I'm assuming that you want to run this on multiple machines (running multiple Apache instances on the one machine makes very little sense).

Unfortunately, you can't find a simple tutorial for HA clustering because it's not a simple topic.  You've got a lot of different concepts, ranging from low-level network stuff to application-specific items like shared data storage.

I started my clustering adventures at http://linuxvirtualserver.org/.  You might like to start at http://www.linuxvirtualserver.org/architecture.html and go from there.

Apache clustering
In 2vs2 game, you often need assistance from teammates such as: asking for minerals, asking for scans, asking for help, etc... When everything is more or less ok, you can just Alt+click on the minimap to take attention or write a text.

However, when a lot of events are going on, your teammate can often miss these indicators.

How can you best grab their attention in absence of a microphone?
