[openstack-dev] [kolla][kolla-kubernetes][kubernetes]

Ryan Hallisey rhallise at redhat.com
Sun May 22 19:50:14 UTC 2016

Hi all,

At the Kolla meeting last week, I brought up some of the challenges around the bootstrapping
process in Kubernetes.  The main highlight revolved around how the bootstrapping process will

Currently, in the kolla-kubernetes spec [1], the process for bootstrapping involves
outside orchestration running Kubernetes 'Jobs' that will handle the database initialization,
creating users, etc...  One of the flaws in this approach, is that kolla-kubernetes can't use
native Kubernetes upgrade tooling. Kubernetes does upgrades as a single action that scales
down running containers and replaces them with the upgraded containers. So instead of having
Kubernetes manage the upgrade, it would be guided by an external engine.  Not saying this is
a bad thing, but it does loosen the control Kubernetes would have over stack management.

Kubernetes does have some incoming new features that are a step in the right direction to
allow for kolla-kubernetes to make complete use of Kubernetes tooling like init containers [2].
There is also the introduction to wait.for conditions in the kubectl [3].

       kubectl get pod my-pod --wait --wait-for="pod-running"

Upgrades will be in the distant future for kolla-kubernetes, but I want to make sure the
community maintains an open mind about bootstrap/upgrades since there are potentially many
options that could come down the road.

I encourage everyone to add your input to the spec!


[1] SPEC - https://review.openstack.org/#/c/304182/
[2] Init containers - https://github.com/kubernetes/kubernetes/pull/23567
[3] wait.for kubectl - https://github.com/kubernetes/kubernetes/issues/1899

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