[openstack-dev] [Nova][Docker] Environment variables
daniel.kuffner at gmail.com
Mon Dec 16 15:19:49 UTC 2013
yes please, I'm eager to see what you have. :)
On Mon, Dec 16, 2013 at 4:12 PM, Chuck Short <chuck.short at canonical.com> wrote:
> Hi Russel,
> I have something that is pushing it for to stay in nova (at least the
> compute drivers). I should have a gerrit branch for people to review soon.
> On Mon, Dec 16, 2013 at 10:07 AM, Russell Bryant <rbryant at redhat.com> wrote:
>> On 12/16/2013 09:27 AM, Daniel Kuffner wrote:
>> > Hi All,
>> > I have submitted a new blueprint which addresses the a common pattern
>> > in the docker world. A usual pattern in the docker world is to use
>> > environment variables to configure a container.
>> > docker run -e "SQL_URL=postgres://user:password@/db" my-app
>> > The nova docker driver doesn't support to set any environment
>> > variables. To work around this issue I used cloud-init which works
>> > fine. But this approach has of course the drawback that a) I have to
>> > install the cloud init service. and b) my docker container doesn't
>> > work outside of openstack.
>> > I propose to allow a user to set docker environment variables via nova
>> > instance metadata. The metadata key should have a prefix like ENV_
>> > which can be used to determine all environment variables. The prefix
>> > should be removed and the remainder key and vaule will be injected.
>> > The metadata can unfortunately not be set in horizon but can be used
>> > from the nova command line tool and from heat. Example heat:
>> > myapp:
>> > Type: OS::Nova::Server
>> > Properties:
>> > flavor: m1.small
>> > image: my-app:latest
>> > meta-data:
>> > - ENV_SQL_URL: postgres://user:password@/db
>> > - ENV_SOMETHING_ELSE: Value
>> > Let me know what you think about that.
>> > Blueprint:
>> > https://blueprints.launchpad.net/nova/+spec/docker-env-via-meta-data
>> Thanks for starting the discussion. More people should do this for
>> their blueprints. :-)
>> One of the things we should be striving for is to provide as consistent
>> of an experience as we can across drivers. Right now, we have the
>> metadata service and config drive, and neither of those are driver
>> specific. In the case of config drive, whether it's used or not is
>> exposed through the API. As you point out, the meta-data service does
>> technically work with the docker driver.
>> I don't think we should support environment variables like this
>> automatically. Instead, I think it would be more appropriate to add an
>> API extension for specifying env vars. That way the behavior is more
>> explicit and communicated through the API. The env vars would be passed
>> through all of the appropriate plumbing and down to drivers that are
>> able to support it.
>> This is all also assuming that containers support is staying in Nova and
>> not a new service. That discussion seems to have stalled. Is anyone
>> still pushing on that? Any updates?
>> Russell Bryant
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
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