Intervals should be staggered

In addition to (or instead of) spreading the initial schedule, it would be beneficial to +/- a random percentage (e.g. between -10% and +10%) to the next interval on each run. This means that instead of running at hard intervals, the runs become skewed but remain at the given interval on average. This avoids synchronisation and consistent load spikes if the initial offset results in it matching another fixed processing schedule (e.g. from a cronjob). The same applies with load distribution on the server side (if applicable).

The attached patch spreads out the various reactor calls +/- 10% and was used as a cowboy in our use case. It's not production ready in that it should be a configurable option (and would also need to do the initial stagger which I couldn't figure out how to do -- mine works over time, not immediately), but should be a good starting point.

Sorry, I should clarify this patch does NOT solve the problem over time, since the +/- 10% theoretically averages out to zero over time. What solved our synchronized load spikes was pushing out the patched landscape-client via landscape, so the units updated themselves over an N-hour window and spread out the initial timers.

Hi, what's the progress here ? Maintaining our own landscape-client package is painful.

Thanks

Hi Junien,

There's a branch in review for this at https://github.com/CanonicalLtd/landscape-client/pull/63

As Ryan noted, the patch he attached will tend towards all the landscape-clients averaging out to the same intervals.

Any feedback you have on the above PR is welcome.

Hello Ryan, or anyone else affected,

Accepted landscape-client into disco-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/landscape-client/18.01-0ubuntu7.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-disco to verification-done-disco. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-disco. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Hello Ryan, or anyone else affected,

Accepted landscape-client into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/landscape-client/18.01-0ubuntu3.4 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Verified bionic and disco proposed, by setting launching a couple of instances and verifying the monitors are scattered in the logs.

Hello Ryan, or anyone else affected,

Accepted landscape-client into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/landscape-client/16.03-0ubuntu2.16.04.7 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

I verified the pacakges in xenial-proposed and the logs indicated scattered start delays, as expected.

The verification of the Stable Release Update for landscape-client has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package landscape-client - 18.01-0ubuntu3.4

---------------
landscape-client (18.01-0ubuntu3.4) bionic; urgency=medium

  * d/p/product-name-vminfo-1828217.patch: Add product_name to things scanned
    for vm_info (LP: #1828217)
  * d/landscape-client.postinst: Set default value if data_path is
    missing. (LP: #1728681)
  * d/p/stagger-launch-1788518.patch: Add option to stagger launch of broker
    plugins. (LP: #1788518)
  * d/landscape-client.init: Fix init script stop action (LP: #1833137)

 -- Simon Poirier <email address hidden> Thu, 27 Jun 2019 11:07:30 -0400

This bug was fixed in the package landscape-client - 18.01-0ubuntu7.1

---------------
landscape-client (18.01-0ubuntu7.1) disco; urgency=medium

  * d/p/product-name-vminfo-1828217.patch: Add product_name to things scanned
    for vm_info (LP: #1828217)
  * d/landscape-client.postinst: Set default value if data_path is
    missing. (LP: #1728681)
  * d/p/stagger-launch-1788518.patch: Add option to stagger launch of broker
    plugins. (LP: #1788518)
  * d/landscape-client.init: Fix init script stop action (LP: #1833137)

 -- Simon Poirier <email address hidden> Thu, 27 Jun 2019 11:07:30 -0400

This bug was fixed in the package landscape-client - 16.03-0ubuntu2.16.04.7

---------------
landscape-client (16.03-0ubuntu2.16.04.7) xenial; urgency=medium

  * d/p/product-name-vminfo-1828217.patch: Add product_name to things scanned
    for vm_info (LP: #1828217)
  * d/landscape-client.postinst: Set default value if data_path is
    missing. (LP: #1728681)
  * d/p/stagger-launch-1788518.patch: Add option to stagger launch of broker
    plugins. (LP: #1788518)
  * d/landscape-client.init: Fix init script stop action (LP: #1833137)

 -- Simon Poirier <email address hidden> Fri, 28 Jun 2019 12:18:32 -0400