Can a load balancer be used with Harvest?

Products

• CA Harvest Software Change Manager
• CA Harvest Software Change Manager - OpenMake Meister

Issue/Introduction

The system administrators want to put all development applications behind a load balancer to standardize the addresses used to access everything to one single hostname.  How will this work with Harvest?

Environment

Harvest Software Change Manager all versions

Resolution

Harvest should not be put behind a load balancer for the following reasons:

1. The client applications like Workbench must be able to access the broker directly by its hostname so that the broker knows how to return the results of the client's request to that client.  If a load balancer stands in the middle between the Harvest broker and client this tracability is lost.
   
   
2. Harvest is its own load balancer since the system architecture is built so that one broker and several hserver processes are running at the same time.  When a client request comes in, such as "check out" or "promote package", the broker checks to see which hserver is free to process the request, and routes the command in that direction.  If it finds that all hservers are busy at the moment it will start up a new hserver process to handle the job.
   
   
3. Having a load balancer would imply the desire to have two SCM Server applications (broker and hservers) running at the same time on different host servers.  This is not advisable or supported since both SCM Server applications would have to access the same database, leading to possible data collisions or corruption.  At any given time, only one SCM Server application should be accessing the database.

Additional Information

More information about the configuration options available for the SCM broker and hservers can be found here: Configure the Broker and Server Communication on Windows