[openstack-dev] [nova] More file injection woes
mriedem at linux.vnet.ibm.com
Sat Nov 12 01:11:51 UTC 2016
Chris Friesen reported a bug  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  - 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 ,
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
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