Step 1: Failover Setup

1. Follow this document and set up the Applications Manager Failover.
   
1. It is recommended that you deploy the database server in the Cloud infrastructure as well.
   
1. To use PGSQL, you can use bundled PGSQL with Applications Manager.
   
2. To use MSSQL, deploy it in the AWS cloud infrastructure (MSSQL in RDS service/MSSQL in EC2 Instance).
2. Deploy two EC2 instances in accordance to the hardware requirements given here to configure the Applications Manager Failover setup.
   

Note: In the failover setup, the primary server, secondary server and the database server should be able to communicate with each other.  Ensure that all resources are in the same network i.e., using the same VPC for setting up resources is preferred.

Step 2: Configure AWS ALB to route the traffic

Step 2.1: Creating a Target Group

1. To create target groups, follow the steps here.
   
1. Register Applications Manager's primary and failover server's instance IDs as targets.
2. Enter the default ports (HTTP: 9090 & HTTPS: 8443).
   
3. Configure health checks with minimum value to ensure quick availability of failover setup.
2. At any given time, only one of the targets will be healthy and the other target will be on standby.

Step 2.2: Creating an ALB

1. To create an Application Load Balancer, follow the steps here.
1. Create a listener and associate it with the target group created in the above step to facilitate request forwarding.
   
2. While specifying the rules, you can use the default rule.
2. After creating the load balancer, note down the DNS and listener port.
3. Access the ALB's DNS in the listener port and check if the Applications Manager is accessible.
   
4. ALB will automatically redirect to the targets based on their health status.

Ensure that the security group of ALB is configured to receive an inbound request at the listener port.

Failover in ALB Flow Chart

Demo setup screenshots

Setup Details:

1. Applications Manager
   
1. HTTP: 9090
   
2. HTTPS: 8443
   
2. MSSQL (Can configure RDS also for Applications Manager backend)
   
1. TCP: 1433

1. Applications Manager
   
1. HTTP: 9090
   
2. HTTPS: 8443

At a given time, only one target will be in a healthy state and the other server will be serving as a failover.