ceph/doc/radosgw/config.rst

=================================
 Configuring Ceph Object Gateway
=================================

Before you can start using the :term:`Ceph Object Gateway`, you must modify your
Ceph configuration file to include a section for the Ceph Object Gateway. You
must also create an ``rgw.conf``  file in the ``/etc/apache2/sites-enabled``
directory. The ``rgw.conf``  file configures Apache to interact with FastCGI.


Add a Gateway Configuration to Ceph
===================================

Add the Ceph Object Gateway configuration to your Ceph Configuration file.  The
Ceph Object Gateway configuration requires you to specify the host name where
you installed the Ceph Object Gateway daemon, a keyring (for use with cephx),
the socket path and a log file.  For example::  

	[client.radosgw.gateway]
		host = {host-name}
		keyring = /etc/ceph/keyring.radosgw.gateway
		rgw socket path = /tmp/radosgw.sock
		log file = /var/log/ceph/radosgw.log

.. note:: ``host`` must be your machine hostname, not FQDN.

Redeploy Ceph Configuration
===========================

If you deploy Ceph with ``mkcephfs``, manually redeploy ``ceph.conf`` to the 
hosts in your cluster. For example:: 

	cd /etc/ceph
	ssh {host-name} sudo tee /etc/ceph/ceph.conf < ceph.conf

If you used ``ceph-deploy``, push a new copy to the hosts in your cluster.
For example:: 

	ceph-deploy config push {host-name [host-name]...}


Create Data Directory
=====================

Deployment scripts may not create the default Ceph Object Gateway data
directory.  Create data directories for each instance of a ``radosgw`` daemon
(if you haven't done so already). The ``host``  variables in the Ceph
configuration file determine which host runs each instance of a ``radosgw``
daemon. The typical form specifies the ``radosgw`` daemon, the cluster name and
the daemon ID. ::

	sudo mkdir -p /var/lib/ceph/radosgw/{$cluster}-{$id}

Using the exemplary ``ceph.conf`` settings above, you would execute the following::

	sudo mkdir -p /var/lib/ceph/radosgw/ceph-radosgw.gateway


Create a Gateway Configuration
==============================

Create an ``rgw.conf`` file under the ``/etc/apache2/sites-available`` directory
on the host where you installed the Ceph Object Gateway.

We recommend deploying FastCGI as an external server, because allowing
Apache to manage FastCGI sometimes introduces high latency. To manage FastCGI 
as an external server, use the ``FastCgiExternalServer`` directive. 
See `FastCgiExternalServer`_ for details on this directive. 
See `Module mod_fastcgi`_ for general details. :: 

	FastCgiExternalServer /var/www/s3gw.fcgi -socket /tmp/radosgw.sock

.. _Module mod_fastcgi: http://www.fastcgi.com/drupal/node/25
.. _FastCgiExternalServer: http://www.fastcgi.com/drupal/node/25#FastCgiExternalServer

Once you have configured FastCGI as an external server, you must 
create the virtual host configuration within your ``rgw.conf`` file. See 
`Apache Virtual Host documentation`_ for details on ``<VirtualHost>`` format 
and settings. Replace the values in brackets. ::

	<VirtualHost *:80>
		ServerName {fqdn}
		ServerAdmin {email.address}
		DocumentRoot /var/www
	</VirtualHost>

.. _Apache Virtual Host documentation: http://httpd.apache.org/docs/2.2/vhosts/

Ceph Object Gateway requires a rewrite rule for the Amazon S3-compatible interface. 
It's required for passing in the ``HTTP_AUTHORIZATION env`` for S3, which is 
filtered out by Apache. The rewrite rule is not necessary for the OpenStack 
Swift-compatible interface. Turn on the rewrite engine and add the following
rewrite rule to your Virtual Host configuration. :: 

	RewriteEngine On
	RewriteRule ^/([a-zA-Z0-9-_.]*)([/]?.*) /s3gw.fcgi?page=$1&params=$2&%{QUERY_STRING} [E=HTTP_AUTHORIZATION:%{HTTP:Authorization},L]
	
Since the ``<VirtualHost>`` is running ``mod_fastcgi.c``, you must include a
section in your ``<VirtualHost>`` configuration for the ``mod_fastcgi.c`` module. 

::

	<VirtualHost *:80>
		...
		<IfModule mod_fastcgi.c>
			<Directory /var/www>
				Options +ExecCGI
				AllowOverride All
				SetHandler fastcgi-script
				Order allow,deny
				Allow from all
				AuthBasicAuthoritative Off
			</Directory>
		</IfModule>
		...
	</VirtualHost>
	
See `<IfModule> Directive`_ for additional details. 

.. _<IfModule> Directive: http://httpd.apache.org/docs/2.2/mod/core.html#ifmodule
	
Finally, you should configure Apache to allow encoded slashes, provide paths for
log files and to turn off server signatures. :: 	

	<VirtualHost *:80>	
	...	
		AllowEncodedSlashes On
		ErrorLog /var/log/apache2/error.log
		CustomLog /var/log/apache2/access.log combined
		ServerSignature Off
	</VirtualHost>
	
.. important:: If you are using CentOS or similar, make sure that ``FastCgiWrapper`` is turned off in ``/etc/httpd/conf.d/fastcgi.conf``.

Enable the Configuration
========================

Enable the site for ``rgw.conf``. :: 

	sudo a2ensite rgw.conf

Disable the default site. :: 

	sudo a2dissite default
	

Add a Ceph Object Gateway Script
================================

Add a ``s3gw.fcgi`` file (use the same name referenced in the first line 
of ``rgw.conf``) to ``/var/www``. The contents of the file should include:: 

	#!/bin/sh
	exec /usr/bin/radosgw -c /etc/ceph/ceph.conf -n client.radosgw.gateway
	
Ensure that you apply execute permissions to ``s3gw.fcgi``. ::

	sudo chmod +x s3gw.fcgi


Generate a Keyring and Key for the Gateway
==========================================

You must create a keyring for the Ceph Object Gateway. For example:: 

	sudo ceph-authtool --create-keyring /etc/ceph/keyring.radosgw.gateway
	sudo chmod +r /etc/ceph/keyring.radosgw.gateway
	

.. topic:: Monitor Key CAPS

   When you provide CAPS to the monitor key, you MUST provide read capability.
   However, you have the option of providing write capability. This is an
   important choice. If you provide write capability to the monitor key, 
   the Ceph Object Gateway will have the ability to create pools automatically; 
   however, it will create pools with either the default number of placement 
   groups (not ideal) or the number of placement groups you specified in your 
   Ceph configuration file. If you allow the Ceph Object Gateway to create 
   pools automatically, ensure that you have reasonable defaults for the number
   of placement groups first. See `Pool Configuration`_ for details.

Generate a key so that the Ceph Object Gateway can identify a user name and authenticate 
the user with the cluster. Then, add capabilities to the key. For example:: 

	sudo ceph-authtool /etc/ceph/keyring.radosgw.gateway -n client.radosgw.gateway --gen-key
	sudo ceph-authtool -n client.radosgw.gateway --cap osd 'allow rwx' --cap mon 'allow rw' /etc/ceph/keyring.radosgw.gateway
	

See the `Cephx Guide`_ for additional details on Ceph authentication.

Add to Ceph Keyring Entries 
===========================

Once you have created a keyring and key for the Ceph Object Gateway to access
the Ceph Storage Cluster, add it as an entry in the Ceph keyring. For example::

	sudo ceph -k /etc/ceph/ceph.client.admin.keyring auth add client.radosgw.gateway -i /etc/ceph/keyring.radosgw.gateway
	

Create Default Pools
====================

If the key that provides Ceph Object Gateway with access to the  Ceph Storage
Cluster does not have write capability to the Ceph Monitor, you must create the
default pools manually. The default pools for the Ceph Object Gateway include:

- ``.rgw``
- ``.rgw.control``
- ``.rgw.gc``
- ``.log``
- ``.intent-log``
- ``.usage``
- ``.users``
- ``.users.email``
- ``.users.swift``
- ``.users.uid``


See `Pools`_ for details on creating pools.


Restart Services and Start the Gateway
======================================

To ensure that all components have reloaded their configurations,  we recommend
restarting your ``ceph`` and ``apache`` services. Then,  start up the
``radosgw`` service. For example:: 

	sudo service ceph restart
	sudo service apache2 restart
	sudo /etc/init.d/radosgw start

See `Operating a Cluster`_ for details. Some versions of Ceph use different
methods for starting and stopping clusters.


Create a Gateway User
=====================

To use the REST interfaces, first create an initial Ceph Object Gateway user.
The Ceph Object Gateway user is not the same user as the
``client.rados.gateway`` user, which identifies the Ceph Object Gateway as a
user of the Ceph Storage Cluster. The Ceph Object Gateway user is a user of the
Ceph Object Gateway. ::

	sudo radosgw-admin user create --uid="{username}" --display-name="{Display Name}"

For example:: 	
	
  radosgw-admin user create --uid=johndoe --display-name="John Doe" --email=john@example.com
  
.. code-block:: javascript
  
  { "user_id": "johndoe",
    "rados_uid": 0,
    "display_name": "John Doe",
    "email": "john@example.com",
    "suspended": 0,
    "subusers": [],
    "keys": [
      { "user": "johndoe",
        "access_key": "QFAMEDSJP5DEKJO0DDXY",
        "secret_key": "iaSFLDVvDdQt6lkNzHyW4fPLZugBAI1g17LO0+87"}],
    "swift_keys": []}

Creating a user also creates an ``access_key`` and ``secret_key`` entry for use
with any S3 API-compatible client. For details on Ceph Object Gateway
administration, see `radosgw-admin`_. 

.. _radosgw-admin: ../../man/8/radosgw-admin/ 

.. important:: Check the key output. Sometimes ``radosgw-admin``
   generates a key with an escape (``\``) character, and some clients
   do not know how to handle escape characters. Remedies include 
   removing the escape character (``\``), encapsulating the string
   in quotes, or simply regenerating the key and ensuring that it 
   does not have an escape character.

Configuring Operations Logging
==============================

By default, Ceph Object Gateway will log every successful operation in the Ceph
Object Gateway backend. This means that every request, whether it is a read
request or a write request will generate a gateway operation that writes data.
This does not come without cost, and may affect overall performance. Turning off
logging completely can be done by adding the following config option to the Ceph
configuration file::

        rgw enable ops log = false

Another way to reduce the logging load is to send operations logging data to a UNIX domain
socket, instead of writing it to the Ceph Object Gateway backend::

        rgw ops log rados = false
        rgw enable ops log = true
        rgw ops log socket path = <path to socket>

When specifying a UNIX domain socket, it is also possible to specify the maximum amount
of memory that will be used to keep the data backlog::

        rgw ops log data backlog = <size in bytes>

Any backlogged data in excess to the specified size will be lost, so the socket
needs to be read constantly.


Enabling Swift Access
=====================

Allowing access to the object store with Swift (OpenStack Object Storage)
compatible clients requires an additional step; namely, the creation of a
subuser and a Swift access key.

::

  sudo radosgw-admin subuser create --uid=johndoe --subuser=johndoe:swift --access=full

.. code-block:: javascript

  { "user_id": "johndoe",
    "rados_uid": 0,
    "display_name": "John Doe",
    "email": "john@example.com",
    "suspended": 0,
    "subusers": [
      { "id": "johndoe:swift",
        "permissions": "full-control"}],
    "keys": [
      { "user": "johndoe",
        "access_key": "QFAMEDSJP5DEKJO0DDXY",
        "secret_key": "iaSFLDVvDdQt6lkNzHyW4fPLZugBAI1g17LO0+87"}],
    "swift_keys": []}

::

  sudo radosgw-admin key create --subuser=johndoe:swift --key-type=swift

.. code-block:: javascript

  { "user_id": "johndoe",
    "rados_uid": 0,
    "display_name": "John Doe",
    "email": "john@example.com",
    "suspended": 0,
    "subusers": [
       { "id": "johndoe:swift",
         "permissions": "full-control"}],
    "keys": [
      { "user": "johndoe",
        "access_key": "QFAMEDSJP5DEKJO0DDXY",
        "secret_key": "iaSFLDVvDdQt6lkNzHyW4fPLZugBAI1g17LO0+87"}],
    "swift_keys": [
      { "user": "johndoe:swift",
        "secret_key": "E9T2rUZNu2gxUjcwUBO8n\/Ev4KX6\/GprEuH4qhu1"}]}

This step enables you to use any Swift client to connect to and use the Ceph
Object Gateway via the Swift-compatible API. As an example, you might use the
``swift`` command-line client utility that ships with the OpenStack Object
Storage packages.

::

  swift -V 1.0 -A http://radosgw.example.com/auth -U johndoe:swift -K E9T2rUZNu2gxUjcwUBO8n\/Ev4KX6\/GprEuH4qhu1 post test  
  swift -V 1.0 -A http://radosgw.example.com/auth -U johndoe:swift -K E9T2rUZNu2gxUjcwUBO8n\/Ev4KX6\/GprEuH4qhu1 upload test myfile

Ceph Object Gateway's ``user:subuser`` tuple maps to the ``tenant:user`` tuple expected by Swift.

.. note:: Ceph Object Gateway's Swift authentication service only supports 
   built-in Swift authentication (``-V 1.0``). To make the gateway authenticate
   users via OpenStack Identity Service (Keystone), see below.


Integrating with OpenStack Keystone
===================================

It is possible to integrate the Ceph Object Gateway with Keystone, the OpenStack
identity service. This sets up the gateway to accept Keystone as the users
authority. A user that Keystone authorizes to access the gateway will also be
automatically created on the Ceph Object Gateway (if didn't exist beforehand). A
token that Keystone validates will be considered as valid by the gateway.

The following configuration options are available for Keystone integration::

	[client.radosgw.gateway]
		rgw keystone url = {keystone server url:keystone server admin port}
		rgw keystone admin token = {keystone admin token}
		rgw keystone accepted roles = {accepted user roles}
		rgw keystone token cache size = {number of tokens to cache}
		rgw keystone revocation interval = {number of seconds before checking revoked tickets}
		nss db path = {path to nss db}

A Ceph Object Gateway user is mapped into a Keystone ``tenant``. A Keystone user
has different roles assigned to it on possibly more than a single tenant. When
the Ceph Object Gateway gets the ticket, it looks at the tenant, and the user
roles that are assigned to that ticket, and accepts/rejects the request
according to the ``rgw keystone accepted roles`` configurable.

Keystone itself needs to be configured to point to the Ceph Object Gateway as an
object-storage endpoint::

	keystone service-create --name swift --type-object store
	keystone endpoint-create --service-id <id> --publicurl http://radosgw.example.com/swift/v1 \
		--internalurl http://radosgw.example.com/swift/v1 --adminurl http://radosgw.example.com/swift/v1


The keystone URL is the Keystone admin RESTful API URL. The admin token is the
token that is configured internally in Keystone for admin requests.

The Ceph Object Gateway will query Keystone periodically for a list of revoked
tokens. These requests are encoded and signed. Also, Keystone may be configured
to provide self-signed tokens, which are also encoded and signed. The gateway
needs to be able to decode and verify these signed messages, and the process
requires that the gateway be set up appropriately. Currently, the Ceph Object
Gateway will only be able to perform the procedure if it was compiled with
``--with-nss``. Configuring the Ceph Object Gateway to work with Keystone also
requires converting the OpenSSL certificates that Keystone uses for creating the
requests to the nss db format, for example::

	mkdir /var/ceph/nss

	openssl x509 -in /etc/keystone/ssl/certs/ca.pem -pubkey | \
		certutil -d /var/ceph/nss -A -n ca -t "TCu,Cu,Tuw"
	openssl x509 -in /etc/keystone/ssl/certs/signing_cert.pem -pubkey | \
		certutil -A -d /var/ceph/nss -n signing_cert -t "P,P,P"


Enabling Subdomain S3 Calls
===========================

To use a Ceph Object Gateway with subdomain S3 calls (e.g.,
``http://bucketname.hostname``), you must add the Ceph Object Gateway DNS name
under the ``[client.radosgw.gateway]`` section of your Ceph configuration file::

	[client.radosgw.gateway]
		...
		rgw dns name = {hostname}

You should also consider installing `Dnsmasq`_ on your client machine(s) when
using ``http://{bucketname}.{hostname}`` syntax. The  ``dnsmasq.conf`` file
should include the following settings:: 

	address=/{hostname}/{host-ip-address}
	listen-address={client-loopback-ip}

Then, add the ``{client-loopback-ip}`` IP address as the first DNS nameserver
on client the machine(s).

.. _Dnsmasq: https://help.ubuntu.com/community/Dnsmasq
.. _Pool Configuration: ../../rados/configuration/pool-pg-config-ref/
.. _Pools: ../../rados/operations/pools
.. _Cephx Guide: ../../rados/operations/authentication/#cephx-guide
.. _Operating a Cluster: ../../rados/rados/operations/operating