如何在Kubernetes上运行高可用的WordPress和MySQL

# storage-class.yamlkind: StorageClassapiVersion: storage.k8s.io/v1metadata:
 name: slowprovisioner: kubernetes.io/gce-pdparameters:
 type: pd-standard  zone: us-central1-a

# mysql-configmap.yamlapiVersion: v1kind: ConfigMapmetadata:
 name: mysql  labels:
   app: mysqldata:
 master.cnf: |    # Apply this config only on the master.
   [mysqld]
   log-bin
   skip-host-cache
   skip-name-resolve  slave.cnf: |    # Apply this config only on slaves.
   [mysqld]
   skip-host-cache
   skip-name-resolve

# mysql-services.yaml# Headless service for stable DNS entries of StatefulSet members.apiVersion: v1kind: Servicemetadata:
 name: mysql  labels:
   app: mysqlspec:
 ports:
 - name: mysql    port: 3306  clusterIP: None  selector:
   app: mysql

apiVersion: apps/v1beta1kind: StatefulSetmetadata:
 name: mysqlspec:
 selector:
   matchLabels:
     app: mysql  serviceName: mysql  replicas: 3  template:
   metadata:
     labels:
       app: mysql    spec:
     initContainers:
     - name: init-mysql        image: mysql:5.7        command:
       - bash        - "-c"
       - |
         set -ex          # Generate mysql server-id from pod ordinal index.
         [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
         ordinal=${BASH_REMATCH[1]}
         echo [mysqld] > /mnt/conf.d/server-id.cnf          # Add an offset to avoid reserved server-id=0 value.
         echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf          # Copy appropriate conf.d files from config-map to emptyDir.
         if [[ $ordinal -eq 0 ]]; then
           cp /mnt/config-map/master.cnf /mnt/conf.d/
         else
           cp /mnt/config-map/slave.cnf /mnt/conf.d/
         fi        volumeMounts:
       - name: conf          mountPath: /mnt/conf.d        - name: config-map          mountPath: /mnt/config-map      - name: clone-mysql        image: gcr.io/google-samples/xtrabackup:1.0        command:
       - bash        - "-c"
       - |
         set -ex          # Skip the clone if data already exists.
         [[ -d /var/lib/mysql/mysql ]] && exit 0          # Skip the clone on master (ordinal index 0).
         [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
         ordinal=${BASH_REMATCH[1]}
         [[ $ordinal -eq 0 ]] && exit 0          # Clone data from previous peer.
         ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql          # Prepare the backup.
         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"
       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"]
         initialDelaySeconds: 30          periodSeconds: 10          timeoutSeconds: 5        readinessProbe:
         exec:
           # Check we can execute queries over TCP (skip-networking is off).
           command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
         initialDelaySeconds: 5          periodSeconds: 2          timeoutSeconds: 1      - name: xtrabackup        image: gcr.io/google-samples/xtrabackup:1.0        ports:
       - name: xtrabackup          containerPort: 3307        command:
       - bash        - "-c"
       - |
         set -ex
         cd /var/lib/mysql          # Determine binlog position of cloned data, if any.
         if [[ -f xtrabackup_slave_info ]]; then            # XtraBackup already generated a partial "CHANGE MASTER TO" query
           # because we're cloning from an existing slave.
           mv xtrabackup_slave_info change_master_to.sql.in            # Ignore xtrabackup_binlog_info in this case (it's useless).
           rm -f xtrabackup_binlog_info
         elif [[ -f xtrabackup_binlog_info ]]; then            # We're cloning directly from master. Parse binlog position.
           [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
           rm xtrabackup_binlog_info
           echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\                  MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
         fi          # Check if we need to complete a clone by starting replication.
         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"
           # In case of container restart, attempt this at-most-once.
           mv change_master_to.sql.in change_master_to.sql.orig
           mysql -h 127.0.0.1 <p>将该文件存为<code>mysql-statefulset.yaml</code>，输入<code>kubectl="" create="" -f="" mysql-statefulset.yaml</code>并让kubernetes部署你的数据库。<br>现在当你调用<code>$="" kubectl="" get="" pods</code>，你应该看到3个pods启动或者准备好，其中每个pod上都有两个容器。主节点pod表示为mysql-0，而附属的pods为<code>mysql-1</code>和<code>mysql-2</code>.让pods执行几分钟来确保<code>xtrabackup</code>服务在pod之间正确同步，然后进行wordpress的部署。<br>您可以检查单个容器的日志来确认没有错误消息抛出。 查看日志的命令为<code>$="" logs="" <container_name></container_name></code></p><p>主节点<code>xtrabackup</code>容器应显示来自附属的两个连接，并且日志中不应该出现任何错误。</p><h2>部署高可用的WordPress</h2><p>整个过程的最后一步是将我们的WordPress pods部署到集群上。为此我们希望为WordPress的服务和部署进行定义。</p><p>为了让WordPress实现高可用，我们希望每个容器运行时都是完全可替换的，这意味着我们可以终止一个，启动另一个而不需要对数据或服务可用性进行修改。我们也希望能够容忍至少一个容器的失误，有一个冗余的容器负责处理slack。</p><p>WordPress将重要的站点相关数据存储在应用程序目录<code>/var/www/html</code>中。对于要为同一站点提供服务的两个WordPress实例，该文件夹必须包含相同的数据。</p><p>当运行高可用WordPress时，我们需要在实例之间共享<code>/var/www/html</code>文件夹，因此我们定义一个NGS服务作为这些卷的挂载点。<br>下面是设置NFS服务的配置，我提供了纯英文的版本：</p><p><img src="https://img.php.cn/upload/image/456/243/673/1623137239811988.png" title="1623137239811988.png" alt="93d34768a751e24a088b12f9a1ed2f8.png"></p><p><img src="https://img.php.cn/upload/image/229/961/277/1623137243449231.png" title="1623137243449231.png" alt="e86e43b49585c73b08fed132723b229.png"></p><p><img src="https://img.php.cn/upload/image/737/299/982/1623137248223155.png" title="1623137248223155.png" alt="e2d53a02b91c92817532f6d2879e9eb.png"></p><p><img src="https://img.php.cn/upload/image/282/959/213/1623137253150095.png" title="1623137253150095.png" alt="c2ff0b7d440911bfac020374d97b228.png"></p><p>使用指令<code>$ kubectl create -f nfs.yaml</code>部署NFS服务。现在，我们需要运行<code>$ kubectl describe services nfs-server</code>获得IP地址，这在后面会用到。</p><p>注意：将来，我们可以使用服务名称讲这些绑定在一起，但现在你需要对IP地址进行硬编码。</p><pre class="brush:php;toolbar:false"># wordpress.yamlapiVersion: v1kind: Servicemetadata:
 name: wordpress  labels:
   app: wordpressspec:
 ports:
   - port: 80  selector:
   app: wordpress    tier: frontend  type: LoadBalancer---apiVersion: v1kind: PersistentVolumemetadata:
 name: nfsspec:
 capacity:
   storage: 20G  accessModes:
   - ReadWriteMany  nfs:
   # FIXME: use the right IP
   server: <ip>    path: "/"---apiVersion: v1kind: PersistentVolumeClaimmetadata:
 name: nfsspec:
 accessModes:
   - ReadWriteMany  storageClassName: ""
 resources:
   requests:
     storage: 20G---apiVersion: apps/v1beta1 # for versions before 1.8.0 use apps/v1beta1kind: Deploymentmetadata:
 name: wordpress  labels:
   app: wordpressspec:
 selector:
   matchLabels:
     app: wordpress      tier: frontend  strategy:
   type: Recreate  template:
   metadata:
     labels:
       app: wordpress        tier: frontend    spec:
     containers:
     - image: wordpress:4.9-apache        name: wordpress        env:
       - name: WORDPRESS_DB_HOST          value: mysql        - name: WORDPRESS_DB_PASSWORD          value: ""
       ports:
       - containerPort: 80          name: wordpress        volumeMounts:
       - name: wordpress-persistent-storage          mountPath: /var/www/html      volumes:
     - name: wordpress-persistent-storage        persistentVolumeClaim:
           claimName: nfs</ip>