1containers-storage.conf(5)(Container)Filecontainers-storage.conf(5)(Container)
2Dan Walsh May 2017
6
9 storage.conf - Syntax of Container Storage configuration file
10
13 The STORAGE configuration file specifies all of the available container
14 storage options for tools using shared container storage, but in a TOML
15 format that can be more easily modified and versioned.
16
19 The [TOML format][toml] is used as the encoding of the configuration
20 file. Every option and subtable listed here is nested under a global
21 "storage" table. No bare options are used. The format of TOML can be
22 simplified to:
23 [table]
26 option = value
27 [table.subtable1]
29 option = value
30 [table.subtable2]
32 option = value
33
37 The storage table supports the following options:
38 driver=""
41 container storage driver
42 Default Copy On Write (COW) container storage driver. Valid drivers
43 are "overlay", "vfs", "devmapper", "aufs", "btrfs", and "zfs". Some
44 drivers (for example, "zfs", "btrfs", and "aufs") may not work if your
45 kernel lacks support for the filesystem.
46 This field is required to guarantee proper operation.
47 Valid rootless drivers are "btrfs", "overlay", and "vfs".
48 Rootless users default to the driver defined in the system configura‐
49 tion when possible.
50 When the system configuration uses an unsupported rootless driver,
51 rootless users default to "overlay" if available, otherwise "vfs".
52 graphroot=""
55 container storage graph dir (default: "/var/lib/containers/storage")
56 Default directory to store all writable content created by container
57 storage programs.
58 The rootless graphroot path supports environment variable substitu‐
59 tions (ie. $HOME/containers/storage)
60 rootless_storage_path="$HOME/.local/share/containers/storage"
63 Storage path for rootless users. By default the graphroot for root‐
64 less users
65 is set to $XDG_DATA_HOME/containers/storage, if XDG_DATA_HOME is set.
66 Otherwise $HOME/.local/share/containers/storage is used. This field
67 can
68 be used if administrators need to change the storage location for all
69 users.
70 The rootless storage path supports environment variable substitutions
71 (ie. $HOME/containers/storage)
72 A common use case for this field is to provide a local storage direc‐
75 tory when user home directories are NFS-mounted (podman does not sup‐
76 port container storage over NFS).
77 runroot=""
80 container storage run dir (default: "/run/containers/storage")
81 Default directory to store all temporary writable content created by
82 container storage programs.
83 The rootless runroot path supports environment variable substitutions
84 (ie. $HOME/containers/storage)
85 STORAGE OPTIONS TABLE
88 The storage.options table supports the following options:
89 additionalimagestores=[]
92 Paths to additional container image stores. Usually these are
93 read/only and stored on remote network shares.
94 remap-uids="" remap-gids=""
97 Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear
98 inside of a container, to the UIDs/GIDs outside of the container, and
99 the length of the range of UIDs/GIDs. Additional mapped sets can be
100 listed and will be heeded by libraries, but there are limits to the
101 number of mappings which the kernel will allow when you later attempt
102 to run a container.
103 Example
106 remap-uids = 0:1668442479:65536
107 remap-gids = 0:1668442479:65536
108 These mappings tell the container engines to map UID 0 inside of the
111 container to UID 1668442479 outside. UID 1 will be mapped to
112 1668442480. UID 2 will be mapped to 1668442481, etc, for the next 65533
113 UIDs in succession.
114 remap-user="" remap-group=""
117 Remap-User/Group is a user name which can be used to look up one or
118 more UID/GID ranges in the /etc/subuid or /etc/subgid file. Mappings
119 are set up starting with an in-container ID of 0 and then a host-level
120 ID taken from the lowest range that matches the specified name, and us‐
121 ing the length of that range. Additional ranges are then assigned, us‐
122 ing the ranges which specify the lowest host-level IDs first, to the
123 lowest not-yet-mapped in-container ID, until all of the entries have
124 been used for maps.
125 Example
128 remap-user = "containers"
129 remap-group = "containers"
130 root-auto-userns-user=""
133 Root-auto-userns-user is a user name which can be used to look up one
134 or more UID/GID ranges in the /etc/subuid and /etc/subgid file. These
135 ranges will be partitioned to containers configured to create automati‐
136 cally a user namespace. Containers configured to automatically create
137 a user namespace can still overlap with containers having an explicit
138 mapping set. This setting is ignored when running as rootless.
139 auto-userns-min-size=1024
142 Auto-userns-min-size is the minimum size for a user namespace created
143 automatically.
144 auto-userns-max-size=65536
147 Auto-userns-max-size is the maximum size for a user namespace created
148 automatically.
149 disable-volatile=true
152 If disable-volatile is set, then the "volatile" mount optimization is
153 disabled for all the containers.
154 STORAGE OPTIONS FOR AUFS TABLE
157 The storage.options.aufs table supports the following options:
158 mountopt=""
161 Comma separated list of default options to be used to mount container
162 images. Suggested value "nodev". Mount options are documented in the
163 mount(8) man page.
164 STORAGE OPTIONS FOR BTRFS TABLE
167 The storage.options.btrfs table supports the following options:
168 min_space=""
171 Specifies the min space in a btrfs volume.
172 size=""
175 Maximum size of a container image. This flag can be used to set
176 quota on the size of container images. (format: [], where unit = b
177 (bytes), k (kilobytes), m (megabytes), or g (gigabytes))
178 STORAGE OPTIONS FOR THINPOOL (devicemapper) TABLE
181 The storage.options.thinpool table supports the following options for
182 the devicemapper driver:
183 autoextend_percent=""
186 Tells the thinpool driver the amount by which the thinpool needs to
187 be grown. This is specified in terms of % of pool size. So a value of
188 20 means that when threshold is hit, pool will be grown by 20% of ex‐
189 isting pool size. (default: 20%)
190 autoextend_threshold=""
193 Tells the driver the thinpool extension threshold in terms of per‐
194 centage of pool size. For example, if threshold is 60, that means when
195 pool is 60% full, threshold has been hit. (default: 80%)
196 basesize=""
199 Specifies the size to use when creating the base device, which limits
200 the size of images and containers. (default: 10g)
201 blocksize=""
204 Specifies a custom blocksize to use for the thin pool. (default: 64k)
205 directlvm_device=""
208 Specifies a custom block storage device to use for the thin pool. Re‐
209 quired for using graphdriver devicemapper.
210 directlvm_device_force=""
213 Tells driver to wipe device (directlvm_device) even if device already
214 has a filesystem. (default: false)
215 fs="xfs"
218 Specifies the filesystem type to use for the base device. (default:
219 xfs)
220 log_level=""
223 Sets the log level of devicemapper.
224 0: LogLevelSuppress 0 (default)
227 2: LogLevelFatal
228 3: LogLevelErr
229 4: LogLevelWarn
230 5: LogLevelNotice
231 6: LogLevelInfo
232 7: LogLevelDebug
233 metadata_size=""
237 metadata_size is used to set the pvcreate --metadatasize options when
238 creating thin devices. (Default 128k)
239 min_free_space=""
242 Specifies the min free space percent in a thin pool required for new
243 device creation to succeed. Valid values are from 0% - 99%. Value 0%
244 disables. (default: 10%)
245 mkfsarg=""
248 Specifies extra mkfs arguments to be used when creating the base de‐
249 vice.
250 mountopt=""
253 Comma separated list of default options to be used to mount container
254 images. Suggested value "nodev". Mount options are documented in the
255 mount(8) man page.
256 size=""
259 Maximum size of a container image. This flag can be used to set
260 quota on the size of container images. (format: [], where unit = b
261 (bytes), k (kilobytes), m (megabytes), or g (gigabytes))
262 use_deferred_deletion=""
265 Marks thinpool device for deferred deletion. If the thinpool is in
266 use when the driver attempts to delete it, the driver will attempt to
267 delete device every 30 seconds until successful, or when it restarts.
268 Deferred deletion permanently deletes the device and all data stored in
269 the device will be lost. (default: true).
270 use_deferred_removal=""
273 Marks devicemapper block device for deferred removal. If the device
274 is in use when its driver attempts to remove it, the driver tells the
275 kernel to remove the device as soon as possible. Note this does not
276 free up the disk space, use deferred deletion to fully remove the thin‐
277 pool. (default: true).
278 xfs_nospace_max_retries=""
281 Specifies the maximum number of retries XFS should attempt to com‐
282 plete IO when ENOSPC (no space) error is returned by underlying storage
283 device. (default: 0, which means to try continuously.)
284 STORAGE OPTIONS FOR OVERLAY TABLE
287 The storage.options.overlay table supports the following options:
288 ignore_chown_errors = "false"
291 ignore_chown_errors can be set to allow a non privileged user running
292 with a single UID within a user namespace to run containers. The user
293 can pull and use any image even those with multiple uids. Note multi‐
294 ple UIDs will be squashed down to the default uid in the container.
295 These images will have no separation between the users in the con‐
296 tainer. (default: false)
297 force_mask = "0000|shared|private"
300 ForceMask specifies the permissions mask that is used for new files
301 and directories. The values "shared" and "private" are accepted. (de‐
302 fault: ""). Octal permission masks are also accepted.
303 ``: Not set
306 All files/directories, get set with the permissions identified
307 within the image.
308 private: it is equivalent to 0700.
311 All files/directories get set with 0700 permissions. The owner
312 has rwx access to the files. No other users on the system can access
313 the files. This setting could be used with networked based home direc‐
314 tories.
315 shared: it is equivalent to 0755.
318 The owner has rwx access to the files and everyone else can read,
319 access and execute them. This setting is useful for sharing containers
320 storage with other users. For instance, a storage owned by root could
321 be shared to rootless users as an additional store. NOTE: All files
322 within the image are made readable and executable by any user on the
323 system. Even /etc/shadow within your image is now readable by any user.
324 OCTAL: Users can experiment with other OCTAL Permissions.
327 Note: The force_mask Flag is an experimental feature, it could change
330 in the future. When "force_mask" is set the original permission mask
331 is stored in the "user.containers.override_stat" xattr and the
332 "mount_program" option must be specified. Mount programs like
333 "/usr/bin/fuse-overlayfs" present the extended attribute permissions to
334 processes within containers rather then the "force_mask" permissions.
335 mount_program=""
338 Specifies the path to a custom program to use instead of using kernel
339 defaults for mounting the file system. In rootless mode, without the
340 CAP_SYS_ADMIN capability, many kernels prevent mounting of overlay file
341 systems, requiring you to specify a mount_program. The mount_program
342 option is also required on systems where the underlying storage is
343 btrfs, aufs, zfs, overlay, or ecryptfs based file systems.
344 mount_program = "/usr/bin/fuse-overlayfs"
345 mountopt=""
348 Comma separated list of default options to be used to mount container
349 images. Suggested value "nodev". Mount options are documented in the
350 mount(8) man page.
351 size=""
354 Maximum size of a container image. This flag can be used to set
355 quota on the size of container images. (format: [], where unit = b
356 (bytes), k (kilobytes), m (megabytes), or g (gigabytes))
357 STORAGE OPTIONS FOR VFS TABLE
360 The storage.options.vfs table supports the following options:
361 ignore_chown_errors = "false"
364 ignore_chown_errors can be set to allow a non privileged user running
365 with a single UID within a user namespace to run containers. The user
366 can pull and use any image even those with multiple uids. Note multi‐
367 ple UIDs will be squashed down to the default uid in the container.
368 These images will have no separation between the users in the con‐
369 tainer. (default: false)
370 STORAGE OPTIONS FOR ZFS TABLE
373 The storage.options.zfs table supports the following options:
374 fsname=""
377 File System name for the zfs driver
378 mountopt=""
381 Comma separated list of default options to be used to mount container
382 images. Suggested value "nodev". Mount options are documented in the
383 mount(8) man page.
384 skip_mount_home=""
387 Tell storage drivers to not create a PRIVATE bind mount on their home
388 directory.
389 size=""
392 Maximum size of a container image. This flag can be used to set
393 quota on the size of container images. (format: [], where unit = b
394 (bytes), k (kilobytes), m (megabytes), or g (gigabytes))
395
398 When running on an SELinux system, if you move the containers storage
399 graphroot directory, you must make sure the labeling is correct.
400 Tell SELinux about the new containers storage by setting up an equiva‐
403 lence record. This tells SELinux to label content under the new path,
404 as if it was stored under /var/lib/containers/storage.
405 semanage fcontext -a -e /var/lib/containers NEWSTORAGEPATH
408 restorecon -R -v NEWSTORAGEPATH
409 The semanage command above tells SELinux to setup the default labeling
413 of NEWSTORAGEPATH to match /var/lib/containers. The restorecon command
414 tells SELinux to apply the labels to the actual content.
415 Now all new content created in these directories will automatically be
418 created with the correct label.
419
422 semanage(8), restorecon(8), mount(8), fuse-overlayfs(1)
423
426 Distributions often provide a /usr/share/containers/storage.conf file
427 to define default storage configuration. Administrators can override
428 this file by creating /etc/containers/storage.conf to specify their own
429 configuration. The storage.conf file for rootless users is stored in
430 the $XDG_CONFIG_HOME/containers/storage.conf file. If $XDG_CONFIG_HOME
431 is not set then the file $HOME/.config/containers/storage.conf is used.
432
435 May 2017, Originally compiled by Dan Walsh dwalsh@redhat.com
436 ⟨mailto:dwalsh@redhat.com⟩ Format copied from crio.conf man page cre‐
437 ated by Aleksa Sarai asarai@suse.de ⟨mailto:asarai@suse.de⟩
438Configuration Storagceontainers-storage.conf(5)(Container)