TiDB Operator备份TiDB集群到NFS持久卷

时间：2023-02-21 17:04:33

Kubernetes 上 TiDB 集群的数据备份到​​持久卷​​​上。本文描述的持久卷，指任何 ​​Kubernetes 支持的持久卷类型​​。本文以备份数据到网络文件系统 (NFS) 存储为例。

使用场景

如果你对数据备份有以下要求，可考虑使用 BR 将 TiDB 集群数据以 ​​Ad-hoc 备份​​(只执行一次)或​​定时快照备份​​(执行多次)的方式备份至持久卷：

  • 需要备份的数据量较大，而且要求备份速度较快
  • 需要直接备份数据的 SST 文件（键值对）

注意

  • BR 只支持 TiDB v3.1 及以上版本。
  • 使用 BR 备份出的数据只能恢复到 TiDB 数据库中，无法恢复到其他数据库中。

一、Ad-hoc 备份

Ad-hoc 备份支持快照备份与增量备份。Ad-hoc 备份通过创建一个自定义的 ​​Backup​​ custom resource (CR) 对象来描述一次备份。TiDB Operator 根据这个 ​​Backup​​ 对象来完成具体的备份过程。如果备份过程中出现错误，程序不会自动重试，此时需要手动处理。

本文档对K8S集群中命名空间为tidb下的lqb数据库集群进行备份，具体操作如下：

准备Ad-hoc备份环境

下载​​backup-rbac.yaml​​

---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: tidb-backup-manager
  labels:
    app.kubernetes.io/component: tidb-backup-manager
rules:
- apiGroups: [""]
  resources: ["events"]
  verbs: ["*"]
- apiGroups: ["pingcap.com"]
  resources: ["backups", "restores"]
  verbs: ["get", "watch", "list", "update"]

---
kind: ServiceAccount
apiVersion: v1
metadata:
  name: tidb-backup-manager

---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: tidb-backup-manager
  labels:
    app.kubernetes.io/component: tidb-backup-manager
subjects:
- kind: ServiceAccount
  name: tidb-backup-manager
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: tidb-backup-manager

创建备份需要的RBAC相关资源在tidb命名空间下

[root@k8s-master backup]# kubectl apply -f backup-rbac.yaml -ntidb
role.rbac.authorization.k8s.io/tidb-backup-manager created
serviceaccount/tidb-backup-manager created
rolebinding.rbac.authorization.k8s.io/tidb-backup-manager created

确保可以从K8S集群中访问用于存储备份数据的NFS服务器，并且配置了TiKV挂载跟备份任务相同的NFS共享目录到相同的本地目录。tikv挂载NFS的具体配置如下：

spec:
  tikv:
    baseImage: pingcap/tikv
    replicas: 4
    maxFailoverCount: 6

#下边是配置tikv挂载nfs
    additionalVolumes:
    - name: nfs
      nfs:
        server: 172.16.5.194
        path: /home/k8s-nfs
    additionalVolumeMounts:
    - name: nfs
      mountPath: /nfs

    requests:
      cpu: "100m"
      storage: 12Gi
      memory: "400Mi"
    limits:
      cpu: "2000m"
      memory: "4Gi"
    mountClusterClientSecret: false
    storageClassName: "local-hostpath"

如果TiDB版本低于V4.0.8则执行如下操作，若高于该版本可以省略。

创建secret用于存放Tidb集群的用户名和密码，由于使用v6.5省略该步骤
kubectl create secret generic backup-demo1-tidb-secret --from-literal=password=${password} --namespace=tidb

备份数据到NFS持久卷

创建备份的自定义资源CR，将数据备份到NFS

##以下以备份yz数据库为例
[root@k8s-master backup]# cat backup-nfs.yaml
---
apiVersion: pingcap.com/v1alpha1
kind: Backup
metadata:
  name: demo1-backup-nfs
  namespace: tidb
spec:
#  backupType: full
#  from:
#    host:
#    port:
#    user:
#    secretName: backup-yz

  tableFilter:
  - "yz.*"

  br:
    cluster: yz
    clusterNamespace: tidb

  local:
    prefix: backup-nfs
    volume:
      name: nfs
      nfs:
        server: 172.16.5.194
        path: /home/k8s-nfs
    volumeMount:
      name: nfs
      mountPath: /nfs

创建应用配置

[root@k8s-master backup]# kubectl apply -f backup-nfs.yaml
backup.pingcap.com/demo1-backup-nfs created

查看备份状态和备份文件

[root@k8s-master backup]# kubectl get bk -n tidb -owide -w
NAME               TYPE   MODE       STATUS    BACKUPPATH                BACKUPSIZE   COMMITTS   LOGTRUNCATEUNTIL   STARTED   COMPLETED   AGE
demo1-backup-nfs          snapshot   Running   local:///nfs/backup-nfs                                                                    57s
demo1-backup-nfs          snapshot   Complete   local:///nfs/backup-nfs   2.8 GB       439178019024666631                      68s       0s          72s
^C[root@k8s-master backup]ls /home/k8s-nfs/backup-nfs/de
1  20001  39461  4  backup.lock  backupmeta  checkpoint.meta  checkpoints

备份实例如下：

备份全部集群数据
---
apiVersion: pingcap.com/v1alpha1
kind: Backup
metadata:
  name: demo1-backup-nfs
  namespace: test1
spec:
  # # backupType: full
  # # Only needed for TiDB Operator < v1.1.10 or TiDB < v4.0.8
  # from:
  #   host: ${tidb-host}
  #   port: ${tidb-port}
  #   user: ${tidb-user}
  #   secretName: backup-demo1-tidb-secret
  br:
    cluster: demo1
    clusterNamespace: test1
  local:
    prefix: backup-nfs
    volume:
      name: nfs
      nfs:
        server: ${nfs_server_ip}
        path: /home/k8s-nfs
    volumeMount:
      name: nfs
      mountPath: /nfs


备份单个数据库的数据
---
apiVersion: pingcap.com/v1alpha1
kind: Backup
metadata:
  name: demo1-backup-nfs
  namespace: test1
spec:
  # # backupType: full
  # # Only needed for TiDB Operator < v1.1.10 or TiDB < v4.0.8
  # from:
  #   host: ${tidb-host}
  #   port: ${tidb-port}
  #   user: ${tidb-user}
  #   secretName: backup-demo1-tidb-secret
  tableFilter:
  - "db1.*"
  br:
    cluster: demo1
    clusterNamespace: test1
  local:
    prefix: backup-nfs
    volume:
      name: nfs
      nfs:
        server: ${nfs_server_ip}
        path: /home/k8s-nfs
    volumeMount:
      name: nfs
      mountPath: /nfs
备份单张表的数据
---
apiVersion: pingcap.com/v1alpha1
kind: Backup
metadata:
  name: demo1-backup-nfs
  namespace: test1
spec:
  # # backupType: full
  # # Only needed for TiDB Operator < v1.1.10 or TiDB < v4.0.8
  # from:
  #   host: ${tidb-host}
  #   port: ${tidb-port}
  #   user: ${tidb-user}
  #   secretName: backup-demo1-tidb-secret
  tableFilter:
  - "db1.table1"
  br:
    cluster: demo1
    clusterNamespace: test1
  local:
    prefix: backup-nfs
    volume:
      name: nfs
      nfs:
        server: ${nfs_server_ip}
        path: /home/k8s-nfs
    volumeMount:
      name: nfs
      mountPath: /nfs
使用表库过滤功能备份多张表的数据
---
apiVersion: pingcap.com/v1alpha1
kind: Backup
metadata:
  name: demo1-backup-nfs
  namespace: test1
spec:
  # # backupType: full
  # # Only needed for TiDB Operator < v1.1.10 or TiDB < v4.0.8
  # from:
  #   host: ${tidb-host}
  #   port: ${tidb-port}
  #   user: ${tidb-user}
  #   secretName: backup-demo1-tidb-secret
  tableFilter:
  - "db1.table1"
  - "db1.table2"
  br:
    cluster: demo1
    clusterNamespace: test1
  local:
    prefix: backup-nfs
    volume:
      name: nfs
      nfs:
        server: ${nfs_server_ip}
        path: /home/k8s-nfs
    volumeMount:
      name: nfs
      mountPath: /nfs

二、定时快照备份

用户通过设置备份策略来对 TiDB 集群进行定时备份，同时设置备份的保留策略以避免产生过多的备份。定时快照备份通过自定义的 ​​BackupSchedule​​ CR 对象来描述。每到备份时间点会触发一次快照备份，定时快照备份底层通过 Ad-hoc 快照备份来实现。下面是创建定时快照备份的具体步骤：

准备定时快照备份环境（和Ad-hoc备份的第一步一样）略

备份数据到NFS持久卷中

创建备份自定义资源BackupSchedule，将数据备份到NFS中

[root@k8s-master backup]# cat backup-schedule-nfs.yaml
apiVersion: pingcap.com/v1alpha1
kind: BackupSchedule
metadata:
  name: demo1-backup-schedule-nfs
  namespace: tidb
spec:

  maxReservedTime: "3h"
  schedule: "*/2 * * * *"
  backupTemplate:

    br:
      cluster: yz
      clusterNamespace: tidb

    local:
      prefix: backup-nfs
      volume:
        name: nfs
        nfs:
          server: 172.16.5.194
          path: /home/k8s-nfs
      volumeMount:
        name: nfs
        mountPath: /nfs

创建应用配置

[root@k8s-master backup]# kubectl apply -f backup-schedule-nfs.yaml
backupschedule.pingcap.com/demo1-backup-schedule-nfs created

查看备份状态和备份文件

[root@k8s-master backup]# kubectl get bks -n tidb -owide
NAME                        SCHEDULE      MAXBACKUPS   LASTBACKUP   LASTBACKUPTIME   AGE
demo1-backup-schedule-nfs   */2 * * * *                                              9s
NAME                        SCHEDULE      MAXBACKUPS   LASTBACKUP   LASTBACKUPTIME   AGE
demo1-backup-schedule-nfs   */2 * * * *                                              46s


demo1-backup-schedule-nfs   */2 * * * *                demo1-backup-schedule-nfs-2023-02-02t10-16-00   6s               89s
demo1-backup-schedule-nfs   */2 * * * *                demo1-backup-schedule-nfs-2023-02-02t10-18-00   6s               3m29s
demo1-backup-schedule-nfs   */2 * * * *                demo1-backup-schedule-nfs-2023-02-02t10-20-00   6s               5m29s
demo1-backup-schedule-nfs   */2 * * * *                demo1-backup-schedule-nfs-2023-02-02t10-22-00   6s               7m29s
demo1-backup-schedule-nfs   */2 * * * *                demo1-backup-schedule-nfs-2023-02-02t10-24-00   6s               9m29s

[root@k8s-master ~]# ls /home/k8s-nfs/backup-nfs/yz-pd.tidb-2379-2023-02-02t10-16-00/
1  20001  39461  4  backup.lock  backupmeta  checkpoint.meta  checkpoints

三、删除备份的 Backup CR

kubectl delete backup ${name} -n ${namespace}
kubectl delete backupschedule ${name} -n ${namespace}


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