/usr/lib/docker-storage-setup/docker-storage-setup

#
# Specify storage driver one wants to use with docker. Default is devicemapper.
# Other possible options are overlay, overlay2 and "". Empty string means do
# not do any storage setup.
#

STORAGE_DRIVER=devicemapper

#
# A set of extra options that should be appended to the generated
# DOCKER_STORAGE_OPTIONS string. These options will be passed to the Docker
# daemon as-is and should be valid Docker storage options.
# EXTRA_DOCKER_STORAGE_OPTIONS="--storage-opt dm.fs=ext4"
#

#
# A quoted, space-separated list of devices to be used.  This currently
# expects the devices to be unpartitioned drives.  If "VG" is not specified,
# then use of the root disk's extra space is implied.
#

# DEVS=/dev/vdb

#
# The volume group to use for docker storage.  Defaults to the
# volume group where the root filesystem resides.  If VG is specified and the
# volume group does not exist, it will be created (which requires that "DEVS"
# be nonempty, since we don't currently support putting a second partition on
# the root disk).
#

# VG=docker_vg

#
# The size to which the root filesystem should be grown.
# Value should be acceptable to -L option of lvextend.
#

# ROOT_SIZE=8G

#
# The desired size for the docker data LV.  It defaults using 60% of all
# free space.
#
# DATA_SIZE can take values acceptable to "lvcreate -L" as well as some
# values acceptable to to "lvcreate -l". If user intends to pass values
# acceptable to "lvcreate -l", then only those values which contains "%"
# in syntax are acceptable.  If value does not contain "%" it is assumed
# value is suitable for "lvcreate -L".
#

DATA_SIZE=40%FREE

#
# MIN_DATA_SIZE specifies the minimum size of data volume otherwise pool
# creation fails.
#
# Value should be a number followed by a optional suffix. "bBsSkKmMgGtTpPeE"
# are valid suffixes. If no suffix is specified then value will be considered
# as mebibyte unit.
#
# Both upper and lower case suffix represent same unit of size. Use suffix B
# for Bytes, S for sectors as 512 bytes, K for kibibytes (1024 bytes), M for
# mebibytes (1024 kibibytes), G for gibibytes, T for tebibytes, P for
# pebibytes and E for exbibytes.
#

MIN_DATA_SIZE=2G

#
# Controls the chunk size/block size of thin pool. Value of CHUNK_SIZE
# be suitable to be passed to --chunk-size option of lvconvert.
#

CHUNK_SIZE=512K

#
# Enable resizing partition table backing root volume group. By default it
# is disabled until and unless GROWPART=true is specified.
#

GROWPART=false

#
# Enable/disable automatic pool extension using lvm
#

AUTO_EXTEND_POOL=yes

#
# Auto pool extension threshold (in % of pool size)
#

POOL_AUTOEXTEND_THRESHOLD=60

#
# Extend the pool by specified percentage when threshold is hit.
#

POOL_AUTOEXTEND_PERCENT=20

#
# Device wait timeout in seconds. This is generic timeout which can be used by
# docker storage setup service to wait on various kind of block devices.
# Setting a value of 0 can disable this wait.
#

DEVICE_WAIT_TIMEOUT=60

#
# Wipe any signatures (partition, filesystem, lvm etc) found on disk.
# This could mean wiping the signature explicitly or using force options
# of various commands to wipe/overwrite signatures. By default signatures
# are not wiped and user needs to wipe these. One can change default behavior
# by setting WIPE_SIGNATURES=true. Be careful before using this option
# as this means if there was any leftover data on disk, it will be lost.
#

WIPE_SIGNATURES=false

#
# By default no new volume and filesystem will be setup for docker
# root dir. Docker creates /var/lib/docker/ on top of underlying filesystem
# for storing images and containers.
#
# To carve out a separate logical volume for storing docker
# images/containers/volumes data, set DOCKER_ROOT_VOLUME=yes
# NOTE: devicemapper stores images/containers on thin pool.
#
# docker-storage-setup creates a logical volume with an XFS filesystem mounted
# on docker root directory (default: /var/lib/docker).
#

DOCKER_ROOT_VOLUME=no

#
# Specify the desired size for docker root volume. It defaults to 40% of all
# free space.
#
# DOCKER_ROOT_VOLUME_SIZE can take values acceptable to "lvcreate -L" as well
# as some values acceptable to to "lvcreate -l". If user intends to pass
# values acceptable to "lvcreate -l", then only those values which
# contains "%" in syntax are acceptable.  If value does not contain "%" it
# is assumed value is suitable for "lvcreate -L".
#
# NOTE: If both STORAGE_DRIVER=devicemapper and DOCKER_ROOT_VOLUME=yes is
# set, docker-storage-setup would set up the thin pool for devicemapper
# first, followed by docker root volume. e.g if free space in the volume
# group is 10G, devicemapper thin pool size would be 4G (40% of 10G)
# and docker root volume would be 2.4G (40% of 6G).
#

DOCKER_ROOT_VOLUME_SIZE=40%FREE