Redis Monitoring and DR

Introduction

A monitor detects your database status, and automatically triggers traffic switching when the database is abnormal.

You can also switch the traffic manually. For details, see Step 4: Switch the Redis Monitor.

This section uses an example of Redis monitor to help you quickly get started. The general process includes:

• Step 1: Prepare Redis Databases
• Step 2: Create an Application
• Step 3: Create a Redis Monitor
• Step 4: Switch the Redis Monitor

Step 1: Prepare Redis Databases

Prepare a MAS instance and two Redis databases before you start. You can use the databases bought on the Huawei Cloud official website or deployed on two local machines.

This section uses two Redis databases bought on Huawei Cloud as an example. Deploy the databases in different AZs of the same region for failover and high availability.

1. Prepare two Redis databases. For details, see Buying a DCS Redis Instance.
2. Configure security group rules by referring to How Do I Configure a Security Group?. The default port for database access is 6379.

Step 2: Create an Application

Applications isolate resources of different users in an instance. Monitors must be associated with applications.

1. Log in to the MAS console. On the Multi-Active Instances page, click an instance to go to its console.
2. Click the Applications tab, and click Create.
3. Enter the application information, then click OK.

   Table 1 Application parameters

   Parameter	Description
   Application	Customize the application name.
   Description	(Optional) Enter a description about the application.

Step 3: Create a Redis Monitor

1. Log in to the MAS console. On the Multi-Active Instances page, click an instance whose namespace type is Intra-city multi-active.
2. Click the Monitor List tab, and click Create Monitor.
3. Configure the basic information, then click Next: Data Centers.
   Figure 1 Basic information configurations
   

   Table 2 Basic information parameters

   Parameter	Description
   Monitor	Select Redis Monitoring.
   Application	Select the application created in Step 2: Create an Application.
   Monitor Name	Customize the monitor name.
   Exception Notification	The default setting (Disabled) is used in this example. If this option is enabled, monitor and database alarms will be sent to you in a timely manner with the Huawei Cloud SMN service. Configure a secret key before enabling this option.
   Monitoring	The default value is Yes. If No, database exceptions will not be monitored.
   Automatic Switchover	The default value is Yes. If No, automatic switchover of the databases will not be triggered.
   Routing Algorithm	Select Single read/write, Local read, asynchronous dual write, or Single read, asynchronous dual write as required.
   Mode	Select Normal (default), Sentinel, or Cluster based on Redis deployment.

4. Configure the data centers, then click Next: Advanced.
   Figure 2 Data center configurations
   

   Table 3 Data center parameters

   Parameter	Description
   Cloud	Select the environments where the Redis databases are deployed. You can select a third-party data center for cross-cloud monitoring.
   Region	Enter the regions of the Redis databases created in Step 1: Prepare Redis Databases.
   AZs	Enter the AZs of the Redis databases created in Step 1: Prepare Redis Databases.
   Connection Address	Enter the access addresses and ports of the Redis databases created in Step 1: Prepare Redis Databases.
   Password	Enter the passwords for logging in to the Redis databases created in Step 1: Prepare Redis Databases.
   Confirm Password	Enter the password again.

5. Configure the advanced settings, then click Next: Confirm. Default values are used in the following figure.
   Figure 3 Advanced configurations
   
6. Confirm settings and click Create.

Step 4: Switch the Redis Monitor

1. On the Monitoring List page, click Switch Over in the row of a target monitor.
2. Click OK. The active (primary) database changes from data center 1 to data center 2.
3. After the database connection and read/write in data center 1 recover, click Switch Back in the row of the target monitor.
4. Click OK. The active (primary) database changes back to data center 1.