   default-scheduler  Successfully assigned default/cicd-mysql-745975859b-gpwzh to k8s-node
  Normal  Pulled     25s   kubelet            Container image "mysql:5.7" already present on machine
  Normal  Created    25s   kubelet            Created container cicd-mysql
  Normal  Started    25s   kubelet            Started container cicd-mysql

查看日志：

[root@k8s-master deployment]# kubectl logs cicd-mysql-745975859b-gpwzh

2022-01-07T01:39:13.425378Z 0 [Note] mysqld: ready for connections.
Version: '5.7.36'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  MySQL Community Server (GPL)

mysql 已经启动成功，等待连接

六，k8s-master 安装 mysql 命令

为 k8s-master 安装 mysql，使 k8s-master 能够使用 mysql 命令，测试数据库使用；

由于 k8s-maste 没有安装 mysql 所以不能使用 mysql 命令

1，k8s-maste 安装 mysql

2，可以进入容器中操作

[root@k8s-master deployment]# kubectl exec -it cicd-mysql-745975859b-gpwzh -- bash
root@cicd-mysql-745975859b-gpwzh:/# mysql -uroot -p123456
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.01 sec)

mysql> show tables;
+----------------+
| Tables_in_cicd |
+----------------+
| users          |
+----------------+
1 row in set (0.00 sec)

mysql> select * from users;
Empty set (0.00 sec)

创建 cicd 数据库，创建表

mysql> create database cicd;
Query OK, 1 row affected (0.04 sec)

mysql> use cicd;
Database changed
mysql> CREATE TABLE `users` (
    ->   `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',
    ->   `name` varchar(255) NOT NULL COMMENT '',
    ->   `age` int(11) NOT NULL COMMENT '',
    ->   `sex` varchar(255) NOT NULL COMMENT '1 2',
    ->   PRIMARY KEY (`id`)
    -> ) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.03 sec)

退出 mysql，退出pod，回到 k8s-master

mysql> exit;
Bye

root@cicd-mysql-745975859b-gpwzh:/# exit
exit

给 k8s-master 安装 mysql：

// 下载MySQL源安装包
wget http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

// 安装MySQL源
yum -y install mysql57-community-release-el7-11.noarch.rpm

// 安装 mysql
yum install mysql-community-server -y

k8s-master 访问 MySQL

[root@k8s-master ~]# cat /etc/hosts
::1	localhost	localhost.localdomain	localhost6	localhost6.localdomain6
127.0.0.1	localhost	localhost.localdomain	localhost4	localhost4.localdomain4

172.17.178.106	k8s-node
172.17.178.105	k8s-master

[root@k8s-master cicd]# mysql -h172.17.178.105 -P3306 -uroot -p123456
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 2003 (HY000): Can't connect to MySQL server on '172.17.178.105' (111)

还不能访问，因为没有服务

七，创建 Service

由于 pod 的 ip 是会漂移的，需要通过 Service 访问 pod，需要创建服务

创建 service：service-cicd-mysql.yaml

[root@k8s-master cicd]# vi service-cicd-mysql.yaml

apiVersion: v1
kind: Service
metadata: #源数据
  name: service-cicd-mysql
spec: #规格
  selector: #选择器
    app: cicd-mysql #与deployment配置中的container-name相对应
  ports: #将pod的 3306端口代理到宿主机的3306端口
  - protocol: TCP
    port: 3306
    targetPort: 3306 #虚拟端口->真正的端口要看Service启动后实际分配的
    
  type: NodePort #不写就不能访问到pod

生效配置，服务启动

[root@k8s-master cicd]# kubectl apply -f service-cicd-mysql.yaml
service/service-cicd-mysql created

[root@k8s-master cicd]# kubectl get service
NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
kubernetes           ClusterIP   10.96.0.1       <none>        443/TCP          16d
service-cicd-mysql   NodePort    10.108.224.96   <none>        3306:30509/TCP   11s
service-pay-v1       NodePort    10.97.250.199   <none>        80:30114/TCP     2d19h
service-user-v1      NodePort    10.104.13.40    <none>        80:31071/TCP     14d

3306:30509 服务的内部端口/外部端口（外部访问 Service 中的 mysql 服务使用的端口号）

数据库端口：访问 Service 的 30509 端口

[root@k8s-master cicd]# mysql -h172.17.178.105 -P30509 -uroot -p123456
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> use cicd;
Database changed

mysql> show tables;
+----------------+
| Tables_in_cicd |
+----------------+
| users          |
+----------------+
1 row in set (0.00 sec)

mysql> exit;
Bye

数据库配置完成；