Cephx Config Reference

The cephx protocol is enabled by default. Cryptographic authentication has some computational costs, though they should generally be quite low. If the network environment connecting your client and server hosts is very safe and you cannot afford authentication, you can turn it off. This is not generally recommended.

Note

If you disable authentication, you are at risk of a man-in-the-middle attack altering your client/server messages, which could lead to disastrous security effects.

For creating users, see User Management. For details on the architecture of Cephx, see Architecture - High Availability Authentication.

Deployment Scenarios

There are two main scenarios for deploying a Ceph cluster, which impact how you initially configure Cephx. Most first time Ceph users use cephadm to create a cluster (easiest). For clusters using other deployment tools (e.g., Chef, Juju, Puppet, etc.), you will need to use the manual procedures or configure your deployment tool to bootstrap your monitor(s).

Manual Deployment

When you deploy a cluster manually, you have to bootstrap the monitor manually and create the client.admin user and keyring. To bootstrap monitors, follow the steps in Monitor Bootstrapping. The steps for monitor bootstrapping are the logical steps you must perform when using third party deployment tools like Chef, Puppet, Juju, etc.

Enabling/Disabling Cephx

Enabling Cephx requires that you have deployed keys for your monitors, OSDs and metadata servers. If you are simply toggling Cephx on / off, you do not have to repeat the bootstrapping procedures.

Enabling Cephx

When cephx is enabled, Ceph will look for the keyring in the default search path, which includes /etc/ceph/$cluster.$name.keyring. You can override this location by adding a keyring option in the [global] section of your Ceph configuration file, but this is not recommended.

Execute the following procedures to enable cephx on a cluster with authentication disabled. If you (or your deployment utility) have already generated the keys, you may skip the steps related to generating keys.

  1. Create a client.admin key, and save a copy of the key for your client host

    ceph auth get-or-create client.admin mon 'allow *' mds 'allow *' mgr 'allow *' osd 'allow *' -o /etc/ceph/ceph.client.admin.keyring
    

    Warning: This will clobber any existing /etc/ceph/client.admin.keyring file. Do not perform this step if a deployment tool has already done it for you. Be careful!

  2. Create a keyring for your monitor cluster and generate a monitor secret key.

    ceph-authtool --create-keyring /tmp/ceph.mon.keyring --gen-key -n mon. --cap mon 'allow *'
    
  3. Copy the monitor keyring into a ceph.mon.keyring file in every monitor’s mon data directory. For example, to copy it to mon.a in cluster ceph, use the following

    cp /tmp/ceph.mon.keyring /var/lib/ceph/mon/ceph-a/keyring
    
  4. Generate a secret key for every MGR, where {$id} is the MGR letter

    ceph auth get-or-create mgr.{$id} mon 'allow profile mgr' mds 'allow *' osd 'allow *' -o /var/lib/ceph/mgr/ceph-{$id}/keyring
    
  5. Generate a secret key for every OSD, where {$id} is the OSD number

    ceph auth get-or-create osd.{$id} mon 'allow rwx' osd 'allow *' -o /var/lib/ceph/osd/ceph-{$id}/keyring
    
  6. Generate a secret key for every MDS, where {$id} is the MDS letter

    ceph auth get-or-create mds.{$id} mon 'allow rwx' osd 'allow *' mds 'allow *' mgr 'allow profile mds' -o /var/lib/ceph/mds/ceph-{$id}/keyring
    
  7. Enable cephx authentication by setting the following options in the [global] section of your Ceph configuration file

    auth cluster required = cephx
    auth service required = cephx
    auth client required = cephx
    
  8. Start or restart the Ceph cluster. See Operating a Cluster for details.

For details on bootstrapping a monitor manually, see Manual Deployment.

Disabling Cephx

The following procedure describes how to disable Cephx. If your cluster environment is relatively safe, you can offset the computation expense of running authentication. We do not recommend it. However, it may be easier during setup and/or troubleshooting to temporarily disable authentication.

  1. Disable cephx authentication by setting the following options in the [global] section of your Ceph configuration file

    auth cluster required = none
    auth service required = none
    auth client required = none
    
  2. Start or restart the Ceph cluster. See Operating a Cluster for details.

Configuration Settings

Enablement

auth cluster required

Description

If enabled, the Ceph Storage Cluster daemons (i.e., ceph-mon, ceph-osd, ceph-mds and ceph-mgr) must authenticate with each other. Valid settings are cephx or none.

Type

String

Required

No

Default

cephx.

auth service required

Description

If enabled, the Ceph Storage Cluster daemons require Ceph Clients to authenticate with the Ceph Storage Cluster in order to access Ceph services. Valid settings are cephx or none.

Type

String

Required

No

Default

cephx.

auth client required

Description

If enabled, the Ceph Client requires the Ceph Storage Cluster to authenticate with the Ceph Client. Valid settings are cephx or none.

Type

String

Required

No

Default

cephx.

Keys

When you run Ceph with authentication enabled, ceph administrative commands and Ceph Clients require authentication keys to access the Ceph Storage Cluster.

The most common way to provide these keys to the ceph administrative commands and clients is to include a Ceph keyring under the /etc/ceph directory. For Octopus and later releases using cephadm, the filename is usually ceph.client.admin.keyring (or $cluster.client.admin.keyring). If you include the keyring under the /etc/ceph directory, you don’t need to specify a keyring entry in your Ceph configuration file.

We recommend copying the Ceph Storage Cluster’s keyring file to nodes where you will run administrative commands, because it contains the client.admin key.

To perform this step manually, execute the following:

sudo scp {user}@{ceph-cluster-host}:/etc/ceph/ceph.client.admin.keyring /etc/ceph/ceph.client.admin.keyring

Tip

Ensure the ceph.keyring file has appropriate permissions set (e.g., chmod 644) on your client machine.

You may specify the key itself in the Ceph configuration file using the key setting (not recommended), or a path to a keyfile using the keyfile setting.

keyring

Description

The path to the keyring file.

Type

String

Required

No

Default

/etc/ceph/$cluster.$name.keyring,/etc/ceph/$cluster.keyring,/etc/ceph/keyring,/etc/ceph/keyring.bin

keyfile

Description

The path to a key file (i.e,. a file containing only the key).

Type

String

Required

No

Default

None

key

Description

The key (i.e., the text string of the key itself). Not recommended.

Type

String

Required

No

Default

None

Daemon Keyrings

Administrative users or deployment tools (e.g., cephadm) may generate daemon keyrings in the same way as generating user keyrings. By default, Ceph stores daemons keyrings inside their data directory. The default keyring locations, and the capabilities necessary for the daemon to function, are shown below.

ceph-mon

Location

$mon_data/keyring

Capabilities

mon 'allow *'

ceph-osd

Location

$osd_data/keyring

Capabilities

mgr 'allow profile osd' mon 'allow profile osd' osd 'allow *'

ceph-mds

Location

$mds_data/keyring

Capabilities

mds 'allow' mgr 'allow profile mds' mon 'allow profile mds' osd 'allow rwx'

ceph-mgr

Location

$mgr_data/keyring

Capabilities

mon 'allow profile mgr' mds 'allow *' osd 'allow *'

radosgw

Location

$rgw_data/keyring

Capabilities

mon 'allow rwx' osd 'allow rwx'

Note

The monitor keyring (i.e., mon.) contains a key but no capabilities, and is not part of the cluster auth database.

The daemon data directory locations default to directories of the form:

/var/lib/ceph/$type/$cluster-$id

For example, osd.12 would be:

/var/lib/ceph/osd/ceph-12

You can override these locations, but it is not recommended.

Signatures

Ceph performs a signature check that provides some limited protection against messages being tampered with in flight (e.g., by a “man in the middle” attack).

Like other parts of Ceph authentication, Ceph provides fine-grained control so you can enable/disable signatures for service messages between the client and Ceph, and you can enable/disable signatures for messages between Ceph daemons.

Note that even with signatures enabled data is not encrypted in flight.

cephx require signatures

Description

If set to true, Ceph requires signatures on all message traffic between the Ceph Client and the Ceph Storage Cluster, and between daemons comprising the Ceph Storage Cluster.

Ceph Argonaut and Linux kernel versions prior to 3.19 do not support signatures; if such clients are in use this option can be turned off to allow them to connect.

Type

Boolean

Required

No

Default

false

cephx cluster require signatures

Description

If set to true, Ceph requires signatures on all message traffic between Ceph daemons comprising the Ceph Storage Cluster.

Type

Boolean

Required

No

Default

false

cephx service require signatures

Description

If set to true, Ceph requires signatures on all message traffic between Ceph Clients and the Ceph Storage Cluster.

Type

Boolean

Required

No

Default

false

cephx sign messages

Description

If the Ceph version supports message signing, Ceph will sign all messages so they are more difficult to spoof.

Type

Boolean

Default

true

Time to Live

auth service ticket ttl

Description

When the Ceph Storage Cluster sends a Ceph Client a ticket for authentication, the Ceph Storage Cluster assigns the ticket a time to live.

Type

Double

Default

60*60