一、容灾级别¶

级别	方式	RPO	RTO
L0	无备源中心,没有灾难恢复能力,只在本地进行数据备份	24小时	4小时+
L1	本地备份+异地保存,本地将关键数据备份,然后送到异地保存。灾难发生后,按预定数据恢复程序恢复系统和数据。	24小时+	8小时+
L2	双中心主备模式,在异地建立一个热备份点,通过网络进行数备份。当出现灾难时,备份站点接替主站点的业务,维护业务连续性	秒级	数分钟到半小时
L3	双中心双活,在相隔较远的地方分别建立两个数据中心,进行相互数据备份。当某个数据中心发生灾难时,另一个数据中心接替其工作任务。	秒级	秒级
L4	双中心双活 + 异地热备 = 两地三中心,在同城分别建立两个数据中心,进行相互数据备份。当该城市的2个中心同时不可用(地震/大面积停电/网络等),快速切换到异地	秒级	分钟级

二、MongoDB 两地三中心集群实现¶

三、两地三中心规划及实施¶

3.1 准备虚拟机及数据库实例¶

1、规划

10.0.0.51

primary:10.0.0.51:10001
s1:10.0.0.51:10002

10.0.0.52

s3:10.0.0.52:10003
s4:10.0.0.52:10004

10.0.0.53

s5:10.0.53:10005

2、准备实例

配置文件 -db01

su - mongod
mkdir -p /mongodb/10001/conf /mongodb/10001/data /mongodb/10001/log
mkdir -p /mongodb/10002/conf /mongodb/10002/data /mongodb/10002/log
cat > /mongodb/10001/conf/mongod.conf <<EOF
systemLog:
  destination: file
  path: /mongodb/10001/log/mongodb.log
  logAppend: true
storage:
  journal:
    enabled: true
  dbPath: /mongodb/10001/data
  directoryPerDB: true
  #engine: wiredTiger
  wiredTiger:
    engineConfig:
      cacheSizeGB: 0.5
      directoryForIndexes: true
    collectionConfig:
      blockCompressor: zlib
    indexConfig:
      prefixCompression: true
processManagement:
  fork: true
net:
  port: 10001
  bindIp: 10.0.0.51,127.0.0.1
replication:
  oplogSizeMB: 2048
  replSetName: my_repl
EOF
cp  /mongodb/10001/conf/mongod.conf  /mongodb/10002/conf/
sed 's#10001#10002#g' /mongodb/10002/conf/mongod.conf -i
mongod -f /mongodb/10001/conf/mongod.conf
mongod -f /mongodb/10002/conf/mongod.conf

配置文件 -db02

su - mongod
mkdir -p /mongodb/10003/conf /mongodb/10003/data /mongodb/10003/log
mkdir -p /mongodb/10004/conf /mongodb/10004/data /mongodb/10004/log
cat > /mongodb/10003/conf/mongod.conf <<EOF
systemLog:
  destination: file
  path: /mongodb/10003/log/mongodb.log
  logAppend: true
storage:
  journal:
    enabled: true
  dbPath: /mongodb/10003/data
  directoryPerDB: true
  #engine: wiredTiger
  wiredTiger:
    engineConfig:
      cacheSizeGB: 0.5
      directoryForIndexes: true
    collectionConfig:
      blockCompressor: zlib
    indexConfig:
      prefixCompression: true
processManagement:
  fork: true
net:
  port: 10003
  bindIp: 10.0.0.52,127.0.0.1
replication:
  oplogSizeMB: 2048
  replSetName: my_repl
EOF
cp  /mongodb/10003/conf/mongod.conf  /mongodb/10004/conf/
sed 's#10003#10004#g' /mongodb/10004/conf/mongod.conf -i
mongod -f /mongodb/10003/conf/mongod.conf
mongod -f /mongodb/10004/conf/mongod.conf

配置文件 -db03

su - mongod
mkdir -p /mongodb/10005/conf /mongodb/10005/data /mongodb/10005/log
cat > /mongodb/10005/conf/mongod.conf <<EOF
systemLog:
  destination: file
  path: /mongodb/10005/log/mongodb.log
  logAppend: true
storage:
  journal:
    enabled: true
  dbPath: /mongodb/10005/data
  directoryPerDB: true
  #engine: wiredTiger
  wiredTiger:
    engineConfig:
      cacheSizeGB: 0.5
      directoryForIndexes: true
    collectionConfig:
      blockCompressor: zlib
    indexConfig:
      prefixCompression: true
processManagement:
  fork: true
net:
  port: 10005
  bindIp: 10.0.53,127.0.0.1
replication:
  oplogSizeMB: 2048
  replSetName: my_repl
EOF
mongod -f /mongodb/10005/conf/mongod.conf

初始化副本集 member信息

config = {
  _id: 'my_repl',
  members: [
    { _id: 0, host: '10.0.0.51:10001' },
    { _id: 1, host: '10.0.0.51:10002' },
    { _id: 2, host: '10.0.0.52:10003' },
    { _id: 3, host: '10.0.0.52:10004' },
    { _id: 4, host: '10.0.0.53:10005' }
  ]
}
rs.initiate(config)

3.2 两地三中心定制化配置¶

cfg = rs.conf()
cfg.members[1].priority = 20
cfg.members[2].priority = 10
cfg.members[3].priority = 10
rs.reconfig(cfg)

3.3 复制集安全加固¶

# db01
openssl rand -base64 756 > /mongodb/10001/conf/keyfile
cp -a  /mongodb/10001/conf/keyfile /mongodb/10002/conf
chmod 600 /mongodb/10001/conf/keyfile /mongodb/10002/conf/keyfile
scp /mongodb/10001/conf/keyfile 10.0.0.52:/mongodb/10003/conf
scp /mongodb/10001/conf/keyfile 10.0.0.52:/mongodb/10004/conf
scp /mongodb/10001/conf/keyfile 10.0.53:/mongodb/10005/conf

每个节点开启验证:

cat >> /mongodb/10001/conf/mongod.conf<<EOF
security:
  keyFile: /mongodb/10001/conf/keyfile
EOF
cat >>/mongodb/10002/conf/mongod.conf<<EOF
security:
  keyFile: /mongodb/10002/conf/keyfile
EOF
cat >> /mongodb/10003/conf/mongod.conf <<EOF
security:
  keyFile: /mongodb/10003/conf/keyfile
EOF
cat >> /mongodb/10004/conf/mongod.conf <<EOF
security:
  keyFile: /mongodb/10004/conf/keyfile
EOF
cat >> /mongodb/10005/conf/mongod.conf <<EOF
security:
  keyFile: /mongodb/10005/conf/keyfile
EOF

use admin
db.shutdownServer()

+++++

Shut down each mongod in the replica set, starting with the secondaries. Continue until all members of the replica set are offline, including any arbiters. The primary must be the last member shut down to avoid potential rollbacks.