1podman-build(1)() podman-build(1)()
2
6 podman-build - Build a container image using a Containerfile
7
10 podman build [options] [context]
11 podman image build [options] [context]
14
17 podman build Builds an image using instructions from one or more Con‐
18 tainerfiles or Dockerfiles and a specified build context directory. A
19 Containerfile uses the same syntax as a Dockerfile internally. For this
20 document, a file referred to as a Containerfile can be a file named ei‐
21 ther 'Containerfile' or 'Dockerfile'.
22 The build context directory can be specified as the http(s) URL of an
25 archive, git repository or Containerfile.
26 If no context directory is specified, then Podman will assume the cur‐
29 rent working directory as the build context, which should contain the
30 Containerfile.
31 Containerfiles ending with a ".in" suffix will be preprocessed via
34 CPP(1). This can be useful to decompose Containerfiles into several
35 reusable parts that can be used via CPP's #include directive. Notice,
36 a Containerfile.in file can still be used by other tools when manually
37 preprocessing them via cpp -E.
38 When the URL is an archive, the contents of the URL is downloaded to a
41 temporary location and extracted before execution.
42 When the URL is an Containerfile, the Containerfile is downloaded to a
45 temporary location.
46 When a Git repository is set as the URL, the repository is cloned lo‐
49 cally and then set as the context.
50 NOTE: podman build uses code sourced from the buildah project to build
53 container images. This buildah code creates buildah containers for the
54 RUN options in container storage. In certain situations, when the pod‐
55 man build crashes or users kill the podman build process, these exter‐
56 nal containers can be left in container storage. Use the podman ps
57 --all --storage command to see these containers. External containers
58 can be removed with the podman rm --storage command.
59
62 --add-host=host
63 Add a custom host-to-IP mapping (host:ip)
64 Add a line to /etc/hosts. The format is hostname:ip. The --add-host op‐
67 tion can be set multiple times.
68 --annotation=annotation
71 Add an image annotation (e.g. annotation=value) to the image metadata.
72 Can be used multiple times.
73 Note: this information is not present in Docker image formats, so it is
76 discarded when writing images in Docker formats.
77 --arch=arch
80 Set the ARCH of the image to the provided value instead of the archi‐
81 tecture of the host.
82 --authfile=path
85 Path of the authentication file. Default is ${XDG_RUNTIME_DIR}/contain‐
86 ers/auth.json, which is set using podman login. If the authorization
87 state is not found there, $HOME/.docker/config.json is checked, which
88 is set using docker login.
89 Note: You can also override the default path of the authentication file
92 by setting the REGISTRY_AUTH_FILE environment variable. export REG‐
93 ISTRY_AUTH_FILE=path
94 --build-arg=arg=value
97 Specifies a build argument and its value, which will be interpolated in
98 instructions read from the Containerfiles in the same way that environ‐
99 ment variables are, but which will not be added to environment variable
100 list in the resulting image's configuration.
101 --cache-from
104 Images to utilize as potential cache sources. Podman does not currently
105 support caching so this is a NOOP. (This option is not available with
106 the remote Podman client)
107 --cap-add=CAP_xxx
110 When executing RUN instructions, run the command specified in the in‐
111 struction with the specified capability added to its capability set.
112 Certain capabilities are granted by default; this option can be used to
113 add more.
114 --cap-drop=CAP_xxx
117 When executing RUN instructions, run the command specified in the in‐
118 struction with the specified capability removed from its capability
119 set. The CAP_AUDIT_WRITE, CAP_CHOWN, CAP_DAC_OVERRIDE, CAP_FOWNER,
120 CAP_FSETID, CAP_KILL, CAP_MKNOD, CAP_NET_BIND_SERVICE, CAP_SETFCAP,
121 CAP_SETGID, CAP_SETPCAP, CAP_SETUID, and CAP_SYS_CHROOT capabilities
122 are granted by default; this option can be used to remove them.
123 If a capability is specified to both the --cap-add and --cap-drop op‐
126 tions, it will be dropped, regardless of the order in which the options
127 were given.
128 --cert-dir=path
131 Use certificates at path (*.crt, *.cert, *.key) to connect to the reg‐
132 istry. Please refer to containers-certs.d(5) for details. (This option
133 is not available with the remote Podman client)
134 --cgroup-parent=path
137 Path to cgroups under which the cgroup for the container will be cre‐
138 ated. If the path is not absolute, the path is considered to be rela‐
139 tive to the cgroups path of the init process. Cgroups will be created
140 if they do not already exist.
141 --compress
144 This option is added to be aligned with other containers CLIs. Podman
145 doesn't communicate with a daemon or a remote server. Thus, compress‐
146 ing the data before sending it is irrelevant to Podman. (This option is
147 not available with the remote Podman client)
148 --cni-config-dir=directory
151 Location of CNI configuration files which will dictate which plugins
152 will be used to configure network interfaces and routing for containers
153 created for handling RUN instructions, if those containers will be run
154 in their own network namespaces, and networking is not disabled.
155 --cni-plugin-path=directory[:directory[:directory[...]]]
158 List of directories in which the CNI plugins which will be used for
159 configuring network namespaces can be found.
160 --cpu-period=limit
163 Set the CPU period for the Completely Fair Scheduler (CFS), which is a
164 duration in microseconds. Once the container's CPU quota is used up, it
165 will not be scheduled to run until the current period ends. Defaults to
166 100000 microseconds.
167 On some systems, changing the CPU limits may not be allowed for
170 non-root users. For more details, see https://github.com/contain‐
171 ers/podman/blob/master/troubleshooting.md#26-running-contain‐
172 ers-with-cpu-limits-fails-with-a-permissions-error
173 --cpu-quota=limit
176 Limit the CPU Completely Fair Scheduler (CFS) quota.
177 Limit the container's CPU usage. By default, containers run with the
180 full CPU resource. The limit is a number in microseconds. If you pro‐
181 vide a number, the container will be allowed to use that much CPU time
182 until the CPU period ends (controllable via --cpu-period).
183 On some systems, changing the CPU limits may not be allowed for
186 non-root users. For more details, see https://github.com/contain‐
187 ers/podman/blob/master/troubleshooting.md#26-running-contain‐
188 ers-with-cpu-limits-fails-with-a-permissions-error
189 --cpu-shares, -c=shares
192 CPU shares (relative weight)
193 By default, all containers get the same proportion of CPU cycles. This
196 proportion can be modified by changing the container's CPU share
197 weighting relative to the weighting of all other running containers.
198 To modify the proportion from the default of 1024, use the --cpu-shares
201 flag to set the weighting to 2 or higher.
202 The proportion will only apply when CPU-intensive processes are run‐
205 ning. When tasks in one container are idle, other containers can use
206 the left-over CPU time. The actual amount of CPU time will vary depend‐
207 ing on the number of containers running on the system.
208 For example, consider three containers, one has a cpu-share of 1024 and
211 two others have a cpu-share setting of 512. When processes in all three
212 containers attempt to use 100% of CPU, the first container would re‐
213 ceive 50% of the total CPU time. If you add a fourth container with a
214 cpu-share of 1024, the first container only gets 33% of the CPU. The
215 remaining containers receive 16.5%, 16.5% and 33% of the CPU.
216 On a multi-core system, the shares of CPU time are distributed over all
219 CPU cores. Even if a container is limited to less than 100% of CPU
220 time, it can use 100% of each individual CPU core.
221 For example, consider a system with more than three cores. If you start
224 one container {C0} with -c=512 running one process, and another con‐
225 tainer {C1} with -c=1024 running two processes, this can result in the
226 following division of CPU shares:
227 PID container CPU CPU share
230 100 {C0} 0 100% of CPU0
231 101 {C1} 1 100% of CPU1
232 102 {C1} 2 100% of CPU2
233 --cpuset-cpus=num
237 CPUs in which to allow execution (0-3, 0,1)
238 --cpuset-mems=nodes
241 Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effec‐
242 tive on NUMA systems.
243 If you have four memory nodes on your system (0-3), use
246 --cpuset-mems=0,1 then processes in your container will only use memory
247 from the first two memory nodes.
248 --creds=creds
251 The [username[:password]] to use to authenticate with the registry if
252 required. If one or both values are not supplied, a command line
253 prompt will appear and the value can be entered. The password is en‐
254 tered without echo.
255 --decryption-key=key[:passphrase]
258 The [key[:passphrase]] to be used for decryption of images. Key can
259 point to keys and/or certificates. Decryption will be tried with all
260 keys. If the key is protected by a passphrase, it is required to be
261 passed in the argument and omitted otherwise.
262 --device=host-device[:container-device][:permissions]
265 Add a host device to the container. Optional permissions parameter can
266 be used to specify device permissions, it is combination of r for read,
267 w for write, and m for mknod(2).
268 Example: --device=/dev/sdc:/dev/xvdc:rwm.
271 Note: if _hostdevice is a symbolic link then it will be resolved first.
274 The container will only store the major and minor numbers of the host
275 device.
276 Note: if the user only has access rights via a group, accessing the de‐
279 vice from inside a rootless container will fail. The crun(1) runtime
280 offers a workaround for this by adding the option
281 --annotation run.oci.keep_original_groups=1.
284 --disable-compression, -D
285 Don't compress filesystem layers when building the image unless it is
286 required by the location where the image is being written. This is the
287 default setting, because image layers are compressed automatically when
288 they are pushed to registries, and images being written to local stor‐
289 age would only need to be decompressed again to be stored. Compression
290 can be forced in all cases by specifying --disable-compression=false.
291 --disable-content-trust
294 This is a Docker specific option to disable image verification to a
295 Docker registry and is not supported by Podman. This flag is a NOOP
296 and provided solely for scripting compatibility. (This option is not
297 available with the remote Podman client)
298 --dns=dns
301 Set custom DNS servers to be used during the build.
302 This option can be used to override the DNS configuration passed to the
305 container. Typically this is necessary when the host DNS configuration
306 is invalid for the container (e.g., 127.0.0.1). When this is the case
307 the --dns flag is necessary for every run.
308 The special value none can be specified to disable creation of /etc/re‐
311 solv.conf in the container by Podman. The /etc/resolv.conf file in the
312 image will be used without changes.
313 --dns-option=option
316 Set custom DNS options to be used during the build.
317 --dns-search=domain
320 Set custom DNS search domains to be used during the build.
321 --file, -f=Containerfile
324 Specifies a Containerfile which contains instructions for building the
325 image, either a local file or an http or https URL. If more than one
326 Containerfile is specified, FROM instructions will only be accepted
327 from the first specified file.
328 If a build context is not specified, and at least one Containerfile is
331 a local file, the directory in which it resides will be used as the
332 build context.
333 If you specify -f -, the Containerfile contents will be read from
336 stdin.
337 --force-rm=true|false
340 Always remove intermediate containers after a build, even if the build
341 fails (default true).
342 --format
345 Control the format for the built image's manifest and configuration
346 data. Recognized formats include oci (OCI image-spec v1.0, the de‐
347 fault) and docker (version 2, using schema format 2 for the manifest).
348 Note: You can also override the default format by setting the BUIL‐
351 DAH_FORMAT environment variable. export BUILDAH_FORMAT=docker
352 --from
355 Overrides the first FROM instruction within the Containerfile. If
356 there are multiple FROM instructions in a Containerfile, only the first
357 is changed.
358 -h, --help
361 Print usage statement
364 --http-proxy
367 Pass through HTTP Proxy environment variables.
368 --iidfile=ImageIDfile
371 Write the image ID to the file.
372 --ignorefile
375 Path to an alternative .dockerignore file.
376 --ipc=how
379 Sets the configuration for IPC namespaces when handling RUN instruc‐
380 tions. The configured value can be "" (the empty string) or "con‐
381 tainer" to indicate that a new IPC namespace should be created, or it
382 can be "host" to indicate that the IPC namespace in which podman itself
383 is being run should be reused, or it can be the path to an IPC name‐
384 space which is already in use by another process.
385 --isolation=type
388 Controls what type of isolation is used for running processes as part
389 of RUN instructions. Recognized types include oci (OCI-compatible run‐
390 time, the default), rootless (OCI-compatible runtime invoked using a
391 modified configuration and its --rootless flag enabled, with
392 --no-new-keyring --no-pivot added to its create invocation, with net‐
393 work and UTS namespaces disabled, and IPC, PID, and user namespaces en‐
394 abled; the default for unprivileged users), and chroot (an internal
395 wrapper that leans more toward chroot(1) than container technology).
396 Note: You can also override the default isolation type by setting the
399 BUILDAH_ISOLATION environment variable. export BUILDAH_ISOLATION=oci
400 --jobs=number
403 Run up to N concurrent stages in parallel. If the number of jobs is
404 greater than 1, stdin will be read from /dev/null. If 0 is specified,
405 then there is no limit in the number of jobs that run in parallel.
406 --label=label
409 Add an image label (e.g. label=value) to the image metadata. Can be
410 used multiple times.
411 Users can set a special LABEL io.containers.capabilities=CAP1,CAP2,CAP3
414 in a Containerfile that specified the list of Linux capabilities re‐
415 quired for the container to run properly. This label specified in a
416 container image tells Podman to run the container with just these capa‐
417 bilities. Podman launches the container with just the specified capa‐
418 bilities, as long as this list of capabilities is a subset of the de‐
419 fault list.
420 If the specified capabilities are not in the default set, Podman will
423 print an error message and will run the container with the default ca‐
424 pabilities.
425 --layers
428 Cache intermediate images during the build process (Default is true).
429 Note: You can also override the default value of layers by setting the
432 BUILDAH_LAYERS environment variable. export BUILDAH_LAYERS=true
433 --logfile=filename
436 Log output which would be sent to standard output and standard error to
437 the specified file instead of to standard output and standard error.
438 --manifest manifest
441 Name of the manifest list to which the image will be added. Creates the
442 manifest list if it does not exist. This option is useful for building
443 multi architecture images.
444 --memory, -m=LIMIT
447 Memory limit (format: <number>[<unit>], where unit = b (bytes), k
448 (kilobytes), m (megabytes), or g (gigabytes))
449 Allows you to constrain the memory available to a container. If the
452 host supports swap memory, then the -m memory setting can be larger
453 than physical RAM. If a limit of 0 is specified (not using -m), the
454 container's memory is not limited. The actual limit may be rounded up
455 to a multiple of the operating system's page size (the value would be
456 very large, that's millions of trillions).
457 --memory-swap=LIMIT
460 A limit value equal to memory plus swap. Must be used with the -m
461 (--memory) flag. The swap LIMIT should always be larger than -m (--mem‐
462 ory) value. By default, the swap LIMIT will be set to double the value
463 of --memory.
464 The format of LIMIT is <number>[<unit>]. Unit can be b (bytes), k
467 (kilobytes), m (megabytes), or g (gigabytes). If you don't specify a
468 unit, b is used. Set LIMIT to -1 to enable unlimited swap.
469 --network=mode, --net
472 Sets the configuration for network namespaces when handling RUN in‐
473 structions.
474 Valid mode values are:
477 • none: no networking.
480 • host: use the Podman host network stack. Note: the host mode
482 gives the container full access to local system services such
483 as D-bus and is therefore considered insecure.
484 • ns:path: path to a network namespace to join.
486 • private: create a new namespace for the container (default).
488 --no-cache
492 Do not use existing cached images for the container build. Build from
493 the start with a new set of cached layers.
494 --os=string
497 Set the OS to the provided value instead of the current operating sys‐
498 tem of the host.
499 --pid=pid
502 Sets the configuration for PID namespaces when handling RUN instruc‐
503 tions. The configured value can be "" (the empty string) or "con‐
504 tainer" to indicate that a new PID namespace should be created, or it
505 can be "host" to indicate that the PID namespace in which podman itself
506 is being run should be reused, or it can be the path to a PID namespace
507 which is already in use by another process.
508 --platform="Linux"
511 This option has no effect on the build. Other container engines use
512 this option to control the execution platform for the build (e.g., Win‐
513 dows, Linux) which is not required for Buildah as it supports only
514 Linux.
515 --pull
518 When the option is specified or set to "true", pull the image. Raise
519 an error if the image could not be pulled, even if the image is present
520 locally.
521 If the option is disabled (with --pull=false) or not specified, pull
524 the image from the registry only if the image is not present locally.
525 Raise an error if the image is not found in the registries and is not
526 present locally.
527 --pull-always
530 Pull the image from the first registry it is found in as listed in reg‐
531 istries.conf. Raise an error if not found in the registries, even if
532 the image is present locally.
533 --pull-never
536 Do not pull the image from the registry, use only the local version.
537 Raise an error if the image is not present locally.
538 --quiet, -q
541 Suppress output messages which indicate which instruction is being pro‐
542 cessed, and of progress when pulling images from a registry, and when
543 writing the output image.
544 --rm=true|false
547 Remove intermediate containers after a successful build (default true).
548 --runtime=path
551 The path to an alternate OCI-compatible runtime, which will be used to
552 run commands specified by the RUN instruction.
553 Note: You can also override the default runtime by setting the BUIL‐
556 DAH_RUNTIME environment variable. export BUILDAH_RUNTIME=/usr/lo‐
557 cal/bin/runc
558 --secret=id=id,src=path
561 Pass secret information to be used in the Containerfile for building
562 images in a safe way that will not end up stored in the final image, or
563 be seen in other stages. The secret will be mounted in the container
564 at the default location of /run/secrets/id.
565 To later use the secret, use the --mount flag in a RUN instruction
568 within a Containerfile:
569 RUN --mount=type=secret,id=mysecret cat /run/secrets/mysecret
572 --security-opt=option
575 Security Options
576 • apparmor=unconfined : Turn off apparmor confinement for the
579 container
580 • apparmor=your-profile : Set the apparmor confinement profile
582 for the container
583 • label=user:USER : Set the label user for the container
585 processes
586 • label=role:ROLE : Set the label role for the container
588 processes
589 • label=type:TYPE : Set the label process type for the con‐
591 tainer processes
592 • label=level:LEVEL : Set the label level for the container
594 processes
595 • label=filetype:TYPE : Set the label file type for the con‐
597 tainer files
598 • label=disable : Turn off label separation for the con‐
600 tainer
601 • no-new-privileges : Not supported
603 • seccomp=unconfined : Turn off seccomp confinement for the con‐
605 tainer
606 • seccomp=profile.json : White listed syscalls seccomp Json
608 file to be used as a seccomp filter
609 --shm-size=size
613 Size of /dev/shm. The format is <number><unit>. number must be greater
614 than 0. Unit is optional and can be b (bytes), k (kilobytes),
615 m(megabytes), or g (gigabytes). If you omit the unit, the system uses
616 bytes. If you omit the size entirely, the system uses 64m.
617 --sign-by=fingerprint
620 Sign the image using a GPG key with the specified FINGERPRINT. (This
621 option is not available with the remote Podman client)
622 --squash
625 Squash all of the image's new layers into a single new layer; any pre‐
626 existing layers are not squashed.
627 --squash-all
630 Squash all of the new image's layers (including those inherited from a
631 base image) into a single new layer.
632 --stdin
635 Pass stdin into the RUN containers. Sometime commands being RUN within
636 a Containerfile want to request information from the user. For example
637 apt asking for a confirmation for install. Use --stdin to be able to
638 interact from the terminal during the build.
639 --tag, -t=imageName
642 Specifies the name which will be assigned to the resulting image if the
643 build process completes successfully. If imageName does not include a
644 registry name, the registry name localhost will be prepended to the im‐
645 age name.
646 --target=stageName
649 Set the target build stage to build. When building a Containerfile
650 with multiple build stages, --target can be used to specify an interme‐
651 diate build stage by name as the final stage for the resulting image.
652 Commands after the target stage will be skipped.
653 --timestamp seconds
656 Set the create timestamp to seconds since epoch to allow for determin‐
657 istic builds (defaults to current time). By default, the created time‐
658 stamp is changed and written into the image manifest with every commit,
659 causing the image's sha256 hash to be different even if the sources are
660 exactly the same otherwise. When --timestamp is set, the created time‐
661 stamp is always set to the time specified and therefore not changed,
662 allowing the image's sha256 hash to remain the same. All files commit‐
663 ted to the layers of the image will be created with the timestamp.
664 --tls-verify=true|false
667 Require HTTPS and verify certificates when talking to container reg‐
668 istries (defaults to true). (This option is not available with the re‐
669 mote Podman client)
670 --ulimit=type=soft-limit[:hard-limit]
673 Specifies resource limits to apply to processes launched when process‐
674 ing RUN instructions. This option can be specified multiple times.
675 Recognized resource types include:
676 "core": maximum core dump size (ulimit -c)
677 "cpu": maximum CPU time (ulimit -t)
678 "data": maximum size of a process's data segment (ulimit -d)
679 "fsize": maximum size of new files (ulimit -f)
680 "locks": maximum number of file locks (ulimit -x)
681 "memlock": maximum amount of locked memory (ulimit -l)
682 "msgqueue": maximum amount of data in message queues (ulimit -q)
683 "nice": niceness adjustment (nice -n, ulimit -e)
684 "nofile": maximum number of open files (ulimit -n)
685 "nproc": maximum number of processes (ulimit -u)
686 "rss": maximum size of a process's (ulimit -m)
687 "rtprio": maximum real-time scheduling priority (ulimit -r)
688 "rttime": maximum amount of real-time execution between blocking
689 syscalls
690 "sigpending": maximum number of pending signals (ulimit -i)
691 "stack": maximum stack size (ulimit -s)
692 --userns=how
695 Sets the configuration for user namespaces when handling RUN instruc‐
696 tions. The configured value can be "" (the empty string) or "con‐
697 tainer" to indicate that a new user namespace should be created, it can
698 be "host" to indicate that the user namespace in which podman itself is
699 being run should be reused, or it can be the path to an user namespace
700 which is already in use by another process.
701 --userns-uid-map=mapping
704 Directly specifies a UID mapping which should be used to set ownership,
705 at the filesystem level, on the working container's contents. Commands
706 run when handling RUN instructions will default to being run in their
707 own user namespaces, configured using the UID and GID maps.
708 Entries in this map take the form of one or more triples of a starting
711 in-container UID, a corresponding starting host-level UID, and the num‐
712 ber of consecutive IDs which the map entry represents.
713 This option overrides the remap-uids setting in the options section of
716 /etc/containers/storage.conf.
717 If this option is not specified, but a global --userns-uid-map setting
720 is supplied, settings from the global option will be used.
721 If none of --userns-uid-map-user, --userns-gid-map-group, or
724 --userns-uid-map are specified, but --userns-gid-map is specified, the
725 UID map will be set to use the same numeric values as the GID map.
726 --userns-gid-map=mapping
729 Directly specifies a GID mapping which should be used to set ownership,
730 at the filesystem level, on the working container's contents. Commands
731 run when handling RUN instructions will default to being run in their
732 own user namespaces, configured using the UID and GID maps.
733 Entries in this map take the form of one or more triples of a starting
736 in-container GID, a corresponding starting host-level GID, and the num‐
737 ber of consecutive IDs which the map entry represents.
738 This option overrides the remap-gids setting in the options section of
741 /etc/containers/storage.conf.
742 If this option is not specified, but a global --userns-gid-map setting
745 is supplied, settings from the global option will be used.
746 If none of --userns-uid-map-user, --userns-gid-map-group, or
749 --userns-gid-map are specified, but --userns-uid-map is specified, the
750 GID map will be set to use the same numeric values as the UID map.
751 --userns-uid-map-user=user
754 Specifies that a UID mapping which should be used to set ownership, at
755 the filesystem level, on the working container's contents, can be found
756 in entries in the /etc/subuid file which correspond to the specified
757 user. Commands run when handling RUN instructions will default to be‐
758 ing run in their own user namespaces, configured using the UID and GID
759 maps. If --userns-gid-map-group is specified, but
760 --userns-uid-map-user is not specified, podman will assume that the
761 specified group name is also a suitable user name to use as the default
762 setting for this option.
763 NOTE: When this option is specified by a rootless user, the specified
766 mappings are relative to the rootless user namespace in the container,
767 rather than being relative to the host as it would be when run root‐
768 full.
769 --userns-gid-map-group=group
772 Specifies that a GID mapping which should be used to set ownership, at
773 the filesystem level, on the working container's contents, can be found
774 in entries in the /etc/subgid file which correspond to the specified
775 group. Commands run when handling RUN instructions will default to be‐
776 ing run in their own user namespaces, configured using the UID and GID
777 maps. If --userns-uid-map-user is specified, but
778 --userns-gid-map-group is not specified, podman will assume that the
779 specified user name is also a suitable group name to use as the default
780 setting for this option.
781 NOTE: When this option is specified by a rootless user, the specified
784 mappings are relative to the rootless user namespace in the container,
785 rather than being relative to the host as it would be when run root‐
786 full.
787 --uts=how
790 Sets the configuration for UTS namespaces when the handling RUN in‐
791 structions. The configured value can be "" (the empty string) or "con‐
792 tainer" to indicate that a new UTS namespace should be created, or it
793 can be "host" to indicate that the UTS namespace in which podman itself
794 is being run should be reused, or it can be the path to a UTS namespace
795 which is already in use by another process.
796 --variant=""
799 Set the architecture variant of the image to be pulled.
800 --volume, -v[=[HOST-DIR:CONTAINER-DIR[:OPTIONS]]]
803 Create a bind mount. If you specify, -v /HOST-DIR:/CONTAINER-DIR, Pod‐
804 man
805 bind mounts /HOST-DIR in the host to /CONTAINER-DIR in the Podman
806 container. (This option is not available with the remote Podman
807 client)
808 The OPTIONS are a comma-separated list and can be: [1] ⟨#Footnote1⟩
811 • [rw|ro]
814 • [z|Z|O]
816 • [U]
818 • [[r]shared|[r]slave|[r]private]
820 The CONTAINER-DIR must be an absolute path such as /src/docs. The
824 HOST-DIR must be an absolute path as well. Podman bind-mounts the
825 HOST-DIR to the path you specify. For example, if you supply /foo as
826 the host path, Podman copies the contents of /foo to the container
827 filesystem on the host and bind mounts that into the container.
828 You can specify multiple -v options to mount one or more mounts to a
831 container.
832 You can add the :ro or :rw suffix to a volume to mount it read-only or
835 read-write mode, respectively. By default, the volumes are mounted
836 read-write. See examples.
837 Chowning Volume Mounts
840 By default, Podman does not change the owner and group of source volume
843 directories mounted. When running using user namespaces, the UID and
844 GID inside the namespace may correspond to another UID and GID on the
845 host.
846 The :U suffix tells Podman to use the correct host UID and GID based on
849 the UID and GID within the namespace, to change recursively the owner
850 and group of the source volume.
851 Warning use with caution since this will modify the host filesystem.
854 Labeling Volume Mounts
857 Labeling systems like SELinux require that proper labels are placed on
860 volume content mounted into a container. Without a label, the security
861 system might prevent the processes running inside the container from
862 using the content. By default, Podman does not change the labels set by
863 the OS.
864 To change a label in the container context, you can add either of two
867 suffixes :z or :Z to the volume mount. These suffixes tell Podman to
868 relabel file objects on the shared volumes. The z option tells Podman
869 that two containers share the volume content. As a result, Podman la‐
870 bels the content with a shared content label. Shared volume labels al‐
871 low all containers to read/write content. The Z option tells Podman to
872 label the content with a private unshared label. Only the current con‐
873 tainer can use a private volume.
874 Overlay Volume Mounts
877 The :O flag tells Podman to mount the directory from the host as a tem‐
880 porary storage using the Overlay file system. The RUN command contain‐
881 ers are allowed to modify contents within the mountpoint and are stored
882 in the container storage in a separate directory. In Overlay FS terms
883 the source directory will be the lower, and the container storage di‐
884 rectory will be the upper. Modifications to the mount point are de‐
885 stroyed when the RUN command finishes executing, similar to a tmpfs
886 mount point.
887 Any subsequent execution of RUN commands sees the original source di‐
890 rectory content, any changes from previous RUN commands no longer ex‐
891 ists.
892 One use case of the overlay mount is sharing the package cache from the
895 host into the container to allow speeding up builds.
896 Note:
899 - Overlay mounts are not currently supported in rootless mode.
902 - The `O` flag is not allowed to be specified with the `Z` or `z` flags.
903 Content mounted into the container is labeled with the private label.
907 On SELinux systems, labels in the source directory needs to be
908 readable by the container label. If not, SELinux container separation
909 must be disabled for the container to work.
910 - Modification of the directory volume mounted into the container
911 with an overlay mount can cause unexpected failures. It is recommended
912 that you do not modify the directory until the container finishes run‐
913 ning.
914 By default bind mounted volumes are private. That means any mounts done
917 inside containers will not be visible on the host and vice versa. This
918 behavior can be changed by specifying a volume mount propagation prop‐
919 erty.
920 When the mount propagation policy is set to shared, any mounts com‐
923 pleted inside the container on that volume will be visible to both the
924 host and container. When the mount propagation policy is set to slave,
925 one way mount propagation is enabled and any mounts completed on the
926 host for that volume will be visible only inside of the container. To
927 control the mount propagation property of volume use the :[r]shared,
928 :[r]slave or :[r]private propagation flag. The propagation property can
929 be specified only for bind mounted volumes and not for internal volumes
930 or named volumes. For mount propagation to work on the source mount
931 point (mount point where source dir is mounted on) has to have the
932 right propagation properties. For shared volumes, the source mount
933 point has to be shared. And for slave volumes, the source mount has to
934 be either shared or slave. [1] ⟨#Footnote1⟩
935 Use df <source-dir> to determine the source mount and then use findmnt
938 -o TARGET,PROPAGATION <source-mount-dir> to determine propagation prop‐
939 erties of source mount, if findmnt utility is not available, the source
940 mount point can be determined by looking at the mount entry in
941 /proc/self/mountinfo. Look at optional fields and see if any propaga‐
942 tion properties are specified. shared:X means the mount is shared,
943 master:X means the mount is slave and if nothing is there that means
944 the mount is private. [1] ⟨#Footnote1⟩
945 To change propagation properties of a mount point use the mount com‐
948 mand. For example, to bind mount the source directory /foo do mount
949 --bind /foo /foo and mount --make-private --make-shared /foo. This will
950 convert /foo into a shared mount point. The propagation properties of
951 the source mount can be changed directly. For instance if / is the
952 source mount for /foo, then use mount --make-shared / to convert / into
953 a shared mount.
954
957 Build an image using local Containerfiles
958 $ podman build .
959 $ podman build -f Containerfile.simple .
961 $ cat $HOME/Dockerfile | podman build -f - .
963 $ podman build -f Dockerfile.simple -f Containerfile.notsosimple .
965 $ podman build -f Dockerfile.in $HOME
967 $ podman build -t imageName .
969 $ podman build --tls-verify=true -t imageName -f Dockerfile.simple .
971 $ podman build --tls-verify=false -t imageName .
973 $ podman build --runtime-flag log-format=json .
975 $ podman build --runtime-flag debug .
977 $ podman build --authfile /tmp/auths/myauths.json --cert-dir $HOME/auth --tls-verify=true --creds=username:password -t imageName -f Dockerfile.simple .
979 $ podman build --memory 40m --cpu-period 10000 --cpu-quota 50000 --ulimit nofile=1024:1028 -t imageName .
981 $ podman build --security-opt label=level:s0:c100,c200 --cgroup-parent /path/to/cgroup/parent -t imageName .
983 $ podman build --volume /home/test:/myvol:ro,Z -t imageName .
985 $ podman build -v /var/lib/yum:/var/lib/yum:O -t imageName .
987 $ podman build --layers -t imageName .
989 $ podman build --no-cache -t imageName .
991 $ podman build --layers --force-rm -t imageName .
993 $ podman build --no-cache --rm=false -t imageName .
995 Building an multi-architecture image using a --manifest option (Requires
999 emulation software)
1000 $ podman build --arch arm --manifest myimage /tmp/mysrc
1001 $ podman build --arch amd64 --manifest myimage /tmp/mysrc
1003 $ podman build --arch s390x --manifest myimage /tmp/mysrc
1005 Building an image using a URL, Git repo, or archive
1009 The build context directory can be specified as a URL to a Container‐
1010 file, a Git repository, or URL to an archive. If the URL is a Contain‐
1011 erfile, it is downloaded to a temporary location and used as the con‐
1012 text. When a Git repository is set as the URL, the repository is cloned
1013 locally to a temporary location and then used as the context. Lastly,
1014 if the URL is an archive, it is downloaded to a temporary location and
1015 extracted before being used as the context.
1016 Building an image using a URL to a Containerfile
1019 Podman will download the Containerfile to a temporary location and then
1020 use it as the build context.
1021 $ podman build https://10.10.10.1/podman/Containerfile
1024 Building an image using a Git repository
1028 Podman will clone the specified GitHub repository to a temporary loca‐
1029 tion and use it as the context. The Containerfile at the root of the
1030 repository will be used and it only works if the GitHub repository is a
1031 dedicated repository.
1032 $ podman build git://github.com/scollier/purpletest
1035 Building an image using a URL to an archive
1039 Podman will fetch the archive file, decompress it, and use its contents
1040 as the build context. The Containerfile at the root of the archive and
1041 the rest of the archive will get used as the context of the build. If
1042 you pass -f PATH/Containerfile option as well, the system will look for
1043 that file inside the contents of the archive.
1044 $ podman build -f dev/Containerfile https://10.10.10.1/podman/context.tar.gz
1047 Note: supported compression formats are 'xz', 'bzip2', 'gzip' and
1051 'identity' (no compression).
1052
1055 .dockerignore
1056 If the file .dockerignore exists in the context directory, buildah copy
1057 reads its contents. Use the --ignorefile flag to override .dockerignore
1058 path location. Podman uses the content to exclude files and directo‐
1059 ries from the context directory, when executing COPY and ADD directives
1060 in the Containerfile/Dockerfile
1061 Users can specify a series of Unix shell globals in a .dockerignore
1064 file to identify files/directories to exclude.
1065 Podman supports a special wildcard string ** which matches any number
1068 of directories (including zero). For example, */.go will exclude all
1069 files that end with .go that are found in all directories.
1070 Example .dockerignore file:
1073 # exclude this content for image
1076 */*.c
1077 **/output*
1078 src
1079 */*.c Excludes files and directories whose names ends with .c in any
1083 top level subdirectory. For example, the source file include/root‐
1084 less.c.
1085 **/output* Excludes files and directories starting with output from any
1088 directory.
1089 src Excludes files named src and the directory src as well as any con‐
1092 tent in it.
1093 Lines starting with ! (exclamation mark) can be used to make exceptions
1096 to exclusions. The following is an example .dockerignore file that uses
1097 this mechanism:
1098 *.doc
1101 !Help.doc
1102 Exclude all doc files except Help.doc from the image.
1106 This functionality is compatible with the handling of .dockerignore
1109 files described here:
1110 https://docs.docker.com/engine/reference/builder/#dockerignore-file
1113 registries.conf (/etc/containers/registries.conf)
1116 registries.conf is the configuration file which specifies which con‐
1119 tainer registries should be consulted when completing image names which
1120 do not include a registry or domain portion.
1121
1124 lastlog sparse file
1125 If you are using a useradd command within a Containerfile with a large
1126 UID/GID, it will create a large sparse file /var/log/lastlog. This can
1127 cause the build to hang forever. Go language does not support sparse
1128 files correctly, which can lead to some huge files being created in
1129 your container image.
1130 If you are using useradd within your build script, you should pass the
1133 --no-log-init or -l option to the useradd command. This option tells
1134 useradd to stop creating the lastlog file.
1135
1138 podman(1), buildah(1), containers-certs.d(5), containers-reg‐
1139 istries.conf(5), crun(8), runc(8), useradd(8), podman-ps(1), pod‐
1140 man-rm(1)
1141
1144 Aug 2020, Additional options and .dockerignore added by Dan Walsh
1145 <dwalsh@redhat.com>
1146 May 2018, Minor revisions added by Joe Doss <joe@solidadmin.com>
1149 December 2017, Originally compiled by Tom Sweeney <tsweeney@redhat.com>
1152
1155 1: The Podman project is committed to inclusivity, a core value of open
1156 source. The master and slave mount propagation terminology used here is
1157 problematic and divisive, and should be changed. However, these terms
1158 are currently used within the Linux kernel and must be used as-is at
1159 this time. When the kernel maintainers rectify this usage, Podman will
1160 follow suit immediately.
1161 podman-build(1)()