Re: Tips for faster openstack instance boot

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The biggest question here is if the OS is using systemctl or not. Cl7 boots extremely quick but our cl6 instances take up to 90 seconds if the cluster has work to do.

I know there a lot to do in the init as well with boot profiling etc that could help.

/Josef

On Tue, 9 Feb 2016 17:11 Vickey Singh <vickey.singh22693@xxxxxxxxx> wrote:
Guys Thanks a lot for your response.

We are running OpenStack Juno + Ceph 94.5

@Jason Dillaman Can you please explain what do you mean by "Glance is configured to cache your RBD image" ? This might give me some clue.

Many Thanks.


On Mon, Feb 8, 2016 at 10:33 PM, Jason Dillaman <dillaman@xxxxxxxxxx> wrote:
If Nova and Glance are properly configured, it should only require a quick clone of the Glance image to create your Nova ephemeral image.  Have you double-checked your configuration against the documentation [1]?  What version of OpenStack are you using?

To answer your questions:

> - From Ceph point of view. does COW works cross pool i.e. image from glance
> pool ---> (cow) --> instance disk on nova pool
Yes, cloning copy-on-write images works across pools

> - Will a single pool for glance and nova instead of separate pool . will help
> here ?
Should be no change -- the creation of the clone is extremely lightweight (add the image to a directory, create a couple metadata objects)

> - Is there any tunable parameter from Ceph or OpenStack side that should be
> set ?
I'd double-check your OpenStack configuration.  Perhaps Glance isn't configured with "show_image_direct_url = True", or Glance is configured to cache your RBD images, or you have an older OpenStack release that requires patches to fully support Nova+RBD.

[1] http://docs.ceph.com/docs/master/rbd/rbd-openstack/

--

Jason Dillaman


----- Original Message -----

> From: "Vickey Singh" <vickey.singh22693@xxxxxxxxx>
> To: ceph-users@xxxxxxxxxxxxxx, "ceph-users" <ceph-users@xxxxxxxx>
> Sent: Monday, February 8, 2016 9:10:59 AM
> Subject: Tips for faster openstack instance boot

> Hello Community

> I need some guidance how can i reduce openstack instance boot time using Ceph

> We are using Ceph Storage with openstack ( cinder, glance and nova ). All
> OpenStack images and instances are being stored on Ceph in different pools
> glance and nova pool respectively.

> I assume that Ceph by default uses COW rbd , so for example if an instance is
> launched using glance image (which is stored on Ceph) , Ceph should take COW
> snapshot of glance image and map it as RBD disk for instance. And this whole
> process should be very quick.

> In our case , the instance launch is taking 90 seconds. Is this normal ? ( i
> know this really depends one's infra , but still )

> Is there any way , i can utilize Ceph's power and can launch instances ever
> faster.

> - From Ceph point of view. does COW works cross pool i.e. image from glance
> pool ---> (cow) --> instance disk on nova pool
> - Will a single pool for glance and nova instead of separate pool . will help
> here ?
> - Is there any tunable parameter from Ceph or OpenStack side that should be
> set ?

> Regards
> Vickey

> _______________________________________________
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com

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