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buildah-from(1) 	     General Commands Manual		 buildah-from(1)

NAME
     buildah-from  - Creates a new working container, either from scratch or us-
     ing a specified image as a starting point.

SYNOPSIS
     buildah from [options] image

DESCRIPTION
     Creates a working container based upon the specified image  name.	 If  the
     supplied  image  name is "scratch" a new empty container is created.  Image
     names use a "transport":"details" format.

     Multiple transports are supported:

     dir:path
       An existing local directory path containing the manifest, layer tarballs,
     and signatures in individual files. This is a non-standardized format, pri-
     marily useful for debugging or noninvasive image inspection.

     docker://docker-reference (Default)
       An image in a registry implementing the "Docker Registry HTTP API V2". By
     default,  uses  the  authorization   state   in   $XDG_RUNTIME_DIR/contain-
     ers/auth.json,  which  is	set  using  (buildah  login).	See  containers-
     auth.json(5) for more information. If the authorization state is not  found
     there, $HOME/.docker/config.json is checked, which is set using (docker lo-
     gin).
       If  docker-reference  does not include a registry name, localhost will be
     consulted first, followed by any registries named in the registries config-
     uration.

     docker-archive:path
       An image is retrieved as a podman load formatted file.

     docker-daemon:docker-reference
       An image docker-reference stored in the docker daemon's internal storage.
     docker-reference must include either a tag  or  a	digest.   Alternatively,
     when  reading  images, the format can also be docker-daemon:algo:digest (an
     image ID).

     oci:path:tag**
       An image tag in a directory compliant with "Open Container  Image  Layout
     Specification" at path.

     oci-archive:path:tag
       An  image  tag in a directory compliant with "Open Container Image Layout
     Specification" at path.

   DEPENDENCIES
     Buildah resolves the path to  the	registry  to  pull  from  by  using  the
     /etc/containers/registries.conf  file,  containers-registries.conf(5).   If
     the buildah from command fails with an "image not known" error, first  ver-
     ify  that	the  registries.conf  file is installed and configured appropri-
     ately.

RETURN VALUE
     The container ID of the container that was created.   On  error  1  is  re-
     turned.

OPTIONS
     --add-host=[]

     Add a custom host-to-IP mapping (host:ip)

     Add  a line to /etc/hosts. The format is hostname:ip. The --add-host option
     can be set multiple times.

     --arch="ARCH"

     Set the ARCH of the image to be pulled to the provided value instead of us-
     ing the architecture of  the  host.  (Examples:  arm,  arm64,  386,  amd64,
     ppc64le, s390x)

     --authfile path

     Path  of  the  authentication  file. Default is ${XDG_RUNTIME_DIR}/contain-
     ers/auth.json. See containers-auth.json(5) for more information. This  file
     is created using buildah login.

     If the authorization state is not found there, $HOME/.docker/config.json is
     checked, which is set using docker login.

     Note:  You can also override the default path of the authentication file by
     setting  the   REGISTRY_AUTH_FILE	 environment   variable.   export   REG-
     ISTRY_AUTH_FILE=path

     --cap-add=CAP_xxx

     Add  the specified capability to the default set of capabilities which will
     be supplied for subsequent buildah run  invocations  which  use  this  con-
     tainer.   Certain	capabilities  are granted by default; this option can be
     used to add more.

     --cap-drop=CAP_xxx

     Remove the specified capability from the default set of capabilities  which
     will be supplied for subsequent buildah run invocations which use this con-
     tainer.  The CAP_CHOWN, CAP_DAC_OVERRIDE, CAP_FOWNER, CAP_FSETID, CAP_KILL,
     CAP_NET_BIND_SERVICE,  CAP_SETFCAP, CAP_SETGID, CAP_SETPCAP, and CAP_SETUID
     capabilities are granted by default; this option  can  be	used  to  remove
     them. The list of default capabilities is managed in containers.conf(5).

     If  a capability is specified to both the --cap-add and --cap-drop options,
     it will be dropped, regardless of the  order  in  which  the  options  were
     given.

     --cert-dir path

     Use certificates at path (*.crt, *.cert, *.key) to connect to the registry.
     The default certificates directory is /etc/containers/certs.d.

     --cgroup-parent=""

     Path  to  cgroups under which the cgroup for the container will be created.
     If the path is not absolute, the path is considered to be relative  to  the
     cgroups  path  of	the init process. Cgroups will be created if they do not
     already exist.

     --cgroupns how

     Sets the configuration for IPC namespaces	when  the  container  is  subse-
     quently  used  for  buildah run.  The configured value can be "" (the empty
     string) or "private" to indicate that a new cgroup namespace should be cre-
     ated, or it can be "host" to indicate that the cgroup  namespace  in  which
     buildah itself is being run should be reused.

     --cidfile ContainerIDFile

     Write the container ID to the file.

     --cpu-period=0

     Limit the CPU CFS (Completely Fair Scheduler) period

     Limit the container's CPU usage. This flag tells the kernel to restrict the
     container's CPU usage to the period you specify.

     --cpu-quota=0

     Limit the CPU CFS (Completely Fair Scheduler) quota

     Limit  the  container's CPU usage. By default, containers run with the full
     CPU resource. This flag tells the kernel to restrict  the	container's  CPU
     usage to the quota you specify.

     --cpu-shares, -c=0

     CPU shares (relative weight)

     By default, all containers get the same proportion of CPU cycles. This pro-
     portion  can  be  modified  by changing the container's CPU share weighting
     relative to the weighting of all other running containers.

     To modify the proportion from the default of  1024,  use  the  --cpu-shares
     flag to set the weighting to 2 or higher.

     The  proportion  will  only apply when CPU-intensive processes are running.
     When tasks in one container are idle, other containers can  use  the  left-
     over  CPU	time.  The  actual amount of CPU time will vary depending on the
     number of containers running on the system.

     For example, consider three containers, one has a cpu-share of 1024 and two
     others have a cpu-share setting of 512. When processes in	all  three  con-
     tainers  attempt  to use 100% of CPU, the first container would receive 50%
     of the total CPU time. If you add a fourth container with	a  cpu-share  of
     1024,  the first container only gets 33% of the CPU. The remaining contain-
     ers receive 16.5%, 16.5% and 33% of the CPU.

     On a multi-core system, the shares of CPU time are distributed over all CPU
     cores. Even if a container is limited to less than 100% of CPU time, it can
     use 100% of each individual CPU core.

     For example, consider a system with more than three cores. If you start one
     container {C0} with -c=512 running one process, and another container  {C1}
     with  -c=1024 running two processes, this can result in the following divi-
     sion of CPU shares:

     PID    container	 CPU  CPU share
     100    {C0}	 0    100% of CPU0
     101    {C1}	 1    100% of CPU1
     102    {C1}	 2    100% of CPU2

     --cpuset-cpus=""

     CPUs in which to allow execution (0-3, 0,1)

     --cpuset-mems=""

     Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only  effective
     on NUMA systems.

     If  you  have four memory nodes on your system (0-3), use --cpuset-mems=0,1
     then processes in your container will only use memory from  the  first  two
     memory nodes.

     --creds creds

     The  [username[:password]]  to use to authenticate with the registry if re-
     quired.  If one or both values are not supplied, a command line prompt will
     appear and the value can be entered.  The password is entered without echo.

     --decryption-key key[:passphrase]

     The [key[:passphrase]] to be used for decryption of images. Key  can  point
     to keys and/or certificates. Decryption will be tried with all keys. If the
     key  is protected by a passphrase, it is required to be passed in the argu-
     ment and omitted otherwise.

     --device=device

     Add a host device, or devices under a directory, to the environment of sub-
     sequent buildah run invocations for the new  working  container.	The  op-
     tional permissions parameter can be used to specify device permissions, us-
     ing any one or more of r for read, w for write, and m for mknod(2).

     Example: --device=/dev/sdc:/dev/xvdc:rwm.

     Note:  if	host-device  is  a symbolic link then it will be resolved first.
     The container will only store the major and minor numbers of the  host  de-
     vice.

     The  device  to share can also be specified using a Container Device Inter-
     face (CDI) specification (https://github.com/cncf-tags/container-device-in-
     terface).

     Note: if the user only has access rights via a group, accessing the  device
     from  inside  a  rootless container will fail. The crun(1) runtime offers a
     workaround for this by adding the option  --annotation  run.oci.keep_origi-
     nal_groups=1.

     --dns=[]

     Set custom DNS servers

     This  option  can	be  used to override the DNS configuration passed to the
     container. Typically this is necessary when the host DNS  configuration  is
     invalid  for  the	container  (e.g.,  127.0.0.1). When this is the case the
     --dns flag is necessary for every run.

     The special value none can be specified to  disable  creation  of	/etc/re-
     solv.conf in the container by Buildah. The /etc/resolv.conf file in the im-
     age will be used without changes.

     --dns-option=[]

     Set custom DNS options

     --dns-search=[]

     Set custom DNS search domains

     --format, -f oci | docker

     Control  the  format for the built image's manifest and configuration data.
     Recognized formats include oci  (OCI  image-spec  v1.0,  the  default)  and
     docker (version 2, using schema format 2 for the manifest).

     Note:  You can also override the default format by setting the BUILDAH_FOR-
     MAT environment variable.	export BUILDAH_FORMAT=docker

     --group-add=group | keep-groups

     Assign additional groups to the primary user running within  the  container
     process.

	    * keep-groups  is a special flag that tells Buildah to keep the sup-
	      plementary group access.

     Allows container to use the user's supplementary group access. If file sys-
     tems or devices are only accessible by the rootless user's group, this flag
     tells the OCI runtime to pass the group access  into  the	container.  Cur-
     rently  only  available with the crun OCI runtime. Note: keep-groups is ex-
     clusive, other groups cannot be specified with this flag.

     --http-proxy

     By default proxy environment variables are passed into the container if set
     for the Buildah process.  This can be disabled by setting the  --http-proxy
     option  to  false.  The environment variables passed in include http_proxy,
     https_proxy, ftp_proxy, no_proxy, and  also  the  upper  case  versions  of
     those.

     Defaults to true

     --ipc how

     Sets  the	configuration  for  IPC  namespaces when the container is subse-
     quently used for buildah run.  The configured value can be  ""  (the  empty
     string)  or "container" to indicate that a new IPC namespace should be cre-
     ated, or it can be "host" to indicate that the IPC namespace in which Buil-
     dah itself is being run should be reused, or it can be the path to  an  IPC
     namespace which is already in use by another process.

     --isolation type

     Controls what type of isolation is used for running processes under buildah
     run.   Recognized	types include oci (OCI-compatible runtime, the default),
     rootless (OCI-compatible runtime invoked using  a	modified  configuration,
     with  --no-new-keyring  added  to its create invocation, reusing the host's
     network and UTS namespaces, and creating private IPC, PID, mount, and  user
     namespaces;  the  default	for unprivileged users), and chroot (an internal
     wrapper that leans more toward chroot(1) than container technology, reusing
     the host's control group, network, IPC, and PID  namespaces,  and	creating
     private  mount  and  UTS namespaces, and creating user namespaces only when
     they're required for ID mapping).

     Note: You can also override the default isolation type by setting the BUIL-
     DAH_ISOLATION environment variable.  export BUILDAH_ISOLATION=oci

     --memory, -m=""

     Memory limit (format: [], where unit = b, k, m or g)

     Allows you to constrain the memory available to a container.  If  the  host
     supports  swap memory, then the -m memory setting can be larger than physi-
     cal RAM. If a limit of 0 is specified (not using -m), the container's  mem-
     ory is not limited. The actual limit may be rounded up to a multiple of the
     operating	system's  page	size (the value would be very large, that's mil-
     lions of trillions).

     --memory-swap="LIMIT"

     A limit value equal to memory plus swap. Must be used with the  -m  (--mem-
     ory) flag. The swap LIMIT should always be larger than -m (--memory) value.
     By default, the swap LIMIT will be set to double the value of --memory.

     The  format  of  LIMIT is <number>[<unit>]. Unit can be b (bytes), k (kilo-
     bytes), m (megabytes), or g (gigabytes). If you don't specify a unit, b  is
     used. Set LIMIT to -1 to enable unlimited swap.

     --name name

     A name for the working container

     --network=mode, --net=mode

     Sets  the configuration for network namespaces when the container is subse-
     quently used for buildah run.

     Valid mode values are:

	    * none: no networking. Invalid if using --dns, --dns-opt, or  --dns-
	      search;

	    * host:  use  the  host network stack. Note: the host mode gives the
	      container full access to local system services such as  D-bus  and
	      is therefore considered insecure;

	    * ns:path: path to a network namespace to join;

	    * private: create a new namespace for the container (default)

	    * <network	name|ID>:  Join  the  network with the given name or ID,
	      e.g. use --network mynet to join the network with the name  mynet.
	      Only supported for rootful users.

	    * slirp4netns[:OPTIONS,...]:  use  slirp4netns(1)  to  create a user
	      network stack. This is the default for rootless containers. It  is
	      possible to specify these additional options, they can also be set
	      with network_cmd_options in containers.conf:

	      * allow_host_loopback=true|false:  Allow	slirp4netns to reach the
		host loopback IP (default is 10.0.2.2  or  the	second	IP  from
		slirp4netns  cidr  subnet  when changed, see the cidr option be-
		low). The default is false.

	      * mtu=MTU: Specify the MTU to use for this  network.  (Default  is
		65520).

	      * cidr=CIDR: Specify ip range to use for this network. (Default is
		10.0.2.0/24).

	      * enable_ipv6=true|false:  Enable IPv6. Default is true. (Required
		for outbound_addr6).

	      * outbound_addr=INTERFACE: Specify the  outbound	interface  slirp
		binds to (ipv4 traffic only).

	      * outbound_addr=IPv4:  Specify  the  outbound  ipv4  address slirp
		binds to.

	      * outbound_addr6=INTERFACE: Specify the outbound	interface  slirp
		binds to (ipv6 traffic only).

	      * outbound_addr6=IPv6:  Specify  the  outbound  ipv6 address slirp
		binds to.

	    * pasta[:OPTIONS,...]: use pasta(1) to create a user-mode networking
	      stack.
	      This is only supported in rootless mode.
	      By default, IPv4 and IPv6 addresses and routes, as well as the pod
	      interface name, are copied from the host. If port forwarding isn't
	      configured, ports are forwarded dynamically as services are  bound
	      on  either side (init namespace or container namespace). Port for-
	      warding preserves the original  source  IP  address.  Options  de-
	      scribed in pasta(1) can be specified as comma-separated arguments.
	      In terms of pasta(1) options, --config-net is given by default, in
	      order  to  configure networking when the container is started, and
	      --no-map-gw is also assumed by default,  to  avoid  direct  access
	      from  container  to host using the gateway address. The latter can
	      be overridden by passing --map-gw in  the  pasta-specific  options
	      (despite not being an actual pasta(1) option).
	      Also,  -t  none  and  -u none are passed to disable automatic port
	      forwarding based on bound ports. Similarly, -T none  and	-U  none
	      are  given  to  disable  the  same functionality from container to
	      host.
	      Some examples:

	      * pasta:--map-gw: Allow the container to directly reach  the  host
		using the gateway address.

	      * pasta:--mtu,1500: Specify a 1500 bytes MTU for the tap interface
		in the container.

	      * pasta:--ipv4-only,-a,10.0.2.0,-n,24,-g,10.0.2.2,--dns-for-
		ward,10.0.2.3,-m,1500,--no-ndp,--no-dhcpv6,--no-dhcp, equivalent
		to   default   slirp4netns(1)	options:  disable  IPv6,  assign
		10.0.2.0/24 to the tap0 interface in the container, with gateway
		10.0.2.3, enable DNS forwarder reachable at 10.0.2.3, set MTU to
		1500 bytes, disable NDP, DHCPv6 and DHCP support.

	      * pasta:-I,tap0,--ipv4-only,-a,10.0.2.0,-n,24,-g,10.0.2.2,--dns-
		forward,10.0.2.3,--no-ndp,--no-dhcpv6,--no-dhcp,  equivalent  to
		default  slirp4netns(1)  options  with Podman overrides: same as
		above, but leave the MTU to 65520 bytes

	      * pasta:-t,auto,-u,auto,-T,auto,-U,auto:	enable	automatic   port
		forwarding based on observed bound ports from both host and con-
		tainer sides

	      * pasta:-T,5201: enable forwarding of TCP port 5201 from container
		to  host, using the loopback interface instead of the tap inter-
		face for improved performance

     --os="OS"

     Set the OS of the image to be pulled to the provided value instead of using
     the current operating system of the host.

     --pid how

     Sets the configuration for PID namespaces	when  the  container  is  subse-
     quently  used  for  buildah run.  The configured value can be "" (the empty
     string) or "container" to indicate that a new PID namespace should be  cre-
     ated, or it can be "host" to indicate that the PID namespace in which Buil-
     dah  itself  is  being run should be reused, or it can be the path to a PID
     namespace which is already in use by another process.

     --platform="OS/ARCH[/VARIANT]"

     Set the OS/ARCH of the image to be pulled to the provided value instead  of
     using  the current operating system and architecture of the host (for exam-
     ple linux/arm).

     OS/ARCH pairs are those used by the Go Programming  Language.   In  several
     cases  the  ARCH  value  for  a platform differs from one produced by other
     tools such as the arch command.  Valid OS and  architecture  name	combina-
     tions    are    listed    as    values    for    $GOOS   and   $GOARCH   at
     https://golang.org/doc/install/source#environment, and can also be found by
     running go tool dist list.

     While buildah from is happy to pull an image for any platform that  exists,
     buildah run will not be able to run binaries provided by that image without
     the help of emulation provided by packages like qemu-user-static.

     NOTE: The --platform option may not be used in combination with the --arch,
     --os, or --variant options.

     --pull

     Pull image policy. If not specified, the default is missing. If an explicit
     --pull argument is provided without any value, use the always behavior.

	    * always:  Pull  base  and	SBOM  scanner images from the registries
	      listed in registries.conf.  Raise an error if a base or SBOM scan-
	      ner image is not found in the registries, even if  an  image  with
	      the same name is present locally.

	    * missing:	SBOM  scanner  images only if they could not be found in
	      the local containers storage.  Raise an error if no image could be
	      found and the pull fails.

	    * never: Do not pull base and SBOM scanner images  from  registries,
	      use  only  the local versions.  Raise an error if the image is not
	      present locally.

	    * newer: Pull base and  SBOM  scanner  images  from  the  registries
	      listed  in  registries.conf if newer.  Raise an error if a base or
	      SBOM scanner image is not found in the registries when image  with
	      the same name is not present locally.

     --quiet, -q

     If an image needs to be pulled from the registry, suppress progress output.

     --retry attempts

     Number  of times to retry in case of failure when performing pull of images
     from registry.

     Defaults to 3.

     --retry-delay duration

     Duration of delay between retry attempts in case of failure when performing
     pull of images from registry.

     Defaults to 2s.

     --security-opt=[]

     Security Options

     "label=user:USER"	 : Set the label user for the container
       "label=role:ROLE"   : Set the label role for the container
       "label=type:TYPE"   : Set the label type for the container
       "label=level:LEVEL" : Set the label level for the container
       "label=disable"	   : Turn off label confinement for the container
       "no-new-privileges" : Not supported

     "seccomp=unconfined" : Turn off seccomp confinement for the container
       "seccomp=profile.json :	White listed syscalls seccomp Json  file  to  be
     used as a seccomp filter

     "apparmor=unconfined" : Turn off apparmor confinement for the container
       "apparmor=your-profile"	:  Set	the apparmor confinement profile for the
     container

     --shm-size=""

     Size of /dev/shm. The format is <number><unit>. number must be greater than
     0.  Unit is optional and can be b (bytes), k (kilobytes), m(megabytes),  or
     g	(gigabytes).   If  you omit the unit, the system uses bytes. If you omit
     the size entirely, the system uses 64m.

     --tls-verify bool-value

     Require HTTPS and verification of certificates when  talking  to  container
     registries  (defaults to true).  TLS verification cannot be used when talk-
     ing to an insecure registry.

     --ulimit type=soft-limit[:hard-limit]

     Specifies resource limits to apply to  processes  launched  during  buildah
     run.   This  option  can  be specified multiple times.  Recognized resource
     types include:
       "core": maximum core dump size (ulimit -c)
       "cpu": maximum CPU time (ulimit -t)
       "data": maximum size of a process's data segment (ulimit -d)
       "fsize": maximum size of new files (ulimit -f)
       "locks": maximum number of file locks (ulimit -x)
       "memlock": maximum amount of locked memory (ulimit -l)
       "msgqueue": maximum amount of data in message queues (ulimit -q)
       "nice": niceness adjustment (nice -n, ulimit -e)
       "nofile": maximum number of open files (ulimit -n)
       "nofile": maximum number of open files (1048576); when run by root
       "nproc": maximum number of processes (ulimit -u)
       "nproc": maximum number of processes (1048576); when run by root
       "rss": maximum size of a process's (ulimit -m)
       "rtprio": maximum real-time scheduling priority (ulimit -r)
       "rttime": maximum amount of real-time execution between blocking syscalls
       "sigpending": maximum number of pending signals (ulimit -i)
       "stack": maximum stack size (ulimit -s)

     --userns how

     Sets the configuration for user namespaces when  the  container  is  subse-
     quently  used  for  buildah run.  The configured value can be "" (the empty
     string) or "container" to indicate that a new user namespace should be cre-
     ated, it can be "host" to indicate that the user namespace in which Buildah
     itself is being run should be reused, or it can be  the  path  to	an  user
     namespace which is already in use by another process.

     --userns-gid-map mapping

     Directly  specifies a GID mapping which should be used to set ownership, at
     the filesystem level, on the working container's  contents.   Commands  run
     when  handling RUN instructions will default to being run in their own user
     namespaces, configured using the UID and GID maps.

     Entries in this map take the form of one or more colon-separated triples of
     a starting in-container GID, a corresponding starting host-level  GID,  and
     the number of consecutive IDs which the map entry represents.

     This  option  overrides  the  remap-gids  setting in the options section of
     /etc/containers/storage.conf.

     If this option is not specified, but a global --userns-gid-map  setting  is
     supplied, settings from the global option will be used.

     --userns-gid-map-group mapping

     Directly  specifies a GID mapping which should be used to set ownership, at
     the filesystem level, on the  container's	contents.   Commands  run  using
     buildah run will default to being run in their own user namespaces, config-
     ured using the UID and GID maps.

     Entries  in this map take the form of one or more triples of a starting in-
     container GID, a corresponding starting host-level GID, and the  number  of
     consecutive IDs which the map entry represents.

     This  option  overrides  the  remap-gids  setting in the options section of
     /etc/containers/storage.conf.

     If this option is not specified, but a global --userns-gid-map  setting  is
     supplied, settings from the global option will be used.

     If  none of --userns-uid-map-user, --userns-gid-map-group, or --userns-gid-
     map are specified, but --userns-uid-map is specified, the GID map	will  be
     set to use the same numeric values as the UID map.

     NOTE:  When this option is specified by a rootless user, the specified map-
     pings are relative to the rootless usernamespace in the  container,  rather
     than being relative to the host as it would be when run rootful.

     --userns-gid-map-group group

     Specifies	that a GID mapping which should be used to set ownership, at the
     filesystem level, on the container's contents, can be found in  entries  in
     the /etc/subgid file which correspond to the specified group.  Commands run
     using  buildah  run will default to being run in their own user namespaces,
     configured using the UID and GID maps.  If --userns-uid-map-user is  speci-
     fied, but --userns-gid-map-group is not specified, Buildah will assume that
     the specified user name is also a suitable group name to use as the default
     setting for this option.

     --userns-uid-map mapping

     Directly  specifies a UID mapping which should be used to set ownership, at
     the filesystem level, on the working container's  contents.   Commands  run
     when  handling RUN instructions will default to being run in their own user
     namespaces, configured using the UID and GID maps.

     Entries in this map take the form of one or more colon-separated triples of
     a starting in-container UID, a corresponding starting host-level  UID,  and
     the number of consecutive IDs which the map entry represents.

     This  option  overrides  the  remap-uids  setting in the options section of
     /etc/containers/storage.conf.

     If this option is not specified, but a global --userns-uid-map  setting  is
     supplied, settings from the global option will be used.

     --userns-uid-map-user mapping

     Directly  specifies a UID mapping which should be used to set ownership, at
     the filesystem level, on the  container's	contents.   Commands  run  using
     buildah run will default to being run in their own user namespaces, config-
     ured using the UID and GID maps.

     Entries  in this map take the form of one or more triples of a starting in-
     container UID, a corresponding starting host-level UID, and the  number  of
     consecutive IDs which the map entry represents.

     This  option  overrides  the  remap-uids  setting in the options section of
     /etc/containers/storage.conf.

     If this option is not specified, but a global --userns-uid-map  setting  is
     supplied, settings from the global option will be used.

     If  none of --userns-uid-map-user, --userns-gid-map-group, or --userns-uid-
     map are specified, but --userns-gid-map is specified, the UID map	will  be
     set to use the same numeric values as the GID map.

     NOTE:  When this option is specified by a rootless user, the specified map-
     pings are relative to the rootless usernamespace in the  container,  rather
     than being relative to the host as it would be when run rootful.

     --userns-uid-map-user user

     Specifies	that a UID mapping which should be used to set ownership, at the
     filesystem level, on the container's contents, can be found in  entries  in
     the  /etc/subuid file which correspond to the specified user.  Commands run
     using buildah run will default to being run in their own  user  namespaces,
     configured using the UID and GID maps.  If --userns-gid-map-group is speci-
     fied,  but --userns-uid-map-user is not specified, Buildah will assume that
     the specified group name is also a suitable user name to use as the default
     setting for this option.

     --uts how

     Sets the configuration for UTS namespaces	when  the  container  is  subse-
     quently  used  for  buildah run.  The configured value can be "" (the empty
     string) or "container" to indicate that a new UTS namespace should be  cre-
     ated, or it can be "host" to indicate that the UTS namespace in which Buil-
     dah  itself  is  being run should be reused, or it can be the path to a UTS
     namespace which is already in use by another process.

     --variant=""

     Set the architecture variant of the image to be pulled.

     --volume, -v[=[HOST-DIR:CONTAINER-DIR[:OPTIONS]]]

     Create a bind mount. If you specify, -v /HOST-DIR:/CONTAINER-DIR, Buildah
	bind mounts /HOST-DIR in the host to /CONTAINER-DIR in the Buildah
	container. The OPTIONS are a comma delimited list and can be:

	    * [rw|ro]

	    * [U]

	    * [z|Z|O]

	    * [[r]shared|[r]slave|[r]private|[r]unbindable] [1] <#Footnote1>

     The CONTAINER-DIR must be an absolute path such as /src/docs. The	HOST-DIR
     must  be  an absolute path as well. Buildah bind-mounts the HOST-DIR to the
     path you specify. For example, if you supply /foo as the host path, Buildah
     copies the contents of /foo to the container filesystem  on  the  host  and
     bind mounts that into the container.

     You  can specify multiple	-v options to mount one or more mounts to a con-
     tainer.

     Write Protected Volume Mounts

     You can add the :ro or :rw suffix to a volume  to	mount  it  read-only  or
     read-write  mode,	respectively.  By default, the volumes are mounted read-
     write.  See examples.

     Chowning Volume Mounts

     By default, Buildah does not change the owner and group  of  source  volume
     directories  mounted  into  containers.  If a container is created in a new
     user namespace, the UID and GID in the container may correspond to  another
     UID and GID on the host.

     The  :U  suffix  tells Buildah to use the correct host UID and GID based on
     the UID and GID within the container, to change the owner and group of  the
     source volume.

     Labeling Volume Mounts

     Labeling systems like SELinux require that proper labels are placed on vol-
     ume  content mounted into a container. Without a label, the security system
     might prevent the processes running inside the  container	from  using  the
     content. By default, Buildah does not change the labels set by the OS.

     To  change a label in the container context, you can add either of two suf-
     fixes :z or :Z to the volume mount. These suffixes tell Buildah to  relabel
     file  objects  on	the  shared volumes. The z option tells Buildah that two
     containers share the volume content. As a result, Buildah labels  the  con-
     tent with a shared content label. Shared volume labels allow all containers
     to  read/write  content.	The  Z option tells Buildah to label the content
     with a private unshared label.  Only the current container can use  a  pri-
     vate volume.

     Overlay Volume Mounts

     The  :O flag tells Buildah to mount the directory from the host as a tempo-
     rary storage using the Overlay file system. The RUN command containers  are
     allowed to modify contents within the mountpoint and are stored in the con-
     tainer storage in a separate directory.  In Overlay FS terms the source di-
     rectory  will be the lower, and the container storage directory will be the
     upper. Modifications to the mount point are destroyed when the RUN  command
     finishes executing, similar to a tmpfs mount point.

     Any subsequent execution of RUN commands sees the original source directory
     content, any changes from previous RUN commands no longer exist.

     One  use  case  of  the overlay mount is sharing the package cache from the
     host into the container to allow speeding up builds.

     Note:

	    * The O flag is not allowed to be specified with the Z or  z  flags.
	      Content mounted into the container is labeled with the private la-
	      bel.
		 On  SELinux  systems, labels in the source directory need to be
	      readable by the container label. If not, SELinux container separa-
	      tion must be disabled for the container to work.

	    * Modification of the directory volume mounted  into  the  container
	      with an overlay mount can cause unexpected failures.  It is recom-
	      mended  that  you  do not modify the directory until the container
	      finishes running.

     By default bind mounted volumes are private. That means any mounts done in-
     side container will not be visible on the host and vice versa. This  behav-
     ior can be changed by specifying a volume mount propagation property.

     When  the	mount  propagation policy is set to shared, any mounts completed
     inside the container on that volume will be visible to both  the  host  and
     container. When the mount propagation policy is set to slave, one way mount
     propagation is enabled and any mounts completed on the host for that volume
     will  be visible only inside of the container.  To control the mount propa-
     gation property of the volume use the :[r]shared, :[r]slave, [r]private  or
     [r]unbindablepropagation  flag.  The  propagation property can be specified
     only for bind mounted volumes and not for internal volumes  or  named  vol-
     umes.  For  mount	propagation to work on the source mount point (the mount
     point where source dir is mounted on) it has to have the right  propagation
     properties.  For  shared  volumes, the source mount point has to be shared.
     And for slave volumes, the source mount has to be either shared  or  slave.
     [1] <#Footnote1>

     Use  df  <source-dir> to determine the source mount and then use findmnt -o
     TARGET,PROPAGATION <source-mount-dir> to determine  propagation  properties
     of  source  mount,  if  findmnt  utility is not available, the source mount
     point  can   be   determined   by	 looking   at	the   mount   entry   in
     /proc/self/mountinfo.  Look  at  optional fields and see if any propagation
     properties are specified.	shared:X means the  mount  is  shared,	master:X
     means  the  mount	is slave and if nothing is there that means the mount is
     private. [1] <#Footnote1>

     To change propagation properties of a mount point use  the  mount	command.
     For  example,  to bind mount the source directory /foo do mount --bind /foo
     /foo and mount --make-private --make-shared /foo. This  will  convert  /foo
     into  a shared mount point.  The propagation properties of the source mount
     can be changed directly. For instance if / is the source  mount  for  /foo,
     then use mount --make-shared / to convert / into a shared mount.

EXAMPLE
     buildah from --pull imagename

     buildah from --pull docker://myregistry.example.com/imagename

     buildah from docker-daemon:imagename:imagetag

     buildah from --name mycontainer docker-archive:filename

     buildah from oci-archive:filename

     buildah from --name mycontainer dir:directoryname

     buildah from --pull-always --name "mycontainer" myregistry.example.com/ima-
     gename

     buildah from --tls-verify=false myregistry/myrepository/imagename:imagetag

     buildah   from   --creds=myusername:mypassword   --cert-dir  ~/auth  myreg-
     istry/myrepository/imagename:imagetag

     buildah from --authfile=/tmp/auths/myauths.json myregistry/myrepository/im-
     agename:imagetag

     buildah from --memory 40m --cpu-shares 2 --cpuset-cpus  0,2  --security-opt
     label=level:s0:c100,c200 myregistry/myrepository/imagename:imagetag

     buildah from --ulimit nofile=1024:1028 --cgroup-parent /path/to/cgroup/par-
     ent myregistry/myrepository/imagename:imagetag

     buildah from --volume /home/test:/myvol:ro,Z myregistry/myrepository/image-
     name:imagetag

     buildah from -v /home/test:/myvol:z,U myregistry/myrepository/imagename:im-
     agetag

     buildah  from -v /var/lib/yum:/var/lib/yum:O myregistry/myrepository/image-
     name:imagetag

     buildah from --arch=arm --variant v7  myregistry/myrepository/imagename:im-
     agetag

ENVIRONMENT
     BUILD_REGISTRY_SOURCES

     BUILD_REGISTRY_SOURCES,  if set, is treated as a JSON object which contains
     lists of registry names  under  the  keys	insecureRegistries,  blockedReg-
     istries, and allowedRegistries.

     When  pulling an image from a registry, if the name of the registry matches
     any of the items in the blockedRegistries list, the image pull  attempt  is
     denied.   If  there  are  registries in the allowedRegistries list, and the
     registry's name is not in the list, the pull attempt is denied.

     TMPDIR The TMPDIR environment variable allows the	user  to  specify  where
     temporary	files  are stored while pulling and pushing images.  Defaults to
     '/var/tmp'.

FILES
     registries.conf (/etc/containers/registries.conf)

     registries.conf is the configuration file which specifies	which  container
     registries should be consulted when completing image names which do not in-
     clude a registry or domain portion.

     policy.json (/etc/containers/policy.json)

     Signature policy file.  This defines the trust policy for container images.
     Controls  which  container registries can be used for image, and whether or
     not the tool should trust the images.

SEE ALSO
     buildah(1),  buildah-pull(1),  buildah-login(1),	docker-login(1),   name-
     spaces(7),  pid_namespaces(7),  containers-policy.json(5),  containers-reg-
     istries.conf(5),	user_namespaces(7),   containers.conf(5),    containers-
     auth.json(5)

FOOTNOTES
     1:  The  Buildah  project is committed to inclusivity, a core value of open
     source. The master and slave mount propagation  terminology  used	here  is
     problematic  and  divisive, and should be changed. However, these terms are
     currently used within the Linux kernel and must be used as-is at this time.
     When the kernel maintainers rectify this usage, Buildah  will  follow  suit
     immediately.

buildah 			   March 2017			 buildah-from(1)

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