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Newbie - OA cannont communicate with blade iLO

Robert.Costa
Occasional Advisor

Newbie - OA cannont communicate with blade iLO

OK, not total newbie but here is the question:
Why is it that if I put my OAs on one subnet and assign EBIPA IPs to my blades' iLO on a different subnet, the two are unable to communicate?

Setup:
c7000 chassis
2 OAs
16 BL460G6 blades2
2 VC Flex-10s (not the issue)

Working Example (std class c subnet):
OA=192.168.100.10
EBIPA=192.168.100.20,21, etc
RESULT= works fine, I can launch iLO remote console and get to the blades.

Non-working Example (again, std class C)
OA=192.168.100.10
EBIPA=192.168.101.20,21, etc
RESULT: OA cannot communicate with iLO - no remote console.

I guess I don't understand how the OA talks to iLO. I would like to have my management interfaces on our production subnet and all of my iLO traffic a private net. If there is no routing between the two subnets will it not work? Would the communication between the OAs and the iLO interfaces on the blades have to leave the chassis, hit my routers and then go back in?

In the past I have just put the OAs and iLO on the same subnet to get around this but I'm still not sure how it actually works.

Sorry for the long post..

7 REPLIES
WFHC-WI
Honored Contributor

Re: Newbie - OA cannont communicate with blade iLO

Hi Robert,

Communication to the iLO ports on your blades is done through the cabling connected to the Onboard Administrator. The OA cannot handle a trunk port, so you can only present one subnet to the OA module. (Even if you have a redundant OA on a separate VLAN, all iLO communication will travel only through the active OA.)

You will need to put your OA and iLO IPs in the same subnet (like your working example above).

Hope that helps, good luck
Robert.Costa
Occasional Advisor

Re: Newbie - OA cannont communicate with blade iLO

I was thinking that but I was not able to find it specifically in the documentation. I'd really like to be able to point it out as published rather than "observed" behavior...

We generally separate our iLO traffic from our production net but I suppose we will just have to place the OAs management interfaces on the iLO VLAN.

Thanks for the reply - I'll leave the post open for a bit in case anyone else has input - or maybe even produces an "Eureka!" moment!

Adrian Clint
Honored Contributor

Re: Newbie - OA cannont communicate with blade iLO

Robert, Question to you. Why are your OAs not required on the ilO network anyway. The OA is the "iLO" for the enclosure. Why would you separate OA and iLO on different networks?

What you are getting is expected behaviour. The OA may be able to give the iLOs and interconnects any IP addresses by the "DHCP server" in the OA. But it does not switch or route the OA subnet if it is different. So you cant access the ILOs or Interconnect IP from the OA if they are on different subnets to the OA. You can still access them directly though.
Robert.Costa
Occasional Advisor

Re: Newbie - OA cannont communicate with blade iLO

Adrian:

You're right there is no really compelling reason to separate out the OA from iLO other than the fact that I was going with the "least administrative effort" route of having the OA on a network I can actually get to from my workstation. The iLO network is non-routable (except for ISM email notifications) so I would have to be physically present at the console to administer the OAs (no KVM over IP). I suppose you could put it in the category of "laziness". Aren't I supposed to be sipping cocktails with little umbrellas somewhere on a beach as I admin this stuff? ;-)
WFHC-WI
Honored Contributor

Re: Newbie - OA cannont communicate with blade iLO

I like your thinking Robert. :)

Check this document:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00705292/c00705292.pdf

Page 57:
"The server blade iLO 2 defaults to DHCP addressing, obtained through the
network connector of the active Onboard Administrator."

That should be a good enough indicator that ilo network traffic goes through the OAs. :)
The Brit
Honored Contributor

Re: Newbie - OA cannont communicate with blade iLO

To be specific, all of the iLO traffic enters and exits the enclosure through the port on the Active OA. This includes direct Telnet/SSH connections to any of the iLOs. It also includes direct Browser connections and CLI connections to interconnect modules.

If "Enclosure IP Mode" is enabled, then the IP address of the "Active" OA will always be the same, regardless of which physical OA is "Active".

Also, it is clearly necessary, that there be a physical connection from each OA to the external network.

Dave.
sdf2sjk
Occasional Advisor

Re: Newbie - OA cannont communicate with blade iLO

I have a chassis that we are using for two different environments. I will give an example, letâ s say A environments servers are 10.12x and B servers are on 10.22x. The OA has 10.12x. The B environment servers are on 10.22x. We really donâ t want to have a B environment server with a A environment ilo address. I was hoping there was a way for the iloâ s to be setup on two different networks but it sounds like that is not possible. Is that the case?