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RDO, multi node, storage clarification questions

asked 2014-02-02 20:09:29 -0500

MrTim gravatar image

Hi all, I have been testing out RDO recently and have pretty good success, but some confusion and questions I wonder if anyone can comment on.

  • I've got 4 systems, each with 4Tb local raid disk; my desire was to have all 4 work as a single openstack cluster such that one host would have most management role (plus compute) and other 3 would be .. more compute resource.
  • I have had some success with setup, with neutron networking, but I'm a bit confused about storage.
  • I thought? I might simply get neutron installed on all nodes, and then configure a local large LVM volume group, "cinder-volumes" on each host.
  • I tried to achieve this via a packstack answers file config stanza, as follows

    # The IP address of the server on which to install Cinder

(However - I am not certain - if I am permitted to have cinder_host setup on multiple instances / or if RDO install is assuming otherwise - but it appears to not break the installer .. and if I add nodes one at a time, they do appear to each get cinder installed..?)!

  • my baseline plan was ~100gig for the root filesystem, and the rest for cinder-volumes LVM volume group.
  • but my first pass on this config - I can't see from web GUI, any space available beyond the ~100gig root filesystem (?)
  • I tried a second config - single large root filesystem, no cinder-volumes LVM - and this was not good.

I'm wondering what people might advise, if there is a 'good' way to use the storage in this hardware in a fairly balanced manner. Clearly I'm not worried about live migration / shared storage requirements for VMs. I just want to be able to provision VMs easily, via the Openstack API / and have each node use its own storage resources.

Any comments or pointers are greatly appreciated.

Many thanks,


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answered 2014-02-02 22:23:09 -0500

aplawson gravatar image

Blockquote I am not certain - if I am permitted to have cinder_host setup on multiple instances

Sure you can install and use Cinder on multiple compute nodes but there's really no need since your VM storage, by default, uses the local disk anyway - just as they would with a Cinder volume. Cinder solves the ephemeral storage issue but that leaves you with compute nodes with potentially stagnant volumes. Best to put Cinder on it's own node. Or use local file storage for your guests. Assuming your guests can tolerate storage going away when/once the guest is destroyed.

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Asked: 2014-02-02 20:09:29 -0500

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Last updated: Feb 02 '14