topic Re: IP Address change on Cluster in Operating System - OpenVMS

IP Address change on Cluster

Zahid Ghani — Thu, 24 Aug 2006 07:36:58 GMT

We have a 4-node split site cluster with Loadbroker for load balancing, TCP/IP 5.4 , Failover IP. We are planning to change our network. This would require new ip addresses. Our users are scattered over uk.
My first thought was that we could NAT our external addresses leaving the cluster as it is. BUT it looks as though load braoker etc can not work on NATted addresses.
Am I correct in assuming that I will have to rebuilt the cluster after adding new IP addresses or is there a less ardous way of achieving this.

Re: IP Address change on Cluster

Heinz W Genhart — Thu, 24 Aug 2006 08:19:33 GMT

Hi Zahid

I think it's not required to rebuild the cluster

During this year we changed hardware at 7 sites. The old hardware was AlphaServer 4100 2 Node cluster, the new hardware is ES45 2 node cluster with MSA100.

I built a systemdisk which I use to build all the 7 configurations. (For this hardware change we have a time slot of only 4 hours!)

What I do is the following:
- We install the hardware in a test room. Then I use the systemdisk, I mentioned before and I change the nodenames, the DECnet addresses and the IP Addresses (we use FailSafe IP with 4 interfaces in each machine)

To change the Nodename, I have to modify SCSNODE and SCSSYSTEMID an do autogen with reboot (The licenses must also be modified if the nodename change).

Then I do a NET$CONFIGURE ADVANCED for changing the DECnet environment.

To Change the IP Adresses I do a BACKUP/DELET SYS$SYSDEVICE:[000000...]TCPIP$*.DAT save_location:tcpipdat.bck/sav

Then I reboot the machine without to start TCPIP. Finnaly I do a TCPIP$CONFIG.

After this configuration, we transport the machine to the final destination and during a timeslot of 4 hours, we exchange the hardware, by first copying some files like sysuaf.dat, rightslist.dat from the old to the new config, then shuting down the old config and booting the new config.

This is a (very) short description of what I'm doing to change Names and Addresses of a OpenVMS Machine.

In Your case you have only to change the IP Addresses. In this case it's not required to delete all the old TCPIPxy.DAT-files. Or optionally you can also restore some of the TCPIP$xx.DAT form tha backup made in the beginning, (eg. TCPIP$EXPORT, TCPIP$PRINTCAP....) after configuring TCPIP

I hope that helps a litle bit.

Regards

Heinz

Re: IP Address change on Cluster

Zahid Ghani — Thu, 24 Aug 2006 08:51:04 GMT

Heinz, Thanks for a prompt reply.
So in order to change the IP Addresses I 'just need to run tcpip$config'?

Re: IP Address change on Cluster

Heinz W Genhart — Thu, 24 Aug 2006 09:02:02 GMT

HI Zahid

It's not so easy. Because the IP name associated with the first address you define is also used for other things. If You do a TCPIP sho config communication, you will find the nodename and the domain.
You will also find the IP name and address of the local node in your hosts file.

I found out, adding some new interfaces is no problem. Changing the Address of the first interface may become tricky. That's why I delete the TCPIP$*.dat. Doing so, I never have problems to change addresses (especialy the address of the first interface)

As mentioned in my first response, you can restore some other tcpip datafiles (eg. TCPIP$EXPORT if used) from the backup you made in the beginnig.

Regards

Heinz