ceph mon #0

Supports: xenial trusty yakkety
Add to new model


Ceph is a distributed storage and network file system designed to provide
excellent performance, reliability, and scalability.


Ceph is a distributed storage and network file system designed to provide
excellent performance, reliability, and scalability.

This charm deploys a Ceph cluster.


The ceph charm has two pieces of mandatory configuration for which no defaults
are provided. You must set these configuration options before deployment or the charm will not work:

    uuid specific to a ceph cluster used to ensure that different
    clusters don't get mixed up - use `uuid` to generate one.

    a ceph generated key used by the daemons that manage to cluster
    to control security.  You can use the ceph-authtool command to
    generate one:

        ceph-authtool /dev/stdout --name=mon. --gen-key

These two pieces of configuration must NOT be changed post bootstrap; attempting
to do this will cause a reconfiguration error and new service units will not join
the existing ceph cluster.

At a minimum you must provide a juju config file during initial deployment
with the fsid and monitor-secret options (contents of cepy.yaml below):

    fsid: ecbb8960-0e21-11e2-b495-83a88f44db01
    monitor-secret: AQD1P2xQiKglDhAA4NGUF5j38Mhq56qwz+45wg==

Boot things up by using:

juju deploy -n 3 --config ceph.yaml ceph

By default the ceph cluster will not bootstrap until 3 service units have been
deployed and started; this is to ensure that a quorum is achieved prior to adding
storage devices.


This charm supports pausing and resuming ceph's health functions on a cluster, for example when doing maintenance on a machine. to pause or resume, call:

juju action do --unit ceph-mon/0 pause-health or juju action do --unit ceph-mon/0 resume-health

Scale Out Usage

You can use the Ceph OSD and Ceph Radosgw charms:

Rolling Upgrades

ceph-mon and ceph-osd charms have the ability to initiate a rolling upgrade.
This is initiated by setting the config value for source. To perform a
rolling upgrade first set the source for ceph-mon. Watch juju status.
Once the monitor cluster is upgraded proceed to setting the ceph-osd source
setting. Again watch juju status for output. The monitors and osds will
sort themselves into a known order and upgrade one by one. As each server is
upgrading the upgrade code will down all the monitor or osd processes on that
server, apply the update and then restart them. You will notice in the
juju status output that the servers will tell you which previous server they
are waiting on.

Supported Upgrade Paths

Currently the following upgrade paths are supported using
the Ubuntu Cloud Archive:
- trusty-firefly -> trusty-hammer
- trusty-hammer -> trusty-jewel

Firefly is available in Trusty, Hammer is in Trusty-Juno (end of life),
Trusty-Kilo, Trusty-Liberty, and Jewel is available in Trusty-Mitaka.

For example if the current config source setting is: cloud:trusty-liberty
changing that to cloud:trusty-mitaka will initiate a rolling upgrade of
the monitor cluster from hammer to jewel.

Edge cases

There's an edge case in the upgrade code where if the previous node never
starts upgrading itself then the rolling upgrade can hang forever. If you
notice this has happened it can be fixed by setting the appropriate key in the
ceph monitor cluster. The monitor cluster will have
keys that look like ceph-mon_ip-ceph-mon-0_1484680239.573482_start and
ceph-mon_ip-ceph-mon-0_1484680274.181742_stop. What each server is looking for
is that stop key to indicate that the previous server upgraded successfully and
it's safe to take itself down. If the stop key is not present it will wait
10 minutes, then consider that server dead and move on.

Network Space support

This charm supports the use of Juju Network Spaces, allowing the charm to be bound to network space configurations managed directly by Juju. This is only supported with Juju 2.0 and above.

Network traffic can be bound to specific network spaces using the public (front-side) and cluster (back-side) bindings:

juju deploy ceph-mon --bind "public=data-space cluster=cluster-space"

alternatively these can also be provided as part of a Juju native bundle configuration:

  charm: cs:xenial/ceph-mon
  num_units: 1
    public: data-space
    cluster: cluster-space

Please refer to the Ceph Network Reference for details on how using these options effects network traffic within a Ceph deployment.

NOTE: Spaces must be configured in the underlying provider prior to attempting to use them.

NOTE: Existing deployments using ceph-*-network configuration options will continue to function; these options are preferred over any network space binding provided if set.

Contact Information


Report bugs on Launchpad


Technical Footnotes

This charm uses the new-style Ceph deployment as reverse-engineered from the
Chef cookbook at https://github.com/ceph/ceph-cookbooks, although we selected
a different strategy to form the monitor cluster. Since we don't know the
names or addresses of the machines in advance, we use the relation-joined
hook to wait for all three nodes to come up, and then write their addresses
to ceph.conf in the "mon host" parameter. After we initialize the monitor
cluster a quorum forms quickly, and OSD bringup proceeds.

See the documentation for more information on Ceph monitor cluster deployment strategies and pitfalls.


(string) Which authentication flavour to use. . Valid options are "cephx" and "none". If "none" is specified, keys will still be created and deployed so that it can be enabled later.
(string) The IP address and netmask of the cluster (back-side) network (e.g., . If multiple networks are to be used, a space-delimited list of a.b.c.d/x can be provided.
(string) The IP address and netmask of the public (front-side) network (e.g., . If multiple networks are to be used, a space-delimited list of a.b.c.d/x can be provided.
(string) User provided Ceph configuration. Supports a string representation of a python dictionary where each top-level key represents a section in the ceph.conf template. You may only use sections supported in the template. . WARNING: this is not the recommended way to configure the underlying services that this charm installs and is used at the user's own risk. This option is mainly provided as a stop-gap for users that either want to test the effect of modifying some config or who have found a critical bug in the way the charm has configured their services and need it fixed immediately. We ask that whenever this is used, that the user consider opening a bug on this charm at http://bugs.launchpad.net/charms providing an explanation of why the config was needed so that we may consider it for inclusion as a natively supported config in the the charm.
(boolean) Setting this to true will tell Ceph to replicate across Juju's Availability Zone instead of specifically by host.
(int) Provides an expected number of OSDs for the cluster. This value is used when calculating the number of placement groups for a pool creation. The number of placement groups for new pools are based upon the actual number of OSDs in the cluster or the expected-osd-count, whichever is greater. A value of 0 will cause the charm to only consider the OSDs which are in the cluster.
(string) fsid of the ceph cluster. To generate a suitable value use `uuid` . This configuration element is mandatory and the service will fail on install if it is not provided.
(string) Apply system hardening. Supports a space-delimited list of modules to run. Supported modules currently include os, ssh, apache and mysql.
(string) Key ID to import to the apt keyring to support use with arbitary source configuration from outside of Launchpad archives or PPA's.
(int) Mon and OSD debug level. Max is 20.
(int) How many nodes to wait for before trying to create the monitor cluster this number needs to be odd, and more than three is a waste except for very large clusters.
(string) This value will become the mon. key. To generate a suitable value use: . ceph-authtool /dev/stdout --name=mon. --gen-key . This configuration element is mandatory and the service will fail on install if it is not provided.
(string) Used by the nrpe-external-master subordinate charm. A string that will be prepended to instance name to set the host name in nagios. So for instance the hostname would be something like: juju-myservice-0 If you're running multiple environments with the same services in them this allows you to differentiate between them.
(string) A comma-separated list of nagios servicegroups. If left empty, the nagios_context will be used as the servicegroup
(int) The number of placement groups per OSD to target. It is important to properly size the number of placement groups per OSD as too many or too few placement groups oer OSD may cause resource constraints and performance degradation. This value comes from the recommendation of the Ceph placement group calculator (http://ceph.com/pgcalc/) and recommended values are: . 100 - If the cluster OSD count is not expected to increase in the foreseeable future. 200 - If the cluster OSD count is expected to increase (up to 2x) in the foreseeable future. 300 - If the cluster OSD count is expected to increase between 2x and 3x in the foreseeable future.
(boolean) If True enables IPv6 support. The charm will expect network interfaces to be configured with an IPv6 address. If set to False (default) IPv4 is expected. NOTE: these charms do not currently support IPv6 privacy extension. In order for this charm to function correctly, the privacy extension must be disabled and a non-temporary address must be configured/available on your network interface.
(string) Optional configuration to support use of additional sources such as: - ppa:myteam/ppa - cloud:trusty-proposed/kilo - http://my.archive.com/ubuntu main The last option should be used in conjunction with the key configuration option. Note that a minimum ceph version of 0.48.2 is required for use with this charm which is NOT provided by the packages in the main Ubuntu archive for precise but is provided in the Ubuntu cloud archive.
(string) YAML-formatted associative array of sysctl key/value pairs to be set persistently. By default we set pid_max, max_map_count and threads-max to a high value to avoid problems with large numbers (>20) of OSDs recovering. very large clusters should set those values even higher (e.g. max for kernel.pid_max is 4194303).
{ kernel.pid_max : 2097152, vm.max_map_count : 524288, kernel.threads-max: 2097152 }
(boolean) Configure use of direct IO for OSD journals.
(boolean) If set to True, supporting services will log to syslog.