MongoDB备份恢复工具pbm介绍

pbm全称percona backup mongodb，是percona公司提供的mongodb的备份恢复工具，支持percona mongodb,community mongodb，支持版本>v3.6，pbm底层是调用mongodump/mongorestore进行转储的逻辑备份，目前对分片集群的支持力度较弱，且不支持增量备份。

pbm部署

本次pbm部署基于v4.2 MongoDB副本集:

192.168.56.108 primary
192.168.56.109 secondary
192.168.56.110 arbiter
选择pbm版本：1.2.0（当前最新）
采用安装方式:rpm

安装pbm:(除arbiter外所有节点执行)

rpm -ivh percona-backup-mongodb-1.2.0-1.el7.x86_64.rpm

安装成功后/usr/bin下会多出三个可执行文件：

创建pbm用户：（在主节点执行）

db.getSiblingDB("admin").createRole({ "role": "pbmAnyAction",
"privileges": [
{ "resource": { "anyResource": true },
"actions": [ "anyAction" ]
}
],
"roles": []
});
db.getSiblingDB("admin").createUser({user: "pbmuser",
"pwd": "secretpwd",
"roles" : [
{ "db" : "admin", "role" : "readWrite", "collection": "" },
{ "db" : "admin", "role" : "backup" },
{ "db" : "admin", "role" : "clusterMonitor" },
{ "db" : "admin", "role" : "restore" },
{ "db" : "admin", "role" : "pbmAnyAction" }
]
});

创建yaml配置文件(在集群其中一台节点配置即可)
pbm备份支持s3存储，远程文件系统服务器，仅单实例支持本地存储
这里搭建了nfs服务器并挂载了远程目录/var/lib/mongobak

pbm_config.yaml
storage:
  type: filesystem
  filesystem:
    path: /var/lib/mongobak

进行初始化配置，指定存储类型（在创建yaml配置文件的那个节点执行）

pbm config --file /opt/pbm_config.yaml --mongodb-uri="mongodb://pbmuser:secretpwd@192.168.56.108:27017,192.168.56.109:27017,192.168.56.110:27017/?replicaSet=rs"

在每个实例启动pbm-agent代理进程

pbm-agent --mongodb-uri "mongodb://pbmuser:secretpwd@192.168.56.108:27017/" > /opt/pbm_agent.log 2>&1 &

到此pbm部署结束

pbm备份恢复

通过pbm list拉取备份列表

pbm list --mongodb-uri "mongodb://pbmuser:secretpwd@192.168.56.108:27017,192.168.56.109:27017/?replicaSet=rs"

Backup history:
  2020-06-23T09:03:40Z
  2020-06-23T09:24:53Z

PS:首次执行没有备份信息

pbm backup备份

单实例的备份不做介绍
副本集的备份指定集群连接串，可以在从节点进行备份（备份任务会根据集群内的节点繁忙程度选择最适合转储的节点）
pbm目前只支持全量备份恢复，在备份过程中会记录备份时段内的oplog

pbm backup --mongodb-uri "mongodb://pbmuser:secretpwd@192.168.56.108:27017,192.168.56.109:27017/?replicaSet=rs"

可以通过--compression=指定压缩类型（默认为s2，支持gzip, snappy, lz4, pgzip）：

pbm backup --compression=gzip --mongodb-uri  "mongodb://pbmuser:secretpwd@192.168.56.108:27017,192.168.56.109:27017/?replicaSet=rs"

pbm备份底层调用mongodump

pbm agent is listening for the commands
2020/06/23 10:45:32 Got command backup [{backup {2020-06-23T02:45:31Z s2} { } 1592880331}]
2020/06/23 10:45:32 Backup 2020-06-23T02:45:31Z started on node rs/192.168.56.109:27017
2020-06-23T10:45:35.187+0800  writing admin.system.users to archive on stdout
2020-06-23T10:45:35.189+0800  done dumping admin.system.users (1 document)
2020-06-23T10:45:35.189+0800  writing admin.system.version to archive on stdout
2020-06-23T10:45:35.190+0800  done dumping admin.system.version (2 documents)
2020-06-23T10:45:35.191+0800  writing admin.pbmBackups to archive on stdout
2020-06-23T10:45:35.194+0800  done dumping admin.pbmBackups (1 document)
2020-06-23T10:45:35.194+0800  writing admin.pbmConfig to archive on stdout
2020-06-23T10:45:35.204+0800  done dumping admin.pbmConfig (1 document)
2020-06-23T10:45:35.204+0800  writing admin.pbmCmd to archive on stdout
2020-06-23T10:45:35.208+0800  done dumping admin.pbmCmd (2 documents)
2020-06-23T10:45:35.208+0800  writing admin.pbmLock to archive on stdout
2020-06-23T10:45:35.211+0800  done dumping admin.pbmLock (1 document)
2020-06-23T10:45:35.212+0800  writing test.test to archive on stdout
2020-06-23T10:45:35.215+0800  done dumping test.test (4 documents)
2020-06-23T10:45:35.215+0800  writing test.mj to archive on stdout
2020-06-23T10:45:35.218+0800  done dumping test.mj (3 documents)
2020/06/23 10:45:35 mongodump finished, waiting for the oplog
2020/06/23 10:45:39 Backup 2020-06-23T02:45:31Z finished

pbm restore恢复

restore:集群restore只能在主库恢复，且要保持服务启动
在恢复时，需要禁止业务写入

pbm restore 2020-06-23T09:03:40Z --mongodb-uri "mongodb://pbmuser:secretpwd@192.168.56.108:27017,192.168.56.109:27017/?replicaSet=rs"

pbm恢复底层调用mongorestore

2020/06/23 17:04:28 Got command restore [{restore { } {2020-06-23T09:04:27.816797402Z 2020-06-23T09:03:40Z} 1592903067}]
2020/06/23 17:04:28 [INFO] Restore of '2020-06-23T09:03:40Z' started
2020-06-23T17:04:31.733+0800  preparing collections to restore from
2020-06-23T17:04:31.766+0800  reading metadata for admin.pbmRUsers from archive on stdin
2020-06-23T17:04:31.770+0800  restoring admin.pbmRUsers from archive on stdin
2020-06-23T17:04:33.737+0800  restoring indexes for collection admin.pbmRUsers from metadata
2020-06-23T17:04:33.746+0800  finished restoring admin.pbmRUsers (2 documents, 0 failures)
2020-06-23T17:04:33.746+0800  reading metadata for admin.pbmRRoles from archive on stdin
2020-06-23T17:04:33.750+0800  restoring admin.pbmRRoles from archive on stdin
2020-06-23T17:04:35.732+0800  restoring indexes for collection admin.pbmRRoles from metadata
2020-06-23T17:04:35.748+0800  finished restoring admin.pbmRRoles (1 document, 0 failures)
2020-06-23T17:04:35.759+0800  reading metadata for test.test from archive on stdin
2020-06-23T17:04:35.763+0800  restoring test.test from archive on stdin
2020-06-23T17:04:37.848+0800  no indexes to restore
2020-06-23T17:04:37.848+0800  finished restoring test.test (4 documents, 0 failures)
2020-06-23T17:04:37.851+0800  reading metadata for test.mj from archive on stdin
2020-06-23T17:04:37.855+0800  restoring test.mj from archive on stdin
2020-06-23T17:04:39.890+0800  no indexes to restore
2020-06-23T17:04:39.890+0800  finished restoring test.mj (3 documents, 0 failures)
2020/06/23 17:04:39 mongorestore finished
2020/06/23 17:04:41 starting the oplog replay
2020/06/23 17:04:41 oplog replay finished
2020/06/23 17:04:41 restoring users and roles
2020/06/23 17:04:41 deleting users
2020/06/23 17:04:41 inserting users
2020/06/23 17:04:41 inserted user

在从库执行恢复命令会提示Node in not suitable for restore，并自动将恢复任务切至主库：

2020/06/23 17:04:28 Got command restore [{restore { } {2020-06-23T09:04:27.816797402Z 2020-06-23T09:03:40Z} 1592903067}]
2020/06/23 17:04:28 Node in not suitable for restore

源码中体现为当前节点非主节点，直接return

备份分片集群：

目前来看，备份分片集群的方式，也是针对每一个shard节点或者shard副本集进行备份，但是官方手册没有说明需要停止业务写入或者关闭balancer。
针对分片集群的恢复，需要提前关闭balancer，最直接的方式是关闭所有mongos节点。

关于增量备份：

pbm在进行全量备份是会记录一个详细的json：


{
  "name": "2020-06-23T09:24:53Z",
  "replsets": [
    {
      "name": "rs",
      "backup_name": "2020-06-23T09:24:53Z_rs.dump.s2",
      "oplog_name": "2020-06-23T09:24:53Z_rs.oplog.s2",
      "start_ts": 1592904293,
      "status": "done",
      "last_transition_ts": 1592904299,
      "last_write_ts": {
        "T": 1592904295,
        "I": 1
      },
      "conditions": [
        {
          "timestamp": 1592904293,
          "status": "running"
        },
        {
          "timestamp": 1592904296,
          "status": "dumpDone"
        },
        {
          "timestamp": 1592904299,
          "status": "done"
        }
      ]
    }
  ],
  "compression": "s2",
  "store": {
    "type": "filesystem",
    "s3": {
      "region": "",
      "endpointUrl": "",
      "bucket": "",
      "credentials": {
        "vault": {}
      }
    },
    "filesystem": {
      "path": "/var/lib/mongobak"
    }
  },
  "mongodb_version": "4.2.7",
  "start_ts": 1592904293,
  "last_transition_ts": 1592904300,
  "last_write_ts": {
    "T": 1592904295,
    "I": 1
  },
  "hb": {
    "T": 1592904298,
    "I": 1
  },
  "status": "done",
  "conditions": [
    {
      "timestamp": 1592904293,
      "status": "starting"
    },
    {
      "timestamp": 1592904295,
      "status": "running"
    },
    {
      "timestamp": 1592904297,
      "status": "dumpDone"
    },
    {
      "timestamp": 1592904300,
      "status": "done"
    }
  ]
}

从上json记录中可以获取最终的时间戳：1592904300，作为增量备份的开始时间戳
增量备份可以通过该命令实现基于oplog的增量备份

/mongodb/bin/mongodump -h 192.168.xxx.xxx --port $port  -d local -c oplog.rs  --query '{ts:{$gte:Timestamp('$paramBakStartDate',1),$lte:Timestamp('$paramBakEndDate',9999)}}' -o $bkdatapath/mongodboplog$bkfilename

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