On 21.9.2017 18:04, Marios Andreou wrote:
On Thu, Sep 21, 2017 at 3:53 PM, Jiří Stránský <ji...@redhat.com> wrote:

On 21.9.2017 12:31, Giulio Fidente wrote:

On 09/20/2017 07:36 PM, James Slagle wrote:

On Tue, Sep 19, 2017 at 8:37 AM, Giulio Fidente <gfide...@redhat.com>
wrote:

On 09/18/2017 05:37 PM, James Slagle wrote:

- The entire sequence and flow is driven via Mistral on the Undercloud
by default. This preserves the API layer and provides a clean reusable
interface for the CLI and GUI.


I think it's worth saying that we want to move the deployment steps out
of heat and in ansible, not in mistral so that mistral will run the
workflow only once and let ansible go through the steps

I think having the steps in mistral would be a nice option to be able to
rerun easily a particular deployment step from the GUI, versus having
them in ansible which is instead a better option for CLI users ... but
it looks like having them in ansible is the only option which permits us
to reuse the same code to deploy an undercloud because having the steps
in mistral would require the undercloud installation itself to depend on
mistral which we don't want to

James, Dan, please comment on the above if I am wrong


That's correct. We don't want to require Mistral to install the
Undercloud. However, I don't think that necessarily means it has to be
a single call to ansible-playbook. We could have multiple invocations
of ansible-playbook. Both Mistral and CLI code for installing the
undercloud could handle that easily.

You wouldn't be able to interleave an external playbook among the
deploy steps however. That would have to be done under a single call
to ansible-playbook (at least how that is written now). We could
however have hooks that could serve as integration points to call
external playbooks after each step.


the benefits of driving the steps from mistral are that then we could
also interleave the deployment steps and we won't need the
ansible-playbook hook for the "external" services:

1) collect the ansible tasks *and* the workflow_tasks (per step) from heat

2) launch the stepN deployment workflow (ansible-playbook)

3) execute any workflow_task defined for stepN (like ceph-ansible
playbook)

4) repeat 2 and 3 for stepN+1

I think this would also provide a nice interface for the UI ... but then
we'd need mistral to be able to deploy the undercloud



Why not launch the _single_  deploy_steps playbook (so we have
when/conditionals with step numbers), passing in the step you want to have
executed (we can pass this in as a parameter to the mistral workflow and
pass through to the ansible-playbook invocation?), otherwise execute all
the steps.

+1 that's the sort of thing i meant by "it's not baked in by default but we could make it so". We could even give it a list of steps like `tripleo_run_steps: [4, 5, 6]`.

In either case whether it should be ansible handling the loop
based on a passed in parameter.
'Ansible-native' looping is currently the
case for the current deploy_steps_playbook here
https://github.com/openstack/tripleo-heat-templates/blob/259cf512b3b7e3539105cdb52421e3239701ef73/common/deploy-steps.j2#L335
- can we not work parameterise that playbook so that we either do loop with
the variable, or just step X?

Then for the upgrade workflow it is as above but  1.5 first launch the
upgrade_tasks_playbook  then the deploy_steps playbook for all the steps
(consider this
https://review.openstack.org/#/c/505624/3/scripts/upgrade-non-controller.sh@162
- download and run the playbooks for non-controllers in O->P upgrade
pointing this out to illustrate the workflow I have in mind). So I don't
see why we can't have mistral invoking ansible-playbook and taking
parameters like which playbook, which step etc.



Alternatively we could do the main step loop in Ansible directly, and have
the tasks do whatever they need to get the particular service deployed,
from  to launching a nested ansible-playbook run if that's what it takes.



I think you can do both, I mean mistral invoking ansible-playbook and still
let ansible handle the steps with a loop.

+1 exactly. FWIW i'm totally on board with wrapping everything in Mistral on the outermost level, as that's required for UI. I'm just not keen on having Mistral enter the process in between each step and drive the step loop.

In fact that is what the current
upgrade_steps_playbook does here
https://github.com/openstack/tripleo-heat-templates/blob/259cf512b3b7e3539105cdb52421e3239701ef73/common/deploy-steps.j2#L363-L365
with a loop variable 'step'. The upgrade_tasks have their 'tags: stepX'
converted to 'when: step == X' in the client here
https://github.com/openstack/python-tripleoclient/blob/4d342826d6c3db38ee88dccc92363b655b1161a5/tripleoclient/v1/overcloud_config.py#L63
- we must come up with a better solution than that; ultimately we can just
update the existing upgrade_tasks to have 'when' and the main reason for
not doing so already was not to break the heat-driven upgrade workflow but
that is going away for Q.


+1 for `when` instead of `tags`, ideally we'd switch the main deployment tasks to that too.




That way we could run the whole thing end-to-end via ansible-playbook, or
if needed one could execute smaller bits by themselves (steps or nested
playbook runs) -- that capability is not baked in by default, but i think
we could make it so.

Also the interface for services would be clean and simple -- it's always
the ansible tasks.

And Mistral-less use cases become easier to handle too (= undercloud
installation when Mistral isn't present yet, or development envs when you
want to tune the playbook directly without being forced to go through
Mistral).


You don't *have* to go through mistral either way I mean you can always
just run ansible-playbook directly using the generated playbooks if that is
what you need for dev/debug etc.



Logging becomes a bit more unwieldy in this scenario though, as for the
nested ansible-playbook execution, all output would go into a task in the
outer playbook, which would be harder to follow and the log of the outer
playbook could be huge.

So this solution is no silver bullet, but from my current point of view it
seems a bit less conceptually foreign than using Mistral to provide step
loop functionality to Ansible, which should be able to handle that on its
own.


just saying using mistral to invoke ansible-playbook doesn't imply having
mistral do the looping/step control. I think it was already mentioned that
we can/will have multiple invocations of ansible-playbook. Having the loop
in the playbook then means organising our templates a certain way so that
there is a _single_ parent playbook which we can parameterise to then run
all or some of the steps (which as pointed above is currently the case for
the upgrade and deployment steps playbooks).

Yup, +1 again :) However, the 1)2)3)4) approach discussed earlier in the thread suggested to hand over the step loop control to Mistral and keep using the Mistral workflow_tasks, which would make it impossible to have a single parent playbook, if i understood correctly. So Mistral would be a requirement for running all steps via a single command (impacting UC install and developer workflow).

Or if you really wanted to create a single playbook from the 1)2)3)4) approach, it could create a Mistral->Ansible[->Mistral->Ansible] chain for things like Ceph install, which sounds suboptimal as well.

Having loop control in Ansible allows going just Mistral->Ansible[->Ansible], with the option to run just Ansible[->Ansible] for UC install and dev workflow.

(^ The bracketed parts only come into play with the external playbooks like for Ceph and Kubernetes.)

Sorry for the overcommunication here in case it's clear. Just want to make sure that we're on the same page about what are the options that we're discussing.

Jirka



For me the main advantage of using mistral is the integration with UI -
we've never had 'proper' client/common support for upgrades or updates and
getting that is a goal for Q (
https://etherpad.openstack.org/p/tripleo-ptg-queens-upgrades - if nothing
else, we need a more decent way of handling the ansible-playbook
invocations than a bash script like upgrade-non-controller). There is
already some relevant work under way here FYI
https://review.openstack.org/#/c/487496/
https://review.openstack.org/#/c/487488/ that will be used for P minor
update.

thanks, marios




- It would still be possible to run ansible-playbook directly for
various use cases (dev/test/POC/demos). This preserves the quick
iteration via Ansible that is often desired.

- The remaining SoftwareDeployment resources in tripleo-heat-templates
need to be supported by config download so that the entire
configuration can be driven with Ansible, not just the deployment
steps. The success criteria for this point would be to illustrate
using an image that does not contain a running os-collect-config.

- The ceph-ansible implementation done in Pike could be reworked to
use this model. "config download" could generate playbooks that have
hooks for calling external playbooks, or those hooks could be
represented in the templates directly. The result would be the same
either way though in that Heat would no longer be triggering a
separate Mistral workflow just for ceph-ansible.


I'd say for ceph-ansible, kubernetes and in general anything else which
needs to run with a standard playbook installed on the undercloud and
not one generated via the heat templates... these "external" services
usually require the inventory file to be in different format, to
describe the hosts to use on a per-service basis, not per-role (and I
mean tripleo roles here, not ansible roles obviously)

About that, we discussed a more long term vision where the playbooks
(static data) needd to describe how to deploy/upgrade a given service is
in a separate repo (like tripleo-apb) and we "compose" from heat the
list of playbooks to be executed based on the roles/enabled services; in
this scenario we'd be much closer to what we had to do for ceph-ansible
and I feel like that might finally allow us merge back the ceph
deployment (or kubernetes deployment) process into the more general
approach driven by tripleo

James, Dan, comments?


Agreed, I think this is the longer term plan in regards to using
APB's, where everything consumed is an external playbook/role.

We definitely want to consider this plan in parallel with the POC work
that Flavio is pulling together and make sure that they are aligned so
that we're not constantly reworking the framework.

I've not yet had a chance to review the material he sent out this
morning, but perhaps we could work together to update the sequence
diagram to also have a "future" state to indicate where we are going
and what it would look like with APB's and external paybooks.


Indeed that would be great :) IIUC, APBs are deployed by running a
short-lived container with Ansible inside, which then connects to
Kubernetes endpoint to create resources. So this should be a less
complicated case than running non-containerized external playbooks.


this would be awesome, note that it isn't only ceph and kubernetes
anymore in this scenario ... I just spotted a submission for the Skydive
composable service and it uses the same mistral/ansible-playbook
approach ... so it's already 3 looking forward for this!

https://review.openstack.org/#/c/502353/


[1] https://github.com/ansibleplaybookbundle/ansible-playbook-
bundle/blob/master/docs/design.md#deploy


__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev




__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev



__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev

Reply via email to