Section 6 Object Storage Gateway (RADOS-GW)

Objectives Understand the Ceph Object Storage Gateway (RADOS- GW) Installing the Object Storage Gateway with ceph-deploy

Understand Ceph Object Gateway Objective Notes:

Common Object Storage APIs OpenStack Swift Native object storage API for OpenStack “The OpenStack Object Store project, known as Swift, offers cloud storage software so that you can store and retrieve lots of data with a simple API. It's built for scale and optimized for durability, availability, and concurrency across the entire data set. Swift is ideal for storing unstructured data that can grow without bound.” - wiki.openstack.org Amazon S3 Commercial Storage solution with well defined API “Amazon Simple Storage Service (Amazon S3), provides developers and IT teams with secure, durable, highly-scalable cloud storage. Amazon S3 is easy to use object storage, with a simple web service interface to store and retrieve any amount of data from anywhere on the web” - aws.amazon.com

Object Storage - Review All data in an object storage system is stored as objects Objects have a unique identifier, data and metadata Access to the object store is via an API, not as a filesystem Ceph provides a native object store API called ‘librados’ Applications written specifically for Ceph must use librados to access the object store Other OpenSource projects and commercial products also offer object storage with different APIs OpenStack Swift Amazon Web Services ‘Simple Storage Service’ (S3)

Connecting to 3rd Party Object APIs In addition to the native librados Ceph API, Ceph supports both Swift and S3 The RADOSGW gateway provides access to the underlying RADOS object store by providing a proxy service for S3 and Swift clients S3 and Swift requests are translated to native librados API requests by the RADOSGW gateway Any application written for either S3 or Swift can then function with a Ceph based storage system such as SUSE Enterprise Server Ceph’s Object Storage uses the term object to describe the data it stores. S3 and Swift objects are not the same as the objects that Ceph writes to the Ceph Storage Cluster. Ceph Object Storage objects are mapped to Ceph Storage Cluster objects. The S3 and Swift objects do not necessarily correspond in a 1:1 manner with an object stored in the storage cluster. It is possible for an S3 or Swift object to map to multiple Ceph objects.

RADOSGW The Ceph Object Storage daemon, radosgw, is a FastCGI service that provides a RESTful HTTP API to store objects and metadata. It layers on top of the Ceph Storage Cluster with its own data formats, and maintains its own user database, authentication, and access control. Gateway specific information is stored in pools created for the gateway service The RADOS Gateway uses a unified namespace, which means you can use either the OpenStack Swift-compatible API or the Amazon S3-compatible API. For example, you can write data using the S3-compatible API with one application and then read data using the Swift- compatible API with another application.

Swift, S3 and RADOSGW Swift Client S3 Client REST RADOS GW (single namespace) librados Socket RADOS Cluster

Gateway Details Uses CivetWeb as the web server Lightweight and fast Shared namespace between S3 and Swift Write data to an S3 Bucket or a Swift Container Read back via either S3 or Swift

Gateway Created Pools .rgw -Domain root .rgw.root -Region/Zone information for the RGW .rgw.gc -Garbage collection pool. Stores information on objects marked to be deleted .users -Access keys for S3 users .users.uid -User names .rgw.buckets -Buckets .rgw.buckets.index -An index on buckets and objects in it .users.swift -Swift subuser info .log -Bucket creation info .intent-log -Stores a copy of the object before an update in case a undo is required. .usage -Per user usage log

Swift Protocol Support

S3 Protocol Support

Testing the gateway RGW listens on the port 7480 If successful, the following XML should be printed # curl http://<RGW-node-IP>:7480 <ListAllMyBucketsResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"> <Owner> <ID>anonymous</ID> <DisplayName/> </Owner> <Buckets/> </ListAllMyBucketsResult>

Suggested Clients for the Gateway There are various available clients which can communicate with S3 or Swift APIs. Useful for learning about the behaviour of Ceph Object Gateway Provide a way to access data on S3/Swift for testing, migration etc S3 Cmd Python S3 tool Available for SLES 12 OpenSource Download from s3tools.org Cyberduck Commercial version available – not for Linux at present Fully featured client

Installing Ceph Object Gateway

Command: ceph-deploy rgw Syntax: ceph-deploy rgw OPTIONS node:gatewayname Option Description create -Create a new Ceph Object Gateway delete -Delete an existing gateway list -Lists existing Ceph Object Gateways The --overwrite-conf statement is often required when creating or deleting a Ceph Object Gateway Notes:

Command: radosgw-admin Syntax: radosgw-admin mode options Mode Description user -create or remove users subuser -create or remove Swift Subusers key -manage access keys quota -manage storage quotas on the gateway Note: radosgw-admin is a native RADOS command, it does not operate via the RESTful interface Notes:

Creating Users

Notes on OpenStack use Ceph Object Gateway supports Swift V1 authentication Can create swift users directly within Ceph More normal to authenticate Ceph against Keystone Ceph becomes a drop in replacement for Swift Visible in Horizon etc

Section 6 Exercises Objective Notes: