1 introduction
Before Redis 3.0, sentinel mechanism was used to monitor the status between nodes. Redis Cluster is a distributed solution of Redis, which was officially launched in version 3.0, effectively solving the needs of Redis in the distributed aspect. Cluster architecture can be used to achieve load balancing when encountering bottlenecks such as single memory, concurrency and flow
2 Redis Cluster Describes the Cluster
The Redis Cluster Cluster mode usually has the features of high availability, scalability, distribution, and fault tolerance. Redis Cluster uses ** virtual slot partitions. ** What is a virtual slot partition
2.1 Virtual Slot Partitioning
Virtual slot partitioning makes clever use of hash space, using well-distributed hash functions to map all data into a fixed range of integers defined as slots. Generally, the range is much larger than the number of nodes. For example, the range of Redis Cluster slots is 0 to 16,383. A slot is the basic unit for data management and migration in a cluster. The main purpose of adopting a wide range of slots is to facilitate data splitting and cluster expansion. Each node is responsible for a certain number of slots, as shown in the figure:
The current cluster has five nodes, and each node is responsible for an average of about 3276 slots. Due to the high quality hash algorithm, the data mapped by each slot is usually fairly uniform, and the data is evenly divided into 5 nodes for data partitioning. Redis Cluster uses virtual slot partitions.
- Node 1: contains hash slots 0 to 3276.
- Node 2: Contains hash slots 3277 through 6553.
- Node 3: contains hash slots 6554 through 9830.
- Node 4: Contains hash slots 9831 through 13107.
- Node 5: Contains hash slots 13108 to 16383.
This structure makes it easy to add or remove nodes. If a node 6 is added, some slots from nodes 1 to 5 are allocated to node 6. If you want to remove node 1, move the slots in node 1 to nodes 2 to 5, and remove node 1 from the cluster.
Since moving a hash slot from one node to another does not stop service, adding or deleting or changing the number of hash slots on a node does not make the cluster unavailable.
2.2 Redis data partitioning
Redis Cluster uses virtual slot partitioning. All keys are mapped into slots 0 to 16383 according to the hash function. Each node is responsible for maintaining a part of slots and the key value data mapped to the slots, as shown in the figure:
3 Redis cluster construction
3.1 Environment Preparation
3.1.1 install GCC
Redis installation requires the GCC environment
\1. Check whether GCC is installed
Run the GCC -v command
If the GCC version information is displayed, GCC is installed. Otherwise, install GCC
\ 2. Install the GCC
Create a directory /usr/local/gccsrc
Upload the following RPM files to the /usr/local/gccsrc directory
CPP – 4.8.5-11. El7. X86_64. RPM
GCC – 4.8.5-11. El7. X86_64. RPM
Glibc – devel – 2.17-157. El7. X86_64. RPM
Glibc – headers – 2.17-157. El7. X86_64. RPM
The kernel – the headers – 3.10.0-514. El7. X86_64. RPM
Libmpc 1.0.1-3. El7. X86_64. RPM
MPFR 3.1.1-4. El7. X86_64. RPM
\3. Install in sequence
The RPM – the ivh MPFR 3.1.1-4. El7. X86_64. RPM
The RPM – the ivh libmpc 1.0.1-3. El7. X86_64. RPM
The RPM – the ivh kernel headers – 3.10.0-514. El7. X86_64. RPM
The RPM – the ivh glibc – headers – 2.17-157. El7. X86_64. RPM
The RPM – the ivh glibc – devel – 2.17-157. El7. X86_64. RPM
The RPM – the ivh CPP – 4.8.5-11. El7. X86_64. RPM
The RPM – the ivh GCC – 4.8.5-11. El7. X86_64. RPM
\4. Verify GCC -V after successful installation
3.1.2 installation zlib
Because Redis cluster environment needs to use ruby interface, need to use Redis gem package, and install gem package needs zlib environment
1. Upload zlib-1.2.11.tar.gz to /usr/local
2. Decompress tar -xzvf zlib-1.2.11.tar.gz
3, CD zlib – 1.2.11
4,. / configure — prefix = / usr/local/zlib
GCC check for GCC check for GCC check for GCC
5, make
6, make install
3.1.3 install openssl
Because Redis cluster environment needs to use Ruby interface, need to use Redis gem package, and install gem package need to have OpenSSL environment
1. Upload openSSL-1.0.1h.tar. gz to /usr/local/
2. Decompress tar -xzvf openSSL-1.0.1h.tar.gz
3, CD openssl – h / 1.0.1
/ config-fpic –prefix=/usr/local/openssl enable-shared
5,. / config – t
6, make && make install
7, which openSSL // Check the path of system OpenSSL
Rm -rf /usr/bin/openssl // /usr/bin/openssl is the path to which openssl of an earlier version is displayed
9, cp/usr/local/openssl/bin/openssl/usr/bin/openssl / / copy the new version of the installation path to the system path
10. Run openSSL version
Output Version Information
3.1.4 install ruby
Ruby is required to install a Redis cluster environment
1. Upload ruby-2.1.7.tar. gz to /usr/local
2, decompress tar -xzvf ruby-2.1.7.tar. gz
3, CD ruby – 2.5.7
/configure — prefix=/usr/local/ruby //-prefix =/usr/local/ruby //-prefix
5, make && make install
The successful installation is shown
6. Configure environment variables
vi /etc/profile
Add environment variables as shown in the figure
7. Run the command to make the configuration file take effect
source /etc/profile
8. Run the following command to check whether the Ruby installation is successful: If the installation is successful, the Ruby version information is displayed
ruby -v
9. Go to the /usr/local/ruby-2.1.7/ex/zlib/directory
CD/usr/local/ruby – 2.5.7 / ext/zlib /
Note: /usr/local/ruby-2.5.7 this directory is used to decompress the ruby installation package.
Ruby extconf.rb –with-zlib-include=/usr/local/ zlib-include / –with-zlib-lib=/usr/local/ zlib-lib
(Note :/usr/local/zlib is the zlib installation directory and a Makefile will be generated after the command is executed.)
11. Open the Makefile and find the following line (third from last) to change the path
Zlib. o: $(top_srcdir)/include/ruby.h: zlib.o:.. /.. /include/ruby.h
12, make && make install
13. Go to the /usr/local/ruby-2.1.7/ex/openssl/directory
CD/usr/local/ruby – 2.5.7 / ext/openssl /
14, execute command:
ruby extconf.rb –with-openssl-include=/usr/local/openssl/include/ –with-openssl-lib=/usr/local/openssl/lib
(Note :/usr/local/openssl is the openSSL installation directory and a Makefile will be generated after the command is executed.)
15, open the Makefile in topdir = / usr/local/ruby/include/ruby – XXX behind a new line top_srcdir = / usr/local/ruby – 2.5.7
(Note that /usr/local/ruby-2.5.7 is the directory where ruby decompresses.)
16, make && make install
3.1.5 installed redis – 4.1.3. Gem
The redis-4.1.3.gem provides an interface to Ruby that is required to install a cluster environment
1. Upload redis-4.1.3.gem to /usr/local/
2. Run the gem install redis-4.1.3.gem command
The successful installation is shown
3.2 Installing single-server Redis
1. Create /usr/local/redis and upload redis-4.0.14.tar.gz to /usr/local/redis
2、cd /usr/local/redis
3, decompress tar -xzvf redis-4.0.14.tar.gz
Redis – 4.0.14/4, CD
5, make && make install
See the following information, The Redis installation is successful
Go to the installation directory CD /usr/local/redis/redis-4.0.14
6. Modify the redis.conf configuration file
Bind 127.0.0.1 to bind 0.0.0.0
Daemonize no daemonize yes
Protected -mode yes change to protected-mode no
Logfile “” logfile “” redis log store file path”
7, start redis command
Go to the redis installation directory /usr/local/redis/redis-4.0.14 and run the following command to start Redis
redis-server redis.conf
Run the following command to connect to Redis
Redis -cli -p 6379 -h 192.169.1.86
(Note: 6379 is the default redis port 192.169.1.86 is the IP address of the server where Redis resides.)
Run the set 1 1 command to save the value to Redis to test
3.3 Deploying a Cluster Environment
The cluster mode is equivalent to dividing data slots. Each node is divided into a data slice. In this case, when a node goes down and the node is not backed up, the shard is no longer available. Therefore, it is recommended that each node in the cluster be equipped with a slave node for cold backup.
The cluster deployment mode recommended on the official website is three-active/three-slave deployment. This section uses the three-active/three-slave deployment as an example.
Node information to be configured
| The name of the node | The port number | It is the Lord from | Owning Primary node |
|---|---|---|---|
| Redis7001 | 7001 | The main | |
| Redis7002 | 7002 | The main | |
| Redis7003 | 7003 | The main | |
| Redis7004 | 7004 | from | Redis7004 |
| Redis7005 | 7005 | from | Redis7001 |
| Redis7006 | 7006 | from | Redis7002 |
1. Access the /usr/local/redis/ directory
cd /usr/local/redis
2. Run mkdir redis700{1,2,3,4,5,6} to create folders redis7001, redis7002, redis7003, redis7004, redis7005, and redis7006
Copy redis-cli and redis-server from /usr/local/bin/ to redis7001… Redis7006 directory
1. Create the redis.conf file in the redis7001 directory
vim redis.conf
The file content
# port number (6 corresponding port numbers)
port 7001
appendonly yes
# start cluster
cluster-enabled yes
#yes Enables the daemon
daemonize yes
Associate the cluster configuration file
cluster-config-file “nodes.conf”
# set timeout
cluster-node-timeout 5000
# log message
logfile “redis7001.log”
# specify the access address
The bind 0.0.0.0
tcp-keepalive 300
Conf file is created in the redis7002 directory
The content of the file is
port 7002
appendonly yes
cluster-enabled yes
daemonize yes
cluster-config-file “nodes.conf”
cluster-node-timeout 5000
logfile “redis7002.log”
The bind 0.0.0.0
tcp-keepalive 300
Conf files are created in redis7003 to redis7006
Each directory (redis7001 through redis7006) should have these three files
Run the command redis-server redis.conf to start each service
/usr/local/redis/ sh script to start redis instance
vim startall.sh
cd redis7001
./redis-server redis.conf
cd ..
cd redis7002
./redis-server redis.conf
cd ..
cd redis7003
./redis-server redis.conf
cd ..
cd redis7004
./redis-server redis.conf
cd ..
cd redis7005
./redis-server redis.conf
cd ..
cd redis7006
./redis-server redis.conf
Grant executable permission to the startall.sh script
chmod 777 startall.sh
Run the startall.sh script
./startall.sh
Perform ps – ef | grep redis situation view redis running situation, start-up success as shown
Create a cluster and add these nodes to the cluster. First go to the directory where redis-trib.rb is located
Go to the /usr/local/redis/redis-4.0.14/src/ directory
CD/usr/local/redis/redis – 4.0.14 / SRC /
Run the following command:
./redis-trib.rb create –replicas 1 192.169.1.86:7001 192.169.1.86:7002 192.169.1.86:7003 192.169.1.86:7004 192.169.1.86:7005 192.169.1.86:7006
[Note :192.169.1.86 is the IP address of the server where Redis resides. Note: this IP address cannot be written as 127.0.0.1, otherwise only the local machine can connect to it.]
Enter yes and press Enter. Redis-trib. rb starts node handshake and slot allocation. As shown in the figure, the node is successfully added to the cluster
Note :M indicates the primary node, S indicates the secondary node.
Perform cluster check to check the number of hash slots and slot coverage occupied by each Redis node. Among 16,384 slots, Redis7001, Redis7002, and Redis7003 occupy 5461, 5462, and 5461 slots, respectively.
Cluster Connection Test
Connection command :redis-cli -p Port of one node -h IP -c of one node
[Note: There must be -c. -C indicates that the connection is in cluster mode. Without -c, the connection is a single point.]
And save a value to Redis for test :set a A, as shown in the following figure, it is successful
3.3 Adding passwords for each node in a Cluster Environment
There are two ways to add a password:
U Method 1: Modify the redis.conf configuration file in all Redis clusters
Masterauth 123456 // Set the master password so that Salve can connect to Master RequirePass 123456 // set the Redis passwordCopy the codeU Method 2: Enter the real-time configuration in each Redis cluster
/redis-cli -c -p 7001 // Set masterauth 123456 config set requirepass 123456 config rewriteCopy the codeNote: The password for each node must be the same or Redirected will fail. The first method is recommended.
To shutdown all redis services, run the redis-cli -p 7001 shutdown command to shutdown redis instances one by one. After the preceding steps, the corresponding node information file (nodes.conf) and data information file (appendone.aof, dump.rdb) are generated. Delete all three files from the redis7001 to redis7006 folders, then modify redis.conf to add the password as shown in the figure
Then go to the client.rb file (use find / -name “client.rb”) and change the password, as shown in the figure below
The script is then used to start all cluster nodes.
Run the./redis-trib.rb create –replicas 1 192.169.1.21:7001 192.169.1.21:7002 192.169.1.21:7003 192.169.1.21:7004 192.169.1.21:7005 192.169.1.21:7006 Create clusters.
Test cluster
Use redis-cli -c -p 7001 to set a set name song, you will be prompted for authentication by typing Auth “123456”, then set name song will redirected 7002, also requiring password Redis -cli -c -p 7001 -a 123456 connection (-a is equivalent to input password authentication), so you can directly jump to. As shown in figure
After the password is added, the script to close the redis instance should be modified accordingly. After the parameter of -a 123456 is added, the modified content is as follows:
