Open Stack

Hi,

First let me describe what our plans for the nearest release. We want to
deliver
role as a simple plugin, it means that plugin developer can define his own
role
with yaml and also it should work fine with our current approach when user
can
define several fields on the settings tab.

Also I would like to mention another thing which we should probably discuss
in separate thread, how plugins should be implemented. We have two types
of plugins, simple and complicated, the definition of simple - I can do
everything
I need with yaml, the definition of complicated - probably I have to write
some
python code. It doesn't mean that this python code should do absolutely
everything it wants, but it means we should implement stable, documented
interface where plugin is connected to the core.

Now lets talk about UI flow, our current problem is how to get the
information
if plugins is used in the environment or not, this information is required
for
backend which generates appropriate tasks for task executor, also this
information can be used in the future if we decide to implement plugins
deletion
mechanism.

I didn't come up with a some new solution, as before we have two options to
solve the problem:

# 1

Use conditional language which is currently used on UI, it will look like
Vitaly described in the example [1].
Plugin developer should:

1. describe at least one element for UI, which he will be able to use in
task

2. add condition which is written in our own programming language

Example of the condition for LBaaS plugin:

    condition: settings:lbaas.metadata.enabled == true

3. add condition to metadata.yaml a condition which defines if plugin is
enabled

    is_enabled: settings:lbaas.metadata.enabled == true

This approach has good flexibility, but also it has problems:

a. It's complicated and not intuitive for plugin developer.
b. It doesn't cover case when the user installs 3rd party plugin
    which doesn't have any conditions (because of # a) and
    user doesn't have a way to disable it for environment if it
    breaks his configuration.

# 2

As we discussed from the very beginning after user selects a release he can
choose a set of plugins which he wants to be enabled for environment.
After that we can say that plugin is enabled for the environment and we send
tasks related to this plugin to task executor.

>> My approach also allows to eliminate "enableness" of plugins which will
cause UX issues and issues like you described above. vCenter and Ceph also
don't have "enabled" state. vCenter has hypervisor and storage, Ceph
provides backends for Cinder and Glance which can be used simultaneously or
only one of them can be used.

Both of described plugins have enabled/disabled state, vCenter is enabled
when vCenter is selected as hypervisor. Ceph is enabled when it's selected
as a backend for Cinder or Glance.

If you don't like the idea of having Ceph/vCenter checkboxes on the first
page,
I can suggest as an idea (research is required) to define groups like
Storage Backend,
Network Manager and we will allow plugin developer to embed his option in
radiobutton
field on wizard pages. But plugin developer should not describe conditions,
he should
just write that his plugin is a Storage Backend, Hypervisor or new Network
Manager.
And the plugins e.g. Zabbix, Nagios, which don't belong to any of this
groups
should be shown as checkboxes on the first page of the wizard.

>
[1]
https://github.com/vkramskikh/fuel-plugins/commit/1ddb166731fc4bf614f502b276eb136687cb20cf

On Sun, Nov 30, 2014 at 3:12 PM, Vitaly Kramskikh <vkramskikh at mirantis.com>
wrote:

>
>
> 2014-11-28 23:20 GMT+04:00 Dmitriy Shulyak <dshulyak at mirantis.com>:
>
>>
>>>    - 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.
>>>
>>>  Initially i had the same thoughts and wanted to use it the way it is,
>> but now i completely agree with Evgeniy that additional DSL will cause a lot
>> of problems with compatibility between versions and developer experience.
>>
> As far as I understand, you want to introduce another approach to describe
> UI part or plugins?
>
>> We need to search for alternatives..
>> 1. for UI i would prefer separate tab for plugins, where user will be
>> able to enable/disable plugin explicitly.
>>
> Of course, we need a separate page for plugin management.
>
>> Currently settings tab is overloaded.
>> 2. on backend we need to validate plugins against certain env before
>> enabling it,
>>    and for simple case we may expose some basic entities like
>> network_mode.
>> For case where you need complex logic - python code is far more flexible
>> that new DSL.
>>
>>>
>>>    - 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".
>>>
>>> How checkbox will help? There is several cases of plugin removal..
>>
> It is not a checkbox, this is condition that determines whether the plugin
> is removable. It allows plugin developer specify when plguin can be safely
> removed from Fuel if there are some environments which were created after
> the plugin had been installed.
>
>> 1. Plugin is installed, but not enabled for any env - just remove the
>> plugin
>> 2. Plugin is installed, enabled and cluster deployed - forget about it
>> for now..
>> 3. Plugin is installed and only enabled - we need to maintain state of db
>> consistent after plugin is removed, it is problematic, but possible
>>
> My approach also allows to eliminate "enableness" of plugins which will
> cause UX issues and issues like you described above. vCenter and Ceph also
> don't have "enabled" state. vCenter has hypervisor and storage, Ceph
> provides backends for Cinder and Glance which can be used simultaneously or
> only one of them can be used.
>
>> My main point that plugin is enabled/disabled explicitly by user, after
>> that we can decide ourselves can it be removed or not.
>>
>>>
>>>    - 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.
>>>
>>> I had some thoughts about using DSL, it seemed to me especially helpfull
>> when you need to disable part of embedded into core functionality,
>> like deploying with another hypervisor, or network dirver (contrail for
>> example). And DSL wont cover all cases here, this quite similar to
>> metadata.yaml, simple cases can be covered by some variables in tasks (like
>> group, unique, etc), but complex is easier to test and describe in python.
>>
> Could you please provide example of such conditions? vCenter and Ceph can
> be turned into plugins using this approach.
>
> Also, I'm not against python version of plugins. It could look like a
> python class with exactly the same fields form YAML files, but conditions
> will be written in python.
>
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>>
>
>
> --
> Vitaly Kramskikh,
> Software Engineer,
> Mirantis, Inc.
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>

On Sun, Nov 30, 2014 at 3:12 PM, Vitaly Kramskikh <vkramskikh at mirantis.com>
wrote:

>
>
> 2014-11-28 23:20 GMT+04:00 Dmitriy Shulyak <dshulyak at mirantis.com>:
>
>>
>>>    - 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.
>>>
>>>  Initially i had the same thoughts and wanted to use it the way it is,
>> but now i completely agree with Evgeniy that additional DSL will cause a lot
>> of problems with compatibility between versions and developer experience.
>>
> As far as I understand, you want to introduce another approach to describe
> UI part or plugins?
>
>> We need to search for alternatives..
>> 1. for UI i would prefer separate tab for plugins, where user will be
>> able to enable/disable plugin explicitly.
>>
> Of course, we need a separate page for plugin management.
>
>> Currently settings tab is overloaded.
>> 2. on backend we need to validate plugins against certain env before
>> enabling it,
>>    and for simple case we may expose some basic entities like
>> network_mode.
>> For case where you need complex logic - python code is far more flexible
>> that new DSL.
>>
>>>
>>>    - 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".
>>>
>>> How checkbox will help? There is several cases of plugin removal..
>>
> It is not a checkbox, this is condition that determines whether the plugin
> is removable. It allows plugin developer specify when plguin can be safely
> removed from Fuel if there are some environments which were created after
> the plugin had been installed.
>
>> 1. Plugin is installed, but not enabled for any env - just remove the
>> plugin
>> 2. Plugin is installed, enabled and cluster deployed - forget about it
>> for now..
>> 3. Plugin is installed and only enabled - we need to maintain state of db
>> consistent after plugin is removed, it is problematic, but possible
>>
> My approach also allows to eliminate "enableness" of plugins which will
> cause UX issues and issues like you described above. vCenter and Ceph also
> don't have "enabled" state. vCenter has hypervisor and storage, Ceph
> provides backends for Cinder and Glance which can be used simultaneously or
> only one of them can be used.
>
>> My main point that plugin is enabled/disabled explicitly by user, after
>> that we can decide ourselves can it be removed or not.
>>
>>>
>>>    - 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.
>>>
>>> I had some thoughts about using DSL, it seemed to me especially helpfull
>> when you need to disable part of embedded into core functionality,
>> like deploying with another hypervisor, or network dirver (contrail for
>> example). And DSL wont cover all cases here, this quite similar to
>> metadata.yaml, simple cases can be covered by some variables in tasks (like
>> group, unique, etc), but complex is easier to test and describe in python.
>>
> Could you please provide example of such conditions? vCenter and Ceph can
> be turned into plugins using this approach.
>
> Also, I'm not against python version of plugins. It could look like a
> python class with exactly the same fields form YAML files, but conditions
> will be written in python.
>
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>>
>
>
> --
> Vitaly Kramskikh,
> Software Engineer,
> Mirantis, Inc.
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>
>
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