We are looking for a solution for "sticky bit routing" based on cookies that will run on Amazon's EC2 cloud.
I've looked at the architecture guide for HAProxy (although not the source yet) and it ~may~ be capable of doing what we need, but I thought I'd ask the mailing list to see if anyone else has already tried this solution. (Without knowing the implementation, it's impossible to say if our requirements can be met by the implementation) The challenge that we have is that unlike a traditional system where the sticky bit routing would be to one of a set of predefined servers, in our case, the servers will be created dynamically in the cloud. We can't "configure" them when we start the HAProxy routing layer. Although we may have some "back up" servers, that can be used if no cookie is in the request OR if the cookie specifies a server that has died, in general the servers that the cookie will be specifying will be dynamically created and we will assign them to the requests "ourselves" (not needing the nginx layer to round-robin assign them to one of a pool of fixed address servers). So my question may come down to: "Can HAProxy route to servers not predefined in the initial configuration"? I can easily imagine an implementation that could handle this, but wanted to ask if HAProxy already does this. Thanks in advance -- Langley
