How to check wether nics are connect to different lans

[candyman_1]

Hi All

I'm configuring serviceguard in a 2 node cluster. there are 3 nics on each, lan0 and lan2 are connected to the network and lan1 for dedicated heartbeat. I want to know how would I know that lan0 and lan2 are on 2 different lans. I want to configure lan2 as a standby for lan0.

Thanks

Candyman

[Mridul Shrivastava · Accepted solution]

lan 0 and lan 2 must be on the same network if you want to configure lan2 as a standby for lan 0 else it won't work.

If you want to configure lan2 as a standby for lan 0 then don't assign any IP to lan2 under netconf and cluster configuration file and put it under lan 0 so it will be treated as standby for lan0.

[Mridul Shrivastava]

If a NIC has no IP assignment but you want it to be a standby NIC, it MUST be on the same LAN as a primary (IP-bearing) NIC.

If you intend that lan0 be registered as having an IP, it must be listed in /etc/rc.config.d/netconf, and the IP must be associated with lan0 in the cluster configuration file and show up when running 'ifconfig lan0'.

[Michael Steele_2]

Use the MC/ServiceGuard command cmscancl.

cmscancl -n node -o outfile

Get use to use this command. Its a very valuable diagnostic utility that includes a lan connection section with exactly what you're looking for:

lan 0 CONNECTED lan 1
lan 0 NOT CONNECTED lan 2

Listed just like above, you can't go wrong.

Additionally, all connections are at the MAC address level. So use 'arp -a' to review.

[candyman_1]

Mridul,

both the nics are connected to the same network, but when i run cmquerycl the template says that lan0 has no possible standby interface, lan2 has no ip assigned.

Michael: I tried cmscancl it gave me the out put that link connectivity for lan0 to lan2 is ok and vice versa. but i'm still getting the warning in the cluster.ascii that no standby for lan0.


The cluster is running ok without the standby inerface, I just need to eliminate this SPOF.

Please assist.

Thanks

Candyman.

[Mridul Shrivastava]

Does the cluster ascii file looks like below

NODE_NAME pippo
NETWORK_INTERFACE lan1
HEARTBEAT_IP 192.168.1.208
NETWORK_INTERFACE lan0
STATIONARY_IP 172.16.1.1
NETWORK_INTERFACE lan2

If yes then could you please post the exact error message ?

[Michael Steele_2]

Re: "..I want to know how would I know that lan0 and lan2 are on 2 different lans. ..."

Are these connected to two different switches?

[candyman_1]

Michael:
I have connected lan0 and lan2 to 2 different switches but still I want to confirm. I cant really trace the cables. how can I confirm that.

[Warren_9]

Hi Candyman,

you can use the command "cmscancl" and the output will show you which nic are connected.

e.g.
# cmscancl -n node1 -n node2 -o /tmp/myscancl.log

OR use the "lanscan" to get the MAC address of the interface and then use "linkloop" to test the connection.

e.g
[srv01] # lanscan <-- get the MAC address

[srv02] # linkloop -i lan0 [MAC of srv01-lan2]

if they are connected to same network, you will get the output "OK"

GOOD LUCK!!

[Michael Steele_2]

Paste in the exact error