Forum Discussion
BIG-IP : best practice to update HA pair under load
F5 BIG-IP Virtual Edition v11.4.1 (Build 635.0) LTM on ESXi
For an HA pair configured as sync-failover device-group with auto-sync enabled, what is best practice to apply config changes ( including irules and data-group-files ) ?
I can think of a two possible mechanisms :
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disable auto-sync; apply changes to active device; if changes working as expected, re-enable auto-sync; if not, failover from active to standby, re-enable auto-sync
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disable auto-sync; apply changes to standby device; if changes working as expected, failover from active to standby, if succeeds re-enable auto-sync; if changes not working as expected, force-sync active to standby, re-enable auto-sync
And is it possible to implement these mechanisms via iControl ? Can iControl submit failover command ? Is it sensible to do so ? What is expected time for failover to occur ?
3 Replies
- nitass
Employee
i prefer the second one.
2. disable auto-sync; apply changes to standby device; if tests show changes working as expected, failover standby to active, re-enable auto-sync; if not, failover active to standby, re-enable auto-sync.i am not familiar with icontrol, so i leave it to the next guy. 🙂
Mohamed_LrhaziAltocumulus
I work in an environment with lots of LTMs pairs with auto-sync enabled. They are being modified on regular basis, no one ever thought about disabling auto-sync, not even during upgrades. Why did you even think about doing this?
R_MarcNimbostratus
You can do the auto-sync toggling and failovers via iControl (at least the rest interface, I've never tried the SOAP version).
As I recall from some training courses, however, F5 recommended taking a config backup as the preferred method of change backout (which also could be done from iControl). I think that is operationally less risky than what you have outlined here. I have run into a lot of sync issues on my devices (mostly fips related, may not apply to you) so I'd be leery of flipping that auto-sync bit a lot.
Also, when you fail over, you are likely to loose in flight transactions. I'm fighting with that right now; Whereas on a restore from backup should only touch those items you've changed. I have not tested this, of course, so your mileage may vary.
