Redis cluster operation method

Redis Methods of cluster operation

This article introduces “Redis Methods of cluster operation ” Knowledge about , During the operation of the actual case , Many people will encounter such difficulties , Next, let Xiaobian lead you to learn how to deal with these situations ！ I hope you will read carefully , Be able to learn ！

Based on a certain foundation , Here is a basic version of "three masters and three slaves" , The structure is as follows

1、 Start cluster

/usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8001/redis.conf /usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8002/redis.conf /usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8003/redis.conf /usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8004/redis.conf /usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8005/redis.conf /usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8006/redis.conf

View the cluster status ：cluster nodes

As can be seen from the above figure , The whole cluster is running normally , Three master Nodes and three slave node ,

• 8001 The instance node of the port stores 0-5460 these hash Slot ,

• 8002 The instance node of the port stores 5461-10922 these hash Slot ,

• 8003 The instance node of the port stores 10923-16383 these hash Slot ,

These three master All that the node stores hash Tank composition redis The storage slot of the cluster ,slave Point is the backup slave node of each master node , The storage slot is not displayed .

2、 Cluster operation

        Let's add another host to the original cluster (8007) ever since (8008), See the figure below for the cluster after adding nodes , The new nodes are represented by dotted lines

2.1、 increase redis example

        stay /usr/local/redis-cluster Create 8007 and 8008 Folder , And copy 8001 Under folder redis.conf File to 8007 and 8008 Under these two folders

mkdir 8007 8008 cd 8001cp redis.conf /usr/local/redis‐cluster/8007/ cp redis.conf /usr/local/redis‐cluster/8008/ #  modify 8007 Under folder redis.conf The configuration file vim /usr/local/redis‐cluster/8007/redis.conf #  Modify the following ：port:8007 dir /usr/local/redis‐cluster/8007/cluster‐config‐file nodes‐8007.conf #  modify 8008 Under folder redis.conf The configuration file vim /usr/local/redis‐cluster/8008/redis.conf#  The modification is as follows ：port:8008dir /usr/local/redis‐cluster/8008/cluster‐config‐file nodes‐8008.conf#  start-up 8007 and 8008 Two services and check the service status /usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8007/redis.conf/usr/local/redis‐5.0.3/src/redis‐server /usr/local/redis‐cluster/8008/redis.confps ‐el | grep redis

2.2、 To configure 8007 Master node

use add-node Command to add a master node 8007(master), Ahead ip:port For new nodes , hinder ip:port For known nodes , At the end of the log is "[OK] New node added correctly" The prompt indicates that the new node has joined successfully

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐‐cluster add‐node 192.168.0.61:8007 192.168.0.61:8001

View the cluster status

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐c ‐h 192.168.0.61 ‐p 8001192.168.0.61:8001> cluster nodes

As shown below ：

Be careful ： When the node is added successfully , The new node will not have any data , Because it hasn't allocated any slot(hash Slot ), We need to manually assign... To new nodes hash Slot

Use redis-cli The order is 8007 Distribute hash Slot , Find any primary node in the cluster , Re slice it

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐‐cluster reshard 192.168.0.61:8001

2.3、 To configure 8008 by 8007 The slave node

Add slave node 8008 Go to the cluster and check the cluster status

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐‐cluster add‐node 192.168.0.61:8008 192.168.0.61:8001

as follows ：

As shown in the figure , Or a master node , Not assigned anything hash Slot .

reason ： We need to implement replicate Command to specify the current node ( From the node ) The primary node of id For which , First you need to connect the new 8008 The client of the node , Then use the cluster command to operate , Put the current 8008(slave) Nodes are assigned to a primary node ( Here we use the 8007 Master node )

Execution instruction

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐c ‐h 192.168.0.61 ‐p 8008 192.168.0.61:8008> cluster replicate 2728a594a0498e98e4b83a537e19f9a0a3790f38 # This string in the back id by 8007 The node of id

View the cluster status ,8008 Node was successfully added as 8007 The slave node of the node

2.4、 Delete 8080 From the node [ Do not delete four master and four slave ]

use del-node Delete from node 8008, Specify delete node ip And port , And nodes id( Red as 8008 node id)

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐‐cluster del‐node 192.168.0.61:8008 a1cfe35722d151cf70585cee212755653 93c0956

Check the cluster status again , As shown in the figure below ,8008 This slave The node has been removed , And the node's redis Services have also been stopped

2.5、 Delete 8007 Master node [ Do not delete four master and four slave ]

Because there are assignments in the master node hash Grooved , So we have to put 8007 Inside hash Slot into other available master nodes , Then remove the node , Otherwise, there will be data loss ( At present, only master Data is migrated to a node , We can't do the average distribution function for the time being ), Execute the order as follows ：

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐‐cluster reshard 192.168.0.61:8007

Migration validation ： Will find 8007 There is no more hash There's a slot , Prove that the migration was successful ！

use del-node Command deletion 8007 The primary node is just

/usr/local/redis‐5.0.3/src/redis‐cli ‐a user ‐‐cluster del‐node 192.168.0.61:8007 2728a594a0498e98e4b83a537e19f9a0a 3790f38

View the final cluster status , Find that everything is restored , This completes the horizontal expansion

“Redis Methods of cluster operation ” That's all for , Thanks for reading . If you want to know more about the industry, you can pay attention to Yisu cloud website , Xiaobian will output more high-quality practical articles for you ！