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： kubernetesincubator/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/
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/deploy
[root@harbor ~]# vim /etc/exports [root@harbor ~]# cat /etc/exports /nfsdata *(rw,sync,no_root_squash) [root@harbor ~]# exportfs -rv exporting *:/nfsdata [root@harbor ~]# showmount -e Export list for harbor: /nfsdata * [kubeadm@server1 ~]$ cd vol/ [kubeadm@server1 vol]$ mkdir nfs-client [kubeadm@server1 vol]$ cd nfs-client/ [kubeadm@server1 nfs-client]$ vim rbac.yml ##添加角色绑定的名称空间 apiVersion: v1 kind: ServiceAccount metadata: name: nfs-client-provisioner # replace with namespace where provisioner is deployed namespace: default --- kind: ClusterRole 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 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: default roleRef: kind: ClusterRole name: nfs-client-provisioner-runner apiGroup: rbac.authorization.k8s.io --- kind: Role apiVersion: rbac.authorization.k8s.io/v1 metadata: name: leader-locking-nfs-client-provisioner # replace with namespace where provisioner is deployed namespace: default rules: - apiGroups: [""] resources: ["endpoints"] verbs: ["get", "list", "watch", "create", "update", "patch"] --- kind: RoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata: name: leader-locking-nfs-client-provisioner # replace with namespace where provisioner is deployed namespace: default subjects: - kind: ServiceAccount # replace with namespace where provisioner is deployed namespace: default roleRef: kind: Role name: leader-locking-nfs-client-provisioner apiGroup: rbac.authorization.k8s.io [kubeadm@server1 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: default 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 ##镜像需要下载并上传到仓库 volumeMounts: - name: nfs-client-root mountPath: /persistentvolumes env: - name: PROVISIONER_NAME value: red.org/nfs - name: NFS_SERVER value: 172.25.1.11 - name: NFS_PATH value: /nfsdata volumes: - name: nfs-client-root nfs: server: 172.25.1.11 path: /nfsdata [kubeadm@server1 nfs-client]$ vim class.yml ##创建存储类 apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: managed-nfs-storage provisioner: red.org/nfs parameters: archiveOnDelete: "false" [kubeadm@server1 nfs-client]$ vim pvc.yml ##创建pvc kind: PersistentVolumeClaim apiVersion: v1 metadata: name: pvc1 annotations: volume.beta.kubernetes.io/storage-class: "managed-nfs-storage" spec: accessModes: - ReadWriteMany resources: requests: storage: 100Mi [kubeadm@server1 nfs-client]$ vim pod.yml kind: Pod apiVersion: v1 metadata: name: test-pod spec: containers: - name: test-pod image: busybox 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再次改为false 以上为动态卷的存储方式
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。
[kubeadm@server1 nfs-client]$ kubectl get pvc No resources found in default namespace. [kubeadm@server1 nfs-client]$ kubectl get pv No resources found in default namespace. [kubeadm@server1 nfs-client]$ kubectl get storageclasses.storage.k8s.io NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE managed-nfs-storage red.org/nfs Delete Immediate false 6m33s [kubeadm@server1 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 [kubeadm@server1 nfs-client]$ kubectl get storageclasses.storage.k8s.io NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE managed-nfs-storage (default) red.org/nfs Delete Immediate false 6m47s这个时候不用指定存储类也可以绑定
[kubeadm@server1 nfs-client]$ vim pvc.yml [kubeadm@server1 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: 1Gi [kubeadm@server1 nfs-client]$ kubectl apply -f pvc.yml persistentvolumeclaim/pvc1 created [kubeadm@server1 nfs-client]$ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE pvc1 Bound pvc-b67fda47-02d6-44f6-bd7d-d22a90369721 1Gi RWX managed-nfs-storage 12s创建service
[kubeadm@server1 nginx]$ pwd /home/kubeadm/vol/nginx [kubeadm@server1 nginx]$ vim service.yml [kubeadm@server1 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 [kubeadm@server1 nginx]$ kubectl apply -f service.yml service/nginx created [kubeadm@server1 nginx]$ kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 13d nginx ClusterIP None <none> 80/TCP 3s创建statefulset控制器
[kubeadm@server1 nginx]$ vim statefulset.yml [kubeadm@server1 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 [kubeadm@server1 nginx]$ kubectl apply -f statefulset.yml statefulset.apps/web created [kubeadm@server1 nginx]$ kubectl get pod NAME READY STATUS RESTARTS AGE nfs-client-provisioner-96649cd96-gvzch 1/1 Running 0 54m web-0 1/1 Running 0 18s web-1 1/1 Running 0 17s [kubeadm@server1 nginx]$ vim /etc/resolv.conf [kubeadm@server1 nginx]$ cat /etc/resolv.conf nameserver 10.96.0.10 nameserver 114.114.114.114 [kubeadm@server1 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: 10.244.1.87:80,10.244.2.104:80 Session Affinity: None Events: <none> [kubeadm@server1 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: 41306 ;; 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 10.244.2.104 nginx.default.svc.cluster.local. 30 IN A 10.244.1.87 ;; Query time: 0 msec ;; SERVER: 10.96.0.10#53(10.96.0.10) ;; WHEN: Thu Jul 02 16:11:09 CST 2020 ;; MSG SIZE rcvd: 154
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。
kubectl 弹缩 首先,想要弹缩的StatefulSet. 需先清楚是否能弹缩该应用. kubectl get statefulsets • 改变StatefulSet副本数量: • $ kubectl scale statefulsets --replicas= • 如果StatefulSet开始由 kubectl apply 或 kubectl create --save-config 创建,更新StatefulSet manifests中的 .spec.replicas, 然后执行命令 kubectl apply: • $ kubectl apply -f • 也可以通过命令 kubectl edit 编辑该字段: • $ kubectl edit statefulsets • 使用 kubectl patch: • $ kubectl patch statefulsets -p '{“spec”:{“replicas”:}}'
PV和PVC的设计，使得StatefulSet对存储状态的管理成为了可能: Pod的创建也是严格按照编号顺序进行的。比如在web-0进入到running状态，并且Conditions为 Ready之前，web-1一直会处于pending状态。
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: 1GiStatefulSet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@harbor ~]# cd /nfsdata/ [root@harbor nfsdata]# ls default-www-web-0-pvc-6afe237f-9c4c-42d3-a337-3d78abd3e44a default-www-web-1-pvc-ee23b027-e71c-43ef-bd87-d156db85397d default-www-web-2-pvc-d8e5aebd-e248-4039-8992-f7e147b7d430 [root@harbor nfsdata]# cd default-www-web-0-pvc-6afe237f-9c4c-42d3-a337-3d78abd3e44a/ [root@harbor default-www-web-0-pvc-6afe237f-9c4c-42d3-a337-3d78abd3e44a]# echo web-0 > index.html [root@harbor default-www-web-0-pvc-6afe237f-9c4c-42d3-a337-3d78abd3e44a]# cd .. [root@harbor nfsdata]# cd default-www-web-1-pvc-ee23b027-e71c-43ef-bd87-d156db85397d/ [root@harbor default-www-web-1-pvc-ee23b027-e71c-43ef-bd87-d156db85397d]# echo web-1 > index.html [root@harbor default-www-web-1-pvc-ee23b027-e71c-43ef-bd87-d156db85397d]# cd .. [root@harbor nfsdata]# cd default-www-web-2-pvc-d8e5aebd-e248-4039-8992-f7e147b7d430/ [root@harbor default-www-web-2-pvc-d8e5aebd-e248-4039-8992-f7e147b7d430]# echo web-2 > index.html再次拉伸回使用原先的标识符
参考官网：https://kubernetes.io/zh/docs/tasks/run-application/run-replicated-stateful-application/ 创建configmap配置文件 这个 ConfigMap 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。
[kubeadm@server1 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 [kubeadm@server1 mysql]$ vim cm.yml [kubeadm@server1 mysql]$ kubectl apply -f cm.yml configmap/mysql created [kubeadm@server1 mysql]$ kubectl get cm. NAME DATA AGE my-config 2 4d21h my-config-2 1 4d21h my-config-3 2 4d21h mysql 2 6s nginx-config 1 4d10h创建service Headless Service 给 StatefulSet 控制器为集合中每个 Pod 创建的 DNS 条目提供了一个宿主。因为 Headless Service 名为 mysql，所以可以通过在同一 Kubernetes 集群和 namespace 中的任何其他 Pod 内解析 .mysql 来访问 Pod。
客户端 Service 称为 mysql-read，是一种常规 Service，具有其自己的群集 IP，该群集 IP 在报告为就绪的所有MySQL Pod 中分配连接。可能端点的集合包括 MySQL 主节点和所有从节点。
请注意，只有读取查询才能使用负载平衡的客户端 Service。因为只有一个 MySQL 主服务器，所以客户端应直接连接到 MySQL 主服务器 Pod (通过其在 Headless Service 中的 DNS 条目)以执行写入操作。
[kubeadm@server1 mysql]$ cat service.yml 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
创建statefulset
[root@server2 mysql]# cat statefulset.yml 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 [[ $ordinal -eq 0 ]]; then cp /mnt/config-map/master.cnf /mnt/conf.d/ else cp /mnt/config-map/slave.cnf /mnt/conf.d/ fi volumeMounts: - name: conf mountPath: /mnt/conf.d - name: config-map mountPath: /mnt/config-map - name: clone-mysql image: xtrabackup:1.0 command: - bash - "-c" - | set -ex # Skip the clone if data already exists. [[ -d /var/lib/mysql/mysql ]] && exit 0 # Skip the clone on master (ordinal index 0). [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 ordinal=${BASH_REMATCH[1]} [[ $ordinal -eq 0 ]] && exit 0 # Clone data from previous peer. ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql # Prepare the backup. xtrabackup --prepare --target-dir=/var/lib/mysql volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d containers: - name: mysql image: mysql:5.7 env: - name: MYSQL_ALLOW_EMPTY_PASSWORD value: "1" ports: - name: mysql containerPort: 3306 volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d resources: requests: cpu: 500m memory: 512M livenessProbe: exec: command: ["mysqladmin", "ping"] initialDelaySeconds: 30 periodSeconds: 10 timeoutSeconds: 5 readinessProbe: exec: # Check we can execute queries over TCP (skip-networking is off). command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"] initialDelaySeconds: 5 periodSeconds: 2 timeoutSeconds: 1 - name: xtrabackup image: xtrabackup:1.0 ##用于打开3307端口，向slave发送数据 ports: - name: xtrabackup containerPort: 3307 command: - bash - "-c" - | set -ex cd /var/lib/mysql # Determine binlog position of cloned data, if any. if [[ -f xtrabackup_slave_info && "x$(<xtrabackup_slave_info)" != "x" ]]; then # XtraBackup already generated a partial "CHANGE MASTER TO" query # because we're cloning from an existing slave. (Need to remove the tailing semicolon!) cat xtrabackup_slave_info | sed -E 's/;$//g' > change_master_to.sql.in # Ignore xtrabackup_binlog_info in this case (it's useless). rm -f xtrabackup_slave_info xtrabackup_binlog_info elif [[ -f xtrabackup_binlog_info ]]; then # We're cloning directly from master. Parse binlog position. [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || 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 "$(<change_master_to.sql.in), \ MASTER_HOST='mysql-0.mysql', \ MASTER_USER='root', \ MASTER_PASSWORD='', \ MASTER_CONNECT_RETRY=10; \ START SLAVE;" || exit 1 # In case of container restart, attempt this at-most-once. mv change_master_to.sql.in change_master_to.sql.orig fi # Start a server to send backups when requested by peers. exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c \ "xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root" volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d resources: requests: cpu: 100m memory: 100Mi volumes: - name: conf emptyDir: {} - name: config-map configMap: name: mysql volumeClaimTemplates: - metadata: name: data spec: accessModes: ["ReadWriteOnce"] resources: requests: storage: 10Gi[kubeadm@server1 mysql]$ kubectl logs mysql-0 -c init-mysql ++ hostname + [[ mysql-0 =~ -([0-9]+)$ ]] + ordinal=0 + echo '[mysqld]' + echo server-id=100 + [[ 0 -eq 0 ]] + cp /mnt/config-map/master.cnf /mnt/conf.d/ [kubeadm@server1 mysql]$ kubectl logs mysql-0 -c clone-mysql + [[ -d /var/lib/mysql/mysql ]] + exit 0 [kubeadm@server1 mysql]$ kubectl logs mysql-1 -c clone-mysql + [[ -d /var/lib/mysql/mysql ]] + exit 0 [kubeadm@server1 mysql]$ kubectl logs mysql-2 -c clone-mysql + [[ -d /var/lib/mysql/mysql ]] ++ hostname + [[ mysql-2 =~ -([0-9]+)$ ]] + ordinal=2 + [[ 2 -eq 0 ]] + ncat --recv-only mysql-1.mysql 3307 + xbstream -x -C /var/lib/mysql + xtrabackup --prepare --target-dir=/var/lib/mysql
salve1复制master数据，slave2复制slave1的数据
[kubeadm@server1 mysql]$ kubectl exec mysql-0 -c mysql -- ls /etc/mysql/conf.d master.cnf server-id.cnf [kubeadm@server1 mysql]$ kubectl exec mysql-0 -c mysql -- cat /etc/mysql/conf.d/master.cnf # Apply this config only on the master. [mysqld] log-bin [kubeadm@server1 mysql]$ kubectl exec mysql-0 -c mysql -- cat /etc/mysql/conf.d/server-id.cnf [mysqld] server-id=100测试主从复制
[kubeadm@server1 mysql]$ mysql -h mysql-0.mysql.default.svc.cluster.local Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 429 Server version: 5.7.30-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MySQL [(none)]> show databases; +------------------------+ | Database | +------------------------+ | information_schema | | mysql | | performance_schema | | sys | | xtrabackup_backupfiles | +------------------------+ 5 rows in set (0.02 sec) MySQL [(none)]> create database test; Query OK, 1 row affected (0.01 sec) MySQL [(none)]> Bye [kubeadm@server1 mysql]$ mysql -h mysql-1.mysql.default.svc.cluster.local Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 455 Server version: 5.7.30 MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MySQL [(none)]> show databases; +------------------------+ | Database | +------------------------+ | information_schema | | mysql | | performance_schema | | sys | | test | | xtrabackup_backupfiles | +------------------------+ 6 rows in set (0.03 sec) MySQL [(none)]> Bye [kubeadm@server1 mysql]$ mysql -h mysql-2.mysql.default.svc.cluster.local Welcome to the MariaDB monitor. Commands end with ; or \g. Your MySQL connection id is 453 Server version: 5.7.30 MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. MySQL [(none)]> show databases; +------------------------+ | Database | +------------------------+ | information_schema | | mysql | | performance_schema | | sys | | test | | xtrabackup_backupfiles | +------------------------+ 6 rows in set (0.01 sec) MySQL [(none)]> Bye
