OpenStack Storage (Swift)
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Clay Gerrard ea8e545a27 Rebuild frags for unmounted disks
Change the behavior of the EC reconstructor to perform a fragment
rebuild to a handoff node when a primary peer responds with 507 to the
REPLICATE request.

Each primary node in a EC ring will sync with exactly three primary
peers, in addition to the left & right nodes we now select a third node
from the far side of the ring.  If any of these partners respond
unmounted the reconstructor will rebuild it's fragments to a handoff
node with the appropriate index.

To prevent ssync (which is uninterruptible) receiving a 409 (Conflict)
we must give the remote handoff node the correct backend_index for the
fragments it will recieve.  In the common case we will use
determistically different handoffs for each fragment index to prevent
multiple unmounted primary disks from forcing a single handoff node to
hold more than one rebuilt fragment.

Handoff nodes will continue to attempt to revert rebuilt handoff
fragments to the appropriate primary until it is remounted or
rebalanced.  After a rebalance of EC rings (potentially removing
unmounted/failed devices), it's most IO efficient to run in
handoffs_only mode to avoid unnecessary rebuilds.

Closes-Bug: #1510342

Change-Id: Ief44ed39d97f65e4270bf73051da9a2dd0ddbaec
2019-02-08 18:04:55 +00:00
api-ref/source Modify the description content 2018-12-08 22:46:38 +08:00
bin Fix locking in swift-recon-cron 2018-08-15 21:51:14 +00:00
doc fix documentation of default 2018-12-18 14:25:23 -08:00
etc Rebuild frags for unmounted disks 2019-02-08 18:04:55 +00:00
examples display swift services in apache2 2017-03-07 19:23:15 +00:00
releasenotes authors/changelog for 2.20.0 release 2018-12-15 00:21:47 +00:00
swift Rebuild frags for unmounted disks 2019-02-08 18:04:55 +00:00
test Rebuild frags for unmounted disks 2019-02-08 18:04:55 +00:00
tools Fix rolling upgrade job 2018-12-14 15:11:19 -08:00
.alltests Apply bash error handling consistently in all bash scripts 2016-10-11 22:13:06 +02:00
.coveragerc Show missing branches in coverage report. 2017-12-14 14:57:48 -08:00
.functests Improved usage of args in .functests 2018-02-14 12:31:17 -08:00
.gitignore Add some reno artifacts to .gitignore 2018-07-30 19:26:37 +00:00
.gitreview Add .gitreview config file for gerrit. 2011-10-24 15:05:49 -04:00
.mailmap authors/changelog for 2.20.0 release 2018-12-15 00:21:47 +00:00
.manpages Script for checking sanity of manpages 2016-02-10 14:16:56 -08:00
.probetests Allow specify arguments to .probetests script 2013-12-24 01:18:19 -08:00
.testr.conf Fix func test --until-failure and --no-discover options 2015-12-16 15:28:25 +00:00
.unittests Fix coverage report for newer versions of coverage 2014-04-24 16:50:03 +00:00
.zuul.yaml add an upgrade job from rocky 2018-12-15 07:50:35 -08:00
AUTHORS authors/changelog for 2.20.0 release 2018-12-15 00:21:47 +00:00
babel.cfg add pybabel setup.py commands and initial .pot 2011-01-27 00:01:24 +00:00
bandit.yaml Attempt to fix pep8 2018-08-17 14:23:18 +00:00
bindep.txt Require gettext for all non-SUSE distros 2018-10-22 18:06:00 +00:00
CHANGELOG authors/changelog for 2.20.0 release 2018-12-15 00:21:47 +00:00
CONTRIBUTING.rst Change openstack-dev to openstack-discuss 2018-12-04 23:37:44 -05:00
LICENSE Convert LICENSE to use unix style line endings. 2012-12-19 12:48:27 -05:00
lower-constraints.txt add lower-constraints job 2018-07-27 01:59:30 +00:00
MANIFEST.in Include s3api schemas in sdists 2018-07-11 16:56:28 -07:00
README.rst Update doc building instructions in Development Guidelines 2018-07-06 07:40:52 +00:00
requirements.txt Lower the required version of ipaddress 2018-07-24 15:51:01 -07:00
REVIEW_GUIDELINES.rst added a quote 2017-01-05 10:24:09 -08:00
setup.cfg Change openstack-dev to openstack-discuss 2018-12-04 23:37:44 -05:00
setup.py taking the global reqs that we can 2014-05-21 09:37:22 -07:00
test-requirements.txt Set lower bounds on all requirements and test-requirements 2018-06-15 10:43:12 -07:00
tox.ini Merge "py3: port object controller in proxy" 2019-02-06 21:09:07 +00:00

Team and repository tags

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Swift

A distributed object storage system designed to scale from a single machine to thousands of servers. Swift is optimized for multi-tenancy and high concurrency. Swift is ideal for backups, web and mobile content, and any other unstructured data that can grow without bound.

Swift provides a simple, REST-based API fully documented at https://docs.openstack.org/swift/latest/.

Swift was originally developed as the basis for Rackspace's Cloud Files and was open-sourced in 2010 as part of the OpenStack project. It has since grown to include contributions from many companies and has spawned a thriving ecosystem of 3rd party tools. Swift's contributors are listed in the AUTHORS file.

Docs

To build documentation run:

pip install -r requirements.txt -r doc/requirements.txt
sphinx-build -W -b html doc/source doc/build/html

and then browse to doc/build/html/index.html. These docs are auto-generated after every commit and available online at https://docs.openstack.org/swift/latest/.

For Developers

Getting Started

Swift is part of OpenStack and follows the code contribution, review, and testing processes common to all OpenStack projects.

If you would like to start contributing, check out these notes to help you get started.

The best place to get started is the "SAIO - Swift All In One". This document will walk you through setting up a development cluster of Swift in a VM. The SAIO environment is ideal for running small-scale tests against Swift and trying out new features and bug fixes.

Tests

There are three types of tests included in Swift's source tree.

  1. Unit tests
  2. Functional tests
  3. Probe tests

Unit tests check that small sections of the code behave properly. For example, a unit test may test a single function to ensure that various input gives the expected output. This validates that the code is correct and regressions are not introduced.

Functional tests check that the client API is working as expected. These can be run against any endpoint claiming to support the Swift API (although some tests require multiple accounts with different privilege levels). These are "black box" tests that ensure that client apps written against Swift will continue to work.

Probe tests are "white box" tests that validate the internal workings of a Swift cluster. They are written to work against the "SAIO - Swift All In One" dev environment. For example, a probe test may create an object, delete one replica, and ensure that the background consistency processes find and correct the error.

You can run unit tests with .unittests, functional tests with .functests, and probe tests with .probetests. There is an additional .alltests script that wraps the other three.

To fully run the tests, the target environment must use a filesystem that supports large xattrs. XFS is strongly recommended. For unit tests and in-process functional tests, either mount /tmp with XFS or provide another XFS filesystem via the TMPDIR environment variable. Without this setting, tests should still pass, but a very large number will be skipped.

Code Organization

  • bin/: Executable scripts that are the processes run by the deployer
  • doc/: Documentation
  • etc/: Sample config files
  • examples/: Config snippets used in the docs
  • swift/: Core code
    • account/: account server
    • cli/: code that backs some of the CLI tools in bin/
    • common/: code shared by different modules
      • middleware/: "standard", officially-supported middleware
      • ring/: code implementing Swift's ring
    • container/: container server
    • locale/: internationalization (translation) data
    • obj/: object server
    • proxy/: proxy server
  • test/: Unit, functional, and probe tests

Data Flow

Swift is a WSGI application and uses eventlet's WSGI server. After the processes are running, the entry point for new requests is the Application class in swift/proxy/server.py. From there, a controller is chosen, and the request is processed. The proxy may choose to forward the request to a back-end server. For example, the entry point for requests to the object server is the ObjectController class in swift/obj/server.py.

For Deployers

Deployer docs are also available at https://docs.openstack.org/swift/latest/. A good starting point is at https://docs.openstack.org/swift/latest/deployment_guide.html There is an ops runbook that gives information about how to diagnose and troubleshoot common issues when running a Swift cluster.

You can run functional tests against a Swift cluster with .functests. These functional tests require /etc/swift/test.conf to run. A sample config file can be found in this source tree in test/sample.conf.

For Client Apps

For client applications, official Python language bindings are provided at https://github.com/openstack/python-swiftclient.

Complete API documentation at https://developer.openstack.org/api-ref/object-store/

There is a large ecosystem of applications and libraries that support and work with OpenStack Swift. Several are listed on the associated projects page.


For more information come hang out in #openstack-swift on freenode.

Thanks,

The Swift Development Team