Kubernetes 部署 MySQL 集群
简介： 在有状态利用中，MySQL是咱们最常见也是最罕用的。本文咱们将实战部署一个一组多从的MySQL集群。
一、配置筹备
configMap
cat > mysql-configmap.yaml << EOF apiVersion: v1kind: ConfigMapmetadata: name: mysql labels: app: mysqldata: master.cnf: | # Apply this config only on the master. [mysqld] log-bin slave.cnf: | # Apply this config only on slaves. [mysqld] super-read-onlyEOFconfigMap能够将配置文件和镜像解耦开。
下面的配置意思是，创立一个master.cnf文件配置内容为：log-bin，即开启bin-log日志，供主节点应用。
创立一个slave.cnf文件配置内容为：super-read-only，设为该节点只读，供备用节点应用。
service
cat > mysql-services.yaml << EOF apiVersion: v1kind: Servicemetadata: name: mysql labels: app: mysqlspec: ports: - name: mysql port: 3306 clusterIP: None selector: app: mysql---# Client service for connecting to any MySQL instance for reads.# For writes, you must instead connect to the master: mysql-0.mysql.apiVersion: v1kind: Servicemetadata: name: mysql-read labels: app: mysqlspec: ports: - name: mysql port: 3306 selector: app: mysqlEOFStatefulSet
apiVersion: apps/v1kind: StatefulSetmetadata: name: mysqlspec: selector: matchLabels: app: mysql serviceName: mysql replicas: 3 template: metadata: labels: app: mysql spec: # 设置初始化容器，进行一些筹备工作 initContainers: - name: init-mysql image: mysql:5.7 # 为每个MySQL节点配置service-id # 如果节点序号是0，则应用master的配置， 其余节点应用slave的配置 command: - bash - "-c" - | set -ex # 基于 Pod 序号生成 MySQL 服务器的 ID。 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 ordinal=${BASH_REMATCH[1]} echo [mysqld] > /mnt/conf.d/server-id.cnf # 增加偏移量以防止应用 server-id=0 这一保留值。 echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf # Copy appropriate conf.d files from config-map to emptyDir. # 将适合的 conf.d 文件从 config-map 复制到 emptyDir。 if [[ $ordinal -eq 0 ]]; then cp /mnt/config-map/master.cnf /mnt/conf.d/ else cp /mnt/config-map/slave.cnf /mnt/conf.d/ fi volumeMounts: - name: conf mountPath: /mnt/conf.d - name: config-map mountPath: /mnt/config-map - name: clone-mysql image: registry.cn-hangzhou.aliyuncs.com/chenby/xtrabackup:1.0 # 为除了节点序号为0的主节点外的其它节点，备份前一个节点的数据 command: - bash - "-c" - | set -ex # 如果已有数据，则跳过克隆。 [[ -d /var/lib/mysql/mysql ]] && exit 0 # 跳过主实例（序号索引 0）的克隆。 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 ordinal=${BASH_REMATCH[1]} [[ $ordinal -eq 0 ]] && exit 0 # 从原来的对等节点克隆数据。 ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql # 筹备备份。 xtrabackup --prepare --target-dir=/var/lib/mysql volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d containers: - name: mysql image: mysql:5.7 # 设置反对免密登录 env: - name: MYSQL_ALLOW_EMPTY_PASSWORD value: "1" ports: - name: mysql containerPort: 3306 volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d resources: # 设置启动pod须要的资源，官网文档上须要500m cpu，1Gi memory。 # 我本地测试的时候，会因为资源有余，报1 Insufficient cpu, 1 Insufficient memory谬误，所以我改小了点 requests: # m是千分之一的意思，100m示意须要0.1个cpu cpu: 1024m # Mi是兆的意思，须要100M 内存 memory: 1Gi livenessProbe: # 应用mysqladmin ping命令，对MySQL节点进行探活检测 # 在节点部署完30秒后开始，每10秒检测一次，超时工夫为5秒 exec: command: ["mysqladmin", "ping"] initialDelaySeconds: 30 periodSeconds: 10 timeoutSeconds: 5 readinessProbe: # 对节点服务可用性进行检测， 启动5秒后开始，每2秒检测一次，超时工夫1秒 exec: # 查看咱们是否能够通过 TCP 执行查问（skip-networking 是敞开的）。 command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"] initialDelaySeconds: 5 periodSeconds: 2 timeoutSeconds: 1 - name: xtrabackup image: registry.cn-hangzhou.aliyuncs.com/chenby/xtrabackup:1.0 ports: - name: xtrabackup containerPort: 3307 # 开始进行备份文件校验、解析和开始同步 command: - bash - "-c" - | set -ex cd /var/lib/mysql # 确定克隆数据的 binlog 地位（如果有的话）。 if [[ -f xtrabackup_slave_info && "x$(<xtrabackup_slave_info)" != "x" ]]; then # XtraBackup 曾经生成了局部的 “CHANGE MASTER TO” 查问 # 因为咱们从一个现有正本进行克隆。(须要删除开端的分号!) cat xtrabackup_slave_info | sed -E 's/;$//g' > change_master_to.sql.in # 在这里要疏忽 xtrabackup_binlog_info （它是没用的）。 rm -f xtrabackup_slave_info xtrabackup_binlog_info elif [[ -f xtrabackup_binlog_info ]]; then # 咱们间接从主实例进行克隆。解析 binlog 地位。 [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1 rm -f xtrabackup_binlog_info xtrabackup_slave_info echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\ MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in fi # 查看咱们是否须要通过启动复制来实现克隆。 if [[ -f change_master_to.sql.in ]]; then echo "Waiting for mysqld to be ready (accepting connections)" until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done echo "Initializing replication from clone position" mysql -h 127.0.0.1 \ -e "$(<change_master_to.sql.in), \ MASTER_HOST='mysql-0.mysql', \ MASTER_USER='root', \ MASTER_PASSWORD='', \ MASTER_CONNECT_RETRY=10; \ START SLAVE;" || exit 1 # 如果容器重新启动，最多尝试一次。 mv change_master_to.sql.in change_master_to.sql.orig fi # 当对等点申请时，启动服务器发送备份。 exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c \ "xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root" volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d resources: requests: cpu: 100m memory: 100Mi volumes: - name: conf emptyDir: {} - name: config-map configMap: name: mysql # 设置PVC volumeClaimTemplates: - metadata: name: data annotations: # 配置PVC应用nfs动静供应 volume.beta.kubernetes.io/storage-class: nfs-storage spec: accessModes: ["ReadWriteOnce"] resources: requests: storage: 1Gi二、创立所需资源
# 创立configMapkubectl apply -f mysql-configmap.yaml # 创立servicekubectl apply -f mysql-services.yaml # 创立statefulSetkubectl apply -f mysql-statefulset.yaml# 查看创立过程kubectl get pods --watchmysql-0 0/2 Pending 0 0smysql-0 0/2 Pending 0 0smysql-0 0/2 Init:0/2 0 0smysql-0 0/2 Init:0/2 0 1smysql-0 0/2 Init:1/2 0 2smysql-0 0/2 PodInitializing 0 3smysql-0 1/2 Running 0 4smysql-0 2/2 Running 0 8smysql-1 0/2 Pending 0 0smysql-1 0/2 Pending 0 0smysql-1 0/2 Init:0/2 0 0smysql-1 0/2 Init:0/2 0 1smysql-1 0/2 Init:1/2 0 1smysql-1 0/2 PodInitializing 0 2smysql-1 1/2 Running 0 3smysql-1 2/2 Running 0 8smysql-2 0/2 Pending 0 0smysql-2 0/2 Pending 0 0smysql-2 0/2 Init:0/2 0 0smysql-2 0/2 Init:0/2 0 1smysql-2 0/2 Init:1/2 0 2smysql-2 0/2 PodInitializing 0 3smysql-2 1/2 Running 0 4smysql-2 2/2 Running 0 9s三、测试主库
进入pod进行操作
# 进入到pod mysql-0中，进行测试kubectl exec -it mysql-0 bash# 用mysql-client链接mysql-0mysql -h mysql-0Welcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 276Server version: 5.7.38-log MySQL Community Server (GPL)Copyright (c) 2000, 2022, Oracle and/or its affiliates.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql>创立库、表
# 创立数据库testmysql> create database cby;Query OK, 1 row affected (0.00 sec)# 应用test库mysql> use cby;Database changed# 创立message表mysql> create table message (message varchar(50));Query OK, 0 rows affected (0.01 sec)# 查看message表构造mysql> show create table message;+---------+------------------------------------------------------------------------------------------------------+| Table | Create Table |+---------+------------------------------------------------------------------------------------------------------+| message | CREATE TABLE `message` ( `message` varchar(50) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=latin1 |+---------+------------------------------------------------------------------------------------------------------+1 row in set (0.00 sec)插入数据
# 插入mysql> insert into message value("hello chenby");Query OK, 1 row affected (0.00 sec)# 查看mysql> select * from message;+---------------+| message |+---------------+| hello chenby |+---------------+1 row in set (0.00 sec)四、测试备库
连贯mysql-1
mysql -h mysql-1.mysqlWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 362Server version: 5.7.38 MySQL Community Server (GPL)Copyright (c) 2000, 2022, Oracle and/or its affiliates.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> mysql> 查看库、表构造
# 查看数据库列表mysql> show databases;+------------------------+| Database |+------------------------+| information_schema || cby || mysql || performance_schema || sys || test || xtrabackup_backupfiles |+------------------------+7 rows in set (0.01 sec)# 应用cby库mysql> use cby;Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -ADatabase changedmysql> # 查看表列表mysql> show tables;+---------------+| Tables_in_cby |+---------------+| message |+---------------+1 row in set (0.00 sec)# 查看message表构造mysql> show create table message;+---------+------------------------------------------------------------------------------------------------------+| Table | Create Table |+---------+------------------------------------------------------------------------------------------------------+| message | CREATE TABLE `message` ( `message` varchar(50) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=latin1 |+---------+------------------------------------------------------------------------------------------------------+1 row in set (0.00 sec)mysql> # 查问数据mysql> select * from message;+---------------+| message |+---------------+| hello chenby |+---------------+1 row in set (0.00 sec)mysql> # 写入数据mysql> insert into message values("hello world");ERROR 1290 (HY000): The MySQL server is running with the --super-read-only option so it cannot execute this statementmysql> # 这是因为mysql-1是一个只读备库，无奈进行写操作。五、测试mysql-read服务
循环中运行 SELECT @@server_id
kubectl run mysql-client-loop --image=mysql:5.7 -i -t --rm --restart=Never --\> bash -ic "while sleep 1; do mysql -h mysql-read -e 'SELECT @@server_id,NOW()'; done"If you don't see a command prompt, try pressing enter.+-------------+---------------------+| @@server_id | NOW() |+-------------+---------------------+| 102 | 2022-06-07 09:52:19 |+-------------+---------------------++-------------+---------------------+| @@server_id | NOW() |+-------------+---------------------+| 101 | 2022-06-07 09:52:20 |+-------------+---------------------++-------------+---------------------+| @@server_id | NOW() |+-------------+---------------------+| 100 | 2022-06-07 09:52:21 |+-------------+---------------------+六、扩缩容
# 扩容至5正本kubectl scale statefulset mysql --replicas=5# 查看扩容过程kubectl get pods --watchmysql-3 0/2 Pending 0 0smysql-3 0/2 Pending 0 1smysql-3 0/2 Pending 0 2smysql-3 0/2 Init:0/2 0 2smysql-3 0/2 Init:0/2 0 2smysql-3 0/2 Init:0/2 0 3smysql-3 0/2 Init:1/2 0 4smysql-3 0/2 Init:1/2 0 5smysql-3 0/2 PodInitializing 0 12smysql-3 1/2 Error 0 13smysql-3 1/2 Running 1 (2s ago) 14smysql-3 2/2 Running 1 (6s ago) 18smysql-4 0/2 Pending 0 0smysql-4 0/2 Pending 0 0smysql-4 0/2 Pending 0 2smysql-4 0/2 Init:0/2 0 2smysql-4 0/2 Init:0/2 0 2smysql-4 0/2 Init:1/2 0 3smysql-4 0/2 Init:1/2 0 4smysql-4 0/2 PodInitializing 0 12smysql-4 1/2 Error 0 13smysql-4 1/2 Running 1 (1s ago) 14smysql-4 2/2 Running 1 (7s ago) 20s# 缩容只2正本kubectl scale statefulset mysql --replicas=2# 查看缩容过程kubectl get pods --watchmysql-4 2/2 Terminating 1 (74s ago) 87smysql-4 2/2 Terminating 1 (104s ago) 117smysql-4 0/2 Terminating 1 118smysql-4 0/2 Terminating 1 118smysql-4 0/2 Terminating 1 118smysql-3 2/2 Terminating 1 (2m4s ago) 2m16smysql-3 2/2 Terminating 1 (2m34s ago) 2m46smysql-3 0/2 Terminating 1 2m47smysql-3 0/2 Terminating 1 2m47smysql-3 0/2 Terminating 1 2m47smysql-2 2/2 Terminating 0 16mmysql-2 2/2 Terminating 0 16mmysql-2 0/2 Terminating 0 16mmysql-2 0/2 Terminating 0 16mmysql-2 0/2 Terminating 0 16mhttps://www.oiox.cn/
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