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I'm adding [trove] to the subject as we're interested in where this ends up. Matt, it may make sense to include other projects that use service VM's if they are using file injection/configDrive/...

-amrith

-----Original Message-----
From: Matt Riedemann [mailto:mriedem at linux.vnet.ibm.com] 
Sent: Friday, November 11, 2016 8:12 PM
To: OpenStack Development Mailing List (not for usage questions) <openstack-dev at lists.openstack.org>; openstack-operators at lists.openstack.org
Subject: [Openstack-operators] [nova] More file injection woes

Chris Friesen reported a bug [1] where injected files on a server aren't in the guest after it's evacuated to another compute host. This is because the injected files aren't persisted in the nova database at all. 
Evacuate and rebuild use similar code paths, but rebuild is a user operation and the command line is similar to boot, but evacuate is an admin operation and the admin doesn't have the original injected files.

We've talked about issues with file injection before [2] - in that case not being able to tell if it can be honored and it just silently doesn't inject the files but the server build doesn't fail. We could eventually resolve that with capabilities discovery in the API.

There are other issues with file injection, like potential security issues, and we've talked about getting rid of it for years because you can use the config drive.

The metadata service is not a replacement, as noted in the code [3], because the files aren't persisted in nova so they can't be served up later.

I'm sure we've talked about this before, but if we were to seriously consider deprecating file injection, what does that look like?  Thoughts off the top of my head are:

1. Add a microversion to the server create and rebuild REST APIs such that the personality files aren't accepted unless:

a) you're also building the server with a config drive
b) or CONF.force_config_drive is True
c) or the image has the 'img_config_drive=mandatory' property

2. Deprecate VFSLocalFS in Ocata for removal in Pike. That means libguestfs is required. We'd do this because I think VFSLocalFS is the one with potential security issues.

----

Am I missing anything? Does this sound like a reasonable path forward? 
Are there other use cases out there for file injection that we don't have alternatives for like config drive?

Note I'm cross-posting to the operators list for operator feedback there too.

[1] https://bugs.launchpad.net/nova/+bug/1638961
[2] http://lists.openstack.org/pipermail/openstack-dev/2016-July/098703.html
[3]
https://github.com/openstack/nova/blob/b761ea47b97c6df09e21755f7fbaaa2061290fbb/nova/api/metadata/base.py#L179-L187

-- 

Thanks,

Matt Riedemann


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