Distributed deployment of Redis has the following advantages:
- High availability : Distributed deployment can avoid single point of failure and improve system availability.
- High performance : Distributed deployment can improve system throughput and response speed by increasing the number of nodes.
- Easy to expand : Distributed deployment can easily expand the capacity and performance of the system, just add new nodes.
There are many ways to distribute Redis, such as master-slave replication, sentinel mode, and cluster mode. Each method has its own advantages and disadvantages, and it needs to be selected according to business needs and actual conditions. During deployment, it is necessary to pay attention to issues such as communication between nodes, data synchronization, and load balancing to ensure the stability and reliability of the system.
Redis master-slave replication deployment
Introduction
In the Redis master-slave replication mode, one Redis node acts as the master node and the other nodes act as slave nodes. The master node is responsible for writing data, and the slave node is responsible for reading data and synchronizing data with the master node. The master node synchronizes the written data to the slave node, and the slave node stores the data after receiving it, and keeps in sync with the master node, so that it can quickly perform failover when the master node is down.
advantage
- High availability : Master-slave replication can improve the availability of Redis. Even if the master node goes down, the slave nodes can quickly take over the work to ensure the normal operation of the system.
- Easy to deploy : Master-slave replication deployment is relatively easy, no complicated configuration is required, only some configurations need to be added on the slave nodes.
- Separation of reading and writing : the master node is responsible for writing data, and the slave node is responsible for reading data, which can distribute the load to multiple nodes and improve system performance.
shortcoming
- Single point of failure : The master node in master-slave replication still has the problem of single point of failure. If the master node goes down, failover is required so that the slave node can take over the work.
- Data consistency : There is a certain delay in data synchronization in master-slave replication, and data inconsistency may occur. If you need to ensure the real-time and consistency of data, you need to use the cluster mode.
deployment steps
- Configure the master node
Create a configuration file redis.conf on the master node, and configure information such as the IP address and port number of the master node.
- Start the master node
When starting the master node, you need to specify the path and name of the configuration file, for example:
redis-server /path/to/redis.conf
- Configure slave nodes
Create a configuration file redis.conf on the slave node, and configure information such as the IP address and port number of the slave node. The IP address and port number of the master node need to be specified in the configuration file.
- Start the slave node
When starting a slave node, you need to specify the path and name of the configuration file, for example:
redis-server /path/to/redis.conf
- Configure the master-slave relationship
Set the IP address and port number of the master node on the slave node, for example:
slaveof <master_ip> <master_port>
- Check master-slave relationship
Use the command info replication to check whether the master-slave relationship has been established. If the master-slave relationship has been established, the slave node will display the information of the master node.
The Redis master-slave replication mode can improve the availability and performance of Redis, and is suitable for scenarios that do not require very high data real-time and consistency. During deployment, it is necessary to pay attention to issues such as communication and data synchronization between master and slave nodes to ensure the stability and reliability of the system.
scenes to be used
Master-slave replication is suitable for scenarios that require high data availability but not very high data real-time and consistency requirements, such as cache systems and business systems that read more and write less.
Redis sentinel mode deployment
Introduction
Redis sentinel mode is a special distributed deployment method, which realizes high availability of master-slave replication by monitoring the status of the master node. In Redis sentinel mode, there are one or more sentinel nodes responsible for monitoring the status of the master node. When the master node goes down, the sentinel node will automatically switch the slave node to the master node and notify other nodes to update. In this way, the problem of system unavailability caused by the downtime of the master node can be avoided.
advantage
- High availability : Sentinel mode can achieve high availability of master-slave replication. Even if the master node goes down, the sentinel node can automatically switch the slave node to the master node to ensure the normal operation of the system.
- Easy to deploy : Compared with the cluster mode, the sentinel mode is relatively easy to deploy, and does not require complicated configurations. It only needs to add some configurations on the sentinel nodes.
- Automatic switching : Sentinel nodes can automatically switch slave nodes to master nodes, avoiding the process of manual switching and improving the availability of the system.
shortcoming
- Performance loss : Sentinel nodes will periodically detect the master node, which will have a certain impact on the performance of the master node.
- Complexity : Sentinel mode involves communication and coordination among multiple nodes. Compared with master-slave replication, the complexity of deployment and maintenance is higher.
scenes to be used
Sentinel mode is suitable for scenarios that require high data availability but not high real-time and consistency requirements, such as cache systems and business systems with more reads and fewer writes.
deployment steps
- Create configuration file
Create a configuration file sentinel.conf on the sentinel node. In the configuration file, you need to specify the IP address and port number of the sentinel node, as well as the information of the master node to be monitored.
- Start sentinel node
When starting a Sentinel node, you need to specify the path and name of the configuration file, for example:
redis-sentinel /path/to/sentinel.conf
- Configure the master node
Create a configuration file redis.conf on the master node, and configure information such as the IP address and port number of the master node.
- Start the master node
When starting the master node, you need to specify the path and name of the configuration file, for example:
redis-server /path/to/redis.conf
- Configure slave nodes
Create a configuration file redis.conf on the slave node, and configure information such as the IP address and port number of the slave node. The IP address and port number of the master node need to be specified in the configuration file.
- Start the slave node
When starting a slave node, you need to specify the path and name of the configuration file, for example:
redis-server /path/to/redis.conf
- Check sentinel node status
Use the command sentinel masters to view the status of the sentinel node and the information of the master node. If the master node goes down, the sentinel node will automatically switch the slave node to the master node.
Summarize
The Redis sentinel mode is a way to achieve high availability of master-slave replication. It can automatically switch the slave node to the master node to ensure the availability of the system. Compared with the cluster mode, the sentinel mode is less complex to deploy and maintain, and is suitable for scenarios that do not require very high data real-time and consistency.
Redis cluster mode deployment
Introduction
Redis cluster mode is a highly available and high-performance distributed deployment method, which can disperse data to multiple nodes for storage, improving system throughput and response speed. In the Redis cluster mode, multiple nodes form a cluster, and each node stores the mapping relationship between some data and other nodes. When data needs to be read and written, the client will send the data to the corresponding node for processing according to the hash algorithm.
advantage
- High availability : Redis cluster mode can avoid single point of failure and improve the availability of Redis. When a node goes down, other nodes can take over the work to ensure the normal operation of the system.
- High performance : Redis cluster mode can increase the throughput and response speed of the system by increasing the number of nodes. When a large number of concurrent requests need to be processed, the load can be distributed to multiple nodes for processing to avoid performance bottlenecks.
- Easy to expand : Redis cluster mode can easily expand the capacity and performance of the system, just add new nodes. When the number of nodes is small, dynamic expansion can be adopted. When the number of nodes is large, static fragmentation can be used for deployment.
shortcoming
- Complexity : The Redis cluster mode involves communication and coordination between multiple nodes. Compared with the master-slave replication and sentinel mode, the complexity of deployment and maintenance is higher.
- Data consistency : There is a certain delay in data synchronization in Redis cluster mode, and data inconsistency may occur. If you need to ensure the real-time and consistency of data, you need to use other methods.
scenes to be used
The Redis cluster mode is suitable for scenarios that require high data availability and performance, such as e-commerce websites, online games, and social platforms.
deployment steps
- Create configuration file
Create a configuration file redis.conf on each node, and configure the node's IP address and port number and other information. Cluster mode parameters need to be specified in the configuration file, such as cluster-enabled, cluster-config-file, cluster-node-timeout, etc.
- start node
When starting each node, you need to specify the path and name of the configuration file, for example:
redis-server /path/to/redis.conf
- create cluster
Use the command redis-cli --cluster create <node1>:<port1> <node2>:<port2> ... <nodeN>:<portN> --cluster-replicas <replicas> to create a Redis cluster. Among them, <node1>:<port1> to <nodeN>:<portN> are the IP addresses and port numbers of the nodes, and <replicas> is the number of slave nodes for each master node.
- Check cluster status
Use the command redis-cli --cluster check <ip>:<port> to check the status of the cluster. If the cluster status is normal, the information and data distribution of each node will be displayed.
Summarize
Redis cluster mode is a highly available and high-performance distributed deployment method, which is suitable for scenarios with high data availability and performance requirements. During deployment, it is necessary to pay attention to issues such as communication between nodes, data synchronization, and load balancing to ensure the stability and reliability of the system.
Deploy Redis cluster on Docker
- Download the Redis mirror
Download the Redis image from Docker Hub with the following command:
docker pull redis
- Create a Docker network
Create a Docker network with the following command:
docker network create redis-network
- Start the Redis container
Start 6 Redis containers with the following commands:
docker run -d --name redis1 --net redis-network redis redis-server --appendonly yes
docker run -d --name redis2 --net redis-network redis redis-server --appendonly yes
docker run -d --name redis3 --net redis-network redis redis-server --appendonly yes
docker run -d --name redis4 --net redis-network redis redis-server --appendonly yes
docker run -d --name redis5 --net redis-network redis redis-server --appendonly yes
docker run -d --name redis6 --net redis-network redis redis-server --appendonly yes
- Create a Redis cluster
Create a Redis cluster with the following command:
docker run -it --rm --net redis-network redis redis-cli --cluster create \\\\
172.18.0.2:6379 172.18.0.3:6379 172.18.0.4:6379 \\\\
172.18.0.5:6379 172.18.0.6:6379 172.18.0.7:6379 \\\\
--cluster-replicas 1
Among them, 172.18.0.2 to 172.18.0.7 is the IP address of the Redis container, 6379 is the port number of the Redis container, --cluster-replicas 1 means that each master node has a slave node.
- Check Redis cluster status
Check the Redis cluster status with the following command:
docker run -it --rm --net redis-network redis redis-cli --cluster check 172.18.0.2:6379
If the cluster status is normal, the information and data distribution of each node will be displayed.
Summarize
Deploying a Redis cluster on Docker can be convenient for testing and development, and it can also improve the availability and performance of Redis. During deployment, it is necessary to pay attention to issues such as communication between nodes, data synchronization, and load balancing to ensure the stability and reliability of the system.