Support for dest=volume

[Alex Smith]

Hi,

I've been trying out the 5.11 version connected to OpenStack and have run into a small issue.

We don't provision any storage locally on our compute hosts, instead preferring to boot from volume all our instances. We normally do this either by selecting the option in Horizon or providing the "dest=volume" option in our calls to Nova.

I've had a look around and I've been unable to find anywhere in Scalr that we can define this as an option (there also seems to be a lack of making this the default in OpenStack too). In the "Storage" section on the farms it states this "Root device configuration is not available for this Farm Role (the root device may not be a volume)" however in this case, with dest=volume that is not true and I would have thought we should be able to configure that.

I have tried adding another volume in storage and optimistically telling it to use / for the mount but that failed (as you'd expect).

I'm not adverse to adjusting the call it makes to Nova as this is the default for us, if that's an option.

Thanks,

Alex

[Marc O'Brien]

Hi Alex,

I have done a bit of digging in to this and have encountered the same issues that you describe.  It would be preferrable to set this "dest=volume" as a default on the Openstack side but I have been unable to find any reasonable way to achieve this.  As this capability does not presently exist within Open Source Scalr, you may need to do some code modification to adjust these nova calls as you had suggested.  The following appears to be the best place for you to start:

https://github.com/Scalr/scalr/blob/master/app/src/Scalr/Service/OpenStack/Services/ServersService.php#L128

https://github.com/Scalr/scalr/blob/3f2b1f07768c773be890c88f3a2a2d197c7eabc9/app/src/Scalr/Service/OpenStack/Services/Servers/V2/ServersApi.php#L173

The $options variable appears to have the actuall request JSON, so you may be able to add something to achieve your desired result here.  Perhaps something like " $options['server']['destination_type '] = 'volume'; " before this line of code.  Please be advised any such modification is untested on our side and may have unintended consequences elsewhere in Scalr.  For instance, the server may be launched but the client likely won't be able to create a server snapshot, because this type of deployment (cinder backed instances) is not supported by Scalr.  Any modification is done at your own risk with no expectation of supportability.  Keep in mind that any such modification would be overwritten by any future updates to Scalr and would need to be re-applied.  Likewise, please be aware that our capability to assist with this type of issue or Feature Request is greatly enhanced for Enterprise Scalr customers.  Please reach out to us if you would like more information on Enterprise Scalr and what such an engagement would entail.

Cheers,
Wm. Marc O'Brien
Scalr Technical Support

[Alex Smith]

Hi Marc,

Thanks for the reply. I'll take a look over those.

When I was doing some digging around I found there's some beta/development options hidden away in the current community build that reference boot from volume. Here is an example of where I found that;

https://github.com/Scalr/scalr/blob/3fb5fbe4372a6c5ab75bd9c42f75a169f864c4d4/app/www/ui2/js/ui/farms/builder/tabs/devel.js#L109

https://github.com/Scalr/scalr/blob/3fb5fbe4372a6c5ab75bd9c42f75a169f864c4d4/app/src/Scalr/Modules/Platforms/Openstack/OpenstackPlatformModule.php#L642

Once I enabled the development panel in the UI (with this option) I could enable the "boot from volume" option it exposed. Sadly this fails with an error;

"Unable to launch instance:Cannot launch new instance. OpenStack error. Invalid input for field/attribute imageRef. Value: None. None is not of type 'string'"

I've not been able to debug past that point yet.

Seeing as it's hidden away, is this something that is already supported in newer versions?

Thanks,

Alex

[Marc O'Brien]

 Hi Alex,

This is not something that is currently supported in the latest version.

Many thanks,

Wm. Marc O'Brien
Scalr Technical Support