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Hello Ben,
> I have been reading about LVS for about a week and I think I
> am suffering from info overload.
I am suffering from thanksgiving-work-potluck overload. Ah well, at least
it's Friday and sunny here in California.
> What I have:
> Debian Stable (I like getting security patches quick)
FYI, Debian released a big security warning on bugtraq today. You might
want to check it out.
> Director: Kernel 2.4.18 patched with ipvs 1.0.2
Update to 2.4.23 & latest ipvs when 2.4.23 comes out. Be aware there are
security issues with 2.4.18. Incidentally, since you use Debian you can
grab Horms's LVS/kernel packages for Debian (Sid or Woody) @
http://www.ultramonkey.org/download/2.0.1/
> Director has two nics, but I am going to remove one, so I
> want a one nic setup on the directors (Direct Routing)
Use high quality NICs. I like eepro100s. This is what Google and Yahoo
etc. use.
> 2 Webservers
> 2 DB machines
> The loadbalancing is working on the 2 webservers, I have
> not set it up on the database servers yet because of concerns
> about database connection state and how LVS handles that (or doesn't).
It's a good idea to do the web stuff first to familiarize yourself with LVS.
Are you on a three-tier network? Your DBs shouldn't be accessible to the
public.
> What I want:
>
> Two Virtual servers (Direct Routing):
> - 1 for http/apache (loadbalanced) (2 machines, more later)
> - 1 for MySQL (simple failover) (2 machines)
> Automatic addition/removal from LVS when failure detected
> Director Failover (I have two machines for director duty)
Ok 8-)
> What I am confused about:
> Director failover:
> - I am planning on setting up heartbeat via serial cable.
> - Which tool should I use for the takeover? vrrpd, Fake
If you want to use a serial cable then you should use heartbeat
(http://www.ultramonkey.org/download/2.0.1/). Documentation is 2
directories up from the listed URL.
> - ldirectord, keepalived ??? or just mon, heartbeat, fake?
Since you will be using heartbeat already, you might as well go with the
whole Ultramonkey package. I have used it here for ~2 years now with almost
no issues. The icing on the cake is Horms provides very quick Debian &
Redhat updates. I'm not 100% certain, but I would guess that Horms is the
package maintainer for Debian.
> - Do I need connection table synchronization?
> http://marc.theaimsgroup.com/?l=linux-virtual-server&m=1054593
> 91703228&w=2
I don't know, do you? What makes you think you need connection table
synchronization?
> - iproute2's advantage over eth0:10 style (is it just an iptables
> issue?) ( I know next to nothing about iproute2 )
So basically you are talking about Keepalived vs. Heartbeat/Ultramonkey.
Keepalived is based on VRRPd and uses the 'iproute2' method of aliasing.
Failovers are very quick, the software is simple and does the job. I use
Keepalived for BGP-flash-linux routers. Ultramonkey uses heartbeat, which
integrated code from the obsolete "fake", for ip failovers and ldirectord
for adding/removing services and real servers. Heartbeat is slower to
failover to the backup, ~10 seconds instead of 2-5, but is much more
configurable than Keepalived. E.g., serial cables can be used, and custom
scripts seem easy to integrate - or at least they seem easier to my simple
mind ;-). Both packages are really nice and well supported. If you use
either package the sun will smile down upon your systems and your bosses
will think you are a genius. That having been said in your case I think
you'd be better off with Ultramonkey due to the serial cable.
> Automatic addition/removal from LVS:
> - mon + script? or is there a better way? ldirector, keepalive??
Both Keepalived and Ultramonkey have this functionality integrated & well
documented.
> Again, Thanks for everything, I cant wait to start testing
> this by pulling network cables and power plugs (I am running a journaled
fs).
Heh, heh. A glutton for punishment eh? ;-)
Cheers,
Peter M.
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