[openstack-dev] [TripleO] containerized undercloud in Queens

Dan Prince dprince at redhat.com
Mon Oct 2 12:02:21 UTC 2017

One of the things the TripleO containers team is planning on tackling
in Queens is fully containerizing the undercloud. At the PTG we created
an etherpad [1] that contains a list of features that need to be
implemented to fully replace instack-undercloud.

Benefits of this work:

 -Alignment: aligning the undercloud and overcloud installers gets rid
of dual maintenance of services.

 -Composability: tripleo-heat-templates and our new Ansible
architecture around it are composable. This means any set of services
can be used to build up your own undercloud. In other words the
framework here isn't just useful for "underclouds". It is really the
ability to deploy Tripleo on a single node with no external
dependencies. Single node TripleO installer. The containers team has
already been leveraging existing (experimental) undercloud_deploy
installer to develop services for Pike.

 -Development: The containerized undercloud is a great development
tool. It utilizes the same framework as the full overcloud deployment
but takes about 20 minutes to deploy.  This means faster iterations,
less waiting, and more testing.  Having this be a first class citizen
in the ecosystem will ensure this platform is functioning for
developers to use all the time.

 -CI resources: better use of CI resources. At the PTG we received
feedback from the OpenStack infrastructure team that our upstream CI
resource usage is quite high at times (even as high as 50% of the
total). Because of the shared framework and single node capabilities we
can re-architecture much of our upstream CI matrix around single node.
We no longer require multinode jobs to be able to test many of the
services in tripleo-heat-templates... we can just use a single cloud VM
instead. We'll still want multinode undercloud -> overcloud jobs for
testing things like HA and baremetal provisioning. But we can cover a
large set of the services (in particular many of the new scenario jobs
we added in Pike) with single node CI test runs in much less time.

 -Containers: There are no plans to containerize the existing instack-
undercloud work. By moving our undercloud installer to a tripleo-heat-
templates and Ansible architecture we can leverage containers.
Interestingly, the same installer also supports baremetal (package)
installation as well at this point. Like to overcloud however I think
making containers our undercloud default would better align the TripleO

We are actively working through a few issues with the deployment
framework Ansible effort to fully integrate that into the undercloud
installer. We are also reaching out to other teams like the UI and
Security folks to coordinate the efforts around those components. If
there are any questions about the effort or you'd like to be involved
in the implementation let us know. Stay tuned for more specific updates
as we organize to get as much of this in M1 and M2 as possible.

On behalf of the containers team,


[1] https://etherpad.openstack.org/p/tripleo-queens-undercloud-containe

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