controller shutdown

asked 2017-07-25 12:16:13 -0500

tcpip gravatar image

HI all,

I have 1 controller with 2 compute servers, I would like to know if my controller shutdown, my compute servers will keep working?


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answered 2017-07-25 17:33:01 -0500

updated 2017-07-25 18:48:22 -0500

They will continue to run existing VMs, but they will be affected.

VMs on tenant networks that are connected with centralized routers will lose most of their network connections, in particular connections between the external world and the VMs. This is so because all network traffic between VMs on different hosts and between VMs and outside goes through the controller.

Compute nodes will also generate log messages about not being able to reach the controller. That might affect disk space and/or performance.

There might be other problems depending on the particular setup; obviously, all services configured on the controller will be unavailable.

If it's for a short time, I guess it might be acceptable.

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answered 2017-07-26 06:22:08 -0500

tcpip gravatar image

Hello Bernd,

I need to run a virtual router, and for what you said, I will loose my external connections with this, so it would be if the router is not working, right?


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The router, if it is centralized (which is likely given the small size of your cloud), will be unavailable while the controller is down.

If that is a problem, I think a distributed router should solve it. It's distributed over network and compute nodes.

Bernd Bausch gravatar imageBernd Bausch ( 2017-07-26 09:11:35 -0500 )edit

If i put one remote contoller as a backup?

tcpip gravatar imagetcpip ( 2017-07-26 18:17:01 -0500 )edit

For high-availability, use three controllers to avoid split-brain. I would use one of the distros rather than trying to set it up from scratch, as it requires considerable experience with both HA technologies and OpenStack.

Bernd Bausch gravatar imageBernd Bausch ( 2017-07-27 04:53:42 -0500 )edit

You could try the HA Guide, but it's not complete.

Bernd Bausch gravatar imageBernd Bausch ( 2017-07-27 04:56:20 -0500 )edit

I think it's easier to set up the distributed router.

Bernd Bausch gravatar imageBernd Bausch ( 2017-07-27 04:57:41 -0500 )edit

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Asked: 2017-07-25 12:16:13 -0500

Seen: 520 times

Last updated: Jul 26 '17