Question: I have a concern of using GPL v2 and GPL v3 licensed software in commercial production environment. I would like to use HaProxy as a load balancing solution. Is it safe against copy-left? I won't modify anything from source code and the architecture of the system requires the use of a load balancer.

It will be embedded in a larger distributed system. So what we sell is the whole system. On another site, we will need to install the load balancer again and could mix with something else. I think it's the "Distributing" term which is confusing me.

Answer: 
If you're distributing (unmodified) binaries along with a product you ship, then you're required to distribute the source with them, or provide a way for people to request the sources. This is not a situation where you can ignore the GPL, but it's not going to be a real problem for you. The GPL won't infect your proprietary software unless you link to it.

Distributing in this sense means giving (or selling) to customers. If you're just using a distributed (multi-node) system inside your company, then you're entirely in the clear, as yan says.

Incidentally, the [GPLv2](http://www.gnu.org/licenses/gpl-2.0.html) ([v3 here](http://www.gnu.org/licenses/gpl-3.0.html)) is written to be read by non-lawyers. I strongly recommend you take a look at it. If English isn't your first language, [translations](http://www.gnu.org/licenses/old-licenses/gpl-2.0-translations.html) are available in many languages.
If you're not modifying the source and using the binaries, you should be entirely in the clear.