OpenStack Storage (Swift)
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Samuel Merritt 0e81ffd1e1 Fix socket leak on object-server death 4 years ago
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bin Fix locking in swift-recon-cron 4 years ago
doc fix documentation of default 4 years ago
etc Merge "s3api: Allow concurrent multi-deletes" 4 years ago
examples display swift services in apache2 6 years ago
releasenotes authors/changelog for 2.20.0 release 4 years ago
swift Fix socket leak on object-server death 4 years ago
test Fix socket leak on object-server death 4 years ago
tools Fix rolling upgrade job 4 years ago
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.functests Improved usage of args in .functests 5 years ago
.gitignore Add some reno artifacts to .gitignore 4 years ago
.gitreview Add .gitreview config file for gerrit. 11 years ago
.mailmap authors/changelog for 2.20.0 release 4 years ago
.manpages Script for checking sanity of manpages 7 years ago
.probetests Allow specify arguments to .probetests script 9 years ago
.testr.conf Fix func test --until-failure and --no-discover options 7 years ago
.unittests Fix coverage report for newer versions of coverage 9 years ago
.zuul.yaml add an upgrade job from rocky 4 years ago
AUTHORS authors/changelog for 2.20.0 release 4 years ago
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LICENSE Convert LICENSE to use unix style line endings. 10 years ago Include s3api schemas in sdists 4 years ago
README.rst Update doc building instructions in Development Guidelines 4 years ago
REVIEW_GUIDELINES.rst added a quote 6 years ago
babel.cfg add pybabel commands and initial .pot 12 years ago
bandit.yaml Attempt to fix pep8 4 years ago
bindep.txt Require gettext for all non-SUSE distros 4 years ago
lower-constraints.txt add lower-constraints job 4 years ago
requirements.txt Lower the required version of ipaddress 4 years ago
setup.cfg Change openstack-dev to openstack-discuss 4 years ago taking the global reqs that we can 9 years ago
test-requirements.txt Set lower bounds on all requirements and test-requirements 5 years ago
tox.ini py3: object server 4 years ago


Team and repository tags



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

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.


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

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.


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/ 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/

For Deployers

Deployer docs are also available at A good starting point is at 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

Complete API documentation at

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.


The Swift Development Team