Jump to: navigation, search

Difference between revisions of "Cinder/how-to-contribute-a-driver"

(Deadline for Mitaka)
m (Third Party CI Requirement Policy)
(25 intermediate revisions by 5 users not shown)
Line 1: Line 1:
 
= How To Contribute a driver to Cinder =
 
= How To Contribute a driver to Cinder =
  
=== Deadline for Mitaka ===
+
=== Deadline for the Current Development Cycle ===
For clarification, a patch is considered a new driver when it's introducing a new protocol into the driver. For example, if your driver supports ISCSI, but your patch proposes support for FibreChannel, that's a new driver patch.
+
For clarification, a patch is considered a new driver when it's introducing a new protocol into the driver. For example, if your driver supports iSCSI, but your patch proposes support for FibreChannel, that's a new driver patch.
  
The deadline for new backend drivers, with working third party CI and no code review issues, will be January 19th, 2016 at 7:59 UTC.
+
The deadline for new backend drivers, with working third party CI and no code review issues, is always posted on the [https://releases.openstack.org/index.html current release] schedule. (Take the link for the "Series" name, and a link to the release schedule will be at the top of the page.)
 
 
Review the OpenStack dev mailing list [http://lists.openstack.org/pipermail/openstack-dev/2015-November/078215.html post] about his for more information.
 
  
 
=== Third Party CI Requirement Policy ===
 
=== Third Party CI Requirement Policy ===
 
See [https://wiki.openstack.org/wiki/Cinder/tested-3rdParty-drivers third party CI] wiki.
 
See [https://wiki.openstack.org/wiki/Cinder/tested-3rdParty-drivers third party CI] wiki.
 +
 +
For people working on getting their CI to handle Python 3, see [https://wiki.openstack.org/wiki/Cinder/3rdParty-drivers-py3-update Cinder Third Party CI update to Python 3.7]
  
 
=== Before you write any code ===
 
=== Before you write any code ===
Line 25: Line 25:
  
 
=== Writing Code ===
 
=== Writing Code ===
* You must implement all of the methods that exist as [http://docs.openstack.org/developer/cinder/devref/drivers.html core features].
+
* You must implement all of the methods that exist as [https://docs.openstack.org/cinder/latest/contributor/drivers.html core features].
  
* Your driver should not make any state changes. (e.g. make Cinder database calls). The [https://github.com/openstack/cinder/blob/master/cinder/volume/manager.py volume manager] is responsible for making state changes after the driver is done talking to the storage backend.
+
* Your driver should not make any state changes. (e.g. make Cinder database calls). The [https://github.com/openstack/cinder/blob/master/cinder/volume/manager.py volume manager] is responsible for making state changes after the driver is done talking to the storage backend. Your driver should try not to read from database if possible.
  
* Unit tests for new code are required.  We're in the process of converting everything to use [http://www.voidspace.org.uk/python/mock/ mock] (rather than mox) for our unit tests.  Be sure when writing unit tests and setting up fakes to use mock, examples of it's usage can be found in the existing tests like cinder/tests/test_volume.py.
+
* Unit tests for new code are required.
  
* Make sure you're not duplicating a configuration option that already exists. To verify this, you'll need to need look at the cinder/etc/cinder.conf.sample file. To generate this file:
+
* Make sure you're not duplicating a configuration option that already exists. To verify this, you'll need to need look at the [https://docs.openstack.org/cinder/latest/configuration/block-storage/samples/cinder.conf.html cinder/etc/cinder.conf.sample file].
** Install [https://pypi.python.org/pypi/tox tox]
+
** Every effort should be made to reuse common config options before introducing driver-specific ones.
** Run tox -egenconfig
+
** If options are added, you will need to run "tox -e genopts" to update the opts.py file that is used to generate our configuration references.
  
 
* Make sure to follow the [http://docs.openstack.org/developer/hacking/ OpenStack Style Guide]. Very likely you'll get nit pick reviews otherwise, which is not productive either way.
 
* Make sure to follow the [http://docs.openstack.org/developer/hacking/ OpenStack Style Guide]. Very likely you'll get nit pick reviews otherwise, which is not productive either way.
Line 40: Line 40:
  
 
=== Submitting Driver For Review ===
 
=== Submitting Driver For Review ===
 +
 +
When submitting your driver, please include a release note along with your patch. See the [http://docs.openstack.org/developer/reno/usage.html#creating-new-release-notes Reno Documentation] for details on how to generate new release notes.
 +
 +
The release note should be something along the lines of:
 +
 +
---
 +
features:
 +
  - Added backend driver for ''vendor'' storage.
 +
 +
* All new code should also be Python 3.7 compatible. Unit tests will be run with both python 2.7 and python 3.7, but additional runtime testing should be performed. Check the [https://governance.openstack.org/tc/reference/runtimes/ supported runtimes] for the current cycle.
 +
 
* Do '''NOT''' bother the Cinder team for reviews. We are aware of your patch being posted.
 
* Do '''NOT''' bother the Cinder team for reviews. We are aware of your patch being posted.
  
Line 45: Line 56:
  
 
* Make sure your driver has appropriate [[Cinder/tested-3rdParty-drivers|third party testing]] done. It is required that your CI posts the [https://wiki.openstack.org/wiki/Cinder/tested-3rdParty-drivers#What_tests_do_I_use.3F necessary tests pass]. Since your driver is not yet merged, follow [https://wiki.openstack.org/wiki/Cinder/tested-3rdParty-drivers#How_do_I_run_my_CI_to_test_all_cinder_patches_with_my_driver_not_yet_merged.3F instructions] to have you unmerged driver properly tested.
 
* Make sure your driver has appropriate [[Cinder/tested-3rdParty-drivers|third party testing]] done. It is required that your CI posts the [https://wiki.openstack.org/wiki/Cinder/tested-3rdParty-drivers#What_tests_do_I_use.3F necessary tests pass]. Since your driver is not yet merged, follow [https://wiki.openstack.org/wiki/Cinder/tested-3rdParty-drivers#How_do_I_run_my_CI_to_test_all_cinder_patches_with_my_driver_not_yet_merged.3F instructions] to have you unmerged driver properly tested.
 +
 +
* Documentation is now kept in the openstack/cinder repo. At a minimum, please add a basic description of your driver and its configuration options under the [https://github.com/openstack/cinder/tree/master/doc/source/configuration/block-storage/drivers volume driver section of the Configuration reference].
  
 
*[http://docs.openstack.org/infra/manual/developers.html#development-workflow Post your review].
 
*[http://docs.openstack.org/infra/manual/developers.html#development-workflow Post your review].
Line 52: Line 65:
  
 
* Make sure there is documentation for your driver
 
* Make sure there is documentation for your driver
** Read and understand third party driver docs hosted on docs.openstack.org, http://docs.openstack.org/kilo/config-reference/content/ch_configuring-openstack-block-storage.html
+
** Add a liaison name to https://wiki.openstack.org/wiki/Documentation/VendorDrivers after reading this [http://specs.openstack.org/openstack/docs-specs/specs/kilo/move-driver-docs.html spec]
** Work with the doc team on any concerns through the openstack-docs mailing list or the #openstack-doc channel on IRC
+
** Refer to [http://docs.openstack.org/contributor-guide/ Documentation Contributor Guide] on how to contribute.
** Add a liaison name to https://wiki.openstack.org/wiki/Documentation/VendorDrivers
 
** Refer to https://wiki.openstack.org/wiki/Documentation/HowTo for how to information
 
 
* Continue to be available on IRC and attend the weekly meetings in case questions come up.
 
* Continue to be available on IRC and attend the weekly meetings in case questions come up.
 
* Subscribe to receive bugs for your driver! The Cinder team will be triaging bugs and will tag bugs with the name of your company that are related to your driver. To subscribe:
 
* Subscribe to receive bugs for your driver! The Cinder team will be triaging bugs and will tag bugs with the name of your company that are related to your driver. To subscribe:
Line 64: Line 75:
 
** Click tags
 
** Click tags
 
** With "match all tags" selected type in the field the name of your company.
 
** With "match all tags" selected type in the field the name of your company.
 +
  
 
[[Category: Cinder]]
 
[[Category: Cinder]]

Revision as of 12:58, 8 August 2019

How To Contribute a driver to Cinder

Deadline for the Current Development Cycle

For clarification, a patch is considered a new driver when it's introducing a new protocol into the driver. For example, if your driver supports iSCSI, but your patch proposes support for FibreChannel, that's a new driver patch.

The deadline for new backend drivers, with working third party CI and no code review issues, is always posted on the current release schedule. (Take the link for the "Series" name, and a link to the release schedule will be at the top of the page.)

Third Party CI Requirement Policy

See third party CI wiki.

For people working on getting their CI to handle Python 3, see Cinder Third Party CI update to Python 3.7

Before you write any code

  • Understand how Cinder works, what it's used for, why the other projects in OpenStack may or may not use it. Fully understand the difference between ephemeral storage on the Nova side versus the persistent storage offered by Cinder
  • Cinder offers a reference implementation that should be used as a model. The reference implementation driver file is cinder/volume/drivers/lvm.py, not to be mistaken for cinder/volume/driver.py which is the base class that all of the drivers inherit from. Note that there are a lot of options that show up there regarding iSCSI targets etc, but this gives you an idea of the expectations in terms of features that are implemented and some of the behaviors. I strongly recommend loading up devstack (you're going to need it to test your driver anyway) and play around with the default LVM. It's really important that you get a feel for how Cinder works and interacts with the other OpenStack projects before you get too far along.
  • You don't need a cinder spec for most drivers. You always need to submit a blueprint in Launchpad introducing your driver, so that it can be targeted for a release.
  • We have a development channel on freenode: #openstack-cinder. There are developers here round the clock, it's a great resource for you get started. Log in, ask questions, don't stare at code in isolation for a week... if you're stuck on something just ask. There's also no need to start off with "Can I ask a question"... you likely won't get a response. Just type in your question, that way anybody monitoring the channel that might know the answer can step in and answer.

Writing Code

  • You must implement all of the methods that exist as core features.
  • Your driver should not make any state changes. (e.g. make Cinder database calls). The volume manager is responsible for making state changes after the driver is done talking to the storage backend. Your driver should try not to read from database if possible.
  • Unit tests for new code are required.
  • Make sure you're not duplicating a configuration option that already exists. To verify this, you'll need to need look at the cinder/etc/cinder.conf.sample file.
    • Every effort should be made to reuse common config options before introducing driver-specific ones.
    • If options are added, you will need to run "tox -e genopts" to update the opts.py file that is used to generate our configuration references.
  • Make sure to follow the OpenStack Style Guide. Very likely you'll get nit pick reviews otherwise, which is not productive either way.
  • Cinder's manager layer will log useful information like failures from the driver that are raised. However, you're more than welcome to add additional logging, but please follow our logging guideline. Use log markers by importing cinder.i18n so that log translations can be made.

Submitting Driver For Review

When submitting your driver, please include a release note along with your patch. See the Reno Documentation for details on how to generate new release notes.

The release note should be something along the lines of:

---
features:
 - Added backend driver for vendor storage.
  • All new code should also be Python 3.7 compatible. Unit tests will be run with both python 2.7 and python 3.7, but additional runtime testing should be performed. Check the supported runtimes for the current cycle.
  • Do NOT bother the Cinder team for reviews. We are aware of your patch being posted.

After Your Driver Is Added

Congratulations! You're not done yet though. After your driver has been merged there are still some things that need to be done.

  • Make sure there is documentation for your driver
  • Continue to be available on IRC and attend the weekly meetings in case questions come up.
  • Subscribe to receive bugs for your driver! The Cinder team will be triaging bugs and will tag bugs with the name of your company that are related to your driver. To subscribe:
    • Go to https://bugs.launchpad.net/openstack/cinder/+bug
    • Click 'Subscribe to bug mail'
    • Click the radio button "are added and changed in any way"
    • Click checkbox 'Bugs must match this filter (...)"
    • Click tags
    • With "match all tags" selected type in the field the name of your company.