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Subject [13/15] git commit: updated refs/heads/4.8 to 8f330b0
Date Wed, 18 May 2016 19:55:20 GMT
Merge pull request #1486 from remibergsma/reimplement-vrrp-setting-47

Reimplement router.redundant.vrrp.interval settingGlobal setting `router.redundant.vrrp.interval`
is not used any more and it is now set to a hardcoded 1.

This results in a failover from master->backup when the backup doesn't hear from the master
in ~3.6sec. This is a bit too tight, as we've seen failovers during live migrations. We could
reproduce it in about half of the cases. Setting this to setting to 2 (tested it by hardcoding
it in the systemvms) gives twice as much time and we didn't see issues any more. Instead of
updating the hardcoded setting from 1 to 2, I reimplemented the global setting by sending
it to the router with the cmd_line, as the non-VPC router also does.

Why is the maximum failover time in the example 3.6 seconds? This comes from the advertisement
interval and the skew time. The default advertisement interval is 1 second (configurable in
keepalived.conf). The skew time helps to keep everyone from trying to transition at once.
It is a number between 0 and 1, based on the formula (256 - priority) / 256

As defined in the RFC, the backup must receive an advertisement from the master every (3 *
advert_int) + skew_time seconds. If it doesn't hear anything from the master, it takes over.
With a backup router priority of 100 (as in the example), the failover will happen at most
3.6 seconds after the master goes down.


* pr/1486:
  Configure rVPC for router.redundant.vrrp.interval advert_int setting
  Have rVPCs use the router.redundant.vrrp.interval setting

Signed-off-by: Will Stevens <>


Branch: refs/heads/4.8
Commit: ebc70a51e2c56de6902be7633237613fe8c2df74
Parents: 9a20ab8 9c0eee4
Author: Will Stevens <>
Authored: Wed May 18 15:52:38 2016 -0400
Committer: Will Stevens <>
Committed: Wed May 18 15:52:38 2016 -0400

 .../cloud/network/router/ | 3 +++
 systemvm/patches/debian/config/opt/cloud/bin/cs/     | 4 ++++
 systemvm/patches/debian/config/opt/cloud/bin/cs/        | 1 +
 systemvm/patches/debian/config/opt/cloud/bin/cs/   | 3 +++
 4 files changed, 11 insertions(+)

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