Why doesn't suspend release vCPUs/memory?

asked 2014-06-22 12:46:29 -0500

rickysaltzer gravatar image

Per the Openstack documentation, it's implied that both vCPUs and memory are to be released when an instance is successfully suspended. However, when I suspend an instance, neither resources are reclaimed.

Documentation: http://docs.openstack.org/user-guide/content/suspend_resume.html (http://docs.openstack.org/user-guide/...)

Administrative users might want to suspend an instance if it is infrequently used or to perform system maintenance. When you suspend an instance, its VM state is stored on disk, all memory is written to disk, and the virtual machine is stopped. Suspending an instance is similar to placing a device in hibernation; memory and vCPUs become available to create other instances.

Releasing resources would be extremely helpful for my situation, which is I have users who have their own instances that they use on demand for a short period of time (basically a lab). The majority of an instance's life is wasted CPU cycles. The only workaround is to create a snapshot, destroy the instance and then re-deploy from the snapshot, but this is both tedious and time consuming...also, in our environment, the services running on the machine will not handle a sudden IP change very gracefully.

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Comments

Thanks for the question! That is odd. Which version of OpenStack are you running? I'd also suggest asking this question on the OpenStack general mailing List ( https://wiki.openstack.org/wiki/Maili... ) if you don't get an answer here in time.

fifieldt gravatar imagefifieldt ( 2014-06-23 04:19:42 -0500 )edit