Object Storage — Swift

Swift is the OpenStack Object Storage service. It stores and retrieves unstructured data — files, blobs, backups, logs, media — as named objects inside containers inside accounts. There is no filesystem hierarchy, no block device, and no POSIX interface. Objects are addressed by a three-level namespace: account/container/object.

Swift was one of the first OpenStack projects and predates the OpenStack Foundation. It is a fully distributed, eventually consistent system with no single point of failure. Every component is horizontally scalable. Data durability is achieved through configurable replication (default: 3 replicas) or erasure coding across failure domains (zones, regions).

When to Read This Skill

• Deploying Swift for the first time or adding capacity
• Creating containers and uploading objects via CLI, API, or SDK
• Configuring container ACLs, object versioning, temp URLs
• Uploading large objects (> 5 GiB) using SLO or DLO
• Building or rebalancing rings after adding or removing hardware
• Understanding replication, auditor, and updater background processes
• Configuring erasure coding storage policies
• Setting up encryption at rest with keymaster middleware
• Diagnosing object loss, ring imbalance, or replication lag
• Tuning proxy pipeline middleware (rate limiting, temp URL, SLO, DLO)

Sub-Files

File	What It Covers
architecture.md	Proxy server, account/container/object servers, ring architecture (partitions, replicas, zones, regions), consistent hashing, eventually consistent model, storage policies, WSGI pipeline
operations.md	CLI and API: containers, objects, large objects (SLO/DLO), ACLs, versioning, temp URLs, bulk operations, static websites; swift-ring-builder overview
internals.md	Ring building in detail, replicator/auditor/updater processes, consistency engine (hashes.pkl), erasure coding (liberasurecode), storage policy configuration, proxy pipeline middleware, encryption at rest, account reaper

Quick Reference

# Create a container
openstack container create my-container

# Upload an object
openstack object create my-container local-file.txt

# List objects in a container
openstack object list my-container

# Download an object
openstack object save my-container local-file.txt

# Delete an object
openstack object delete my-container local-file.txt

# Delete a container
openstack container delete my-container

# Make a container publicly readable
openstack container set --property 'read-acl=.r:*,.rlistings' my-container

# Generate a temp URL (valid 1 hour)
swift tempurl GET 3600 /v1/AUTH_<account-id>/my-container/local-file.txt <temp-url-key>

# Show container metadata
openstack container show my-container

# Upload a large file as a Static Large Object
openstack object create --use-slo my-container large-file.iso

Dependencies

Dependency	Purpose	Notes
Keystone	Authentication and account mapping	Swift maps Keystone project ID to account; authtoken middleware validates tokens
Memcached	Auth token cache, account/container metadata cache in proxy	Required in production; dramatically reduces account/container DB lookups
SQLite (per-server)	Account and container databases	One SQLite DB per account, per container; stored on local disk alongside objects
python-openstackclient + python-swiftclient	Unified CLI and Swift-specific CLI	openstack for standard ops; swift CLI for advanced Swift-specific features
liberasurecode	Erasure coding library	Required only when EC storage policies are configured
python-keystonemiddleware	Auth token validation in proxy pipeline	Validates Keystone tokens; required for Keystone-integrated deployments

Releases Covered

This skill covers OpenStack 2025.1 (Epoxy), 2025.2, and 2026.1.

Swift release notes: https://docs.openstack.org/releasenotes/swift/ Swift admin guide: https://docs.openstack.org/swift/latest/admin_guide.html Swift API reference: https://docs.openstack.org/api-ref/object-store/ Swift ring overview: https://docs.openstack.org/swift/latest/overview_ring.html