Connecting to Redis on redis-cli

Prerequisites

• A Redis instance is created, and is in the Running state. To create a Redis instance, see Buying a DCS Redis Instance.
• An ECS has been created. For details about how to create an ECS, see Purchasing a Custom ECS.
• If the ECS runs the Linux OS, ensure that the GCC compilation environment has been installed on the ECS.

  Run the following command to install GCC on the ECS if needed:

  yum install -y make
  yum install -y pcre-devel
  yum install -y zlib-devel
  yum install -y libevent-devel
  yum install -y openssl-devel
  yum install -y gcc-c++

• The client and the Redis instance must be interconnected before connecting to the instance. For details, see Network Conditions for Accessing DCS Redis.

Connecting to Redis on redis-cli (Linux)

1. View the IP address/domain name and port number of the DCS Redis instance to be accessed.

   See Viewing Instance Details to obtain Connection Address or IP Address in the instance information. For more information, see Should I Use a Domain Name or an IP Address to Connect to a DCS Redis Instance?.

   For public access to Redis on a client, see Enabling Public Access to Redis 4.0/5.0/6.0 and Obtaining the Access Addresses to obtain the instance public addresses and ports.

   Figure 1 Obtaining the instance addresses
   
   

   • The following uses the port 6379. Replace 6379 with the actual port.
   • For Proxy Cluster Redis 4.0 and later instances, Connection Address and IP Address are load balancer addresses. The system distributes requests to different proxies.
   • You can use Backend Addresses to directly connect to the specified proxy node of a Proxy Cluster DCS Redis 3.0 instance.

2. Install redis-cli.

   The following steps assume that your client is installed on the Linux OS.

   1. Log in to the ECS.
   2. Run the following command to download the source code package of your Redis client from https://download.redis.io/releases/redis-6.2.13.tar.gz:

      wget http://download.redis.io/releases/redis-6.2.13.tar.gz

      

      The following uses redis-6.2.13 as an example. For details, see the Redis official website.

   3. Run the following command to decompress the source code package of your Redis client:

      tar -xzf redis-6.2.13.tar.gz

   4. Run the following commands to go to the Redis directory and compile the source code of your Redis client:

      cd redis-6.2.13
      make
      cd src

      

      If the source code of your Redis client is v6.0 and later, and redis-cli that supports TLS/SSL is required, replace the make command with make BUILD_TLS=yes to enable TLS.

3. Access the DCS Redis instance.
   • Access a DCS instance of a type other than Redis Cluster.
     Perform the following procedure to access a single-node, master/standby, read/write splitting, or Proxy Cluster instance.

     1. Run the following command to access the chosen DCS Redis instance:

        ./redis-cli -h {dcs_instance_address} -p {port}

        {dcs_instance_address} indicates the IP address/domain name of the DCS instance and {port} is the port used for accessing the instance. The IP address/domain name and port number are obtained in 1.

        The following example uses the domain name address of a DCS Redis instance. Change the connection address and port as required.

        [root@ecs-redis src]# ./redis-cli -h redis-069949a-dcs-lxy.dcs.huaweicloud.com -p 6379
        redis-069949a-dcs-lxy.dcs.huaweicloud.com:6379> 

     2. If you have set a password for the DCS instance, enter the password in this step. You can read and write cached data only after the password is verified. Skip this step if the instance is not password-protected.

        auth {password}

        {password} indicates the password used for logging in to the chosen DCS Redis instance. This password is defined during DCS Redis instance creation.

        The command output is as follows:

        redis-069949a-dcs-lxy.dcs.huaweicloud.com:6379> auth *******
        OK
        redis-069949a-dcs-lxy.dcs.huaweicloud.com:6379> 

   • Access a DCS instance of the Redis Cluster type.

     Perform the following procedure to access a Redis Cluster instance.

     1. Run the following command to access the chosen DCS Redis instance:

        ./redis-cli -h {dcs_instance_address} -p {port} -a {password} -c

        {dcs_instance_address} indicates the IP address/domain name of the DCS Redis instance, {port} is the port used for accessing the instance, {password} is the password of the instance, and -c is used for accessing Redis Cluster nodes. The IP address/domain name and port number are obtained in 1.

        

        • When connecting to a Redis Cluster instance using redis-cli, ensure that -c is added to the command. Otherwise, the connection will fail.
        • To connect to Redis on a client over a private network, you can set {dcs_instance_address} to Connection Address or IP Address in the Connection section, or IP Address in the Instance Topology section. The addresses can be obtained on the instance basic information page on the console, as shown in Figure 2.
        • For a password-protected instance, you do not need to enter the instance access password -a {password}. If you have forgotten the password or need to reset the password, see Resetting an Instance Password.
        • The IP Address field provides multiple IP addresses. You can use any of them to connect to the instance. The CRC16(key) mod 16384 algorithm is used to compute what is the hash slot of a given key. For higher reliability, configure all IP addresses.
        • By using the IP Address in the Instance Topology section, you can connect to the specified shard.
        Figure 2 Obtaining the addresses for connecting to a Redis Cluster DCS instance
        
        • The following example uses the IP address of a DCS Redis instance. Change the IP address and port as required.

          root@ecs-redis:~/redis-6.2.13/src# ./redis-cli -h 192.168.0.85 -p 6379 -a ****** -c
          192.168.0.85:6379> 

        • The following example uses the domain name of a DCS Redis instance. Change the domain name and port as required.

          root@ecs-redis:~/redis-6.2.13/src# ./redis-cli -h redis-51e463c-dcs-lxy.dcs.huaweicloud.com -p 6379 -a ****** -c
          redis-51e463c-dcs-lxy.dcs.huaweicloud.com:6379> 

     2. Run the cluster nodes command to view the Redis Cluster node information:

        Each shard in a Redis Cluster has a master and a replica by default. The proceeding command provides all the information of cluster nodes.

        192.168.0.85:6379> cluster nodes
        0988ae8fd3686074c9afdcce73d7878c81a33ddc 192.168.0.231:6379@16379 slave f0141816260ca5029c56333095f015c7a058f113 0 1568084030
        000 3 connected
        1a32d809c0b743bd83b5e1c277d5d201d0140b75 192.168.0.85:6379@16379 myself,master - 0 1568084030000 2 connected 5461-10922
        c8ad7af9a12cce3c8e416fb67bd6ec9207f0082d 192.168.0.130:6379@16379 slave 1a32d809c0b743bd83b5e1c277d5d201d0140b75 0 1568084031
        000 2 connected
        7ca218299c254b5da939f8e60a940ac8171adc27 192.168.0.22:6379@16379 master - 0 1568084030000 1 connected 0-5460
        f0141816260ca5029c56333095f015c7a058f113 192.168.0.170:6379@16379 master - 0 1568084031992 3 connected 10923-16383
        19b1a400815396c6223963b013ec934a657bdc52 192.168.0.161:6379@16379 slave 7ca218299c254b5da939f8e60a940ac8171adc27 0 1568084031
        000 1 connected

        Write operations can only be performed on master nodes. The CRC16(key) mod 16384 algorithm is used to compute what is the hash slot of a given key.

        As shown in the following, the value of CRC16 (KEY) mode 16384 determines the hash slot that a given key is located at and redirects the client to the node where the hash slot is located at.

        192.168.0.170:6379> set hello world
        -> Redirected to slot [866] located at 192.168.0.22:6379
        OK
        192.168.0.22:6379> set happy day
        OK
        192.168.0.22:6379> set abc 123
        -> Redirected to slot [7638] located at 192.168.0.85:6379
        OK
        192.168.0.85:6379> get hello
        -> Redirected to slot [866] located at 192.168.0.22:6379
        "world"
        192.168.0.22:6379> get abc
        -> Redirected to slot [7638] located at 192.168.0.85:6379
        "123"
        192.168.0.85:6379> 

   

   If SSL is enabled for a DCS Redis 6.0 basic edition instance, configure an SSL certificate path.

   • Run the following command to connect to a Redis Cluster instance:

     ./redis-cli -h {dcs_instance_address} -p {port} -a {password} -c --tls --cacert {certification file path}

   • Run the following command to connect to a single-node or master/standby instance:

     ./redis-cli -h {dcs_instance_address} -p {port} -a {password} --tls --cacert {certification file path}

   To connect to Redis with SSL encryption, use redis-cli 6.x or later.

Connecting to Redis on redis-cli (Windows)

Click here to download the Redis client installation package for Windows. Decompress the package in any directory, open the CLI tool cmd.exe, and go to the directory. Then, run the following command to access the DCS Redis instance:

redis-cli.exe -h XXX -p 6379

XXX indicates the IP address/domain name of the DCS instance and 6379 is an example port number used for accessing the DCS instance. For details about how to obtain the IP address/domain name and port number, see Viewing Instance Details.