Multiple health check jobs started for devices

[Senthil Kumaran S]

When a device comes from offline to online state, there are multiple health check jobs started for the device.

When forcing a health check job irrespective of whether there is a health check job already scheduled, a new job gets created, which is also a cause of creating multiple health jobs and running them at the same time by the scheduler.

[Senthil Kumaran S (stylesen)]

Fix available for review - https://review.linaro.org/#/c/772/

[Senthil Kumaran S (stylesen)]

New fix available for review here - https://review.linaro.org/#/c/786/

[Senthil Kumaran S (stylesen)]

This popped up again, since the patch was removed from dbjobsource.py during the scheduler stabilization effort.

[Senthil Kumaran S (stylesen)]

New patch available here for review - https://review.linaro.org/#/c/1000/

[Senthil Kumaran S (stylesen)]

In order to reproduce this issue, take 3 or more devices offline. After sometime (1 minute) take all the offlined devices online at one shot with the help of admin pages. There must be more than one health check job created for some devices as time passes by.

[Senthil Kumaran S (stylesen)]

Improved fix - https://review.linaro.org/#/c/1013/