Configure the load balancer

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You can configure a load balancer for the Red Hat RPM orchestrator deployment option using the Red Hat RPM orchestrator.

Limitations

The following limitations apply:

  • The endpoint is limited to the ReadWrite endpoint. Readonly endpoints will be supported in future.

Before you begin

Before you configure the load balancer, make sure that you meet the following requirements:

  • To define load balancer nodes, in your deployment specification file, include a load_balancer_nodes group that contains the hostnames or IP addresses of your dedicated load balancer VMs:

    alloydbomni:
  vars:
    ...
  children:
    load_balancer_nodes:
      hosts:
        lb-node-1:
        lb-node-2:

  • To configure the firewall, allow the following incoming traffic:

    • On dedicated load balancer VMs:

      • Port 5432 (TCP): for HAProxy database traffic.

      • Port 6432 (TCP): for PgBouncer connection pooling traffic, if applicable.

      • VRRP protocol: for keepalived leader election and health checks.

    • On database nodes:

      • Port 8086 (HTTP): for load balancer health checks.

Configure the load balancer

The Red Hat RPM orchestrator uses HAProxy to distribute traffic and Keepalived to provide high availability with a virtual IP (VIP).

Update the resource specification

In your DBCluster specification file, add dbLoadBalancerOptions, which makes sure that the cluster manager and orchestrator know how to manage the load balancer endpoints.

DBCluster:
  metadata:
    name: DBCLUSTER_NAME
  spec:
    primarySpec:
      # ... other primary settings ...
      dbLoadBalancerOptions:
        gcp:
          loadBalancerIP: "VIRTUAL_IP"
          loadBalancerType: "internal"
          loadBalancerInterface: "VIRTUAL_IP_INTERFACE"

Replace the following:

  • DBCLUSTER_NAME: the name of your AlloyDB Omni database cluster—for example, my-db-cluster.

  • VIRTUAL_IP: static IP address used for the floating, virtual IP. Database client applications use the IP address defined here. To make sure that Keepalived can broadcast Gratuitous Address Resolution Protocols (GARPs) successfully, this IP address must meet the following conditions: it must be available; it can't loopback; and in the case of on-premises, it belongs to the same subnet as your primary node interfaces.

  • VIRTUAL_IP_INTERFACE: network interface where VIRTUAL_IP is configured. The default value is eth0.

Apply the configuration

Apply the configuration changes using your preferred orchestrator interface.

Ansible

Run the bootstrap playbook using your inventory and resource specification files:

ansible-playbook DBCLUSTER_PLAYBOOK -i "DEPLOYMENT_SPECIFICATION" \
      -e resource_spec="DBCLUSTER_SPECIFICATION"

Replace the following variables:

  • DBCLUSTER_PLAYBOOK: path to the playbook that you created for your database cluster in Create a cluster.

  • DEPLOYMENT_SPECIFICATION: path to the deployment specification that you created in Install AlloyDB Omni components.

  • DBCLUSTER_SPECIFICATION: path to your cluster specifications.

alloydbctl

Apply the resource and deployment specifications:

alloydbctl apply -d "DEPLOYMENT_SPECIFICATION" -r "DBCLUSTER_SPECIFICATION"

Replace the following variables:

  • DEPLOYMENT_SPECIFICATION: path to the deployment specification you created in Install AlloyDB Omni components.

  • DBCLUSTER_SPECIFICATION: path to your cluster specifications.

Verify the load balancer

After the Red Hat RPM orchestrator completes the setup, verify that you can connect to the database cluster using the VIP:

psql -h VIRTUAL_IP -U postgres

Replace VIRTUAL_IP with the IP address you configured in the loadBalancerIP field.

The load balancer automatically routes your connection to the current primary node.