kubernetes集群实战——Volumes配置管理(StatefulSet控制器应用)

1.StorageClass功能属性

StorageClass提供了一种描述存储类（class）的方法，不同的class可能会映射到不同的服务质量等级和备份策略或其他策略等。

每个 StorageClass 都包含 provisioner、parameters 和 reclaimPolicy 字段， 这些字段会在StorageClass需要动态分配 PersistentVolume 时会使用到。

StorageClass的属性
Provisioner（存储分配器）：用来决定使用哪个卷插件分配 PV，该字段必须指定。可以指定内部分配器，也可以指定外部分配器。外部分配器的代码地址为： kubernetes-incubator/external-storage，其中包括NFS和Ceph等。
Reclaim Policy（回收策略）：通过reclaimPolicy字段指定创建的Persistent Volume的回收策略，
回收策略包括：Delete 或者 Retain，没有指定默认为Delete。
更多属性查看：https://kubernetes.io/zh/docs/concepts/storage/storage-classes/

2.配置NFS Client Provisioner

NFS Client Provisioner是一个automatic provisioner，使用NFS作为存储，自动创建PV和对应的PVC，本身不提供NFS存储，需要外部先有一套NFS存储服务。

PV以 ${namespace}-${pvcName}-${pvName}的命名格式提供（在NFS服务器上）
PV回收的时候以 archieved-${namespace}-${pvcName}-${pvName} 的命名格式（在NFS服务器上）

nfs-client-provisioner源码地址：
https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client

• 动态卷存储方式

[root@server1 ~]# vim /etc/exports
[root@server1 ~]# cat /etc/exports
/nfsdata    *(rw,sync,no_root_squash)
[root@server1 ~]# exportfs -rv
exporting *:/nfsdata
[root@server1 ~]# showmount -e
Export list for server1:
/nfsdata *
[root@server1 ~]# 

NFS动态分配PV示例：
配置授权

[root@server2 vol]# mkdir nfs-client
[root@server2 vol]# cd nfs-client/
[root@server2 nfs-client]# vim rbac.yml	##基于角色的权限控制，在集群当中作授权
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
---
kind: ClusterRole	##集群角色
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-provisioner-runner
rules:
  - apiGroups: [""]
    resources: ["persistentvolumes"]
    verbs: ["get", "list", "watch", "create", "delete"]
  - apiGroups: [""]
    resources: ["persistentvolumeclaims"]
    verbs: ["get", "list", "watch", "update"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses"]
    verbs: ["get", "list", "watch"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["create", "update", "patch"]
---
kind: ClusterRoleBinding	##集群角色绑定
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: nfs-client-provisioner
roleRef:
  kind: ClusterRole
  name: nfs-client-provisioner-runner
  apiGroup: rbac.authorization.k8s.io
---
kind: Role	##角色
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
rules:
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding	##角色绑定
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: nfs-client-provisioner
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io

部署NFS Client Provisioner

[root@server2 nfs-client]# vim deployment.yml	####删除重复的选择器字段
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-client-provisioner
  labels:
    app: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-client-provisioner
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-client-provisioner
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: nfs-client-provisioner:latest	##下载此镜像并上传到仓库
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: westos.org/nfs	##定义一个分配器的名字，做一个标识
            - name: NFS_SERVER
              value: 172.25.12.1	##定义nfs server
            - name: NFS_PATH
              value: /nfsdata	##nfs输出路径
      volumes:
        - name: nfs-client-root
          nfs:
            server: 172.25.12.1
            path: /nfsdata

创建 NFS SotageClass

[root@server2 nfs-client]# vim class.yml	##创建存储类
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: westos.org/nfs
  archiveOnDelete: "false"	##控制存储在回收时要不要打包，false表示不打包

创建PVC

[root@server2 nfs-client]# vim pvc.yml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1
  annotations:
    volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi

创建测试Pod

[root@server2 nfs-client]# vim pod.yml
kind: Pod
apiVersion: v1
metadata:
  name: test-pod
spec:
  containers:
  - name: test-pod
    image: busybox:1.27
    command:
      - "/bin/sh"
    args:
      - "-c"
      - "touch /mnt/SUCCESS && exit 0 || exit 1"
    volumeMounts:
      - name: nfs-pvc
        mountPath: "/mnt"
  restartPolicy: "Never"
  volumes:
    - name: nfs-pvc
      persistentVolumeClaim:
        claimName: pvc1

上传实验所需镜像到仓库



应用yaml文件



删除pod，不会影响到pvc


编辑存储类yaml文件，false改为true


删除pvc后会打包（archived标识）

默认的 StorageClass 将被用于动态的为没有特定 storage class 需求的 PersistentVolumeClaims 配置存储：（只能有一个默认StorageClass）
如果没有默认StorageClass，PVC 也没有指定storageClassName 的值，那么意味着它只能够跟 storageClassName 也是“”的 PV 进行绑定。
kubectl patch storageclass -p ‘{“metadata”: {“annotations”:{“storageclass.kubernetes.io/is-default-class”:“true”}}}’

[root@server2 nfs-client]# kubectl get pvc
No resources found in default namespace.
[root@server2 nfs-client]# kubectl get pv
No resources found in default namespace.
[root@server2 nfs-client]# kubectl get storageclasses.storage.k8s.io 
NAME                  PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage   westos.org/nfs   Delete          Immediate           false                  146m
[root@server2 nfs-client]# kubectl patch storageclass managed-nfs-storage -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
storageclass.storage.k8s.io/managed-nfs-storage patched
[root@server2 nfs-client]# kubectl get storageclasses.storage.k8s.io 
NAME                            PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage (default)   westos.org/nfs   Delete          Immediate           false                  147m
[root@server2 nfs-client]# 

此时不指定存储类也可以进行pv绑定

[root@server2 nfs-client]# vim pvc.yml 
[root@server2 nfs-client]# cat pvc.yml 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1
#  annotations:
#    volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi
[root@server2 nfs-client]# kubectl apply -f pvc.yml 
persistentvolumeclaim/pvc1 created
[root@server2 nfs-client]# kubectl get pvc
NAME   STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS          AGE
pvc1   Bound    pvc-5fbe822f-378d-4c60-a1a0-86e006265231   100Mi      RWX            managed-nfs-storage   9s
[root@server2 nfs-client]# 

3. StatefulSet控制器

StatefulSet将应用状态抽象成了两种情况：
拓扑状态：应用实例必须按照某种顺序启动。新创建的Pod必须和原来Pod的网络标识一样
存储状态：应用的多个实例分别绑定了不同存储数据

StatefulSet给所有的Pod进行了编号，编号规则是：$(statefulset名称)-$(序号)，从0开始

Pod被删除后重建，重建Pod的网络标识也不会改变,Pod的拓扑状态按照Pod的“名字+编号”的方式固定下来,并且为每个Pod提供了一个固定且唯一的访问入口,即Pod对应的DNS记录。

3.1 StatefulSet通过Headless Service维持Pod的拓扑状态

创建Headless service

[root@server2 vol]# mkdir nginx
[root@server2 vol]# cd nginx/
[root@server2 nginx]# vim service.yml
[root@server2 nginx]# cat service.yml 
apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
[root@server2 nginx]# kubectl apply -f service.yml 
service/nginx created
[root@server2 nginx]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1            443/TCP   5d4h
nginx        ClusterIP   None                 80/TCP    14s
[root@server2 nginx]# 

创建statefulset控制器

[root@server2 nginx]# vim statefulset.yml
[root@server2 nginx]# cat statefulset.yml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web created
[root@server2 nginx]# kubectl get pod
NAME    READY   STATUS    RESTARTS   AGE
web-0   1/1     Running   0          6s
web-1   1/1     Running   0          4s
[root@server2 nginx]# 

添加一条dns解析10.96.0.10（集群中的svc）

[root@server2 nginx]# vim /etc/resolv.conf
[root@server2 nginx]# cat /etc/resolv.conf
nameserver 10.96.0.10
nameserver 114.114.114.114
[root@server2 nginx]# kubectl describe svc nginx
Name:              nginx
Namespace:         default
Labels:            app=nginx
Annotations:       Selector:  app=nginx
Type:              ClusterIP
IP:                None
Port:              web  80/TCP
TargetPort:        80/TCP
Endpoints:         10.244.1.25:80,10.244.2.23:80
Session Affinity:  None
Events:            
[root@server2 nginx]# dig nginx.default.svc.cluster.local

; <<>> DiG 9.9.4-RedHat-9.9.4-72.el7 <<>> nginx.default.svc.cluster.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 17580
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;nginx.default.svc.cluster.local. IN	A

;; ANSWER SECTION:
nginx.default.svc.cluster.local. 30 IN	A	10.244.1.25
nginx.default.svc.cluster.local. 30 IN	A	10.244.2.23
;; Query time: 1 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Tue Jul 07 20:13:16 CST 2020
;; MSG SIZE  rcvd: 154

编辑statefulset.yml文件，副本数改为4，进行应用，再次创建了两个pod，可以实时解析到


kubectl StatefulSet控制器弹缩
回缩是有序回收，从控制器配置回缩

[root@server2 nginx]# vim statefulset.yml 
[root@server2 nginx]# cat statefulset.yml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 0
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web configured
[root@server2 nginx]# kubectl get pod
NAME    READY   STATUS        RESTARTS   AGE
web-0   1/1     Running       0          24m
web-1   0/1     Terminating   0          24m
[root@server2 nginx]# kubectl get pod
No resources found in default namespace.
[root@server2 nginx]# 

3.2 StatefulSet存储

PV和PVC的设计，使得StatefulSet对存储状态的管理成为了可能:
Pod的创建是严格按照pod号顺序进行的
在web-0进入到running状态，并且Conditions为 Ready之前，web-1会一直处于pending状态

[root@server2 nginx]# vim statefulset.yml 
[root@server2 nginx]# cat statefulset.yml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
          - name: www
            mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
    - metadata:
        name: www
      spec:
        storageClassName: managed-nfs-storage
        accessModes:
- ReadWriteOnce
        resources:
          requests:
            storage: 1Gi
[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web created
[root@server2 nginx]# kubectl get pod -o wide
NAME                                     READY   STATUS      RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
nfs-client-provisioner-89b96db68-sc5pr   1/1     Running     0          57s   10.244.1.27   server3              
test-pod                                 0/1     Completed   0          58s   10.244.2.25   server4              
web-0                                    1/1     Running     0          12s   10.244.2.26   server4              
web-1                                    1/1     Running     0          11s   10.244.1.28   server3              
web-2                                    1/1     Running     0          8s    10.244.2.27   server4              
[root@server2 nginx]# kubectl get pvc
NAME        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS          AGE
pvc1        Bound    pvc-212c94d5-7370-4e01-ba48-debb52e7205c   1Gi        RWX            managed-nfs-storage   8m23s
www-web-0   Bound    pvc-6a2c03fc-3570-4a2d-b6f3-897e3d4b7374   1Gi        RWO            managed-nfs-storage   40m
www-web-1   Bound    pvc-45875509-a147-4a3d-8363-d6fb290da1f3   1Gi        RWO            managed-nfs-storage   43s
www-web-2   Bound    pvc-5ce94179-b562-40e1-aca4-2cd6fc439a7a   1Gi        RWO            managed-nfs-storage   40s
[root@server2 nginx]# kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM               STORAGECLASS          REASON   AGE
pvc-212c94d5-7370-4e01-ba48-debb52e7205c   1Gi        RWX            Delete           Bound    default/pvc1        managed-nfs-storage            76s
pvc-45875509-a147-4a3d-8363-d6fb290da1f3   1Gi        RWO            Delete           Bound    default/www-web-1   managed-nfs-storage            49s
pvc-5ce94179-b562-40e1-aca4-2cd6fc439a7a   1Gi        RWO            Delete           Bound    default/www-web-2   managed-nfs-storage            46s
pvc-6a2c03fc-3570-4a2d-b6f3-897e3d4b7374   1Gi        RWO            Delete           Bound    default/www-web-0   managed-nfs-storage            76s
[root@server2 nginx]# 

StatefulSet还会为每一个Pod分配并创建一个同样编号的PVC。这样，kubernetes就可以通过Persistent Volume机制为这个PVC绑定对应的PV，从而保证每一个Pod都拥有一个独立的Volume


设置负载均衡

[root@server1 nfsdata]# cd default-www-web-0-pvc-6a2c03fc-3570-4a2d-b6f3-897e3d4b7374/
[root@server1 default-www-web-0-pvc-6a2c03fc-3570-4a2d-b6f3-897e3d4b7374]# echo web-0 > index.html
[root@server1 default-www-web-0-pvc-6a2c03fc-3570-4a2d-b6f3-897e3d4b7374]# cd ..
[root@server1 nfsdata]# cd default-www-web-1-pvc-45875509-a147-4a3d-8363-d6fb290da1f3/
[root@server1 default-www-web-1-pvc-45875509-a147-4a3d-8363-d6fb290da1f3]# echo web-1 > index.html
[root@server1 default-www-web-1-pvc-45875509-a147-4a3d-8363-d6fb290da1f3]# cd ..
[root@server1 nfsdata]# cd default-www-web-2-pvc-5ce94179-b562-40e1-aca4-2cd6fc439a7a/
[root@server1 default-www-web-2-pvc-5ce94179-b562-40e1-aca4-2cd6fc439a7a]# echo web-2 > index.html
[root@server1 default-www-web-2-pvc-5ce94179-b562-40e1-aca4-2cd6fc439a7a]# 

访问测试：实现负载均衡

3.3. 使用statefullset部署mysql主从集群

官网：https://kubernetes.io/zh/docs/tasks/run-application/run-replicated-stateful-application/

(1) 创建configmap配置文件
提供 my.cnf 覆盖，使可以独立控制 MySQL 主服务器和从服务器的配置

[root@server2 vol]# mkdir mysql
[root@server2 vol]# cd mysql/
[root@server2 mysql]# vim cm.yml
[root@server2 mysql]# cat cm.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  labels:
    app: mysql
data:
  master.cnf: |
    # Apply this config only on the master.
    [mysqld]
    log-bin
  slave.cnf: |
    # Apply this config only on slaves.
    [mysqld]
    super-read-only
[root@server2 mysql]# kubectl apply cm.yml 
error: must specify one of -f and -k
[root@server2 mysql]# kubectl apply -f cm.yml 
configmap/mysql created
[root@server2 mysql]# kubectl get cm
NAME    DATA   AGE
mysql   2      14s
[root@server2 mysql]# 

(2) 创建service

[root@server2 mysql]# \vi service.yml
[root@server2 mysql]# cat service.yml 
# Headless service for stable DNS entries of StatefulSet members.
apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  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: v1
kind: Service
metadata:
  name: mysql-read
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  selector:
    app: mysql
[root@server2 mysql]# kubectl apply -f service.yml 
service/mysql created
service/mysql-read created
[root@server2 mysql]# kubectl get svc
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
kubernetes   ClusterIP   10.96.0.1              443/TCP    5d6h
mysql        ClusterIP   None                   3306/TCP   9s
mysql-read   ClusterIP   10.108.69.62           3306/TCP   9s
nginx        ClusterIP   None                   80/TCP     119m
[root@server2 mysql]# 

(3) 创建statefulset

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
spec:
  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: 512Mi
        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 && "x$( change_master_to.sql.in
            # Ignore xtrabackup_binlog_info in this case (it's useless).
            rm -f xtrabackup_slave_info xtrabackup_binlog_info
          elif [[ -f xtrabackup_binlog_info ]]; then
            # We're cloning directly from master. Parse binlog position.
            [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
            rm -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

          # 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"
            mysql -h 127.0.0.1 \
                  -e "$(