Ah, iptables is the missing ingredient. I really appreciate the heads-up. 

-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of William Seligman
Sent: Tuesday, August 21, 2012 11:55 AM
To: General Linux-HA mailing list
Subject: Re: [Linux-HA] IP Clone

On 8/20/12 6:54 PM, Yount, William D wrote:
> No, no complaining. Just glad to get a definitive answer on it. Active/Active 
> made me think something that I guess isn't true. No worries. Honestly, thanks 
> for the reply. Without you, I would have kept trying and trying and trying.
> 
> 
> 
> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf Of Dimitri 
> Maziuk
> Sent: Monday, August 20, 2012 5:50 PM
> To: [email protected]
> Subject: Re: [Linux-HA] IP Clone
> 
> On 08/20/2012 05:01 PM, Yount, William D wrote:
>> I am trying to set up an Active/Active cluster. I have an
> Active/Passive cluster up and running.
> 
> I don't remember seeing a clear explanation of when, where, and why you'd 
> actually want an active/active cluster. I never needed one myself, so can't 
> really help you there.
> 
>> I don't understand how it could be called an Active/Active cluster if 
>> you aren't allowed to run the IP address on two servers at once.
> 
> You are not allowed to run the IP address on two servers at once, full stop. 
> Complain to Rob Kahn and Vint Cerf.

For what it's worth, I run an Active/Active cluster (probably for all the wrong 
reasons). IP cloning works fine for me. Here's my setup:

primitive IP_cluster ocf:heartbeat:IPaddr2 \
        params ip="129.236.252.11" cidr_netmask="32" nic="eth0" \
        op monitor interval="30s" \
        meta resource-stickiness="0"

clone IPClone IP_cluster \
        meta globally-unique="true" clone-max="2" clone-node-max="2" \
        interleave="false" target-role="Started"

Pretty much the canonical version from "Clusters From Scratch". Here's what I've
noticed:

- I needed iptables running to make this work.

- This gave me a consistent MAC address for the cluster IP address of 
129.236.252.11, improving the availability of the connection.

- I didn't see much load balancing after the first time I set it up. Mostly 
both clone instances run on a single node of my two-node cluster. For my needs, 
that's OK, since for me load-balancing is a much lower priority than 
availability.
-- 
Bill Seligman             | Phone: (914) 591-2823
Nevis Labs, Columbia Univ | mailto://[email protected]
PO Box 137                |
Irvington NY 10533 USA    | http://www.nevis.columbia.edu/~seligman/

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