Open Stack

On Mon, Mar 27, 2017 at 01:43:39PM -0700, Dan Sneddon wrote:
> I've been trying to figure out a workflow for previewing the results of
> importing custom templates in an overcloud deployment (without actually
> deploying). For instance, I am overriding some parameters using custom
> templates, and I want to make sure those parameters will be expressed
> correctly when I deploy.
> 
> I know about "heat stack-preview", but between the complexity of the
> overcloud stack and the jinja2 template processing, I can't figure out a
> way to preview the entire overcloud stack.
> 
> Is this possible? If not, any hints on what would it take to write a
> script that would accomplish this?

Yes this is possible, but when I tested it I ran into this bug:

https://bugs.launchpad.net/heat/+bug/1676823

Which it seems from IRC discussion may be a duplicate of:

https://bugs.launchpad.net/heat/+bug/1669571

I'll re-test later with the patch proposed applied, but the basic steps
are:

1. Get a rendered copy of the tripleo-heat-templates

There are two ways to do this, either run ./tools/process-templates.py
in a local t-h-t tree, or create a plan (either via openstack overcloud
plan create, or openstack overcloud plan deploy --update-plan-only).

If you do this via creating a plan you can download the rendered files from
swift, e.g mkdir tmp-tht; cd tmp-tht; swift download overcloud

2. Run the stack preview

To do this, you need to generate an environment file with all the passwords
normally created by tripleo-common.  The easiest way to do it is to look
at an existing deployment and run "mistral environment-get overcloud", then
copy/paste and sed an environment like: http://paste.openstack.org/show/604475/

Then you just run the preview like:

openstack stack create test --dry-run -t overcloud.yaml -e overcloud-resource-registry-puppet.yaml -e dummy_passwords.yaml

This will break due to the bug above, but in the past it's worked fine for
me, and as mentioned by Saravanan it's also possible to do a template
validate:

openstack orchestration template validate --show-nested -t overcloud.yaml -e overcloud-resource-registry-puppet.yaml -e dummy_passwords.yaml

Hopefully we can confirm the heat bugfix later then you'll be able to use
one of the above to do what you need.

Thanks,

Steve