HA Cluster questions
 

Hey all,

Sometime during the next 6 months to a year, we're looking at finding a way to load balance our servers in such a way that if one system goes down, the others will pick up the load and not cause anything to crash. I believe this is what a high availability cluster is used for. Ideally here, I'd like to be able to create a few groups of systems, have the group assigned a single IP address, and direct the apps to those IPs.

For example, we're going to have probably 5 or 6 app servers, running python and apache for the most part. What I'd like to have happen is that a request is sent to the cluster IP, where it is run on whichever system is available at the time. If 1 of these systems goes down, the cluster stays running.

The problem seems to be finding a product that can do this. I've tried some products like Open Mosix. It runs ok, but can't distrubute python or apache apps, and it doesn't really have a single IP to address the entire cluster, although there are ways around that.

Most of the systems that we're running right now are running Fedora Core, 1 and 2. All systems would be made identical in terms of OS version, and hardware as well.

So, what I'm looking for are some recommendations on clustering apps to provide load balancing and high availability. If I can find a product that works, I could be setting up a handful of clusters: app servers, file servers, web servers, etc.

Thanks in advance for any advice.

try this: http://open-ha-cluster.sf.net
 

Hi.
For HA stuff, I've wrote a very simple HA software, which can be used for this kind of things.
You can have up to 16 nodes, mix different OS, ...
For ex, you can have 5 active nodes, with 5 services defined (each one with its own virtual IP address), and 1 passive node.
If you need shared storage, you can also create a HA NFS service, hosted by 2 of the cluster nodes, ...

Sam.

Bump... still looking around for options. Sam028, your software looks very promising, and I'll play around with it, but for a production business environment I'm going to be looking for something with a bit more documentation and support.

Has anyone heard much or used Ultra Monkey? Their software sounds promising, but they dont' really go into which services it can distibute, other than web services. Apache is something I definitely need, but so is Python, which nobody really seems to mention.

Any other suggestions for this?

right
 

For the doc part of openha, you're right, I have some work to do...
But it already runs in production environment, in the firm I'm working for (about 50 clusters, in most cases big Sparc Solaris boxes, V880 and F15K ...). But they have the developer (me) with them ...
Did you had a look to linux-ha ?

Sam.

Re: try this: http://open-ha-cluster.sf.net
 

Hi Sam, your simple software seems to be just what i need.

i just want my 2 web servers (of different hardware configuration) to heartbeat each other, sync with each other, files/ folders i can define to sync via rsync/ others and basically take over the job should one goes down.

Does Ultramonkey/ Open HA Cluter do syncing of files?

Hi.
It's not the job of an HA cluster software to rsync for you !
If you want to rsync data between your nodes, every X minutes, you might add a script in a cron which check "Am I running this service ? If Yes: rsync to the other node...".
Quite easy ...

Sam.