Forum Discussion
Zhinjio_101470
Sep 22, 2011Nimbostratus
Active/Passive NODE question
Hey folks,
Having a friendly argument with a coworker about the best way to implement a particular failover scenario.
General Behavior Definition:
We want one node to be receiving all traffic until it fails.
Failover to the secondary node should be automated and quick.
Once a node is "promoted" to active, it should remain that way, even if the old node comes back into service.
A failed node returning to service (monitoring succeeds) should be a MANUAL step.
We want to minimize the work required to return a failed node into service again (but it should not be completely automated).
We currently have two different methods we're implementing this, but it seems to me there should be a better way than either of these methods:
-------------------
Method 1:
Round Robin, Priority Pool (nodes set to, say ... 3 and 5) (Less than 1)
Monitor set "Manual Resume" to "YES"
No persistence profile
When active node fails, secondary node is promoted due to load balancing method. Recovered node will NOT return to service until manually checked back to "Enabled". At that time, I would also adjust its Priority to be LOWER than the active node so it will not receive traffic until the newly promoted node fails. Enable the node. All is well.
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Method 2:
Round Robin, Priority Pool (nodes set to 3 and 5) (Less than 1)
Monitor set "Manual Resume" to "YES"
Persistence profile set to "Dest.Addr Affinity" and Timeout set to "Indefinite"
Similar to above, active node fails, secondary node is promoted. Recovered node will not return to service until manually checked back to Enabled. UNLIKE the above method though, it will not receive traffic due to the persistence profile and timeout setting.
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So it seems to me that with the second method, you are setting the priority pool settings, but not really "taking advantage" of them. The only purpose is really serves is to ensure that only one node is getting traffic, but then ignoring it with the persistence profile. The one advantage of the second method is that I don't have to muck with priority values when I bring a node back into service.
Either way, it seems that either of these methods are kind of "hacks" and it is really just cover for the fact that there is no "real" active/passive node implementation that covers our requirements.
Y'all are smart. Are we missing some feature or method for doing this that would still cover our requirements?
Thanks in advance,
- ZJ
- The_BhattmanNimbostratusHi ZJ,
http://devcentral.f5.com/wiki/iRules.SingleNodePersistence.ashx
You can alter it so that you can toggle to turn on persistance for one node over the other via HTTP request.
- Zhinjio_101470NimbostratusThat is a great solution. However... you noted:
- The_BhattmanNimbostratusHI Zhinjio,
- hooleylistCirrostratusYou could try using Manual Resume on the monitor. From the online help:
- Zhinjio_101470NimbostratusPosted By hoolio on 09/27/2011 10:47 AM
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