[TriLUG] Re: RHEL. LVS, piranha

[Jon Carnes]

On Fri, 2003-12-05 at 12:35, Lance A. Brown wrote:
> Ryan Leathers wrote:
> > I'd love to see what you've done, but I want to stay with piranha if I
> > can.  The only reason is that I want this to be easily supported by
> > somebody else, so "the less custom stuff the better" has been my goal.
> > 
> > One of the things that I've been grumbling about is that the RHEL 2.1
> > docs say that lvs-nat is the only supported option.  I want to use the
> > lvs-dr option.  I get the feeling that piranha is the limiting factor. 
> > I really just need this to work reliably.  I could care less about
> > having a configuration gui so its kind of frustrating right now.
> 
> I've had good luck using UltraMonkey (www.ultramonkey.org) with Red Hat 
> 9 to implement a webserver farm using lvs-dr.  The farm has two 
> directors (primary and secondary using heartbeat) and two web servers 
> (so far).  It took me a bit to wrap my head around the ultramonkey 
> documentation vs. the config files but once I realized what was going 
> on, setup was easy.
> 
> --[Lance]

I have to second Lance's endorsement of Ultra-Monkey.  In an LVS
situation Ultra-Monkey is good stuff!

Here is a set of "actual" scripts, in use at a client for running a
Master/Slave Fail-over pair for a SquidGuard installation.  The slave
kicks in and takes over if the master goes off-line.  If the master
comes back on-line then the slave backs down again.

http://www.trilug.org/~jonc/Failover_scripts

All these scripts run on the Slave:
  Server_Sync  - Keeps the Slave up-to-date with the Master.
                 Runs once a night.

  conf_files   - The files and directories to be updated nightly
                 by Server_Sync (Not a script... just a list)

  Server_check - Runs every minute out of cron to check on 
                 the status of the Master server. Initiates
                 the Failover or the Return scripts

  Server_Failover - Script to move the slave onto the network
                 as the master, and startup any necessary services

  Server_Return - script to move the slave back off the network
                 and into stand-by mode.

I hope you find them entertaining!

The interesting thing about this setup is that the Master can be totally
ignorant of the Slave. The Slave server can also be doing other tasks
for the company while in standby mode, and can actually continue those
tasks as well as taking on the new tasks of the Failed Master (whenever
that happens).

Jon Carnes