Kubernetes集群部署有状态主从容器mysql5.7集群

0 前言

本文主要的工作是解决容器集群的有状态化的问题以及进行验证相关技术。

1 相关环境

名称	版本
Kubernetes	v1.18.6
RKE	1.1.4
网络插件	calico

2.拓扑图

Kubernetes集群部署有状态主从容器mysql5.7集群

3.创建测试ns

apiVersion: v1
kind: Namespace
metadata:
  name: mysql
  labels:
    app: mysql

4.创建Storgeclass

apiVersion: v1
kind: PersistentVolume
metadata:
  name: example-mysql-pv
spec:
  capacity:
    storage:  3Gi
  volumeMode: Filesystem
  accessModes:
  - ReadWriteOnce
  persistentVolumeReclaimPolicy: Delete
  storageClassName: local-storage
  local:
    path: /data/mysql/
  nodeAffinity:
    required:
      nodeSelectorTerms:
      - matchExpressions:
        - key: kubernetes.io/hostname
          operator: In
          values:
          - node(name)  #此处务必是节点名称，也就是kubectl get node获得的节点名称

5.创建ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  namespace: mysql
  labels:
    app: mysql
data:
  master.cnf: |
    # Master节点配置
    [mysqld]
    log-bin=mysqllog
    skip-name-resolve
  slave.cnf: |
    # Slave节点配置
    [mysqld]
    super-read-only
    skip-name-resolve
    log-bin=mysql-bin
    replicate-ignore-db=mysql

apiVersion: v1
kind: Secret
metadata:
  name: mysql-secret
  namespace: mysql
  labels:
    app: mysql
type: Opaque
data:
  password: aGVsbG93b3JsZA== # helloworld

6.部署无头服务

apiVersion: v1
kind: Service
metadata:
  name: mysql
  namespace: mysql
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  clusterIP: None
  selector:
    app: mysql

7. 部署有状态容器集群

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  namespace: mysql
  labels:
    app: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  serviceName: mysql
  replicas: 2
  template:
    metadata:
      labels:
        app: mysql
    spec:
      initContainers:
      - name: init-mysql
        image: mysql:5.7
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        command:
        - bash
        - "-c"
        - |
          set -ex
          # 从 Pod 的序号，生成 server-id
          [[ $(hostname) =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          echo [mysqld] > /mnt/conf.d/server-id.cnf
          # 由于 server-id 不能为 0，因此给 ID 加 100 来避开它
          echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf
          # 如果 Pod 的序号为 0，说明它是 Master 节点，从 ConfigMap 里把 Master 的配置文件拷贝到 /mnt/conf.d 目录下
          # 否则，拷贝 ConfigMap 里的 Slave 的配置文件
          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: gcr.io/google-samples/xtrabackup:1.0
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        command:
        - bash
        - "-c"
        - |
          set -ex
          # 拷贝操作只需要在第一次启动时进行，所以数据已经存在则跳过
          [[ -d /var/lib/mysql/mysql ]] && exit 0
          # Master 节点（序号为 0）不需要这个操作
          [[ $(hostname) =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          [[ $ordinal == 0 ]] && exit 0
          # 使用 ncat 指令，远程地从前一个节点拷贝数据到本地
          ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
          # 执行 --prepare，这样拷贝来的数据就可以用作恢复了
          xtrabackup --prepare --target-dir=/var/lib/mysql
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
      containers:
      - name: mysql
        image: mysql:5.7
        env:
#        - name: MYSQL_ALLOW_EMPTY_PASSWORD
#          value: "1"
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        ports:
        - name: mysql
          containerPort: 3306
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
        resources:
          requests:
            cpu: 500m
            memory: 1Gi
        livenessProbe:
          exec:
            command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
          initialDelaySeconds: 30
          periodSeconds: 10
          timeoutSeconds: 5
        readinessProbe:
          exec:
            command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
          initialDelaySeconds: 5
          periodSeconds: 2
          timeoutSeconds: 1
      - name: xtrabackup
        image: gcr.io/google-samples/xtrabackup:1.0
        ports:
        - name: xtrabackup
          containerPort: 3307
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-secret
              key: password
        command:
        - bash
        - "-c"
        - |
          set -ex
          cd /var/lib/mysql
          # 从备份信息文件里读取 MASTER_LOG_FILE 和 MASTER_LOG_POS 这 2 个字段的值，用来拼装集群初始化 SQL
          if [[ -f xtrabackup_slave_info ]]; then
            # 如果 xtrabackup_slave_info 文件存在，说明这个备份数据来自于另一个 Slave 节点
            # 这种情况下，XtraBackup 工具在备份的时候，就已经在这个文件里自动生成了 "CHANGE MASTER TO" SQL 语句
            # 所以，只需要把这个文件重命名为 change_master_to.sql.in，后面直接使用即可
            mv xtrabackup_slave_info change_master_to.sql.in
            # 所以，也就用不着 xtrabackup_binlog_info 了
            rm -f xtrabackup_binlog_info
          elif [[ -f xtrabackup_binlog_info ]]; then
            # 如果只是存在 xtrabackup_binlog_info 文件，说明备份来自于 Master 节点，就需要解析这个备份信息文件，读取所需的两个字段的值
            [[ $(cat xtrabackup_binlog_info) =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
            rm xtrabackup_binlog_info
            # 把两个字段的值拼装成 SQL，写入 change_master_to.sql.in 文件
            echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
                  MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
          fi
          # 如果存在 change_master_to.sql.in，就意味着需要做集群初始化工作
          if [[ -f change_master_to.sql.in ]]; then
            # 但一定要先等 MySQL 容器启动之后才能进行下一步连接 MySQL 的操作
            echo "Waiting for mysqld to be ready（accepting connections）"
            until mysql -h 127.0.0.1 -uroot -p${MYSQL_ROOT_PASSWORD} -e "SELECT 1"; do sleep 1; done
            echo "Initializing replication from clone position"
            # 将文件 change_master_to.sql.in 改个名字
            # 防止这个 Container 重启的时候，因为又找到了 change_master_to.sql.in，从而重复执行一遍初始化流程
            mv change_master_to.sql.in change_master_to.sql.orig
            # 使用 change_master_to.sql.orig 的内容，也就是前面拼装的 SQL，组成一个完整的初始化和启动 Slave 的 SQL 语句
            mysql -h 127.0.0.1 -uroot -p${MYSQL_ROOT_PASSWORD} << EOF
          $(< change_master_to.sql.orig),
            MASTER_HOST='mysql-0.mysql.mysql',
            MASTER_USER='root',
            MASTER_PASSWORD='${MYSQL_ROOT_PASSWORD}',
            MASTER_CONNECT_RETRY=10;
          START SLAVE;
          EOF
          fi
          # 使用 ncat 监听 3307 端口。
          # 它的作用是，在收到传输请求的时候，直接执行 xtrabackup --backup 命令，备份 MySQL 的数据并发送给请求者
          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 --password=${MYSQL_ROOT_PASSWORD}"
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
      volumes:
      - name: conf
        emptyDir: {}
      - name: config-map
        configMap:
          name: mysql
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes:
      - "ReadWriteOnce"
      storageClassName: local-storage
      resources:
        requests:
          storage: 3Gi

8 制作mycat-1.5.1镜像

#**注意：本地打的镜像，需要从本地复制jdk以及mycat文件，不要直接复制**
FROM centos:8

RUN mkdir -p /root/soft
RUN mkdir -p /usr/local/java
RUN mkdir -p /usr/local/mycat
COPY ./jdk1.8.0_261 /usr/local/java/
ENV JAVA_HOME /usr/local/java
ENV JRE_HOME ${JAVA_HOME}/jre
ENV CLASSPATH .:${JAVA_HOME}/lib:${JRE_HOME}/lib
ENV PATH ${JAVA_HOME}/bin:$PATH
COPY ./mycat /usr/local/mycat
RUN cd /usr/local/mycat/
RUN mv /usr/local/mycat/conf/schema.xml /usr/local/mycat/conf/schema.xml.backup
RUN mv /usr/local/mycat/conf/server.xml /usr/local/mycat/conf/server.xml.backup
COPY ./schema.xml /usr/local/mycat/conf/schema.xml
COPY ./server.xml /usr/local/mycat/conf/server.xml

9 运行mycat镜像

kubectl run mycat --image=mycat:1.5.1

来源：oschina

链接：https://my.oschina.net/u/4402060/blog/4535908

标签

Kubernetes

mycat

mysql

Calico