Thanks David... it is looking like to reliably do this I'm going to have to leverage an HA application with static VIP but I still wonder if I can get away with iptables CLUSTERIP option.
We have our own HA application tool that we use and will need to pursue using it... -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, April 19, 2012 12:18 PM To: rsyslog-users Subject: Re: [rsyslog] rsyslog | VIP You can use heartbeat (http://linux-ha.org) running on your rsyslog servers to manage a VIP on the servers themselves (no need for an external load balancer device) The hard part of the question comes when you need to determine under what conditions you want to declare a box dead to force a failover. >From a practical point of view, rsyslog is pretty darn reliable, so if you >just run rsyslog on both systems and only configure heartbeat to failover if a >box is completely dead you will be in pretty good shape. Hoever, this would not work in the case where rsyslog stops on a box that is otherwise healthy. How much checking you want to do to decide if rsyslog is healthy can be complex, various tests can include: 1. is rsyslog running (simple ps |grep check) 2. is rsyslog listening to a port (lsof check, netstat check, or probing a port) 3. is rsyslog processing the message (sec watching for a message from rsyslog on a file or named pipe) 4. internal status checking in rsyslog There are also other subtle prroblems that a box can have that will make a box still think it's healthy, but not be working properly for your logging For example: Routing problems could cause a box to still be up, but be unable to talk to boxes on other networks Disk I/O problems could cause the box to be unable to write logs, even though it can still receive them (or if the box is a relay, a downstream box could be not responding so it can't forward the log messages) If a box runs out of memory, various things on the box will get killed, which may leave a box not working the way it should I have had about a hundred pairs of boxes running heartbeat for the last decade (more at some points than at others, but averaging around a hundred pairs) and I've only had about a dozen or so problems stranger than what the simplist heartbeat configuration detects (full box down issues) during that time, which is why I say that as a practical matter, you are probably just fine with the simplest configuration, without trying to monitor rsyslog explicitly. David Lang On Thu, 19 Apr 2012, Martinez, Carlos R wrote: > Date: Thu, 19 Apr 2012 13:47:39 +0000 > From: "Martinez, Carlos R" <[email protected]> > Reply-To: rsyslog-users <[email protected]> > To: "[email protected]" <[email protected]> > Subject: [rsyslog] rsyslog | VIP > > I'm looking for the best way to put my rsyslog servers behind a VIP for TCP & > UDP traffic. > > It appears that the best solution thus far at least for TCP is fault tolerant > setup with port probing. I have tried a VIP load balance/round-robin > configuration but it takes a while for the syslog/rsyslog client to start > logging to the surviving rsyslog server when I bring one down. As for UDP > I'm not having good results at all and I'm starting to wonder if the best > solution would be to have a static VIP IP where I use CLUSTERIP configuration > on my systems where the failover occurs over the virtual network interface. > > Any suggestions is appreciated. > > > Here is my configuration: > > > syslog/rsyslog client ->->->-> VIP ->->->-> rsyslog_server1, > rsyslog_server2 > > VIP options: 1) fault tolerant w/port probing 2) load balance/round robin 3) > static IP (multicast) utilizing CLUSTERIP option. > > I prefer the load balance configuration for data center HA. > _______________________________________________ > rsyslog mailing list > http://lists.adiscon.net/mailman/listinfo/rsyslog > http://www.rsyslog.com/professional-services/ > What's up with rsyslog? Follow https://twitter.com/rgerhards > _______________________________________________ rsyslog mailing list http://lists.adiscon.net/mailman/listinfo/rsyslog http://www.rsyslog.com/professional-services/ What's up with rsyslog? Follow https://twitter.com/rgerhards _______________________________________________ rsyslog mailing list http://lists.adiscon.net/mailman/listinfo/rsyslog http://www.rsyslog.com/professional-services/ What's up with rsyslog? Follow https://twitter.com/rgerhards
