Manipulating Member State
Turning Primaries into Secondaries
rs.stepDown(300);
MongoDB Enterprise OurReplica:PRIMARY> db.printReplicationInfo()
log length start to end: 51327secs (14.26hrs)
oplog first event time: Fri Sep 14 2018 12:52:15 GMT+0530 (IST)
oplog last event time: Sat Sep 15 2018 03:07:42 GMT+0530 (IST)
now: Sat Sep 15 2018 03:07:50 GMT+0530 (IST)
MongoDB Enterprise OurReplica:PRIMARY>
MongoDB
Enterprise OurReplica:PRIMARY> rs.stepDown(300)
2018-09-15T02:36:43.720+0530
E QUERY [js] Error: error doing query:
failed: network
error while attempting to run command 'replSetStepDown' on host
'127.0.0.1:6666' :
DB.prototype.runCommand@src/mongo/shell/db.js:168:1
DB.prototype.adminCommand@src/mongo/shell/db.js:186:16
rs.stepDown@src/mongo/shell/utils.js:1398:12
@(shell):1:1
2018-09-15T02:36:43.722+0530
I NETWORK [js] trying reconnect to
127.0.0.1:6666 failed
2018-09-15T02:36:43.722+0530
I NETWORK [js] reconnect 127.0.0.1:6666
ok
MongoDB
Enterprise OurReplica:SECONDARY>
Preventing Election
If you need to do
some maintenance on the Primary but don't want to any of the other eligible
members to become Primary in the interim, you can force them to stay
secondaries by running freeze on each of them.
port: 7777
MongoDB
Enterprise OurReplica:SECONDARY> rs.freeze(1200)
{
"ok" : 1,
"operationTime" :
Timestamp(1536959629, 1),
"$clusterTime" : {
"clusterTime" :
Timestamp(1536959629, 1),
"signature" : {
"hash" :
BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" :
NumberLong(0)
}
}
}
MongoDB
Enterprise OurReplica:SECONDARY>
port : 8888
MongoDB
Enterprise OurReplica:SECONDARY> rs.freeze(1200)
{
"ok" : 1,
"operationTime" :
Timestamp(1536959649, 1),
"$clusterTime" : {
"clusterTime" :
Timestamp(1536959649, 1),
"signature" : {
"hash" :
BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" :
NumberLong(0)
}
}
}
MongoDB
Enterprise OurReplica:SECONDARY>
port: 6666(Primary)
now: I tried to
stepDown Primary server 6666. Let see what will happen now.
MongoDB
Enterprise OurReplica:PRIMARY> rs.stepDown(300)
2018-09-15T02:44:58.439+0530
E QUERY [js] Error: error doing query:
failed: network error while attempting to run command 'replSetStepDown' on host
'127.0.0.1:6666' :
DB.prototype.runCommand@src/mongo/shell/db.js:168:1
DB.prototype.adminCommand@src/mongo/shell/db.js:186:16
rs.stepDown@src/mongo/shell/utils.js:1398:12
@(shell):1:1
2018-09-15T02:44:58.440+0530
I NETWORK [js] trying reconnect to
127.0.0.1:6666 failed
2018-09-15T02:44:58.441+0530
I NETWORK [js] reconnect 127.0.0.1:6666
ok
MongoDB
Enterprise OurReplica:SECONDARY>
MongoDB
Enterprise OurReplica:SECONDARY>
MongoDB
Enterprise OurReplica:SECONDARY>
MongoDB
Enterprise OurReplica:SECONDARY>
Verify the status
of the replication, All nodes are secondaries and there is no primary in the
replica set for 5 minutes ((we gave command rs.stepDown(300)). If you verify
after 5 minutes in current secondary server (6666) it will be back to primary
state automatically after our maintenance activity.
MongoDB
Enterprise OurReplica:SECONDARY> rs.status();
{
"set" :
"OurReplica",
"date" :
ISODate("2018-09-14T21:16:32.594Z"),
"myState" : 2,
"term" : NumberLong(12),
"syncingTo" : "",
"syncSourceHost" :
"",
"syncSourceId" : -1,
"heartbeatIntervalMillis" :
NumberLong(2000),
"optimes" : {
"lastCommittedOpTime"
: {
"ts" :
Timestamp(1536959689, 1),
"t" :
NumberLong(12)
},
"readConcernMajorityOpTime" : {
"ts" :
Timestamp(1536959689, 1),
"t" :
NumberLong(12)
},
"appliedOpTime" : {
"ts" :
Timestamp(1536959689, 1),
"t" :
NumberLong(12)
},
"durableOpTime" : {
"ts" :
Timestamp(1536959689, 1),
"t" :
NumberLong(12)
}
},
"lastStableCheckpointTimestamp" : Timestamp(1536959689, 1),
"members" : [
{
"_id" : 0,
"name" :
"127.0.0.1:6666",
"health" : 1,
"state" : 2,
"stateStr" :
"SECONDARY",
"uptime" :
4100,
"optime" : {
"ts"
: Timestamp(1536959689, 1),
"t" : NumberLong(12)
},
"optimeDate"
: ISODate("2018-09-14T21:14:49Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId"
: -1,
"infoMessage"
: "could not find member to sync from",
"configVersion" : 22,
"self" :
true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" :
"127.0.0.1:7777",
"health" : 1,
"state" : 2,
"stateStr" :
"SECONDARY",
"uptime" :
4098,
"optime" : {
"ts"
: Timestamp(1536959689, 1),
"t" :
NumberLong(12)
},
"optimeDurable" : {
"ts" :
Timestamp(1536959689, 1),
"t" :
NumberLong(12)
},
"optimeDate"
: ISODate("2018-09-14T21:14:49Z"),
"optimeDurableDate" : ISODate("2018-09-14T21:14:49Z"),
"lastHeartbeat" :
ISODate("2018-09-14T21:16:32.485Z"),
"lastHeartbeatRecv" :
ISODate("2018-09-14T21:16:32.469Z"),
"pingMs" :
NumberLong(0),
"lastHeartbeatMessage" :
"",
"syncingTo" :
"",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage"
: "",
"configVersion" : 22
},
{
"_id" : 2,
"name" :
"127.0.0.1:8888",
"health" : 1,
"state" : 2,
"stateStr" :
"SECONDARY",
"uptime" : 3760,
"optime" : {
"ts"
: Timestamp(1536959689, 1),
"t" :
NumberLong(12)
},
"optimeDurable" : {
"ts"
: Timestamp(1536959689, 1),
"t" : NumberLong(12)
},
"optimeDate"
: ISODate("2018-09-14T21:14:49Z"),
"optimeDurableDate" :
ISODate("2018-09-14T21:14:49Z"),
"lastHeartbeat" :
ISODate("2018-09-14T21:16:32.485Z"),
"lastHeartbeatRecv" :
ISODate("2018-09-14T21:16:32.486Z"),
"pingMs" :
NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" :
"",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage"
: "",
"configVersion"
: 22
},
{
"_id" : 3,
"name" :
"127.0.0.1:9999",
"health" : 1,
"state" : 7,
"stateStr" :
"ARBITER",
"uptime" :
4098,
"lastHeartbeat" :
ISODate("2018-09-14T21:16:32.485Z"),
"lastHeartbeatRecv" :
ISODate("2018-09-14T21:16:32.485Z"),
"pingMs" :
NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" :
"",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage"
: "",
"configVersion" : 22
}
],
"ok" : 1,
"operationTime" :
Timestamp(1536959689, 1),
"$clusterTime" : {
"clusterTime" :
Timestamp(1536959689, 1),
"signature" : {
"hash" :
BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" :
NumberLong(0)
}
}
}
MongoDB
Enterprise OurReplica:SECONDARY>
I reconnected after 5 minutes in primary. It is
back to earlier state. i.e. PRIMARY
MongoDB
Enterprise OurReplica:SECONDARY>
exit
bye
[root@nosqlDB
mongodb]# mongo --port 6666
MongoDB shell
version v4.0.0
connecting to:
mongodb://127.0.0.1:6666/
MongoDB server
version: 4.0.0
Server has
startup warnings:
2018-09-15T01:38:12.762+0530
I STORAGE [initandlisten]
2018-09-15T01:38:12.762+0530
I STORAGE [initandlisten] ** WARNING:
Using the XFS filesystem is strongly recommended with the WiredTiger storage
engine
2018-09-15T01:38:12.762+0530
I STORAGE [initandlisten] ** See http://dochub.mongodb.org/core/prodnotes-filesystem
2018-09-15T01:38:13.868+0530
I CONTROL [initandlisten]
2018-09-15T01:38:13.868+0530
I CONTROL [initandlisten] ** WARNING:
Access control is not enabled for the database.
2018-09-15T01:38:13.868+0530
I CONTROL [initandlisten] ** Read and write access to data and
configuration is unrestricted.
2018-09-15T01:38:13.868+0530
I CONTROL [initandlisten] ** WARNING:
You are running this process as the root user, which is not recommended.
2018-09-15T01:38:13.868+0530
I CONTROL [initandlisten]
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten]
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten] ** WARNING:
/sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten] ** We suggest setting it to 'never'
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten]
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten] ** WARNING:
/sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten] ** We suggest setting it to 'never'
2018-09-15T01:38:13.869+0530
I CONTROL [initandlisten]
MongoDB
Enterprise OurReplica:PRIMARYMongoDB Enterprise OurReplica:SECONDARY> rs.freeze(0);
{
"info" : "unfreezing",
"ok" : 1,
"operationTime" : Timestamp(1536960082, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1536960082, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
MongoDB Enterprise OurReplica:SECONDARY>
MongoDB Enterprise OurReplica:SECONDARY> rs.freeze(0)
{
"info" : "unfreezing",
"ok" : 1,
"operationTime" : Timestamp(1536960092, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1536960092, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
MongoDB Enterprise OurReplica:SECONDARY>
