Hearbeat interface IP adress.

[Xavier Pitz_1]

Hello,

I plan to re-IP the hearbeat addresses of our nodes/clusters.
For the moment some nodes have the same heartbeat IP (not in the same cluster...)
But on our network we have many times the same heartbeat IPs on different nodes. It works but it's not clean for me. What I want to do now is to take IPs in 192.168.1.XXX with a 255.255.255.252.
I've tried to configure on a test system an interface with address 192.168.1.253 & mask 255.255.255.252, but SAM does not accept such an IP for an interface. Where am I wrong ? Is there a better design for heartbeat IPs ?

[Roger Baptiste]

hi,

I am not sure what you mean by reconfiguring heartbeat IPS.

Heartbeat Lan cards are normally dedicated lan cards on a node and are connected in a loop to the dedicated lan card on the other nodes of the cluster. It can be assigned any
IP address, as long as it does not clash with any existing IP address on the network.

HTH
raj

[Xavier Pitz_1]

Yes those interfaces and IPs attached to them are dedicated for the heartbeat. I have a cross-cable between both interfaces.
What I want to do in terms of IPs is to take a private network and subnet it at the maximum so I can have for example as heartbeat IPs:

Cluster1:
network : 192.168.1.252
node1-1 : 192.168.1.253
node1-2 : 192.168.1.254
broadcast : 192.168.1.255
netmask : 255.255.255.252

Cluster2:
network : 192.168.1.248
node2-1 : 192.168.1.249
node2-2 : 192.168.1.250
broadcast : 192.168.1.251
netmask : 255.255.255.252

It does look good for me.
It does not look good for SAM.
Does it looks good for you ?
Does it looks good for you.

[BFA6]

Hello,

Generally on our SG clusters we use a private address e.g. 1.1.1.1 & 1.1.1.2 for the heartbeat lans.

Hilary

[Xavier Pitz_1]

From RFC 1918 :

The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:

10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

Therefore 1.1.1.* is not a private network for me...

[Roger Baptiste]

I think you can use any range of IP address you want. No need to stick to the same subnet as the primary Lan network. Anyway, since these IPs are local to the system and your site, you are free to use any IP (as long as they dont clash with your local IPs). Once you do this, you can even use a subnet mask of 255.255.0.0 ! This way, you can use the same subnet number for all your heartbeat ips.

HTH
raj

[Xavier Pitz_1]

Ok, I know that in theory I can set any kind of IPs that I want for heartbeats.

So... Why not to do it clean with a private IP like a 192.168.something ?

I want to take 192.168.1.XXX and subnet it into many smaller subnets (1 small subnet will regroup heartbeats IP of all nodes in the cluster).

If I take the whole 192.168.1.0 with a 255.255.255.0 netmask, i suspect software like NNM to detect a big subnet composed of different nodes that are not able to contact each others.

That's why I want to cut 192.168.1.0 in different sub-subnets by using 255.255.255.X netmask with X in 128,192,224,240,248 or 252.
Is it possible to do it in HP-UX or am I stuck with 255.255.255.0 netmask ?

[Ron Kinner · Accepted solution]

First and last subnets are not normally usable when you break a net down into multiple subnets. They get confused with subnet network and broadcast so the RFC forbids them. On a Cisco you can turn off this rule with ip subnet-zero. On HP 11.0 there is an unsupported NDD setting which I assume does the equivalent:
ip_check_subnet_addr. If you set it to 0 it's supposed to be more lenient in what subnets it allows.

Drop down to the next lower 252 subnet and it should take it.

Ron

[Xavier Pitz_1]

Thank you Ron, it takes it now...

Xavier