MC/SG Downgrade

[Ralph Grothe]

Hi,

I was given the bizarre appearing task to downgrade the MC/SG release from 11.16 to 11.14.
The reason being that one wants to mix cluster nodes with hpux releases 11.00 and 11.11.
From the published compatibility matrices one found out that the latest applicable MC/SG release was 11.14

This is currently installed, as part of the Mission Critical OE bundle:

# swlist HPUX11i-OE-MC.ServiceGuard|tail -4

# HPUX11i-OE-MC B.11.11.0412 HP-UX Mission Critical Operating Environme
nt Component
# HPUX11i-OE-MC.ServiceGuard A.11.16.00 ServiceGuard
HPUX11i-OE-MC.ServiceGuard.CM-SG A.11.16.00 Serviceguard


Usually (as upgrades go) I would simply swinstall the other depot.
But with downgrading I am a bit undecided
if I need to swremove the current version first.
Also, what about the required patches?
I've got a whole bunch of patches especially for 11.14.
But I assume that the current patch level is more recent since this is a brand new box.
Would it then be wise to enforce the installation of the special 11.14 patches?

Regards
Ralph

[Steven E. Protter]

See if you can swremove the two major components and reinstall 11.14.

You are going to lose use of the node for some period of time.

I think you will need to install 11.14 and patches prior to joining this node into this environment.

Question for you:
"The reason being that one wants to mix cluster nodes with hpux releases 11.00 and 11.11."

Is that configuration supported? I don't know and you might want that clarified before you continue.

SEP

[Ralph Grothe]

Hi SEP,

many thanks for the quick response.

You are mentioning the two major components.
What is the 2nd?
I was only thinking of removing
HPUX11i-OE-MC.ServiceGuard.CM-SG
but leaving the rest of HPUX11i-OE-MC untouched,
if this is possible at all.

I was told by our more influencial project leaders and implementers who gave me the order to install and setup everything
that they checked with the sales reps. of HP that mixing of nodes with deviating hpux releases is possible with the 11.14 SG.

[Duncan Edmonstone]

Ralph,

They got the OK fom a *sales* guy? Did his sale depend on this?

Just because you *can* fo this, doesn't mean you should.

The Serviceguard manual is quite clear on this:

http://docs.hp.com/en/B3936-90079/apes03.html

Note this point:

"Rolling upgrades are not intended as a means of using mixed releases of Serviceguard or HP-UX within the cluster. It is highly recommended that you upgrade all cluster nodes as quickly as possible to the new release level."

If this were me, I would want written confirmation from HP support that they would do this before even considering it.

KB Doc UMCSGKBRC00008723 seems to suggest it is supported, but it's not quite explicit enough for me - the implication is that different OS versions are only supported during the upgrade.

Or maybe you've already been through this...

HTH

Duncan

[Zeev Schultz · Accepted solution]

Mixed clusters are supported (for 11i,11.0) as far as they have same revision.Last for 11.0 is SG 11.14 (http://docs.hp.com/en/B3935-90050/ch01s03.html#d0e499)

Patches:

http://docs.hp.com/en/B3935-90050/ch01s04.html

Basically,swremove does the work.Obviously,sg is halted on the node. As to patches - check in the list and compare to yours "swlist -l patch" outputs.

[Stephen Doud]

Downgrading a currently running cluster is not supported - ie. there is no downgrade procedure similar to the rolling upgrade procedure described in Appendix E in the Managing Serviceguard manual. Be prepared to recreate your cluster after getting all nodes at the same revision of Serviceguard.

Swremove (precursor to swinstalling an older version of SG) causes the cluster binary to be zero'ed out on all nodes in the cluster, effectively removing the old cluster. If you want to keep the cluster intact, I suggest you copy /etc/cmclster/cmclconfig to a new name on each node, and after downgrading to 11.14, copy the file back into place. You may have to run /usr/sbin/convert on the binary on the node that you downgraded. I can't guarantee that the command will work on a downgraded system. Hence, be prepared to recreate the cluster.

[Ralph Grothe]

Hi Duncan, Hi Zeev,

obviously a bit of a controversial issue here, but since Zeev is bearing an HP logo I take his statement as another "official" confirmation.
I know this mixing is pretty weird and I'm not particular fond of it.
I would rather have it setup neatly with equivalent nodes in most every respect.
But I am here to fulfill our customers' wishes and my supervisors' demands.
I mustn't tell this, but our administration (i.e. the influencial guys) have been making so many silly concessions towards our customers (and in a way pampered them thereby), neglecting our more technically based concerns, that I haven't got any strong feelings about this anymore.
If they want it, and it can be done without real violation of the laws of Physics, then they get it.