Re: [atomic-devel] The atomic command and setting hostname for containers

[Daniel J Walsh <dwalsh redhat com>]

On 02/17/2016 10:36 AM, Jan Pazdziora wrote:
> On Wed, Feb 17, 2016 at 04:25:20PM +0100, Jan Pazdziora wrote:
>> It'd be nice if the atomic command could support -h option, and make
>> that value available for use in the INSTALL / RUN / UNINSTALL LABELs.
>> I envision something like
>>
>> 	docker install -h ipa.example.com freeipa-server --realm EXAMPLE.COM ...
>>
>> and
>>
>> 	docker run freeipa-server
>>
>> and be able to use
>>
>> 	LABEL INSTALL 'docker run -h ${OPT_HOSTNAME} ... ${IMAGE} ...'
>>
>> and
>>
>> 	LABEL RUN 'docker run -h ${OPT_HOSTNAME} ... ${IMAGE} ...'
>>
>> and have that OPT_HOSTNAME expand to
>>
>> 	-h ipa.example.com
> Dan notes that atomic run will start an existing container, so if the
> user used the install to create a container with the -h flag, then
> it would work properly.
>
> I'm not sure we can rely on this in general case. The man page
> atomic-install(1) shows an example LABEL INSTALL to be
>
> 	/usr/bin/docker run  -t -i --rm ... /bin/install.sh
>
> With that --rm, the container is removed after the install.sh finishes,
> so docker run has no existing container to use. Besides, INSTALL
> would typically use
>
> 	--privileged -v /:/host
>
> while RUN might want to run unprivileged and with a bunch of
> (potentially read-only) specific directories and files bind-mounted.
>
> So atomic run does not start existing container -- it needs to be
> able to run a new one.
>
Right but your install script could communicate with docker to create a
container.
IE You separate out the act of running the install script from the
actual creation of the
container.

You install.sh could execute

docker create -h ipa.execample.com FOOBAR