[openstack-dev] [Fuel] [Plugins] Further development of plugin metadata format
vkramskikh at mirantis.com
Fri Nov 28 17:46:40 UTC 2014
Please participate in this discussion. We already have a few meetings on
this topic and there is still no decision. I understand entry level is
pretty high, but please find some time for this.
2014-11-28 20:03 GMT+03:00 Evgeniy L <eli at mirantis.com>:
> >> Yes, but is already used in a few places. I want to notice once again
> - even a simple LBaaS plugin with a single checkbox needed to utilize this
> Yes, but you don't need to specify it in each task.
Just by adding conditions to tasks we will be able to pluginize all current
functionality that can be pluginized. On the other hand, 1 line will be
added to task definition and you are concerned about this that much that
you want to create a separate interface for "complex" plugins. Am I right?
> >> So, you're still calling this interface complicated. Ok, I'm looking
> forward to seeing your proposal about dealing with complex plugins.
> All my concerns were related to simple plugins and that we should
> find a way not to force a plugin developer to do this copy-paste work.
I don't understand what copy-paste work you are talking about. Copying
conditions from tasks to is_removable? Yes, it will be so in most cases,
but not always, so we need to give a plugin writer a way to define
is_removable manually. If you are talking about copypasting conditions
between tasks (though I don't understand why we need a few tasks with the
same conditions), YAML links can be used - we use them a lot in
> >> If you have several checkboxes, then it is a complex plugin with
> complex configuration ...
> Here we need a definition of s simple plugins, in the current
> release with simple plugins you can define some fields on the UI (not a
> single checkbox) and run several tasks if plugin is enabled.
Ok, we can define simple plugin as a plugin which doesn't require
modification of generated YAML files at all. But with proposed approach
there is no need to somehow separate "simple" and "complex" plugins.
> On Fri, Nov 28, 2014 at 7:01 PM, Vitaly Kramskikh <vkramskikh at mirantis.com
> > wrote:
>> Responses inline:
>> 2014-11-28 18:31 GMT+03:00 Evgeniy L <eli at mirantis.com>:
>>> Hi Vitaly,
>>> I agree with you that conditions can be useful in case of complicated
>>> plugins, but
>>> at the same time in case of simple cases it adds a huge amount of
>>> I would like to avoid forcing user to know about any conditions if he
>>> to add several text fields on the UI.
>>> I have several reasons why we shouldn't do that:
>>> 1. conditions are described with yet another language with it's own
>> Yes, but is already used in a few places. I want to notice once again -
>> even a simple LBaaS plugin with a single checkbox needed to utilize this
>>> 2. the language is not documented (solvable)
>> It is documented:
>>> 3. complicated interface will lead to a lot of bugs for the end user,
>>> and it will be
>>> a Fuel team's problem
>> So, you're still calling this interface complicated. Ok, I'm looking
>> forward to seeing your proposal about dealing with complex plugins.
>>> 4. in case of several checkboxes you'll have to write a huge conditions
>>> a lot of "and" statements and it'll be really easy to forget about
>>> some of them
>> If you have several checkboxes, then it is a complex plugin with complex
>> configuration, so I see no problem here. There will be many more places
>> where you can "forget" stuff.
>>> As result in simple cases plugin developer will have to specify the same
>>> condition of every task in tasks.yaml file, add it to metadata.yaml.
>>> If you add new checkbox, you should go through all of this files,
>>> add "and lbaas:new_checkbox_name" statement.
>> Once again, in simple cases checkbox and the conditions (one for task and
>> one for is_removable) can be easily pregenerated by FPB, so plugin
>> developer has to do nothing more. If you add a new checkbox which doesn't
>> affect plugin removeability and tasks, you have to change nothing in plugin
>>> On Thu, Nov 27, 2014 at 7:57 PM, Vitaly Kramskikh <
>>> vkramskikh at mirantis.com> wrote:
>>>> In the 6.0 release we'll support simple plugins for Fuel. The current
>>>> architecture allows to create only very simple plugins and doesn't allow to
>>>> "pluginize" complex features like Ceph, vCenter, etc. I'd like to propose
>>>> some changes to make it possible. They are subtle enough and the plugin
>>>> template still can be autogenerated by Fuel Plugin Builder. Here they are:
>>>> 1. environment_config.yaml should contain exact config which will
>>>> be mixed into cluster_attributes. No need to implicitly generate any
>>>> controls like it is done now.
>>>> 2. metadata.yaml should also contain "is_removable" field. This
>>>> field is needed to determine whether it is possible to remove installed
>>>> plugin. It is impossible to remove plugins in the current implementation.
>>>> This field should contain an expression written in our DSL which we already
>>>> use in a few places. The LBaaS plugin also uses it to hide the checkbox if
>>>> Neutron is not used, so even simple plugins like this need to utilize it.
>>>> This field can also be autogenerated, for more complex plugins plugin
>>>> writer needs to fix it manually. For example, for Ceph it could look like
>>>> "settings:storage.volumes_ceph.value == false and
>>>> settings:storage.images_ceph.value == false".
>>>> 3. For every task in tasks.yaml there should be added new
>>>> "condition" field with an expression which determines whether the task
>>>> should be run. In the current implementation tasks are always run for
>>>> specified roles. For example, vCenter plugin can have a few tasks with
>>>> conditions like "settings:common.libvirt_type.value == 'vcenter'" or
>>>> "settings:storage.volumes_vmdk.value == true". Also, AFAIU, similar
>>>> approach will be used in implementation of Granular Deployment feature.
>>>> These simple changes will allow to write much more complex plugins.
>>>> What do you think?
>>>> Vitaly Kramskikh,
>>>> Software Engineer,
>>>> Mirantis, Inc.
>>>> OpenStack-dev mailing list
>>>> OpenStack-dev at lists.openstack.org
>>> OpenStack-dev mailing list
>>> OpenStack-dev at lists.openstack.org
>> Vitaly Kramskikh,
>> Software Engineer,
>> Mirantis, Inc.
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
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