charm-ceph-osd/README.md

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Overview
========
Ceph is a distributed storage and network file system designed to provide
excellent performance, reliability, and scalability.
This charm deploys additional Ceph OSD storage service units and should be
used in conjunction with the 'ceph-mon' charm to scale out the amount of
storage available in a Ceph cluster.
Usage
=====
The charm also supports specification of the storage devices to use in the ceph
cluster::
osd-devices:
A list of devices that the charm will attempt to detect, initialise and
activate as ceph storage.
If the charm detects pre-existing data on a device it will go into a
blocked state and the operator must resolve the situation utilizing the
`list-disks`, `zap-disk` and/or `blacklist-*` actions.
This this can be a superset of the actual storage devices presented to
each service unit and can be changed post ceph-osd deployment using
`juju set`.
For example::
ceph-osd:
options:
osd-devices: /dev/vdb /dev/vdc /dev/vdd /dev/vde
Example utilizing Juju storage::
ceph-osd:
storage:
osd-devices: cinder,20G
Please refer to [Juju Storage Documentation](https://docs.jujucharms.com/devel/en/charms-storage) for details on support for various storage providers and cloud substrates.
How to deploy::
juju deploy -n 3 ceph-osd
juju deploy ceph-mon --to lxd:0
juju add-unit ceph-mon --to lxd:1
juju add-unit ceph-mon --to lxd:2
juju add-relation ceph-osd ceph-mon
Once the 'ceph-mon' charm has bootstrapped the cluster, it will notify the
ceph-osd charm which will scan for the configured storage devices and add them
to the pool of available storage.
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-osd --bind "public=data-space cluster=cluster-space"
alternatively these can also be provided as part of a Juju native bundle configuration:
ceph-osd:
charm: cs:xenial/ceph-osd
num_units: 1
bindings:
public: data-space
cluster: cluster-space
Please refer to the [Ceph Network Reference](http://docs.ceph.com/docs/master/rados/configuration/network-config-ref) 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.
AppArmor Profiles
=================
AppArmor is not enforced for Ceph by default. An AppArmor profile can be generated by the charm. However, great care must be taken.
Changing the value of the ```aa-profile-mode``` option is disruptive to a running Ceph cluster as all ceph-osd processes must be restarted as part of changing the AppArmor profile enforcement mode.
The generated AppArmor profile currently has a narrow supported use case, and it should always be verified in pre-production against the specific configurations and topologies intended for production.
The AppArmor profile(s) which are generated by the charm should NOT yet be used in the following scenarios:
- When there are separate journal devices.
- On any version of Ceph prior to Luminous.
- On any version of Ubuntu other than 16.04.
- With Bluestore enabled.
Block Device Encryption
=======================
The ceph-osd charm supports encryption of underlying block devices supporting OSD's.
To use the 'native' key management approach (where dm-crypt keys are stored in the
ceph-mon cluster), simply set the 'osd-encrypt' configuration option::
ceph-osd:
options:
osd-encrypt: True
**NOTE:** This is supported for Ceph Jewel or later.
Alternatively, encryption keys can be stored in Vault; this requires deployment of
the vault charm (and associated initialization of vault - see the Vault charm for
details) and configuration of the 'osd-encrypt' and 'osd-encrypt-keymanager'
options::
ceph-osd:
options:
osd-encrypt: True
osd-encrypt-keymanager: vault
**NOTE:** This option is only supported with Ceph Luminous or later.
**NOTE:** Changing these options post deployment will only take effect for any
new block devices added to the ceph-osd application; existing OSD devices will
not be encrypted.
Actions
=======
The charm offers [actions](https://docs.jujucharms.com/devel/en/actions) which
may be used to perform operational tasks on individual units.
pause
-----
**USE WITH CAUTION** - Set the local osd units in the charm to 'out' but
does not stop the osds. Unless the osd cluster is set to noout (see below),
this removes them from the ceph cluster and forces ceph to migrate the PGs
to other OSDs in the cluster.
From [upstream documentation](http://docs.ceph.com/docs/master/rados/operations/add-or-rm-osds/#removing-the-osd)
"Do not let your cluster reach its full ratio when removing an OSD.
Removing OSDs could cause the cluster to reach or exceed its full ratio."
Also note that for small clusters you may encounter the corner case where
some PGs remain stuck in the active+remapped state. Refer to the above link
on how to resolve this.
`pause-health` (on a ceph-mon) unit can be used before pausing a ceph-osd
unit to stop the cluster rebalancing the data off this ceph-osd unit.
`pause-health` sets 'noout' on the cluster such that it will not try to
rebalance the data accross the remaining units.
It is up to the user of the charm to determine whether pause-health should
be used as it depends on whether the osd is being paused for maintenance or
to remove it from the cluster completely.
**NOTE** the `pause` action does NOT stop the ceph-osd processes.
resume
------
Set the local osd units in the charm to 'in'.
list-disks
----------
List disks
The 'disks' key is populated with block devices that are known by udev,
are not mounted and not mentioned in 'osd-journal' configuration option.
The 'blacklist' key is populated with osd-devices in the blacklist stored
in the local kv store of this specific unit.
The 'non-pristine' key is populated with block devices that are known by
udev, are not mounted, not mentioned in 'osd-journal' configuration option
and are currently not eligible for use because of presence of foreign data.
add-disk
--------
Add disk(s) to Ceph
#### Parameters
- `osd-devices` (required)
- The devices to format and set up as osd volumes.
- `bucket`
- The name of the bucket in Ceph to add these devices into
blacklist-add-disk
------------------
Add disk(s) to blacklist. Blacklisted disks will not be
initialized for use with Ceph even if listed in the application
level osd-devices configuration option.
The current blacklist can be viewed with list-disks action.
**NOTE** This action and blacklist will not have any effect on
already initialized disks.
#### Parameters
- `osd-devices` (required)
- A space-separated list of devices to add to blacklist.
Each element should be a absolute path to a device node or filesystem
directory (the latter is supported for ceph >= 0.56.6).
Example: '/dev/vdb /var/tmp/test-osd'
blacklist-remove-disk
---------------------
Remove disk(s) from blacklist.
#### Parameters
- `osd-devices` (required)
- A space-separated list of devices to remove from blacklist.
Each element should be a existing entry in the units blacklist.
Use list-disks action to list current blacklist entries.
Example: '/dev/vdb /var/tmp/test-osd'
zap-disk
--------
Purge disk of all data and signatures for use by Ceph
This action can be necessary in cases where a Ceph cluster is being
redeployed as the charm defaults to skipping disks that look like Ceph
devices in order to preserve data. In order to forcibly redeploy, the
admin is required to perform this action for each disk to be re-consumed.
In addition to triggering this action, it is required to pass an additional
parameter option of `i-really-mean-it` to ensure that the
administrator is aware that this *will* cause data loss on the specified
device(s)
#### Parameters
- `devices` (required)
- A space-separated list of devices to remove the partition table from.
- `i-really-mean-it` (required)
- This must be toggled to enable actually performing this action
Contact Information
===================
Author: James Page <james.page@ubuntu.com>
Report bugs at: http://bugs.launchpad.net/charm-ceph-osd/+filebug
Location: http://jujucharms.com/ceph-osd