mirror of https://github.com/docker/cli.git
Closes #13323 and carries
Entering comments Signed-off-by: Mary Anthony <mary@docker.com>
This commit is contained in:
Mary Anthony
Tibor Vass
parent
2feacfe882
commit
5fbf370b98
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@ -178,7 +178,24 @@ Particular storage-driver can be configured with options specified with
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`--storage-opt` flags. Options for `devicemapper` are prefixed with `dm` and
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options for `zfs` start with `zfs`.
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Currently supported options of `devicemapper`:
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* `dm.thinpooldev`
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Specifies a custom block storage device to use for the thin pool.
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If using a block device for device mapper storage, it is best to use `lvm`
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to create and manage the thin-pool volume. This volume is then handed to Docker
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to exclusively create snapshot volumes needed for images and containers.
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Managing the thin-pool outside of Docker makes for the most feature-rich
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method of having Docker utilize device mapper thin provisioning as the
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backing storage for Docker's containers. The highlights of the lvm-based
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thin-pool management feature include: automatic or interactive thin-pool
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resize support, dynamically changing thin-pool features, automatic thinp
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metadata checking when lvm activates the thin-pool, etc.
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Example use:
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docker -d --storage-opt dm.thinpooldev=/dev/mapper/thin-pool
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* `dm.basesize`
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@ -188,9 +205,9 @@ Currently supported options of `devicemapper`:
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10 GB of space on the pool. However, the filesystem will use more space for
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the empty case the larger the device is.
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**Warning:** This value affects the system-wide "base" empty filesystem
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This value affects the system-wide "base" empty filesystem
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that may already be initialized and inherited by pulled images. Typically,
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a change to this value will require additional steps to take effect:
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a change to this value requires additional steps to take effect:
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$ sudo service docker stop
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$ sudo rm -rf /var/lib/docker
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@ -202,9 +219,12 @@ Currently supported options of `devicemapper`:
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* `dm.loopdatasize`
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Specifies the size to use when creating the loopback file for the "data"
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device which is used for the thin pool. The default size is 100G. Note that
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the file is sparse, so it will not initially take up this much space.
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>**Note**: This option configures devicemapper loopback, which should not be used in production.
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Specifies the size to use when creating the loopback file for the
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"data" device which is used for the thin pool. The default size is
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100G. The file is sparse, so it will not initially take up this
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much space.
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Example use:
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@ -212,10 +232,12 @@ Currently supported options of `devicemapper`:
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* `dm.loopmetadatasize`
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>**Note**: This option configures devicemapper loopback, which should not be used in production.
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Specifies the size to use when creating the loopback file for the
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"metadata" device which is used for the thin pool. The default size is 2G.
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Note that the file is sparse, so it will not initially take up this much
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space.
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"metadadata" device which is used for the thin pool. The default size
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is 2G. The file is sparse, so it will not initially take up
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this much space.
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Example use:
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@ -248,6 +270,8 @@ Currently supported options of `devicemapper`:
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* `dm.datadev`
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(Deprecated, use `dm.thinpooldev`)
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Specifies a custom blockdevice to use for data for the thin pool.
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If using a block device for device mapper storage, ideally both datadev and
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@ -256,12 +280,12 @@ Currently supported options of `devicemapper`:
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Example use:
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$ docker -d \
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--storage-opt dm.datadev=/dev/sdb1 \
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--storage-opt dm.metadatadev=/dev/sdc1
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$ docker -d --storage-opt dm.datadev=/dev/sdb1 --storage-opt dm.metadatadev=/dev/sdc1
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* `dm.metadatadev`
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(Deprecated, use `dm.thinpooldev`)
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Specifies a custom blockdevice to use for metadata for the thin pool.
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For best performance the metadata should be on a different spindle than the
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@ -274,9 +298,7 @@ Currently supported options of `devicemapper`:
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Example use:
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$ docker -d \
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--storage-opt dm.datadev=/dev/sdb1 \
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--storage-opt dm.metadatadev=/dev/sdc1
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$ docker -d --storage-opt dm.datadev=/dev/sdb1 --storage-opt dm.metadatadev=/dev/sdc1
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* `dm.blocksize`
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@ -337,6 +359,7 @@ Currently supported options of `devicemapper`:
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> Otherwise, set this flag for migrating existing Docker daemons to
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> a daemon with a supported environment.
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## Docker execdriver option
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Currently supported options of `zfs`:
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209
man/docker.1.md
209
man/docker.1.md
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@ -297,79 +297,198 @@ inside it)
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# STORAGE DRIVER OPTIONS
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Options to storage backend can be specified with **--storage-opt** flags. The
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only backend which currently takes options is *devicemapper*. Therefore use these
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Docker uses storage backends (known as "graphdrivers" in the Docker
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internals) to create writable containers from images. Many of these
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backends use operating system level technologies and can be
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configured.
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Specify options to the storage backend with **--storage-opt** flags. The only
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backend that currently takes options is *devicemapper*. Therefore use these
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flags with **-s=**devicemapper.
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Specifically for devicemapper, the default is a "loopback" model which
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requires no pre-configuration, but is extremely inefficient. Do not
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use it in production.
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To make the best use of Docker with the devicemapper backend, you must
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have a recent version of LVM. Use `lvm` to create a thin pool; for
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more information see `man lvmthin`. Then, use `--storage-opt
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dm.thinpooldev` to tell the Docker engine to use that pool for
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allocating images and container snapshots.
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Here is the list of *devicemapper* options:
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#### dm.thinpooldev
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Specifies a custom block storage device to use for the thin pool.
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If using a block device for device mapper storage, it is best to use
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`lvm` to create and manage the thin-pool volume. This volume is then
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handed to Docker to create snapshot volumes needed for images and
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containers.
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Managing the thin-pool outside of Docker makes for the most feature-rich method
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of having Docker utilize device mapper thin provisioning as the backing storage
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for Docker's containers. The highlights of the LVM-based thin-pool management
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feature include: automatic or interactive thin-pool resize support, dynamically
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changing thin-pool features, automatic thinp metadata checking when lvm activates
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the thin-pool, etc.
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Example use: `docker -d --storage-opt dm.thinpooldev=/dev/mapper/thin-pool`
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#### dm.basesize
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Specifies the size to use when creating the base device, which limits the size
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of images and containers. The default value is 10G. Note, thin devices are
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inherently "sparse", so a 10G device which is mostly empty doesn't use 10 GB
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of space on the pool. However, the filesystem will use more space for the empty
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case the larger the device is. **Warning**: This value affects the system-wide
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"base" empty filesystem that may already be initialized and inherited by pulled
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images.
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#### dm.loopdatasize
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Specifies the size to use when creating the loopback file for the "data"
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device which is used for the thin pool. The default size is 100G. Note that the
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file is sparse, so it will not initially take up this much space.
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Specifies the size to use when creating the base device, which limits
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the size of images and containers. The default value is 10G. Note,
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thin devices are inherently "sparse", so a 10G device which is mostly
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empty doesn't use 10 GB of space on the pool. However, the filesystem
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will use more space for base images the larger the device
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is.
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#### dm.loopmetadatasize
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Specifies the size to use when creating the loopback file for the "metadadata"
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device which is used for the thin pool. The default size is 2G. Note that the
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file is sparse, so it will not initially take up this much space.
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This value affects the system-wide "base" empty filesystem that may already
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be initialized and inherited by pulled images. Typically, a change to this
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value requires additional steps to take effect:
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$ sudo service docker stop
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$ sudo rm -rf /var/lib/docker
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$ sudo service docker start
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Example use: `docker -d --storage-opt dm.basesize=20G`
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#### dm.fs
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Specifies the filesystem type to use for the base device. The supported
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options are "ext4" and "xfs". The default is "ext4"
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Specifies the filesystem type to use for the base device. The
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supported options are `ext4` and `xfs`. The default is `ext4`.
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Example use: `docker -d --storage-opt dm.fs=xfs`
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#### dm.mkfsarg
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Specifies extra mkfs arguments to be used when creating the base device.
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Example use: `docker -d --storage-opt "dm.mkfsarg=-O ^has_journal"`
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#### dm.mountopt
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Specifies extra mount options used when mounting the thin devices.
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#### dm.datadev
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Specifies a custom blockdevice to use for data for the thin pool.
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Example use: `docker -d --storage-opt dm.mountopt=nodiscard`
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If using a block device for device mapper storage, ideally both datadev and
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metadatadev should be specified to completely avoid using the loopback device.
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#### dm.use_deferred_removal
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Enables use of deferred device removal if `libdm` and the kernel driver
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support the mechanism.
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Deferred device removal means that if device is busy when devices are
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being removed/deactivated, then a deferred removal is scheduled on
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device. And devices automatically go away when last user of the device
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exits.
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For example, when a container exits, its associated thin device is removed. If
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that device has leaked into some other mount namespace and can't be removed,
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the container exit still succeeds and this option causes the system to schedule
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the device for deferred removal. It does not wait in a loop trying to remove a busy
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device.
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Example use: `docker -d --storage-opt dm.use_deferred_removal=true`
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#### dm.loopdatasize
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**Note**: This option configures devicemapper loopback, which should not be used in production.
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Specifies the size to use when creating the loopback file for the
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"data" device which is used for the thin pool. The default size is
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100G. The file is sparse, so it will not initially take up
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this much space.
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Example use: `docker -d --storage-opt dm.loopdatasize=200G`
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#### dm.loopmetadatasize
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**Note**: This option configures devicemapper loopback, which should not be used in production.
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Specifies the size to use when creating the loopback file for the
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"metadadata" device which is used for the thin pool. The default size
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is 2G. The file is sparse, so it will not initially take up
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this much space.
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Example use: `docker -d --storage-opt dm.loopmetadatasize=4G`
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#### dm.datadev
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(Deprecated, use `dm.thinpooldev`)
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Specifies a custom blockdevice to use for data for a
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Docker-managed thin pool. It is better to use `dm.thinpooldev` - see
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the documentation for it above for discussion of the advantages.
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#### dm.metadatadev
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Specifies a custom blockdevice to use for metadata for the thin pool.
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For best performance the metadata should be on a different spindle than the
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data, or even better on an SSD.
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(Deprecated, use `dm.thinpooldev`)
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If setting up a new metadata pool it is required to be valid. This can be
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achieved by zeroing the first 4k to indicate empty metadata, like this:
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dd if=/dev/zero of=/dev/metadata_dev bs=4096 count=1
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Specifies a custom blockdevice to use for metadata for a
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Docker-managed thin pool. See `dm.datadev` for why this is
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deprecated.
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#### dm.blocksize
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Specifies a custom blocksize to use for the thin pool. The default blocksize
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is 64K.
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Specifies a custom blocksize to use for the thin pool. The default
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blocksize is 64K.
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Example use: `docker -d --storage-opt dm.blocksize=512K`
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#### dm.blkdiscard
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Enables or disables the use of blkdiscard when removing devicemapper devices.
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This is enabled by default (only) if using loopback devices and is required to
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resparsify the loopback file on image/container removal.
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Disabling this on loopback can lead to *much* faster container removal times,
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but will prevent the space used in `/var/lib/docker` directory from being returned to
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the system for other use when containers are removed.
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Enables or disables the use of `blkdiscard` when removing devicemapper
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devices. This is disabled by default due to the additional latency,
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but as a special case with loopback devices it will be enabled, in
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order to re-sparsify the loopback file on image/container removal.
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# EXAMPLES
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Launching docker daemon with *devicemapper* backend with particular block devices
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for data and metadata:
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Disabling this on loopback can lead to *much* faster container removal
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times, but it also prevents the space used in `/var/lib/docker` directory
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from being returned to the system for other use when containers are
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removed.
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docker -d -s=devicemapper \
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--storage-opt dm.datadev=/dev/vdb \
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--storage-opt dm.metadatadev=/dev/vdc \
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--storage-opt dm.basesize=20G
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Example use: `docker -d --storage-opt dm.blkdiscard=false`
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#### dm.override_udev_sync_check
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By default, the devicemapper backend attempts to synchronize with the
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`udev` device manager for the Linux kernel. This option allows
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disabling that synchronization, to continue even though the
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configuration may be buggy.
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To view the `udev` sync support of a Docker daemon that is using the
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`devicemapper` driver, run:
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$ docker info
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[...]
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Udev Sync Supported: true
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[...]
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When `udev` sync support is `true`, then `devicemapper` and `udev` can
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coordinate the activation and deactivation of devices for containers.
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When `udev` sync support is `false`, a race condition occurs between
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the`devicemapper` and `udev` during create and cleanup. The race
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condition results in errors and failures. (For information on these
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failures, see
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[docker#4036](https://github.com/docker/docker/issues/4036))
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To allow the `docker` daemon to start, regardless of whether `udev` sync is
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`false`, set `dm.override_udev_sync_check` to true:
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$ docker -d --storage-opt dm.override_udev_sync_check=true
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When this value is `true`, the driver continues and simply warns you
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the errors are happening.
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**Note**: The ideal is to pursue a `docker` daemon and environment
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that does support synchronizing with `udev`. For further discussion on
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this topic, see
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[docker#4036](https://github.com/docker/docker/issues/4036).
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Otherwise, set this flag for migrating existing Docker daemons to a
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daemon with a supported environment.
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# EXEC DRIVER OPTIONS
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