Creating a Replica Set Instance

Scenarios

This section describes how to create a replica set instance on the DDS management console. DDS allows you to tailor your computing resources and storage space to your business needs.

You can use your account to create up to 50 replica set instances.

Procedure

1. Log in to the DDS console.
2. On the Instance Management page, click Create DB Instance.
3. On the displayed page, select your DB instance specifications and click Create Now.

   Table 1 Basic information

   Parameter	Description
   Region	A region where the tenant is located. It can be changed in the upper left corner. For details, see section Regions and AZs. NOTE: DB instances deployed in different regions cannot communicate with each other through a private network, and you cannot change the region of a DB instance once it is created. Exercise caution when selecting a region.
   DB Instance Name	The DB instance name can be 4 to 64 characters long. It must start with a letter and can contain only uppercase letters, lowercase letters, digits, hyphens (-), and underscores (_). After the DB instance is created, you can change the DB instance name. For details, see section Changing a DB Instance Name.
   Database Type	Community Edition
   DB Instance Type	Select Replica set. A replica set consists of the primary node, secondary node, and hidden node. If a primary node goes down or becomes faulty, a secondary node is automatically assigned to the primary role and continues normal operation. If a secondary node is unavailable, a hidden node will take the role of the secondary to ensure high availability.
   Compatible MongoDB Version	3.4 3.2
   Storage Type	Ultra-high I/O
   Storage Engine	WiredTiger
   AZ	An AZ is a part of a region with its own independent power supplies and networks. AZs are physically isolated but can communicate through an internal network connection.

   Table 2 Specifications

   Parameter	Description
   Specifications	In the x86 CPU architecture, the following specifications can be selected to suit different application scenarios: General-purpose (s6), Enhanced (c3), and Enhanced II (c6).
   Node Class	For details about the DB instance specifications, see section DB Instance Specifications. After a DB instance is created, you can change its CPU and memory. For details, see section Changing the CPU or Memory of a Replica Set DB Instance.
   Storage Space	The value ranges from 10 GB to 2000 GB and must be a multiple of 10.

   Table 3 Network

   Parameter	Description
   VPC	The VPC where your DB instances are located. A VPC isolates networks for different services, so you can easily manage and configure internal networks and change network configuration. You need to create or select the required VPC. For details about how to create a VPC, see section "Creating a VPC" in the Virtual Private Cloud User Guide. For details about the constraints on the use of VPCs, see Connection Methods.
   Subnet	A subnet provides dedicated network resources that are logically isolated from other networks for network security. After the instance is created, you can change the private IP address assigned by the subnet. For details, see Changing a Private IP Address.
   Security Group	A security group controls access between DDS and other services for security. NOTE: Ensure that the security group rule you set allows clients to access DB instances. For example, select the TCP protocol with inbound direction, input the default port number 8635, and enter a subnet IP address or select a security group that the DB instance belongs to.
   SSL	Secure Sockets Layer (SSL) certificates set up encrypted connections between clients and servers, preventing data from being tampered with or stolen during transmission. You can enable SSL to improve data security. After a DB instance is created, you can connect to it using SSL.
   Cross-Subnet Access	Configure Add the VPC subnet of your client. Ensure that the ECS where your client is installed can connect to the DB instance. NOTE: To ensure the ECS and the DB instance can communicate with each other, configure the connection by referring to section "VPC Peering Connection Overview" in the Virtual Private Cloud User Guide. VPCs and subnets can only be added, but not modified or deleted. Up to 9 subnets can be configured, and each of them does not overlap. Skip Configure the subnet of the client later. After a DB instance is created, you can configure cross-subnet access by referring to Configuring Cross-Subnet Access.

   Table 4 Database configuration

   Parameter	Description
   Administrator	The default account is rwuser.
   Administrator Password	Set a password for the administrator. The password is a string of 8 to 32 characters. It must be a combination of uppercase letters, lowercase letters, digits, and special characters. You can also use the following special characters: ~!@#%^*-_=+? Keep this password secure. If lost, the system cannot retrieve it for you.
   Confirm Password	Enter the administrator password again.
   Replica Set Parameter Group	The parameters that apply to the replica set instances. After a DB instance is created, you can change the parameter group you configured for the DB instance to bring out the best performance. For details, see Parameter Group Settings.
   Enterprise Project	Only enterprise users can use this function. To use this function, contact customer service. An enterprise project is a cloud resource management mode, in which cloud resources and members are centrally managed by project. Select an enterprise project from the drop-down list. The default project is default.

   

   DB instance performance is determined by how you configure it during the creation. The hardware configuration items that can be selected include the class and storage space of the replica set.

4. On the displayed page, confirm the DB instance information.
   • If you need to modify the specifications, click Previous to return to the previous page.
   • If you do not need to modify the specifications, click Submit to start the instance creation.

5. After a DDS DB instance is created, you can view and manage it on the Instance Management page.
   • When a DB instance is being created, the status displayed in the Status column is Creating. This process takes about 15 minutes. After the creation is complete, the status changes to Available.
   • DDS enables the automated backup policy by default. After a DB instance is created, you can modify or disable the automated backup policy. An automated full backup is immediately triggered after the creation of a DB instance.
   • The default DDS port is 8635, but this port can be modified if necessary. If you change the port, you need to add the security group rule to enable access.