MC/SG neebie question

[peter demus]

hello !

how can i prevent that one setting on one node is changed and is configuration isn't the same on the others ?

i mean regulare tasks like adding users UID GID, DNS adding, perhaps kernel parameters like NFILES ?

can i have one virtualized serial number ('uname -a' should return always the same) on the cluster ? many applications depend on the hostname or S/N for the license. like having one relocatable virtual IP-adress for the app on the cluster.

so i do not want to buy 2 license for two nodes for 125 users each if they work only on one node and never on both. only in case of failover.

thanks pete

[Jeff Schussele · Accepted solution]

Hi Peter,

I'll try to answer your questions.

1) You'll have to make changes on both systems somehow. I'd suggest automating the process by, say, creating a script to rcp the passwd & group files, the hosts file etc & put it in cron. You'd probably have to manually set kernel parms on both systems. Heck you'd have to reboot anyway. When I want to do this I make the changes on the standby. I can do this easier as it's just standby & not running anything. Then I schedule a short outage, move the pkgs over to the standby. Make the changes on the primary & reboot. Then switch the pkgs back over on another short outage.
On an active/active cluster you have to schedule a longer outage & just go ahead & do both @ the same time.

2) As far as I know, most SW & vendors will require you to license both systems in the cluster. But you should discuss this with the sales rep. You may be able to negotiate a discount as it will in fact be running on only one system at a time. BUT they will know that this could be an active/active cluster & could in fact be running on both at the same time & may not budge. You'll probably just have to bite the bullet & purchase 2 licenses.
It's going to be up to each vendor as to how they deal with cluster - can't hurt to ask.

Rgds,
Jeff

[Christopher McCray_1]

Hello,

The answer to your "bottom line":

All nodes in the cluster must have MC/ServiceGuard installed and , hence, a license.

To question #2: You should have everything the same on all nodes in the cluster so that the application packages you run work the sam on all nodes.

#3: you should implement a virtual host and IP for each package you have and point your application to it, rather than the actual hostname. The uname -a command will always return the name of the actual hostname of the server.

Hope this helps

Chris