UNIX for Dummies Questions & Answers

Hi ! I have a simple setup of 2 PC (with linux Red-Hat) where the first PC is the primary machine and the second the backup. I use DRBD for data replication and Red-Hat cluster suite for HA (High Availability). I have tested both.

Now I NEED a COMMON IP ADDRESS (or Master/unique IP address) for my two system. When the primary machine fails (or shutdown), the backup system will do the job. From the external world, client who connect to my cluster will "connect to one address" or virtual IP and won't know if this is the primary system or the backup.

For now, my 2 machines have the same /etc/hosts file:

which contains: 10.60.1.23 PrimaryMachine
10.60.1.77 BackupMachine

Maybe I need to change the IP address for something local (192.168.1.0), I don't know. Theses address where created dynamically I think with DHCP when I installed Red-Hat on both machine.

I red many document about BONDING, IP ALIAS and VIRTUAL IP but now I am LOST !!!

What I do really need (keep it as simple as possible) and how to do it ???

Thank you very much.

The main idea of IP bonding is to have two NICs read as one IP..
Of course your IP need to be the same on both NICs.. You can not assign different IP on each NIC..
Maybe you have to stop the DHCP service first so you can set your IP manually..

CMIIW

It sounds like a virtual IP is the one you want. However you should avoid using DHCP in this scenario. Ask your network administrator to allocate 3 permanent IP addresses for you, one for PrimaryMachine, one for BackupMachine, and one for VirtualIP. You should be able to configure the VirtualIP as a service in Red Hat Cluster Suite so that it will be automatically failed over if there is a problem with PrimaryMachine.

Thank you guys. Yes, now I have 3 fixed-IP address and it works.
My virtual IP is on eth0:1 and the 2 other IP (one per system) is on eth0.
I control the eth0:1 by myself setting it up or down with ifup and ifdown commands. I control it in my script used as service group in Cluster Manager.