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: [""]
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: /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./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: /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: /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: /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: /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: /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./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}
