MC Service Guard: clustering 2 hosts

[RATEFIARIVONY]

Hi All,

I Would like to know if it is possible with MC Service Guard on HP-UX 11.00 to build a cluster of 2 servers with same configuration like:
- same Hostname
- same IP Address

If it is, how do I proceed then ??
If not, is there any other way to build that configuration on HP-UX 11.00 ??

Any help would be greatly appreciated!!!
Thanks!

[melvyn burnard]

You cannot have two nodes with hte same hostnakme and IP address, they have to be unique.
The package(s) that are shared between the nodes have their own unique hostname and ip addresses, which is maybe what you were after.

Read the Managing Serviceguard manual available at:
http://docs.hp.com/hpux/ha

[Jose Mosquera]

Hi,

The suggested way to proceed is:
1.- Assign different names and IP's at each of two nodes in /etc/cmcluster/cluster.conf file:

# Definition of nodes in the cluster.
# Repeat node definitions as necessary for additional nodes.

NODE_NAME
HEARTBEAT_IP
NODE_NAME
HEARTBEAT_IP

2.- Configure your /etc/cmcluster//.conf file:
# Enter a name for this package. This name will be used to identify the
# package when viewing or manipulating it. It must be different from
# the other configured package names.

PACKAGE_NAME

# If all nodes in cluster is to be specified and order is not
# important, "NODE_NAME *" may be specified.
#
# Example : NODE_NAME *

NODE_NAME
NODE_NAME


Critical steps:
3.- Configure the IP and Subnet address pairs which are used by this package in /etc/cmcluster//.cntl file:
IP[0]=nn.nn.nn.nn
SUBNET[0]=nn.nn.0.0

4.- Setup a flotant IP in your primary_node lan card that correspond with the same IP[0] parameter configured above.

5.- Setup a resolution name technique for your PACKAGE NAME definition (DNS) ussing, of course, IP[0] parameter.

7.- Finally, you will always make reference at PACKAGE NAME definition when you try a Telnet, ftp, etc session.

I'm giving you an idea about the technique of the use of two nodes, I am omitting a quantity of previous considerations of redundancy of devices (including LAN cards) that constitute the first step in the configuration of high availability concept.
Also, details are omitted of sharing of VG, FS, etc. The generation of binaries from the previuos ascii configuration files have been ommited too.

Rgds.

[Bharat Katkar]

HI,
HAve a look at the Doc below.
Thought it would be usefull for you.

http://docs.hp.com/hpux/onlinedocs/B3936-90073/B3936-90073.html


Regards,

[RAJESH GANGADHARAN]

Hi,
You can not have 2 nodes with same host name, but You can have a package (application) with an IP and a hostname, which can be running either of these nodes.

Raj

[Geoff Wild]

No - not with MC/SG.

MC/SG allows you to have a "floating" ip address - that moves with the package (this is what your Application would be part of). If the server that the package is running on fails, it will move to the second node along with the ip address. The nice thing about that is, you give that floating IP a DNS name - say "myapp", and your users always point to "myapp", not to the actual hostnames of the servers.

If that doesn't do what you want, then, exactly, what is it that you need to accomplish and/or why do you need 2 servers with the same hostname?

Rgds...Geoff

[RATEFIARIVONY]

Hi,
Geoff >> I'm new to HP clustering :) ...
I think what you told is the configuration we will adopt.

Please can you post, steps and commands i will have to go thru ???

And if i see what you mean, i will have to set up a DNS on which clients's query will be addressed to ?

Thanks!

[Geoff Wild]

As Bharat mentioned - best to go through the "Managing MC/ServiceGuard" doc:

See this page for online and pdf:

http://docs.hp.com/hpux/ha/index.html#ServiceGuard

Steps to setup/configure a cluster are in there - so I won't go into too much detail.

You will need a cluster lock disk - so you will have to configure your shared volumes first (cluster lock can be a disk in a package).

Basically - configure cluster first:

cmquerycl -v -C /etc/cmcluster/clustername.ascii -n server1 -n server2

Edit that file, put in cluster name, heartbeats, max packages, etc.

Verify it:

cmcheckconf -k -v -C /etc/cmcluster/clustername.ascii

Then apply it:

cmapplyconf -k -v -C /etc/cmcluster/clustername.ascii

After that, add your package(s).

But really, go through the doc above - even print out the pdf - it is very good.

The DNS is correct - just setup A records for the ips that you want in the cluster.


Rgds...Geoff

[Bharat Katkar]

Hi,
As again suggested by Geoff, it is really important to go thr' the Doc once and understand the Concept completely. Clustering is normally done for Online Realtime Applications and downtime is really critical.
On the other hand it will also help you get quicker on the problem. It is always helpfull to get tips from the forum.

Regards,