[openstack-dev] [devstack] - suggested development workflow without ./rejoin-stack.sh ?

Kashyap Chamarthy kchamart at redhat.com
Tue May 3 12:52:14 UTC 2016

On Mon, May 02, 2016 at 03:10:56PM -0700, Kevin Benton wrote:
> This patch removed the ./rejoin-stack.sh script:
> https://review.openstack.org/#/c/291453/
> I relied on this heavily in my development VM which sees lots of restarts
> because of various things (VM becomes unresponsive in load testing, my
> laptop has a kernel panic, etc). Normally this was not a big deal because I
> could ./rejoin-stack.sh and pick up where I left off (all db objects,
> virtual interfaces, instance images, etc all intact).
> Now am I correct in understanding that when this happens there is no way to
> restart the services in a simple manner without blowing away everything and
> starting over? Unless I'm missing some way to run ./stack.sh without losing
> previous state, this seems like a major regression (went from mostly
> working ./rejoin-stack.sh to nothing).
> What is the recommended way to use devstack without being a power outage
> away from losing hours of work?

FWIW, whenever I feel I have a working env. in DevStack, I take a qcow2
live internal snapshot:

    $ sudo virsh snapshot-create-as devstack \
        snap1 "Working setup for bug#123"

If something goes terribly wrong in my env, revert to a known sane state:

    $ virsh snapshot-revert devstack snap1

This stipulates[*] that you use Qcow2 format.  Also it does not exactly
solve your 'sudden power outage' issue, but comes reasonably close if
you save the work at points-in-time you care about.

[*] There are other methods like 'external disk snapshots' (when you
    create a snapshot, the current disk becomes a 'backing file' & a new
    qcow2 overlay is created to track all the new writes from the point
    of taking snapshot) that allow you both Raw and Qcow2 file formats. 


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