:Step 3: Connect to a Tair instance

Endpoint types

• If your client is deployed on an ECS instance in the same VPC as your Tair instance, we recommend that you connect to the Tair instance over the VPC by using a private endpoint. This improves security and reduces network latency.

• If your client is deployed on an on-premises device or an ECS instance that resides in a different region and a different VPC from your Tair instance, you can connect to the Tair instance over the Internet by using a public endpoint. Otherwise, connection to the Tair instance fails.

Prerequisites

• The public IP address of your client is added to a whitelist of the Tair instance.

  Before you can connect to your Tair instance over a VPC or the Internet, you must add the IP address or CIDR block of your client to a whitelist of the Tair instance. For more information, see Step 2: Configure whitelists.

• The username and password of an account are configured to connect to the Tair instance.

  You can connect to your Tair instance by using a default or custom account. For more information, see Connect to a Tair instance.

Procedure

This example describes how to connect to a Tair instance by using redis-cli from an ECS Linux instance that is deployed in the same VPC as the Tair instance.

1. Log on to the ECS instance. Then, download and install redis-cli.

   1. Run the following command to install GCC:

      sudo yum -y install gcc

   2. Run the following command to download the Redis source code package:

      wget https://download.redis.io/releases/redis-7.0.0.tar.gz

      Note

      In this example, Redis 7.0.0 is used to demonstrate the operations. You can install other versions. For more information, visit the Redis official website.

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

      tar xzf redis-7.0.0.tar.gz

   4. Run the following command to go to the directory to which the Redis source code package is decompressed. Then, compile and install Redis.

      cd redis-7.0.0&&make

      It generally takes 2 to 3 minutes to compile and install Redis.

   5. Run the following command to go to the src directory and connect to the instance:

      cd src

2. Obtain the connection information and run the following command in redis-cli to connect to the Tair instance:

   ./redis-cli -h hostname -p port [-c]

   Table 1. Parameters

   Parameter	Description	Method to obtain the parameter value
   hostname	The endpoint of the Tair instance.	If you connect to the Tair instance over a VPC, obtain the VPC endpoint of the instance. If you connect to the Tair instance over the Internet, obtain the public endpoint of the instance. For more information, see View endpoints.
   port	The port number of the Tair instance.	The default port number is 6379.
   -c	Specifies whether to enable the cluster mode.	The cluster mode is available only if the Tair instance is a cluster instance that uses a private endpoint. For more information, see Cluster master-replica instances and Enable the direct connection mode.

   Examples:

   • The following sample command is suitable for scenarios where Tair instances are connected by using default endpoints, such as endpoints of standard instances and proxy endpoints of cluster instances:

     ./redis-cli -h r-bp1zxszhcgatnx****.redis.rds.aliyuncs.com -p 6379

   • The following sample command is suitable for scenarios where Tair cluster instances are connected by using private endpoints:

     ./redis-cli -h r-bp1zxszhcgatnx****.redis.rds.aliyuncs.com -p 6379 -c

3. Run the following command to verify the password:

   AUTH password

   Table 2. Parameters

   Parameter

   Description

   password

   The password of the account. If you use the default account, enter the password. For example, if the username of the default account is r-bp1zxszhcgatnx**** and the password is Password21, the command used to verify the password is AUTH Password21. If you use a custom account, enter the password in the user:password format. For example, if the username of the custom account is testaccount and the password is Rp829dlwa, the command used to verify the password is AUTH testaccount:Rp829dlwa. Note If you forget your password, reset the password. If you have not set a password, set a password. For more information, see Change or reset the password. If you use a third-party database management tool such as RDM to connect to your Tair instance, specify user:password as the password and leave the username field empty. Otherwise, connection to the instance fails. If password-free access is enabled for your Tair instance, you can run Tair commands without performing this step when you connect to the instance over a VPC.

   Example:

   AUTH testaccount:Rp829dlwa

   If OK is returned, you succeed in connecting to the Tair instance and you can run Tair commands.

Common connection methods

Special connection methods

• Use a client to connect to a Tair instance for which TLS (SSL) encryption is enabled: TLS encryption improves transport link security and ensures data integrity.

• Connect to a Tair cluster instance in direct connection mode: If your instance is a Tair cluster instance, you can use a private endpoint to bypass proxy nodes and directly access backend data shards. This connection to cluster instances is similar to the connection to open source Redis clusters. Compared with the proxy mode, the direct connection mode reduces the response time of Tair because requests do not need to pass through proxy nodes.

• Use the Sentinel-compatible mode to connect to a Tair instance: Tair provides the Sentinel-compatible mode. After you enable this mode, Tair instances can be connected from the client in the same manner as the native Redis Sentinel.

Common errors and troubleshooting