GitHub user remibergsma opened a pull request:
https://github.com/apache/cloudstack/pull/1486
Reimplement router.redundant.vrrp.interval setting
Global 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.
Background:
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.
Source: http://www.hollenback.net/KeepalivedForNetworkReliability
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/remibergsma/cloudstack
reimplement-vrrp-setting-47
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/cloudstack/pull/1486.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1486
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commit c33358db848faf8c8891e00e0100a2627b177407
Author: Remi Bergsma <[email protected]>
Date: 2016-03-23T15:33:20Z
Have rVPCs use the router.redundant.vrrp.interval setting
It defaults to 1, which is hardcoded in the template:
./cosmic/cosmic-core/systemvm/patches/debian/config/opt/cloud/templates/keepalived.conf.templ
As non-VPC redundant routers use this setting, I think it makes sense to
use it for rVPCs as well.
We also need a change to pickup the cmd_line parameter and use it in the
Python code that configures the router.
commit 408478413ad0469265dfa0ce9101d6337f558ab2
Author: Remi Bergsma <[email protected]>
Date: 2016-03-23T15:56:54Z
Configure rVPC for router.redundant.vrrp.interval advert_int setting
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