8:08 a.m.
All,
I recently had some discussion about HA orchestration this morning with
Petr Chalupa. Particular around the HA Controller node deployment.
This particular role behaves slightly differently to the other roles in
a Staypuft deployment in that it requires more than one puppet run to
complete.
Up to now we have worked on the assumption that once we have received a
successful puppet run report in foreman, then the node associated with
the role is configured and ready to go. We use this for scheduling the
next list of nodes in a given deployment.
We do have a work around for HA Controller issue described above in the
astapor modules. Blocking is implemented in the subsequent puppet
modules that are dependent on the HA Controller services. This means
that any depdendent modules will wait until controller completes before
proceeding. This results in the following behaviour.
Sequence
- Controller Nodes Provisioned.
- First puppet run returns successful.
- LVM Block Storage is provisioned.
- Controller Node puppet run 2 completes
- LVM Block storage puppet run completes.
In this case, the LVM block storage is provisioned before the
controllers are complete, but will block until the Controller puppet run
2 completes.
This work around is sufficient for the time being. But really what we
would like is to have Staypuft orchestrate the whole process, rather
than it be partially orchestrated by the puppet modules, partially by
Staypuft orchestration.
The difficulty we have right now in Staypuft is that (with out knowing
the specific implementation details of the puppet modules), there is no
clear way to detect whether a node with role X is complete and we are
able to schedule the next roles in the sequence.
What we need here is a clear interface for determining status of puppet
class and/or HostGroup status for the Astapor modules.
I have 2 questions around this,
1. Does there currently exist anyway to consistently detect the status
of a role/list of classes within Foreman for Astapor classes that we can
utilize?
-. If so can we do this without knowing the implementation details
of the Astapor puppet modules? (We do not want to, for example, look
for class specific facts in foreman, since these vary between classes
and may change in Astapor)?
2. If not 1. Is is possible to add something to the puppet modules to
explicitly show that a class/Hostgroup is complete? I am thinking
something along the lines of reporting a "Ready" flag back to foreman.
If none of the above, any other suggestions?
Cheers
Martyn