Notice

This document is for a development version of Ceph.

Multi-Site

Single-zone Configurations and Multi-site Configurations

Single-zone Configurations

A single-zone configuration typically consists of two things:

  1. One “zonegroup”, which contains one zone.

  2. One or more ceph-radosgw instances that have ceph-radosgw client requests load-balanced between them.

In a typical single-zone configuration, there are multiple ceph-radosgw instances that make use of a single Ceph storage cluster.

Varieties of Multi-site Configuration

New in version Jewel.

Since the Kraken release, Ceph has supported several multi-site configurations for the Ceph Object Gateway:

  • Multi-zone: The “multi-zone” configuration has a complex topology. A multi-zone configuration consists of one zonegroup and multiple zones. Each zone consists of one or more ceph-radosgw instances. Each zone is backed by its own Ceph Storage Cluster.

    The presence of multiple zones in a given zonegroup provides disaster recovery for that zonegroup in the event that one of the zones experiences a significant failure. Each zone is active and can receive write operations. A multi-zone configuration that contains multiple active zones enhances disaster recovery and can be used as a foundation for content-delivery networks.

  • Multi-zonegroups: Ceph Object Gateway supports multiple zonegroups (which were formerly called “regions”). Each zonegroup contains one or more zones. If two zones are in the same zonegroup and that zonegroup is in the same realm as a second zonegroup, then the objects stored in the two zones share a global object namespace. This global object namespace ensures unique object IDs across zonegroups and zones.

    Each bucket is owned by the zonegroup where it was created (except where overridden by the LocationConstraint on bucket creation), and its object data will replicate only to other zones in that zonegroup. Any request for data in that bucket that is sent to other zonegroups will redirect to the zonegroup where the bucket resides.

    It can be useful to create multiple zonegroups when you want to share a namespace of users and buckets across many zones and isolate the object data to a subset of those zones. Maybe you have several connected sites that share storage but require only a single backup for purposes of disaster recovery. In such a case, you could create several zonegroups with only two zones each to avoid replicating all objects to all zones.

    In other cases, you might isolate data in separate realms, with each realm having a single zonegroup. Zonegroups provide flexibility by making it possible to control the isolation of data and metadata separately.

  • Multiple Realms: Since the Kraken release, the Ceph Object Gateway supports “realms”, which are containers for zonegroups. Realms make it possible to set policies that apply to multiple zonegroups. Realms have a globally unique namespace and can contain either a single zonegroup or multiple zonegroups. If you choose to make use of multiple realms, you can define multiple namespaces and multiple configurations (this means that each realm can have a configuration that is distinct from the configuration of other realms).

Diagram - Replication of Object Data Between Zones

The replication of object data between zones within a zonegroup looks something like this:

../../_images/zone-sync.svg

At the top of this diagram, we see two applications (also known as “clients”). The application on the right is both writing and reading data from the Ceph Cluster, by means of the RADOS Gateway (RGW). The application on the left is only reading data from the Ceph Cluster, by means of an instance of RADOS Gateway (RGW). In both cases (read-and-write and read-only), the transmssion of data is handled RESTfully.

In the middle of this diagram, we see two zones, each of which contains an instance of RADOS Gateway (RGW). These instances of RGW are handling the movement of data from the applications to the zonegroup. The arrow from the master zone (US-EAST) to the secondary zone (US-WEST) represents an act of data synchronization.

At the bottom of this diagram, we see the data distributed into the Ceph Storage Cluster.

For additional details on setting up a cluster, see Ceph Object Gateway for Production.

Functional Changes from Infernalis

Beginning with Kraken, each Ceph Object Gateway can be configured to work in an active-active zone mode. This makes it possible to write to non-master zones.

The multi-site configuration is stored within a container called a “realm”. The realm stores zonegroups, zones, and a time “period” with multiple epochs (which (the epochs) are used for tracking changes to the configuration).

Beginning with Kraken, the ceph-radosgw daemons handle the synchronization of data across zones, which eliminates the need for a separate synchronization agent. This new approach to synchronization allows the Ceph Object Gateway to operate with an “active-active” configuration instead of with an “active-passive” configuration.

Requirements and Assumptions

A multi-site configuration requires at least two Ceph storage clusters. The multi-site configuration must have at least two Ceph object gateway instances (one for each Ceph storage cluster).

This guide assumes that at least two Ceph storage clusters are in geographically separate locations; however, the configuration can work on the same site. This guide also assumes two Ceph object gateway servers named rgw1 and rgw2.

Important

Running a single geographically-distributed Ceph storage cluster is NOT recommended unless you have low latency WAN connections.

A multi-site configuration requires a master zonegroup and a master zone. Each zonegroup requires a master zone. Zonegroups may have one or more secondary or non-master zones.

In this guide, the rgw1 host will serve as the master zone of the master zonegroup; and, the rgw2 host will serve as the secondary zone of the master zonegroup.

See Pools for instructions on creating and tuning pools for Ceph Object Storage.

See Sync Policy Config for instructions on defining fine-grained bucket sync policy rules.

Configuring a Master Zone

All gateways in a multi-site configuration retrieve their configurations from a ceph-radosgw daemon that is on a host within both the master zonegroup and the master zone. To configure your gateways in a multi-site configuration, choose a ceph-radosgw instance to configure the master zonegroup and master zone.

Create a Realm

A realm contains the multi-site configuration of zonegroups and zones. The realm enforces a globally unique namespace within itself.

  1. Create a new realm for the multi-site configuration by opening a command line interface on a host that will serve in the master zonegroup and zone. Then run the following command:

    radosgw-admin realm create --rgw-realm={realm-name} [--default]
    

    For example:

    radosgw-admin realm create --rgw-realm=movies --default
    

    Note

    If you intend the cluster to have a single realm, specify the --default flag.

    If --default is specified, radosgw-admin uses this realm by default.

    If --default is not specified, you must specify either the --rgw-realm flag or the --realm-id flag to identify the realm when adding zonegroups and zones.

  2. After the realm has been created, radosgw-admin echoes back the realm configuration. For example:

    {
        "id": "0956b174-fe14-4f97-8b50-bb7ec5e1cf62",
        "name": "movies",
        "current_period": "1950b710-3e63-4c41-a19e-46a715000980",
        "epoch": 1
    }
    

    Note

    Ceph generates a unique ID for the realm, which can be used to rename the realm if the need arises.

Create a Master Zonegroup

A realm must have at least one zonegroup which serves as the master zonegroup for the realm.

  1. To create a new master zonegroup for the multi-site configuration, open a command-line interface on a host in the master zonegroup and zone. Then run the following command:

    radosgw-admin zonegroup create --rgw-zonegroup={name} --endpoints={url} [--rgw-realm={realm-name}|--realm-id={realm-id}] --master --default
    

    For example:

    radosgw-admin zonegroup create --rgw-zonegroup=us --endpoints=http://rgw1:80 --rgw-realm=movies --master --default
    

    Note

    If the realm will have only a single zonegroup, specify the --default flag.

    If --default is specified, radosgw-admin uses this zonegroup by default when adding new zones.

    If --default is not specified, you must use either the --rgw-zonegroup flag or the --zonegroup-id flag to identify the zonegroup when adding or modifying zones.

  2. After creating the master zonegroup, radosgw-admin echoes back the zonegroup configuration. For example:

    {
        "id": "f1a233f5-c354-4107-b36c-df66126475a6",
        "name": "us",
        "api_name": "us",
        "is_master": "true",
        "endpoints": [
            "http:\/\/rgw1:80"
        ],
        "hostnames": [],
        "hostnames_s3website": [],
        "master_zone": "",
        "zones": [],
        "placement_targets": [],
        "default_placement": "",
        "realm_id": "0956b174-fe14-4f97-8b50-bb7ec5e1cf62"
    }
    

Create a Master Zone

Important

Zones must be created on a Ceph Object Gateway node that will be within the zone.

Create a new master zone for the multi-site configuration by opening a command line interface on a host that serves in the master zonegroup and zone. Then run the following command:

radosgw-admin zone create --rgw-zonegroup={zone-group-name} \
                            --rgw-zone={zone-name} \
                            --master --default \
                            --endpoints={http://fqdn}[,{http://fqdn}]

For example:

radosgw-admin zone create --rgw-zonegroup=us --rgw-zone=us-east \
                            --master --default \
                            --endpoints={http://fqdn}[,{http://fqdn}]

Note

The --access-key and --secret aren’t specified. These settings will be added to the zone once the user is created in the next section.

Important

The following steps assume a multi-site configuration that uses newly installed systems that aren’t storing data yet. DO NOT DELETE the default zone and its pools if you are already using the zone to store data, or the data will be deleted and unrecoverable.

Delete Default Zonegroup and Zone

  1. Delete the default zone if it exists. Remove it from the default zonegroup first.

    radosgw-admin zonegroup delete --rgw-zonegroup=default --rgw-zone=default
    radosgw-admin period update --commit
    radosgw-admin zone delete --rgw-zone=default
    radosgw-admin period update --commit
    radosgw-admin zonegroup delete --rgw-zonegroup=default
    radosgw-admin period update --commit
    
  2. Delete the default pools in your Ceph storage cluster if they exist.

    Important

    The following step assumes a multi-site configuration that uses newly installed systems that aren’t currently storing data. DO NOT DELETE the default zonegroup if you are already using it to store data.

    ceph osd pool rm default.rgw.control default.rgw.control --yes-i-really-really-mean-it
    ceph osd pool rm default.rgw.data.root default.rgw.data.root --yes-i-really-really-mean-it
    ceph osd pool rm default.rgw.gc default.rgw.gc --yes-i-really-really-mean-it
    ceph osd pool rm default.rgw.log default.rgw.log --yes-i-really-really-mean-it
    ceph osd pool rm default.rgw.users.uid default.rgw.users.uid --yes-i-really-really-mean-it
    

Create a System User

  1. The ceph-radosgw daemons must authenticate before pulling realm and period information. In the master zone, create a “system user” to facilitate authentication between daemons.

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

    For example:

    radosgw-admin user create --uid="synchronization-user" --display-name="Synchronization User" --system
    
  2. Make a note of the access_key and secret_key. The secondary zones require them to authenticate against the master zone.

  3. Add the system user to the master zone:

    radosgw-admin zone modify --rgw-zone={zone-name} --access-key={access-key} --secret={secret}
    radosgw-admin period update --commit
    

Update the Period

After updating the master zone configuration, update the period.

radosgw-admin period update --commit

Note

Updating the period changes the epoch, and ensures that other zones will receive the updated configuration.

Update the Ceph Configuration File

Update the Ceph configuration file on master zone hosts by adding the rgw_zone configuration option and the name of the master zone to the instance entry.

[client.rgw.{instance-name}]
...
rgw_zone={zone-name}

For example:

[client.rgw.rgw1]
host = rgw1
rgw frontends = "civetweb port=80"
rgw_zone=us-east

Start the Gateway

On the object gateway host, start and enable the Ceph Object Gateway service:

systemctl start ceph-radosgw@rgw.`hostname -s`
systemctl enable ceph-radosgw@rgw.`hostname -s`

Configuring Secondary Zones

Zones that are within a zonegroup replicate all data in order to ensure that every zone has the same data. When creating a secondary zone, run the following operations on a host identified to serve the secondary zone.

Note

To add a second secondary zone (that is, a second non-master zone within a zonegroup that already contains a secondary zone), follow the same procedures that are used for adding a secondary zone. Be sure to specify a different zone name than the name of the first secondary zone.

Important

Metadata operations (for example, user creation) must be run on a host within the master zone. Bucket operations can be received by the master zone or the secondary zone, but the secondary zone will redirect bucket operations to the master zone. If the master zone is down, bucket operations will fail.

Pulling the Realm Configuration

The URL path, access key, and secret of the master zone in the master zone group are used to pull the realm configuration to the host. When pulling the configuration of a non-default realm, specify the realm using the --rgw-realm or --realm-id configuration options.

radosgw-admin realm pull --url={url-to-master-zone-gateway}
--access-key={access-key} --secret={secret}

Note

Pulling the realm configuration also retrieves the remote’s current period configuration, and makes it the current period on this host as well.

If this realm is the only realm, run the following command to make it the default realm:

radosgw-admin realm default --rgw-realm={realm-name}

Creating a Secondary Zone

Important

When a zone is created, it must be on a Ceph Object Gateway node within the zone.

In order to create a secondary zone for the multi-site configuration, open a command line interface on a host identified to serve the secondary zone. Specify the zonegroup ID, the new zone name, and an endpoint for the zone. DO NOT use the --master or --default flags. Beginning in Kraken, all zones run in an active-active configuration by default, which means that a gateway client may write data to any zone and the zone will replicate the data to all other zones within the zonegroup. If you want to prevent the secondary zone from accepting write operations, include the --read-only flag in the command in order to create an active-passive configuration between the master zone and the secondary zone. In any case, don’t forget to provide the access_key and secret_key of the generated system user that is stored in the master zone of the master zonegroup. Run the following command:

radosgw-admin zone create --rgw-zonegroup={zone-group-name} \
                             --rgw-zone={zone-name} \
                             --access-key={system-key} --secret={secret} \
                             --endpoints=http://{fqdn}:80 \
                             [--read-only]

For example:

radosgw-admin zone create --rgw-zonegroup=us --rgw-zone=us-west \
                             --access-key={system-key} --secret={secret} \
                             --endpoints=http://rgw2:80

Important

The following steps assume a multi-site configuration that uses newly installed systems that have not yet begun storing data. DO NOT DELETE the default zone or its pools if you are already using it to store data, or the data will be irretrievably lost.

Delete the default zone if needed:

radosgw-admin zone delete --rgw-zone=default

Finally, delete the default pools in your Ceph storage cluster if needed:

ceph osd pool rm default.rgw.control default.rgw.control --yes-i-really-really-mean-it
ceph osd pool rm default.rgw.data.root default.rgw.data.root --yes-i-really-really-mean-it
ceph osd pool rm default.rgw.gc default.rgw.gc --yes-i-really-really-mean-it
ceph osd pool rm default.rgw.log default.rgw.log --yes-i-really-really-mean-it
ceph osd pool rm default.rgw.users.uid default.rgw.users.uid --yes-i-really-really-mean-it

Updating the Ceph Configuration File

To update the Ceph configuration file on the secondary zone hosts, add the rgw_zone configuration option and the name of the secondary zone to the instance entry.

[client.rgw.{instance-name}]
...
rgw_zone={zone-name}

For example:

[client.rgw.rgw2]
host = rgw2
rgw frontends = "civetweb port=80"
rgw_zone=us-west

Updating the Period

After updating the master zone configuration, update the period:

radosgw-admin period update --commit

Note

Updating the period changes the epoch, and ensures that other zones will receive the updated configuration.

Starting the Gateway

To start the gateway, start and enable the Ceph Object Gateway service by running the following commands on the object gateway host:

systemctl start ceph-radosgw@rgw.`hostname -s`
systemctl enable ceph-radosgw@rgw.`hostname -s`

If the cephadm command was used to deploy the cluster, you will not be able to use systemctl to start the gateway because no services will exist on which systemctl could operate. This is due to the containerized nature of the cephadm-deployed Ceph cluster. If you have used the cephadm command and you have a containerized cluster, you must run a command of the following form to start the gateway:

ceph orch apply rgw <name> --realm=<realm> --zone=<zone> --placement --port

Checking Synchronization Status

After the secondary zone is up and running, you can check the synchronization status. The process of synchronization will copy users and buckets that were created in the master zone from the master zone to the secondary zone.

radosgw-admin sync status

The output reports the status of synchronization operations. For example:

realm f3239bc5-e1a8-4206-a81d-e1576480804d (earth)
    zonegroup c50dbb7e-d9ce-47cc-a8bb-97d9b399d388 (us)
         zone 4c453b70-4a16-4ce8-8185-1893b05d346e (us-west)
metadata sync syncing
              full sync: 0/64 shards
              metadata is caught up with master
              incremental sync: 64/64 shards
    data sync source: 1ee9da3e-114d-4ae3-a8a4-056e8a17f532 (us-east)
                      syncing
                      full sync: 0/128 shards
                      incremental sync: 128/128 shards
                      data is caught up with source

Note

Secondary zones accept bucket operations; however, secondary zones redirect bucket operations to the master zone and then synchronize with the master zone to receive the result of the bucket operations. If the master zone is down, bucket operations executed on the secondary zone will fail, but object operations should succeed.

Verifying an Object

By default, after the successful synchronization of an object there is no subsequent verification of the object. However, you can enable verification by setting rgw_sync_obj_etag_verify to true. After this value is set to true, an MD5 checksum is used to verify the integrity of the data that was transferred from the source to the destination. This ensures the integrity of any object that has been fetched from a remote server over HTTP (including multisite sync). This option may decrease the performance of your RGW because it requires more computation.

Maintenance

Checking the Sync Status

Information about the replication status of a zone can be queried with:

radosgw-admin sync status
    realm b3bc1c37-9c44-4b89-a03b-04c269bea5da (earth)
zonegroup f54f9b22-b4b6-4a0e-9211-fa6ac1693f49 (us)
     zone adce11c9-b8ed-4a90-8bc5-3fc029ff0816 (us-2)
    metadata sync syncing
          full sync: 0/64 shards
          incremental sync: 64/64 shards
          metadata is behind on 1 shards
          oldest incremental change not applied: 2017-03-22 10:20:00.0.881361s
data sync source: 341c2d81-4574-4d08-ab0f-5a2a7b168028 (us-1)
                  syncing
                  full sync: 0/128 shards
                  incremental sync: 128/128 shards
                  data is caught up with source
          source: 3b5d1a3f-3f27-4e4a-8f34-6072d4bb1275 (us-3)
                  syncing
                  full sync: 0/128 shards
                  incremental sync: 128/128 shards
                  data is caught up with source

The output might be different, depending on the sync status. During sync, the shards are of two types:

  • Behind shards are shards that require a data sync (either a full data sync or an incremental data sync) in order to be brought up to date.

  • Recovery shards are shards that encountered an error during sync and have been marked for retry. The error occurs mostly on minor issues, such as acquiring a lock on a bucket. Errors of this kind typically resolve on their own.

Check the logs

For multi-site deployments only, you can examine the metadata log (mdlog), the bucket index log (bilog), and the data log (datalog). You can list them and also trim them. Trimming is not needed in most cases because rgw_sync_log_trim_interval is set to 20 minutes by default. It should not be necessary to trim the logs unless rgw_sync_log_trim_interval has been manually set to 0.

Changing the Metadata Master Zone

Important

Care must be taken when changing the metadata master zone by promoting a zone to master. A zone that isn’t finished syncing metadata from the current master zone will be unable to serve any remaining entries if it is promoted to master, and those metadata changes will be lost. For this reason, we recommend waiting for a zone’s radosgw-admin sync status to complete the process of synchronizing the metadata before promoting the zone to master.

Similarly, if the current master zone is processing changes to metadata at the same time that another zone is being promoted to master, these changes are likely to be lost. To avoid losing these changes, we recommend shutting down any radosgw instances on the previous master zone. After the new master zone has been promoted, the previous master zone’s new period can be fetched with radosgw-admin period pull and the gateway(s) can be restarted.

To promote a zone to metadata master, run the following commands on that zone (in this example, the zone is zone us-2 in zonegroup us):

radosgw-admin zone modify --rgw-zone=us-2 --master
radosgw-admin zonegroup modify --rgw-zonegroup=us --master
radosgw-admin period update --commit

This generates a new period, and the radosgw instance(s) in zone us-2 sends this period to other zones.

Failover and Disaster Recovery

Setting Up Failover to the Secondary Zone

If the master zone fails, you can fail over to the secondary zone for disaster recovery by following these steps:

  1. Make the secondary zone the master and default zone. For example:

    radosgw-admin zone modify --rgw-zone={zone-name} --master --default
    

    By default, Ceph Object Gateway runs in an active-active configuration. However, if the cluster is configured to run in an active-passive configuration, the secondary zone is a read-only zone. To allow the secondary zone to receive write operations, remove its --read-only status. For example:

    radosgw-admin zone modify --rgw-zone={zone-name} --master --default \
                                 --read-only=false
    
  2. Update the period to make the changes take effect.

    radosgw-admin period update --commit
    
  3. Finally, restart the Ceph Object Gateway.

    systemctl restart ceph-radosgw@rgw.`hostname -s`
    

Reverting from Failover

If the former master zone recovers, you can revert the failover operation by following these steps:

  1. From within the recovered zone, pull the latest realm configuration from the current master zone:

    radosgw-admin realm pull --url={url-to-master-zone-gateway} \
                                --access-key={access-key} --secret={secret}
    
  2. Make the recovered zone the master and default zone:

    radosgw-admin zone modify --rgw-zone={zone-name} --master --default
    
  3. Update the period so that the changes take effect:

    radosgw-admin period update --commit
    
  4. Restart the Ceph Object Gateway in the recovered zone:

    systemctl restart ceph-radosgw@rgw.`hostname -s`
    
  5. If the secondary zone needs to be a read-only configuration, update the secondary zone:

    radosgw-admin zone modify --rgw-zone={zone-name} --read-only
    
  6. Update the period so that the changes take effect:

    radosgw-admin period update --commit
    
  7. Restart the Ceph Object Gateway in the secondary zone:

    systemctl restart ceph-radosgw@rgw.`hostname -s`
    

Migrating a Single-Site Deployment to Multi-Site

To migrate from a single-site deployment with a default zonegroup and zone to a multi-site system, follow these steps:

  1. Create a realm. Replace <name> with the realm name:

    radosgw-admin realm create --rgw-realm=<name> --default
    
  2. Rename the default zonegroup and zone. Replace <name> with the zone name or zonegroup name:

    radosgw-admin zonegroup rename --rgw-zonegroup default --zonegroup-new-name=<name>
    radosgw-admin zone rename --rgw-zone default --zone-new-name us-east-1 --rgw-zonegroup=<name>
    
  3. Rename the default zonegroup’s api_name. Replace <name> with the zonegroup name:

    radosgw-admin zonegroup modify --api-name=<name> --rgw-zonegroup=<name>
    
  4. Configure the master zonegroup. Replace <name> with the realm name or zonegroup name. Replace <fqdn> with the fully qualified domain name(s) in the zonegroup:

    radosgw-admin zonegroup modify --rgw-realm=<name> --rgw-zonegroup=<name> --endpoints http://<fqdn>:80 --master --default
    
  5. Configure the master zone. Replace <name> with the realm name, zone name, or zonegroup name. Replace <fqdn> with the fully qualified domain name(s) in the zonegroup:

    radosgw-admin zone modify --rgw-realm=<name> --rgw-zonegroup=<name> \
                              --rgw-zone=<name> --endpoints http://<fqdn>:80 \
                              --access-key=<access-key> --secret=<secret-key> \
                              --master --default
    
  6. Create a system user. Replace <user-id> with the username. Replace <display-name> with a display name. The display name is allowed to contain spaces:

    radosgw-admin user create --uid=<user-id> \
    --display-name="<display-name>" \
    --access-key=<access-key> \
    --secret=<secret-key> --system
    
  7. Commit the updated configuration:

    radosgw-admin period update --commit
    
  8. Restart the Ceph Object Gateway:

    systemctl restart ceph-radosgw@rgw.`hostname -s`
    

After completing this procedure, proceed to Configure a Secondary Zone and create a secondary zone in the master zonegroup.

Multi-Site Configuration Reference

The following sections provide additional details and command-line usage for realms, periods, zonegroups and zones.

For more details on every available configuration option, see src/common/options/rgw.yaml.in.

Alternatively, go to the Ceph Dashboard configuration page (found under Cluster), where you can view and set all of the options. While on the page, set the level to advanced and search for RGW to see all basic and advanced configuration options.

Realms

A realm is a globally unique namespace that consists of one or more zonegroups. Zonegroups contain one or more zones. Zones contain buckets. Buckets contain objects.

Realms make it possible for the Ceph Object Gateway to support multiple namespaces and their configurations on the same hardware.

Each realm is associated with a “period”. A period represents the state of the zonegroup and zone configuration in time. Each time you make a change to a zonegroup or zone, you should update and commit the period.

To ensure backward compatibility with Infernalis and earlier releases, the Ceph Object Gateway does not by default create a realm. However, as a best practice, we recommend that you create realms when creating new clusters.

Create a Realm

To create a realm, run realm create and specify the realm name. If the realm is the default, specify --default.

radosgw-admin realm create --rgw-realm={realm-name} [--default]

For example:

radosgw-admin realm create --rgw-realm=movies --default

By specifying --default, the realm will be called implicitly with each radosgw-admin call unless --rgw-realm and the realm name are explicitly provided.

Make a Realm the Default

One realm in the list of realms should be the default realm. There may be only one default realm. If there is only one realm and it wasn’t specified as the default realm when it was created, make it the default realm. Alternatively, to change which realm is the default, run the following command:

radosgw-admin realm default --rgw-realm=movies

Note

When the realm is default, the command line assumes --rgw-realm=<realm-name> as an argument.

Delete a Realm

To delete a realm, run realm rm and specify the realm name:

radosgw-admin realm rm --rgw-realm={realm-name}

For example:

radosgw-admin realm rm --rgw-realm=movies

Get a Realm

To get a realm, run realm get and specify the realm name:

radosgw-admin realm get --rgw-realm=<name>

For example:

radosgw-admin realm get --rgw-realm=movies [> filename.json]
{
    "id": "0a68d52e-a19c-4e8e-b012-a8f831cb3ebc",
    "name": "movies",
    "current_period": "b0c5bbef-4337-4edd-8184-5aeab2ec413b",
    "epoch": 1
}

Set a Realm

To set a realm, run realm set, specify the realm name, and use the --infile= option (make sure that the --infile option has an input file name as an argument):

radosgw-admin realm set --rgw-realm=<name> --infile=<infilename>

For example:

radosgw-admin realm set --rgw-realm=movies --infile=filename.json

List Realms

To list realms, run realm list:

radosgw-admin realm list

List Realm Periods

To list realm periods, run realm list-periods:

radosgw-admin realm list-periods

Pull a Realm

To pull a realm from the node that contains both the master zonegroup and master zone to a node that contains a secondary zonegroup or zone, run realm pull on the node that will receive the realm configuration:

radosgw-admin realm pull --url={url-to-master-zone-gateway} --access-key={access-key} --secret={secret}

Rename a Realm

A realm is not part of the period. Consequently, any renaming of the realm is applied only locally, and will therefore not get pulled when you run realm pull. If you are renaming a realm that contains multiple zones, run the rename command on each zone.

To rename a realm, run the following:

radosgw-admin realm rename --rgw-realm=<current-name> --realm-new-name=<new-realm-name>

Note

DO NOT use realm set to change the name parameter. Doing so changes the internal name only. If you use realm set to change the name parameter, then --rgw-realm still expects the realm’s old name.

Zonegroups

Zonegroups make it possible for the Ceph Object Gateway to support multi-site deployments and a global namespace. Zonegroups were formerly called “regions” (in releases prior to and including Infernalis).

A zonegroup defines the geographic location of one or more Ceph Object Gateway instances within one or more zones.

The configuration of zonegroups differs from typical configuration procedures, because not all of the zonegroup configuration settings are stored to a configuration file.

You can list zonegroups, get a zonegroup configuration, and set a zonegroup configuration.

Creating a Zonegroup

Creating a zonegroup consists of specifying the zonegroup name. Newly created zones reside in the default realm unless a different realm is specified by using the option --rgw-realm=<realm-name>.

If the zonegroup is the default zonegroup, specify the --default flag. If the zonegroup is the master zonegroup, specify the --master flag. For example:

radosgw-admin zonegroup create --rgw-zonegroup=<name> [--rgw-realm=<name>][--master] [--default]

Note

Use zonegroup modify --rgw-zonegroup=<zonegroup-name> to modify an existing zonegroup’s settings.

Making a Zonegroup the Default

One zonegroup in the list of zonegroups must be the default zonegroup. There can be only one default zonegroup. In the case that there is only one zonegroup which was not designated the default zonegroup when it was created, use the following command to make it the default zonegroup. Commands of this form can be used to change which zonegroup is the default.

  1. Designate a zonegroup as the default zonegroup:

    radosgw-admin zonegroup default --rgw-zonegroup=comedy
    

    Note

    When the zonegroup is default, the command line assumes that the name of the zonegroup will be the argument of the --rgw-zonegroup=<zonegroup-name> option. (In this example, <zonegroup-name> has been retained for the sake of consistency and legibility.)

  2. Update the period:

    radosgw-admin period update --commit
    

Adding a Zone to a Zonegroup

This procedure explains how to add a zone to a zonegroup.

  1. Run the following command to add a zone to a zonegroup:

    radosgw-admin zonegroup add --rgw-zonegroup=<name> --rgw-zone=<name>
    
  2. Update the period:

    radosgw-admin period update --commit
    

Removing a Zone from a Zonegroup

  1. Run this command to remove a zone from a zonegroup:

    radosgw-admin zonegroup remove --rgw-zonegroup=<name> --rgw-zone=<name>
    
  2. Update the period:

    radosgw-admin period update --commit
    

Renaming a Zonegroup

  1. Run this command to rename the zonegroup:

    radosgw-admin zonegroup rename --rgw-zonegroup=<name> --zonegroup-new-name=<name>
    
  2. Update the period:

    radosgw-admin period update --commit
    

Deleting a Zonegroup

  1. To delete a zonegroup, run the following command:

    radosgw-admin zonegroup delete --rgw-zonegroup=<name>
    
  2. Update the period:

    radosgw-admin period update --commit
    

Listing Zonegroups

A Ceph cluster contains a list of zonegroup. To list the zonegroups, run this command:

radosgw-admin zonegroup list

The radosgw-admin returns a JSON formatted list of zonegroups.

{
    "default_info": "90b28698-e7c3-462c-a42d-4aa780d24eda",
    "zonegroups": [
        "us"
    ]
}

Getting a Zonegroup Map

To list the details of each zonegroup, run this command:

radosgw-admin zonegroup-map get

Note

If you receive a failed to read zonegroup map error, run radosgw-admin zonegroup-map update as root first.

Getting a Zonegroup

To view the configuration of a zonegroup, run this command:

radosgw-admin zonegroup get [--rgw-zonegroup=<zonegroup>]

The zonegroup configuration looks like this:

{
    "id": "90b28698-e7c3-462c-a42d-4aa780d24eda",
    "name": "us",
    "api_name": "us",
    "is_master": "true",
    "endpoints": [
        "http:\/\/rgw1:80"
    ],
    "hostnames": [],
    "hostnames_s3website": [],
    "master_zone": "9248cab2-afe7-43d8-a661-a40bf316665e",
    "zones": [
        {
            "id": "9248cab2-afe7-43d8-a661-a40bf316665e",
            "name": "us-east",
            "endpoints": [
                "http:\/\/rgw1"
            ],
            "log_meta": "true",
            "log_data": "true",
            "bucket_index_max_shards": 0,
            "read_only": "false"
        },
        {
            "id": "d1024e59-7d28-49d1-8222-af101965a939",
            "name": "us-west",
            "endpoints": [
                "http:\/\/rgw2:80"
            ],
            "log_meta": "false",
            "log_data": "true",
            "bucket_index_max_shards": 0,
            "read_only": "false"
        }
    ],
    "placement_targets": [
        {
            "name": "default-placement",
            "tags": []
        }
    ],
    "default_placement": "default-placement",
    "realm_id": "ae031368-8715-4e27-9a99-0c9468852cfe"
}

Setting a Zonegroup

The process of defining a zonegroup consists of creating a JSON object and specifying the required settings. Here is a list of the required settings:

  1. name: The name of the zonegroup. Required.

  2. api_name: The API name for the zonegroup. Optional.

  3. is_master: Determines whether the zonegroup is the master zonegroup. Required. note: You can only have one master zonegroup.

  4. endpoints: A list of all the endpoints in the zonegroup. For example, you may use multiple domain names to refer to the same zonegroup. Remember to escape the forward slashes (\/). You may also specify a port (fqdn:port) for each endpoint. Optional.

  5. hostnames: A list of all the hostnames in the zonegroup. For example, you may use multiple domain names to refer to the same zonegroup. Optional. The rgw dns name setting will be included in this list automatically. Restart the gateway daemon(s) after changing this setting.

  6. master_zone: The master zone for the zonegroup. Optional. Uses the default zone if not specified. note: You can only have one master zone per zonegroup.

  7. zones: A list of all zones within the zonegroup. Each zone has a name (required), a list of endpoints (optional), and a setting that determines whether the gateway will log metadata and data operations (false by default).

  8. placement_targets: A list of placement targets (optional). Each placement target contains a name (required) for the placement target and a list of tags (optional) so that only users with the tag can use the placement target (that is, the user’s placement_tags field in the user info).

  9. default_placement: The default placement target for the object index and object data. Set to default-placement by default. It is also possible to set a per-user default placement in the user info for each user.

Setting a Zonegroup - Procedure

  1. To set a zonegroup, create a JSON object that contains the required fields, save the object to a file (for example, zonegroup.json), and run the following command:

    radosgw-admin zonegroup set --infile zonegroup.json
    

    Where zonegroup.json is the JSON file you created.

    Important

    The default zonegroup is_master setting is true by default. If you create an additional zonegroup and want to make it the master zonegroup, you must either set the default zonegroup is_master setting to false or delete the default zonegroup.

  2. Update the period:

    radosgw-admin period update --commit
    

Setting a Zonegroup Map

The process of setting a zonegroup map comprises (1) creating a JSON object that consists of one or more zonegroups, and (2) setting the master_zonegroup for the cluster. Each zonegroup in the zonegroup map consists of a key/value pair where the key setting is equivalent to the name setting for an individual zonegroup configuration and the val is a JSON object consisting of an individual zonegroup configuration.

You may only have one zonegroup with is_master equal to true, and it must be specified as the master_zonegroup at the end of the zonegroup map. The following JSON object is an example of a default zonegroup map:

{
    "zonegroups": [
        {
            "key": "90b28698-e7c3-462c-a42d-4aa780d24eda",
            "val": {
                "id": "90b28698-e7c3-462c-a42d-4aa780d24eda",
                "name": "us",
                "api_name": "us",
                "is_master": "true",
                "endpoints": [
                    "http:\/\/rgw1:80"
                ],
                "hostnames": [],
                "hostnames_s3website": [],
                "master_zone": "9248cab2-afe7-43d8-a661-a40bf316665e",
                "zones": [
                    {
                        "id": "9248cab2-afe7-43d8-a661-a40bf316665e",
                        "name": "us-east",
                        "endpoints": [
                            "http:\/\/rgw1"
                        ],
                        "log_meta": "true",
                        "log_data": "true",
                        "bucket_index_max_shards": 0,
                        "read_only": "false"
                    },
                    {
                        "id": "d1024e59-7d28-49d1-8222-af101965a939",
                        "name": "us-west",
                        "endpoints": [
                            "http:\/\/rgw2:80"
                        ],
                        "log_meta": "false",
                        "log_data": "true",
                        "bucket_index_max_shards": 0,
                        "read_only": "false"
                    }
                ],
                "placement_targets": [
                    {
                        "name": "default-placement",
                        "tags": []
                    }
                ],
                "default_placement": "default-placement",
                "realm_id": "ae031368-8715-4e27-9a99-0c9468852cfe"
            }
        }
    ],
    "master_zonegroup": "90b28698-e7c3-462c-a42d-4aa780d24eda",
    "bucket_quota": {
        "enabled": false,
        "max_size_kb": -1,
        "max_objects": -1
    },
    "user_quota": {
        "enabled": false,
        "max_size_kb": -1,
        "max_objects": -1
    }
}
  1. To set a zonegroup map, run the following command:

    radosgw-admin zonegroup-map set --infile zonegroupmap.json
    

    In this command, zonegroupmap.json is the JSON file you created. Ensure that you have zones created for the ones specified in the zonegroup map.

  2. Update the period:

    radosgw-admin period update --commit
    

Zones

A zone defines a logical group that consists of one or more Ceph Object Gateway instances. All RGWs in a given zone serve S3 objects that are backed by RADOS objects that are stored in the same set of pools in the same cluster. Ceph Object Gateway supports zones.

The procedure for configuring zones differs from typical configuration procedures, because not all of the settings end up in a Ceph configuration file.

Zones can be listed. You can “get” a zone configuration and “set” a zone configuration.

Creating a Zone

To create a zone, specify a zone name. If you are creating a master zone, specify the --master flag. Only one zone in a zonegroup may be a master zone. To add the zone to a zonegroup, specify the --rgw-zonegroup option with the zonegroup name.

radosgw-admin zone create --rgw-zone=<name> \
                 [--zonegroup=<zonegroup-name]\
                 [--endpoints=<endpoint>[,<endpoint>] \
                 [--master] [--default] \
                 --access-key $SYSTEM_ACCESS_KEY --secret $SYSTEM_SECRET_KEY

After you have created the zone, update the period:

radosgw-admin period update --commit

Deleting a Zone

To delete a zone, first remove it from the zonegroup:

radosgw-admin zonegroup remove --zonegroup=<name>\
                                  --zone=<name>

Then, update the period:

radosgw-admin period update --commit

Next, delete the zone:

radosgw-admin zone delete --rgw-zone<name>

Finally, update the period:

radosgw-admin period update --commit

Important

Do not delete a zone without removing it from a zonegroup first. Otherwise, updating the period will fail.

If the pools for the deleted zone will not be used anywhere else, consider deleting the pools. Replace <del-zone> in the example below with the deleted zone’s name.

Important

Only delete the pools with prepended zone names. Deleting the root pool (for example, .rgw.root) will remove all of the system’s configuration.

Important

When the pools are deleted, all of the data within them are deleted in an unrecoverable manner. Delete the pools only if the pool’s contents are no longer needed.

ceph osd pool rm <del-zone>.rgw.control <del-zone>.rgw.control --yes-i-really-really-mean-it
ceph osd pool rm <del-zone>.rgw.meta <del-zone>.rgw.meta --yes-i-really-really-mean-it
ceph osd pool rm <del-zone>.rgw.log <del-zone>.rgw.log --yes-i-really-really-mean-it
ceph osd pool rm <del-zone>.rgw.otp <del-zone>.rgw.otp --yes-i-really-really-mean-it
ceph osd pool rm <del-zone>.rgw.buckets.index <del-zone>.rgw.buckets.index --yes-i-really-really-mean-it
ceph osd pool rm <del-zone>.rgw.buckets.non-ec <del-zone>.rgw.buckets.non-ec --yes-i-really-really-mean-it
ceph osd pool rm <del-zone>.rgw.buckets.data <del-zone>.rgw.buckets.data --yes-i-really-really-mean-it

Modifying a Zone

To modify a zone, specify the zone name and the parameters you wish to modify.

radosgw-admin zone modify [options]

Where [options]:

  • --access-key=<key>

  • --secret/--secret-key=<key>

  • --master

  • --default

  • --endpoints=<list>

Then, update the period:

radosgw-admin period update --commit

Listing Zones

As root, to list the zones in a cluster, run the following command:

radosgw-admin zone list

Getting a Zone

As root, to get the configuration of a zone, run the following command:

radosgw-admin zone get [--rgw-zone=<zone>]

The default zone looks like this:

{ "domain_root": ".rgw",
  "control_pool": ".rgw.control",
  "gc_pool": ".rgw.gc",
  "log_pool": ".log",
  "intent_log_pool": ".intent-log",
  "usage_log_pool": ".usage",
  "user_keys_pool": ".users",
  "user_email_pool": ".users.email",
  "user_swift_pool": ".users.swift",
  "user_uid_pool": ".users.uid",
  "system_key": { "access_key": "", "secret_key": ""},
  "placement_pools": [
      {  "key": "default-placement",
         "val": { "index_pool": ".rgw.buckets.index",
                  "data_pool": ".rgw.buckets"}
      }
    ]
  }

Setting a Zone

Configuring a zone involves specifying a series of Ceph Object Gateway pools. For consistency, we recommend using a pool prefix that is the same as the zone name. See Pools for details of configuring pools.

To set a zone, create a JSON object consisting of the pools, save the object to a file (e.g., zone.json); then, run the following command, replacing {zone-name} with the name of the zone:

radosgw-admin zone set --rgw-zone={zone-name} --infile zone.json

Where zone.json is the JSON file you created.

Then, as root, update the period:

radosgw-admin period update --commit

Renaming a Zone

To rename a zone, specify the zone name and the new zone name.

radosgw-admin zone rename --rgw-zone=<name> --zone-new-name=<name>

Then, update the period:

radosgw-admin period update --commit

Zonegroup and Zone Settings

When configuring a default zonegroup and zone, the pool name includes the zone name. For example:

  • default.rgw.control

To change the defaults, include the following settings in your Ceph configuration file under each [client.radosgw.{instance-name}] instance.

Name

Description

Type

Default

rgw_zone

The name of the zone for the gateway instance.

String

None

rgw_zonegroup

The name of the zonegroup for the gateway instance.

String

None

rgw_zonegroup_root_pool

The root pool for the zonegroup.

String

.rgw.root

rgw_zone_root_pool

The root pool for the zone.

String

.rgw.root

rgw_default_zone_group_info_oid

The OID for storing the default zonegroup. We do not recommend changing this setting.

String

default.zonegroup

Zone Features

Some multisite features require support from all zones before they can be enabled. Each zone lists its supported_features, and each zonegroup lists its enabled_features. Before a feature can be enabled in the zonegroup, it must be supported by all of its zones.

On creation of new zones and zonegroups, all known features are supported and some features (see table below) are enabled by default. After upgrading an existing multisite configuration, however, new features must be enabled manually.

Supported Features

Feature

Release

Default

resharding

Reef

Enabled

compress-encrypted

Reef

Disabled

resharding

This feature allows buckets to be resharded in a multisite configuration without interrupting the replication of their objects. When rgw_dynamic_resharding is enabled, it runs on each zone independently, and zones may choose different shard counts for the same bucket. When buckets are resharded manually with radosgw-admin bucket reshard, only that zone’s bucket is modified. A zone feature should only be marked as supported after all of its RGWs and OSDs have upgraded.

Note

Dynamic resharding is not supported in multisite deployments prior to the Reef release.

compress-encrypted

This feature enables support for combining Server-Side Encryption and Compression on the same object. Object data gets compressed before encryption. Prior to Reef, multisite would not replicate such objects correctly, so all zones must upgrade to Reef or later before enabling.

Warning

The compression ratio may leak information about the encrypted data, and allow attackers to distinguish whether two same-sized objects might contain the same data. Due to these security considerations, this feature is disabled by default.

Commands

Add support for a zone feature

On the cluster that contains the given zone:

radosgw-admin zone modify --rgw-zone={zone-name} --enable-feature={feature-name}
radosgw-admin period update --commit

Remove support for a zone feature

On the cluster that contains the given zone:

radosgw-admin zone modify --rgw-zone={zone-name} --disable-feature={feature-name}
radosgw-admin period update --commit

Enable a zonegroup feature

On any cluster in the realm:

radosgw-admin zonegroup modify --rgw-zonegroup={zonegroup-name} --enable-feature={feature-name}
radosgw-admin period update --commit

Disable a zonegroup feature

On any cluster in the realm:

radosgw-admin zonegroup modify --rgw-zonegroup={zonegroup-name} --disable-feature={feature-name}
radosgw-admin period update --commit

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