Public bug reported: In 21.3, we added udev rules to enable the cloud-init hotplug functionality. If a new device is detected, we call into cloud-init to see if hotplug is supported/enabled, then proceed accordingly based on the results. There are cloud users that are creating and disposing docker containers at a very high rate. This causes many virtual ethernet adapters to be created and disposed. This is triggering cloud-init events at a high volume, consuming significant CPU. Even with the hotplug functionality being disabled, the act of checking if hotplug is enabled is causing the spikes in CPU.
The path taken is: https://github.com/canonical/cloud-init/blob/main/udev/10-cloud-init-hook-hotplug.rules to https://github.com/canonical/cloud-init/blob/main/tools/hook-hotplug to https://github.com/canonical/cloud-init/blob/main/cloudinit/cmd/devel/hotplug_hook.py#L158 For more context, see IRC conversations from 10/1/2021 and 10/4/2021: https://irclogs.ubuntu.com/2021/10/01/%23cloud-init.html https://irclogs.ubuntu.com/2021/10/04/%23cloud-init.html ** Affects: cloud-init Importance: Critical Status: Triaged ** Changed in: cloud-init Status: New => Triaged ** Changed in: cloud-init Importance: Undecided => Critical -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to cloud-init. https://bugs.launchpad.net/bugs/1946003 Title: hotplug causing cloud-init to spike CPU usage Status in cloud-init: Triaged Bug description: In 21.3, we added udev rules to enable the cloud-init hotplug functionality. If a new device is detected, we call into cloud-init to see if hotplug is supported/enabled, then proceed accordingly based on the results. There are cloud users that are creating and disposing docker containers at a very high rate. This causes many virtual ethernet adapters to be created and disposed. This is triggering cloud-init events at a high volume, consuming significant CPU. Even with the hotplug functionality being disabled, the act of checking if hotplug is enabled is causing the spikes in CPU. The path taken is: https://github.com/canonical/cloud-init/blob/main/udev/10-cloud-init-hook-hotplug.rules to https://github.com/canonical/cloud-init/blob/main/tools/hook-hotplug to https://github.com/canonical/cloud-init/blob/main/cloudinit/cmd/devel/hotplug_hook.py#L158 For more context, see IRC conversations from 10/1/2021 and 10/4/2021: https://irclogs.ubuntu.com/2021/10/01/%23cloud-init.html https://irclogs.ubuntu.com/2021/10/04/%23cloud-init.html To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-init/+bug/1946003/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
