How-to dedicate APP-Servers to front-/backend

For performance optimisation in a multi-line setup, it can be a good idea to dedicate the workload of app servers. The goal is to have one app server dedicated to background processes and the other to client requests (front end processes).

Let’s say we have two app servers. The first one has the hostname IAMAPP01 (with IP 192.168.0.1) and the second is named IAMAPP02 (IP 192.168.0.2). IAMAPP01 is going to be the one for the frontend - and IAMAPP02 the one for the backend processes.

Here are the steps that need to be done

• set moving_site.config_server.enable_scheduled_tasks for IAMAPP01 to 0

• edit the hosts file on both servers and have the adress of the workflow dashboard point to 192.168.0.2
  for example: 192.168.0.2 iam-wf.coreone.ch

• on IAMAPP02 change the ElsaWorkflow_ApplicationConfiguration.json to have the key IpAddress in ElsaApiEndpoints point to 192.168.0.2
  (you might need to use the machine crypto tool)

• stop the Workflow Runner Service on IAMAPP01 and set the start mode to manual

• on IAMAPP02 you might have to add a local firewall rule to allow TCP connections on port 9001 (Elsa Workflow API as well as Swagger)

• restart the backend Services on both servers

To check your work you can inspect the table moving_appcustomer_900000.taskscheduler_task_definition
After the restart of the services all tasks should be running on IAMAPP02 (column lastrun_processor)