Service Activation and Automation
So I've been trying to solve a problem. Here is the basic configuration...
For simplicity's sake in explaining this, I will explain this using Apache with vhosts configured. The actual products and services being used are being concealed to protect the innocent, or something...
Anyway, I will have a pool of servers, each configured identically with, let's say, 10 vhosts configured, each to its own port on the same VIP. Lets also assume that each port is actually a completely independent instance of apache, that can be started independently of one another.
On the F5, I will have separate VIPs configured (one per port).
The kicker is that of the pool of servers, I want to be able to arbitrarily add/remove nodes from the individual VIPs. Since every node can theoretically service ANY of the ports (by enabling/disabling the various instances of the web servers), I should be able to move these nodes between the various VIPs easily.
I know I can do this by hand... what I want to know is if there is any mechanism whereby adding a node to a VIP or pool can kick off the associated script on the node to enable the appropriate service. And likewise, removing a node would disable the service.
The goal is to make the pool of servers completely generic, be able to add/remove services from all nodes at the same time, and be able to have those nodes participate in the pools in a dynamic fashion. If I find that a certain service (port) is getting high load, I can enable the service on the node, add it into the pool, and leave it there until load subsides, and then drop it back down again after.
I also don't know if I'm explaining this well enough. Maybe a picture would be better. Anyway, feedback please... looking forward to reading your thoughts on the topic.