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Last pushed: 2 years ago
Short Description
Image containing all the Ceph daemons
Full Description

Daemon container

This Dockerfile may be used to bootstrap a Ceph cluster with all the Ceph daemons running.
To run a certain type of daemon, simply use the name of the daemon as $1.
Valid values are:

  • mon deploys a Ceph monitor
  • osd deploys an OSD using the method specified by OSD_TYPE
  • osd_directory deploys an OSD using a prepared directory (used in scenario where the operator doesn't want to use --privileged=true)
  • osd_ceph_disk deploys an OSD using ceph-disk, so you have to provide a whole device (ie: /dev/sdb)
  • mds deploys a MDS
  • rgw deploys a Rados Gateway

Usage

You can use this container to bootstrap any Ceph daemon.

  • CLUSTER is the name of the cluster (DEFAULT: ceph)
  • HOSTNAME is the hostname of the machine (DEFAULT: $(hostname))

SELinux

If SELinux is enabled, run the following commands:

$ sudo chcon -Rt svirt_sandbox_file_t /etc/ceph
$ sudo chcon -Rt svirt_sandbox_file_t /var/lib/ceph

KV backends

We currently support 2 KV backends to store our configuration flags, keys and maps:

  • etcd
  • consul

There is a ceph.defaults config file in the image that is used for defaults to bootstrap daemons.
It will add the keys if they are not already present.
You can either pre-populate the KV store with your own settings, or provide a ceph.defaults config file
To supply your own defaults, make sure to mount the /etc/ceph/ volume and place your ceph.defaults file there.

Important variables in ceph.defaults to add/change when you bootstrap an OSD:

  • /osd/journal_size
  • /osd/cluster_network
  • /osd/public_network

Note: cluster_network and public_network are currently not populated in the defaults, but can be passed as environment
variables with -e CEPH_PUBLIC_NETWORK=... for more flexibility

Populate Key Value store

$ sudo docker run -d --net=host \
-e KV_TYPE=etcd \
-e KV_IP=127.0.0.1 \
-e KV_PORT=4001 \
ceph/daemon populate_kvstore

Deploy a monitor

A monitor requires some persistent storage for the docker container. If a KV
store is used, /etc/ceph will be auto-generated from data kept in the KV
store. /var/lib/ceph, however, must be provided by a docker volume.
The ceph mon will periodically store data into /var/lib/ceph, including the
latest copy of the CRUSH map. If a mon restarts, it will attempt to download
the latest monmap and CRUSH map from other peer monitors. However, if all
mon daemons have gone down, monitors must be able to recover their previous
maps. The docker volume used for /var/lib/ceph should be backed by some
durable storage, and must be able to survive container and node restarts.

Without KV store, run:

$ sudo docker run -d --net=host \
-v /etc/ceph:/etc/ceph \
-v /var/lib/ceph/:/var/lib/ceph/ \
-e MON_IP=192.168.0.20 \
-e CEPH_PUBLIC_NETWORK=192.168.0.0/24 \
ceph/daemon mon

With KV store, run:

$ sudo docker run -d --net=host \
-v /var/lib/ceph:/var/lib/ceph \
-e MON_IP=192.168.0.20 \
-e CEPH_PUBLIC_NETWORK=192.168.0.0/24 \
-e KV_TYPE=etcd \
-e KV_IP=192.168.0.20 \
ceph/daemon mon

List of available options:

  • MON_NAME: name of the monitor (default to hostname)
  • CEPH_PUBLIC_NETWORK: CIDR of the host running Docker, it should be in the same network as the MON_IP
  • CEPH_CLUSTER_NETWORK: CIDR of a secondary interface of the host running Docker. Used for the OSD replication traffic
  • MON_IP: IP address of the host running Docker
  • NETWORK_AUTO_DETECT: Whether and how to attempt IP and network autodetection. Meant to be used without --net=host.
    • 0 = Do not detect (default)
    • 1 = Detect IPv6, fallback to IPv4 (if no globally-routable IPv6 address detected)
    • 4 = Detect IPv4 only
    • 6 = Detect IPv6 only

Deploy an OSD

There are four available OSD_TYPE values:

  • <none> - if no OSD_TYPE is set; one of disk, activate or directory will be used based on autodetection of the current OSD bootstrap state
  • activate - the daemon expects to be passed a block device of a ceph-disk-prepared disk (via the OSD_DEVICE environment variable); no bootstrapping will be performed
  • directory - the daemon expects to find the OSD filesystem(s) already mounted in /var/lib/ceph/osd/
  • disk - the daemon expects to be passed a block device via the OSD_DEVICE environment variable
  • prepare - the daemon expects to be passed a block device and run ceph-disk prepare to bootstra the disk (via the OSD_DEVICE environment variable)

Options for OSDs (TODO: consolidate these options between the types):

  • JOURNAL_DIR - if provided, new OSDs will be bootstrapped to use the specified directory as a common journal area. This is usually used to store the journals for more than one OSD on a common, separate disk. This currently only applies to the directory OSD type.
  • JOURNAL - if provided, the new OSD will be bootstrapped to use the specified journal file (if you do not wish to use the default). This is currently only supported by the directory OSD type
  • OSD_DEVICE - mandatory for activate and disk OSD types; this specifies which block device to use as the OSD
  • OSD_JOURNAL - optional override of the OSD journal file.

Without OSD_TYPE

If the operator does not specify an OSD_TYPE autodetection happens:

  • disk is used if no bootstrapped OSD is found. OSD_FORCE_ZAP=1 must be set at this point.
  • activate is used if a bootstrapped OSD is found and OSD_DEVICE is also provided.
  • directory is used if a bootstrapped OSD is found and no OSD_DEVICE is provided.

Without KV backend:

$ sudo docker run -d --net=host \
--pid=host \
--privileged=true \
-v /etc/ceph:/etc/ceph \
-v /var/lib/ceph/:/var/lib/ceph/ \
-v /dev/:/dev/ \
-e OSD_DEVICE=/dev/vdd \
-e OSD_FORCE_ZAP=1 \
ceph/daemon osd

With KV backend:

$ sudo docker run -d --net=host \
--privileged=true \
--pid=host \
-v /dev/:/dev/ \
-e OSD_DEVICE=/dev/vdd \
-e OSD_FORCE_ZAP=1 \
-e KV_TYPE=etcd \
-e KV_IP=192.168.0.20 \
ceph/daemon osd

Ceph disk

Without KV backend:

$ sudo docker run -d --net=host \
--privileged=true \
--pid=host \
-v /etc/ceph:/etc/ceph \
-v /var/lib/ceph/:/var/lib/ceph/ \
-v /dev/:/dev/ \
-e OSD_DEVICE=/dev/vdd \
-e OSD_TYPE=disk \
ceph/daemon osd

With KV backend:

$ sudo docker run -d --net=host \
--privileged=true \
--pid=host \
-v /dev/:/dev/ \
-e OSD_DEVICE=/dev/vdd \
-e OSD_TYPE=disk \
-e KV_TYPE=etcd \
-e KV_IP=192.168.0.20 \
ceph/daemon osd

List of available options:

  • OSD_DEVICE is the OSD device
  • OSD_JOURNAL is the journal for a given OSD
  • HOSTNAME is used to place the OSD in the CRUSH map

If you do not want to use --privileged=true, please fall back on the second example.

Ceph disk activate

This function is balance between ceph-disk and osd directory where the operator can use ceph-disk outside of the container (directly on the host) to prepare the devices.
Devices will be prepared with ceph-disk prepare, then they will get activated inside the container.
A priviledged container is still required as ceph-disk needs to access /dev/.
So this has minimum value compare to the ceph-disk but might fit some use cases where the operators want to prepare their devices outside of a container.

$ sudo docker run -d --net=host \
--privileged=true \
--pid=host \
-v /etc/ceph:/etc/ceph \
-v /var/lib/ceph/:/var/lib/ceph/ \
-v /dev/:/dev/ \
-e OSD_DEVICE=/dev/vdd \
-e OSD_TYPE=activate \
ceph/daemon osd

Ceph OSD directory

There are a number of environment variables which are used to configure
the execution of the OSD:

  • CLUSTER is the name of the ceph cluster (defaults to ceph)

If the OSD is not already created (key, configuration, OSD data), the
following environment variables will control its creation:

  • WEIGHT is the of the OSD when it is added to the CRUSH map (default is 1.0)
  • JOURNAL is the location of the journal (default is the journal file inside the OSD data directory)
  • HOSTNAME is the name of the host; it is used as a flag when adding the OSD to the CRUSH map
  • OSD_JOURNAL<osd-id> optional - providing for each OSD directory to be used will prepare and mount the supplied block device
  • JOURNAL_PRESERVE optional - if set, skips the prepare step for OSD_JOURNAL

The old option OSD_ID is now unused. Instead, the script will scan for each directory in /var/lib/ceph/osd of the form <cluster>-<osd-id>.

To create your OSDs simply run the following command:

docker exec <mon-container-id> ceph osd create.

Note that we now default to dropping root privileges, so it is important to set the proper ownership for your OSD directories. The Ceph OSD runs as UID:64045, GID:64045, so:

chown -R 64045:64045 /var/lib/ceph/osd/*

Multiple OSDs

There is a problem when attempting run run multiple OSD containers on a single docker host. See issue #19.

There are two workarounds, at present:

  • Run each OSD with the --pid=host option
  • Run multiple OSDs within the same container

To run multiple OSDs within the same container, simply bind-mount each OSD datastore directory:

  • docker run -v /osds/1:/var/lib/ceph/osd/ceph-1 -v /osds/2:/var/lib/ceph/osd/ceph-2

To run multiple OSDs (for example: osd.5 & osd.11) in the same container, with multiple journals on block devices:

  • docker run -v /var/lib/ceph:/var/lib/ceph -v /dev:/dev -e OSD_TYPE=directory -e OSD_JOURNAL5=/dev/sdb1 -e OSD_JOURNAL11=/dev/sdb2 ...

BTRFS and journal

If your OSD is BTRFS and you want to use PARALLEL journal mode, you will need to run this container with --privileged set to true. Otherwise, ceph-osd will have insufficient permissions and it will revert to the slower WRITEAHEAD mode.

Note

Re: [https://github.com/Ulexus/docker-ceph/issues/5]

A user has reported a consterning (and difficult to diagnose) problem wherein the OSD crashes frequently due to Docker running out of sufficient open file handles. This is understandable, as the OSDs use a great many ports during periods of high traffic. It is, therefore, recommended that you increase the number of open file handles available to Docker.

On CoreOS (and probably other systemd-based systems), you can do this by creating the a file named /etc/systemd/system/docker.service.d/limits.conf with content something like:

  [Service]
  LimitNOFILE=4096

Deploy a MDS

By default, the MDS does NOT create a ceph filesystem. If you wish to have this MDS create a ceph filesystem (it will only do this if the specified CEPHFS_NAME does not already exist), you must set, at a minimum, CEPHFS_CREATE=1. It is strongly recommended that you read the rest of this section, as well.

For most people, the defaults for the following optional environment variables are fine, but if you wish to customize the data and metadata pools in which your CephFS is stored, you may override the following as you wish:

  • CEPHFS_CREATE: Whether to create the ceph filesystem (0 = no / 1 = yes), if it doesn't exist. Defaults to 0 (no)
  • CEPHFS_NAME: The name of the new ceph filesystem and the basis on which the later variables are created. Defaults to cephfs
  • CEPHFS_DATA_POOL: The name of the data pool for the ceph filesystem. If it does not exist, it will be created. Defaults to ${CEPHFS_NAME}_data
  • CEPHFS_DATA_POOL_PG: The number of placement groups for the data pool. Defaults to 8
  • CEPHFS_METADATA_POOL: The name of the metadata pool for the ceph filesystem. If it does not exist, it will be created. Defaults to ${CEPHFS_NAME}_metadata
  • CEPHFS_METADATA_POOL_PG: The number of placement groups for the metadata pool. Defaults to 8

Without KV backend, run:

$ sudo docker run -d --net=host \
-v /var/lib/ceph/:/var/lib/ceph/ \
-v /etc/ceph:/etc/ceph \
-e CEPHFS_CREATE=1 \
ceph/daemon mds

With KV backend, run:

$ sudo docker run -d --net=host \
-e CEPHFS_CREATE=1 \
-e KV_TYPE=etcd \
-e KV_IP=192.168.0.20 \
ceph/daemon mds

List of available options:

  • MDS_NAME is the name the MDS server (DEFAULT: mds-$(hostname)).
    One thing to note is that metadata servers are not machine-restricted.
    They are not bound by their data directories and can move around the cluster.
    As a result, you can run more than one MDS on a single machine.
    If you plan to do so, you better set this variable and do something like: mds-$(hostname)-a, mds-$(hostname)-betc...

Deploy a Rados Gateway

For the Rados Gateway, we deploy it with civetweb enabled by default.
However it is possible to use different CGI frontends by simply giving remote address and port.

Without kv backend, run:

$ sudo docker run -d --net=host \
-v /var/lib/ceph/:/var/lib/ceph/ \
-v /etc/ceph:/etc/ceph \
ceph/daemon rgw

With kv backend, run:

$ sudo docker run -d --net=host \
-e KV_TYPE=etcd \
-e KV_IP=192.168.0.20 \
ceph/daemon rgw

List of available options:

  • RGW_CIVETWEB_PORT is the port to which civetweb is listening on (DEFAULT: 80)
  • RGW_NAME: default to hostname

Administration via radosgw-admin from the Docker host if the RGW_NAME variable hasn't been supplied:

docker exec <containerId> radosgw-admin -n client.rgw.$(hostname) -k /var/lib/ceph/radosgw/$(hostname)/keyring <commands>

If otherwise, $(hostname) has to be replaced by the value of RGW_NAME.

To enable an external CGI interface instead of civetweb set:

  • RGW_REMOTE_CGI=1
  • RGW_REMOTE_CGI_HOST=192.168.0.1
  • RGW_REMOTE_CGI_PORT=9000

And run the container like this docker run -d -v /etc/ceph:/etc/ceph -v /var/lib/ceph/:/var/lib/ceph -e CEPH_DAEMON=RGW -e RGW_NAME=myrgw -p 9000:9000 -e RGW_REMOTE_CGI=1 -e RGW_REMOTE_CGI_HOST=192.168.0.1 -e RGW_REMOTE_CGI_PORT=9000 ceph/daemon

Deploy a REST API

This is pretty straighforward. The --net=host is not mandatory, if you don't use it do not forget to expose the RESTAPI_PORT.

$ sudo docker run -d --net=host \
-e KV_TYPE=etcd \
-e KV_IP=192.168.0.20 \
ceph/daemon restapi

List of available options:

  • RESTAPI_IP is the IP address to listen on (DEFAULT: 0.0.0.0)
  • RESTAPI_PORT is the listening port of the REST API (DEFAULT: 5000)
  • RESTAPI_BASE_URL is the base URL of the API (DEFAULT: /api/v0.1)
  • RESTAPI_LOG_LEVEL is the log level of the API (DEFAULT: warning)
  • RESTAPI_LOG_FILE is the location of the log file (DEFAULT: /var/log/ceph/ceph-restapi.log)
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