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Can i scale up/scale down computing resource(i.e. cpu, ram, disk) on running vm instances without shutting it down?

asked 2013-05-31 07:27:11 -0500

sudhir gravatar image

updated 2013-06-08 22:32:37 -0500

fifieldt gravatar image

Can i add more computing power i.e. cpu, ram, disk to live/running vm instances without shutting it down?

can i set a threshold in such a way that if cpu usage exceeds 80% then automatically add additional computing power such as add couple of more CPU cores to running VM instance, can do this ? how do i configure this in nova? pls suggest.

Thanks in advance.

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answered 2013-05-31 08:32:34 -0500

Sagar Ratnakara Nikam gravatar image

You can use the resize API to add a different flavor to that VM. Check this doc

This is a user initiated action. You cannot set a threshold and resize it automatically on reaching that threshold.

To set threshold and the increase the size of the VM, you can do the following

HealthNMon, a opensource “Cloud Resource Monitor” provides among other features, a feature for fetching CPU utilization of a VM launched in Openstack

You can write a custom script/cron job, which keeps checking the CPU utilization using HealthNMon, and when it reaches the threshold, call the resize API and change the flavor

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answered 2013-05-31 07:37:50 -0500

Short answer no, there is no such option in OpenStack or at any public cloud provider as I know. On running instances you can just edit security group, attach volumes or associate floating IP-s. So to change memory or cpu, you can just create snapshot from running instance and spin up new one from that snapshot using different size.

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Asked: 2013-05-31 07:27:11 -0500

Seen: 14,973 times

Last updated: Jan 20 '14