VPC peering is a way to connect two Amazon Virtual Private Clouds (VPCs) together, allowing resources in one VPC to communicate with resources in the other VPC. Here are the steps to set up VPC peering in AWS:
1.Create the VPCs: The first step is to create the two VPCs that you want to connect. You can do this using the AWS Management Console, the AWS CLI, or the AWS SDKs.
2.Request a VPC peering connection: Next, navigate to the VPC Dashboard in the AWS Management Console and select the VPCs that you want to connect. From there, choose "Actions" and then "Create VPC Peering Connection."
3.Accept the VPC peering connection: Once the request is sent, the owner of the other VPC will receive a notification and must accept the VPC peering connection in the VPC Dashboard.
4.Configure the route tables: After the VPC peering connection is accepted, you will need to update the route tables for both VPCs to allow communication between them. In the VPC Dashboard, select the VPCs and choose "Route Tables." Then, add a route for the CIDR block of the other VPC.
5.Test the connection: Once the route tables are updated, you can test the connection by launching an instance in one VPC and trying to ping it from an instance in the other VPC.
Few more points to consider when setting up VPC peering:
1.Security groups: When creating a VPC peering connection, the security groups for the instances in the VPCs do not change. You will need to update the security groups to allow traffic between the instances in the VPCs.
2.Network ACLs: In addition to security groups, you may also need to update the network ACLs for the VPCs to allow traffic between the instances.
3.DNS resolution: When VPCs are peered, instances in one VPC can communicate with instances in the other VPC using private IP addresses. If you want to use hostnames to communicate between instances, you will need to configure your own custom DNS service or use a third-party DNS service.
4.Transitive peering: VPC peering only allows communication between the peered VPCs, it does not allow communication between instances in other VPCs connected to the peered VPCs. If you need to establish a connection between three or more VPCs, you can do this by creating multiple VPC peering connections, but it is not a transitive peering.
5.VPC Peering Limits: AWS has limits on the number of VPC peering connections that you can create per VPC, per account and per region. It is important to check these limits before creating a new VPC peering connection.
6.Cost: There is no additional cost for creating and using a VPC peering connection, but the data transfer between the VPCs is charged at the standard data transfer rate.