Shulou(Shulou.com)06/01 Report--

Introduction to the preface

The principle of replication:

The replication operation is based on oplog, similar to bin-log in mysql, and records only the records that have changed.

The principle of the election:

Nodes are divided into standard nodes, passive nodes and arbitration nodes.

Standard nodes (high priority value): only standard nodes can become primary

Passive node (low priority value): passive node can only be secondary

Arbitration node: cannot copy data, cannot become an active point, and only has the right to vote

Election result: the person with the highest number of votes wins; if the number of votes is the same, the newcomer wins.

I. introduction of replica set election experiment

Experimental procedure

View oplog Log

Configure the priority of the replication set

Simulate the failure of the primary node

Simulate all standard node failures

Second, copy set election experiment content

-- View oplog logs-

> use schoolswitched to db school > db.info.insert ({"id": 1, "name": "tom"}) WriteResult ({"nInserted": 1}) > db.info.find () {"_ id": ObjectId ("5b9a0873692de658bd931c64"), "id": 1, "name": "tom"} > use localswitched to db local > show collectionsmeoplog.rs... > db.oplog.rs.find () {"ts": Timestamp (1536723445, 3), … : {"create": "transactions", "idIndex": {"v": 2, "key": {"_ id": 1}, "name": "_ id_", "ns": "config.transactions"} {"ts": Timestamp (1536723445, 5), … : {"create": "system.keys", "idIndex": {"v": 2, "key": {"_ id": 1}, "name": "_ id_", "ns": "admin.system.keys"}

-configure the priority of replication sets-

Cfg= {"_ id": "yandada", "members": [{"_ id": 0, "host": "192.168.218.149 id 27017", "priority": 100}, {"_ id": 1, "host": "192.168.218.149 id 27018", "priority": 100}, {"_ id": 2, "host": "192.168.218.149 members" 27019 "," priority ": 0}, {" _ id ": 3 "host": "192.168.218.149 true 27020", "arbiterOnly": true}]}

Rs.reconfig (cfg)

{"ok": 1} / / when OK:1 is displayed, the node is configured successfully

Rs.status () / / View status information

Rs.isMaster () / / View node information

{/ / the display information is as follows

"hosts": [

"192.168.218.149Disc 27017"

"192.168.218.149Frey 27018"

]

"passives": [

"192.168.218.149Frey 27019"

]

"arbiters": [

"192.168.218.149Frey 27020"

]

-simulate the failure of the primary node

Shut down the primary node server

Yandada:PRIMARY > use admin # enter the admin collection to proceed to the next step

Switched to db admin

Yandada:PRIMARY > db.shutdownServer () # shut down the server

Server should be down...

The above operation is equivalent to [root@yandada3] # mongod-f / etc/mongod.conf-- shutdown

[root@yandada3] # mongo-- port 27018

Yandada:PRIMARY > rs.status ()

After viewing the status information, you will find that the MongoDB replication set elects the second standard node as the primary node.

-- simulate all standard node failures

[root@yandada3] # mongod-f / etc/mongod.conf-- shutdown

Killing process with pid: 4238

[root@yandada3] # mongo-- port 27019

Yandada:SECONDARY > rs.status ()

After viewing the status information, you will find that there is no primary node, and the passive node cannot become the primary node.

III. Brief introduction to replication set management

1. Configuration allows data to be read from nodes

Yandada:SECONDARY > rs.slaveOk ()

two。 View replication set status information

Rs.help ()

Yandada:PRIMARY > rs.printReplicationInfo ()

Configured oplog size: 990MB # oplog storage size is 990MB

Log length start to end: 101403secs (28.17hrs)

Oplog first event time: Wed Sep 12 2018 11:37:13 GMT+0800 (CST)

Oplog last event time Thu Sep 13 2018 15:47:16 GMT+0800 (CST)

Now Thu Sep 13 2018 15:47:17 GMT+0800 (CST)

Yandada:PRIMARY > rs.printSlaveReplicationInfo ()

Source: 192.168.218.149:27018

SyncedTo Thu Sep 13 2018 15:47:26 GMT+0800 (CST)

0 secs (0 hrs) behind the primary

Source: 192.168.218.149:27019

SyncedTo Thu Sep 13 2018 15:47:26 GMT+0800 (CST)

0 secs (0 hrs) behind the primary

3. Change the oplog siz

1. First step, exit the replication set

Yandada:PRIMARY > use admin

Switched to db admin

Yandada:PRIMARY > db.shutdownServer ()

Server should be down...

two。 The second step is to change the port (the source port is included in the replication set), close the replication set name in the configuration file, and start mongod

Vim / etc/mongod.conf

Net:

Port: 2

# replication:

# replSetName: yandada

Mongod-f / etc/mongod.conf

3. Step 3: change the oplog size

[root@yandada3] # mongo-- port 27028

> use local

Switched to db local

> db.oplog.rs.drop ()

True

> db.runCommand ({create: "oplog.rs", capped:true,size: (2,048,2048,2048)})

{"ok": 1}

[root@yandada3] # mongod-f / etc/mongod.conf-- shutdown

Killing process with pid: 8296

[root@yandada3 ~] # vim / etc/mongod.conf

Net:

Port: 27017

Replication:

ReplSetName: yandada

OplogSizeMB: 16384

[root@yandada3] # mongod-f / etc/mongod.conf

[root@yandada3 ~] # mongo

Yandada:SECONDARY > rs.printReplicationInfo ()

Configured oplog size: 16384MB # oplog size changed to 16G

4. Certified deployment

1. The first step is to create a certified user

Yandada:PRIMARY > use admin

Switched to db admin

Yandada:PRIMARY > db.createUser ({"user": "root", "pwd": "123"," roles ": [" root "]})

Successfully added user: {"user": "root", "roles": ["root"]}

two。 Step 2, edit the authentication configuration

Vim / etc/mongod.conf

Security:

KeyFile: / usr/bin/kgcrskey1

ClusterAuthMode:keyFile note: need to be flush with the previous line

In the same way, modify the mongod [2je 3je 4] file.

[root@yandada3 ~] # echo "kgcrskey" > / usr/bin/kgcrskey [1, 2, 3, 4]

[root@yandada3 bin] # echo "kgcrskey" > / usr/bin/kgcrskey1

[root@yandada3 bin] # echo "kgcrskey" > / usr/bin/kgcrskey2

[root@yandada3 bin] # echo "kgcrskey" > / usr/bin/kgcrskey3

[root@yandada3 bin] # echo "kgcrskey" > / usr/bin/kgcrskey4

[root@yandada3 bin] # chmod 600 / usr/bin/kgcrskey {1,2,3,4}

3. Step 3: restart the service

[root@yandada3 bin] # mongod-f / etc/mongod.conf-- shutdown

[root@yandada3 bin] # mongod-f / etc/mongod.conf

By the same token, restart mongod [2pr 3pr 4]

4. Step 4: check the configuration status

Yandada:PRIMARY > show dbs

"ok": 0 # No right to view

Yandada:PRIMARY > use admin

Switched to db admin

Yandada:PRIMARY > db.auth ("root", "123")

1 # the returned value is 1, which indicates that the authorization is successful

Yandada:PRIMARY > show dbs

Admin 0.000GB

Config 0.000GB

Local 0.000GB

School 0.000GB

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