DOCKER(1) Docker User Manuals DOCKER(1)
NAME
docker-run - Create and run a new container from an image
SYNOPSIS
docker run [-a|--attach[=[]]] [--add-host[=[]]] [--annotation[=[]]]
[--blkio-weight[=[BLKIO-WEIGHT]]] [--blkio-weight-device[=[]]]
[-c|--cpu-shares[=0]] [--cap-add[=[]]] [--cap-drop[=[]]]
[--cgroupns[=[]]] [--cgroup-parent[=CGROUP-PATH]] [--cidfile[=CIDFILE]]
[--cpu-count[=0]] [--cpu-percent[=0]] [--cpu-period[=0]] [--cpu-
quota[=0]] [--cpu-rt-period[=0]] [--cpu-rt-runtime[=0]] [--cpus[=0.0]]
[--cpuset-cpus[=CPUSET-CPUS]] [--cpuset-mems[=CPUSET-MEMS]] [-d|--de-
tach] [--detach-keys[=[]]] [--device[=[]]] [--device-cgroup-rule[=[]]]
[--device-read-bps[=[]]] [--device-read-iops[=[]]] [--device-write-
bps[=[]]] [--device-write-iops[=[]]] [--dns[=[]]] [--dns-option[=[]]]
[--dns-search[=[]]] [--domainname[=DOMAINNAME]] [-e|--env[=[]]] [--en-
trypoint[=ENTRYPOINT]] [--env-file[=[]]] [--expose[=[]]] [--group-
add[=[]]] [-h|--hostname[=HOSTNAME]] [--help] [--init] [-i|--interac-
tive] [--ip[=IPv4-ADDRESS]] [--ip6[=IPv6-ADDRESS]] [--ipc[=IPC]]
[--isolation[=default]] [--kernel-memory[=KERNEL-MEMORY]] [-l|--la-
bel[=[]]] [--label-file[=[]]] [--link[=[]]] [--link-local-ip[=[]]]
[--log-driver[=[]]] [--log-opt[=[]]] [-m|--memory[=MEMORY]] [--mac-ad-
dress[=MAC-ADDRESS]] [--memory-reservation[=MEMORY-RESERVATION]]
[--memory-swap[=LIMIT]] [--memory-swappiness[=MEMORY-SWAPPINESS]]
[--mount[=[MOUNT]]] [--name[=NAME]] [--network-alias[=[]]] [--net-
work[="bridge"]] [--oom-kill-disable] [--oom-score-adj[=0]] [-P|--pub-
lish-all] [-p|--publish[=[]]] [--pid[=[PID]]] [--userns[=[]]] [--pids-
limit[=PIDS_LIMIT]] [--privileged] [--read-only] [--restart[=RESTART]]
[--rm] [--security-opt[=[]]] [--storage-opt[=[]]] [--stop-signal[=SIG-
NAL]] [--stop-timeout[=TIMEOUT]] [--shm-size[=[]]] [--sig-proxy[=true]]
[--sysctl[=[]]] [-t|--tty] [--tmpfs[=[CONTAINER-DIR[:OPTIONS]]]
[-u|--user[=USER]] [--ulimit[=[]]] [--uts[=[]]] [-v|--volume[=[[HOST-
DIR:]CONTAINER-DIR[:OPTIONS]]]] [--volume-driver[=DRIVER]] [--volumes-
from[=[]]] [-w|--workdir[=WORKDIR]] IMAGE [COMMAND] [ARG...]
DESCRIPTION
Run a process in a new container. docker run starts a process with its
own file system, its own networking, and its own isolated process tree.
The IMAGE which starts the process may define defaults related to the
process that will be run in the container, the networking to expose,
and more, but docker run gives final control to the operator or admin-
istrator who starts the container from the image. For that reason
docker run has more options than any other Docker command.
If the IMAGE is not already loaded then docker run will pull the IMAGE,
and all image dependencies, from the repository in the same way running
docker pull IMAGE, before it starts the container from that image.
OPTIONS
-a, --attach=[]
Attach to STDIN, STDOUT or STDERR.
In foreground mode (the default when -d is not specified), docker run
can start the process in the container and attach the console to the
process's standard input, output, and standard error. It can even pre-
tend to be a TTY (this is what most commandline executables expect) and
pass along signals. The -a option can be set for each of stdin, stdout,
and stderr.
--add-host=[]
Add a custom host-to-IP mapping (host=ip, or host:ip)
Add a line to /etc/hosts. The format is hostname=ip, or hostname:ip.
The --add-host option can be set multiple times.
--annotation=[]
Add an annotation to the container (passed through to the OCI run-
time).
The annotations are provided to the OCI runtime.
--blkio-weight=0
Block IO weight (relative weight) accepts a weight value between 10
and 1000.
--blkio-weight-device=[]
Block IO weight (relative device weight, format: DE-
VICE_NAME:WEIGHT).
-c, --cpu-shares=0
CPU shares (relative weight)
By default, all containers get the same proportion of CPU cycles. This
proportion 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 -c or --cpu-
shares flag to set the weighting to 2 or higher.
The proportion will only apply when CPU-intensive processes are run-
ning. When tasks in one container are idle, other containers can use
the left-over CPU time. The actual amount of CPU time will vary depend-
ing 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
containers attempt to use 100% of CPU, the first container would re-
ceive 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 containers 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 con-
tainer {C1} with -c=1024 running two processes, this can result in the
following division 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
--cap-add=[]
Add Linux capabilities
--cap-drop=[]
Drop Linux capabilities
--cgroupns=""
Set the cgroup namespace mode for the container.
host: run the container in the host's cgroup namespace
private: run the container in its own private cgroup namespace
"": (unset) use the daemon's default configuration (host on
cgroup v1, private on cgroup v2)
--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 rel-
ative to the cgroups path of the init process. Cgroups will be created
if they do not already exist.
--cidfile=""
Write the container ID to the file
--cpu-count=0
Limit the number of CPUs available for execution by the container.
On Windows Server containers, this is approximated as a percentage of total CPU usage.
On Windows Server containers, the processor resource controls are mutually exclusive, the order of precedence is CPUCount first, then CPUShares, and CPUPercent last.
--cpu-percent=0
Limit the percentage of CPU available for execution by a container
running on a Windows daemon.
On Windows Server containers, the processor resource controls are mutually exclusive, the order of precedence is CPUCount first, then CPUShares, and CPUPercent last.
--cpu-period=0
Limit the CPU CFS (Completely Fair Scheduler) period
Limit the container's CPU usage. This flag tell the kernel to restrict
the container's CPU usage to the period you specify.
--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 ef-
fective on NUMA systems.
If you have four memory nodes on your system (0-3), use --cpuset-
mems=0,1 then processes in your Docker container will only use memory
from the first two memory nodes.
--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 tell the kernel to restrict the con-
tainer's CPU usage to the quota you specify.
--cpu-rt-period=0
Limit the CPU real-time period in microseconds
Limit the container's Real Time CPU usage. This flag tell the kernel to
restrict the container's Real Time CPU usage to the period you specify.
--cpu-rt-runtime=0
Limit the CPU real-time runtime in microseconds
Limit the containers Real Time CPU usage. This flag tells the kernel to
limit the amount of time in a given CPU period Real Time tasks may con-
sume. Ex:
Period of 1,000,000us and Runtime of 950,000us means that this con-
tainer could consume 95% of available CPU and leave the remaining 5% to
normal priority tasks.
The sum of all runtimes across containers cannot exceed the amount al-
lotted to the parent cgroup.
--cpus=0.0
Number of CPUs. The default is 0.0 which means no limit.
-d, --detach=true|false
Detached mode: run the container in the background and print the new
container ID. The default is false.
At any time you can run docker ps in the other shell to view a list of
the running containers. You can reattach to a detached container with
docker attach.
When attached in the tty mode, you can detach from the container (and
leave it running) using a configurable key sequence. The default se-
quence is CTRL-p CTRL-q. You configure the key sequence using the
--detach-keys option or a configuration file. See config-json(5) for
documentation on using a configuration file.
--detach-keys=key
Override the key sequence for detaching a container; key is a single
character from the [a-Z] range, or ctrl-value, where value is one of:
a-z, @, ^, [, ,, or _.
--device=onhost:incontainer[:mode]
Add a host device onhost to the container under the incontainer
name. Optional mode parameter can be used to specify device permis-
sions, it is a combination of r (for read), w (for write), and m (for
mknod(2)).
For example, --device=/dev/sdc:/dev/xvdc:rwm will give a container all
permissions for the host device /dev/sdc, seen as /dev/xvdc inside the
container.
--device-cgroup-rule="type major:minor mode"
Add a rule to the cgroup allowed devices list. The rule is expected
to be in the format specified in the Linux kernel documentation (Docu-
mentation/cgroup-v1/devices.txt):
- type: a (all), c (char), or b (block);
- major and minor: either a number, or * for all;
- mode: a composition of r (read), w (write), and m (mknod(2)).
Example: --device-cgroup-rule "c 1:3 mr": allow for a character device
idendified by 1:3 to be created and read.
--device-read-bps=[]
Limit read rate from a device (e.g. --device-read-bps=/dev/sda:1mb)
--device-read-iops=[]
Limit read rate from a device (e.g. --device-read-
iops=/dev/sda:1000)
--device-write-bps=[]
Limit write rate to a device (e.g. --device-write-bps=/dev/sda:1mb)
--device-write-iops=[]
Limit write rate to a device (e.g. --device-write-
iops=/dev/sda:1000)
--dns-search=[]
Set custom DNS search domains (Use --dns-search=. if you don't wish
to set the search domain)
--dns-option=[]
Set custom DNS options
--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 flags is necessary for every run.
--domainname=""
Container NIS domain name
Sets the container's NIS domain name (see also setdomainname(2)) that
is
available inside the container.
-e, --env=[]
Set environment variables
This option allows you to specify arbitrary environment variables that
are available for the process that will be launched inside of the con-
tainer.
--entrypoint=""
Overwrite the default ENTRYPOINT of the image
This option allows you to overwrite the default entrypoint of the image
that is set in the Dockerfile. The ENTRYPOINT of an image is similar to
a COMMAND because it specifies what executable to run when the con-
tainer starts, but it is (purposely) more difficult to override. The
ENTRYPOINT gives a container its default nature or behavior, so that
when you set an ENTRYPOINT you can run the container as if it were that
binary, complete with default options, and you can pass in more options
via the COMMAND. But, sometimes an operator may want to run something
else inside the container, so you can override the default ENTRYPOINT
at runtime by using a --entrypoint and a string to specify the new EN-
TRYPOINT.
--env-file=[]
Read in a line delimited file of environment variables
--expose=[]
Expose a port, or a range of ports (e.g. --expose=3300-3310) informs
Docker that the container listens on the specified network ports at
runtime. Docker uses this information to interconnect containers using
links and to set up port redirection on the host system.
--group-add=[]
Add additional groups to run as
-h, --hostname=""
Container host name
Sets the container host name that is available inside the container.
--help
Print usage statement
--init
Run an init inside the container that forwards signals and reaps
processes
-i, --interactive=true|false
Keep STDIN open even if not attached. The default is false.
When set to true, keep stdin open even if not attached.
--ip=""
Sets the container's interface IPv4 address (e.g., 172.23.0.9)
It can only be used in conjunction with --network for user-defined net-
works
--ip6=""
Sets the container's interface IPv6 address (e.g., 2001:db8::1b99)
It can only be used in conjunction with --network for user-defined net-
works
--ipc=""
Sets the IPC mode for the container. The following values are ac-
cepted:
┌─────────────────────┬────────────────────────────┐
│Value │ Description │
├─────────────────────┼────────────────────────────┤
│(empty) │ Use daemon's default. │
├─────────────────────┼────────────────────────────┤
│none │ Own private IPC namespace, │
│ │ with /dev/shm not mounted. │
├─────────────────────┼────────────────────────────┤
│private │ Own private IPC namespace. │
├─────────────────────┼────────────────────────────┤
│shareable │ Own private IPC namespace, │
│ │ with a possibility to │
│ │ share it with other con- │
│ │ tainers. │
├─────────────────────┼────────────────────────────┤
│container:name-or-ID │ Join another ("shareable") │
│ │ container's IPC namespace. │
├─────────────────────┼────────────────────────────┤
│host │ Use the host system's IPC │
│ │ namespace. │
└─────────────────────┴────────────────────────────┘
If not specified, daemon default is used, which can either be private
or shareable, depending on the daemon version and configuration.
--isolation="default"
Isolation specifies the type of isolation technology used by con-
tainers. Note that the default on Windows server is process, and the
default on Windows client is hyperv. Linux only supports default.
-l, --label key=value
Set metadata on the container (for example, --label com.exam-
ple.key=value).
--kernel-memory=number[S]
Kernel memory limit; S is an optional suffix which can be one of b,
k, m, or g.
Constrains the kernel memory available to a container. If a limit of 0
is specified (not using --kernel-memory), the container's kernel memory
is not limited. If you specify a limit, it may be rounded up to a mul-
tiple of the operating system's page size and the value can be very
large, millions of trillions.
--label-file=[]
Read in a line delimited file of labels
--link=name-or-id[:alias]
Add link to another container.
If the operator uses --link when starting the new client container,
then the client container can access the exposed port via a private
networking interface. Docker will set some environment variables in the
client container to help indicate which interface and port to use.
--link-local-ip=[]
Add one or more link-local IPv4/IPv6 addresses to the container's
interface
--log-driver="json-file|syslog|journald|gelf|flu-
entd|awslogs|splunk|etwlogs|gcplogs|none"
Logging driver for the container. Default is defined by daemon --log-
driver flag.
Warning: the docker logs command works only for the json-file and
journald logging drivers.
--log-opt=[]
Logging driver specific options.
-m, --memory=number[*S]
Memory limit; S is an optional suffix which can be one of 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 physical RAM. If a limit of 0 is specified (not using -m), the
container's memory 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 millions of trillions).
--memory-reservation=number[*S]
Memory soft limit; S is an optional suffix which can be one of b, k,
m, or g.
After setting memory reservation, when the system detects memory con-
tention or low memory, containers are forced to restrict their consump-
tion to their reservation. So you should always set the value below
--memory, otherwise the hard limit will take precedence. By default,
memory reservation will be the same as memory limit.
--memory-swap=number[S]
Combined memory plus swap limit; S is an optional suffix which can
be one of b, k, m, or g.
This option can only be used together with --memory. The argument
should always be larger than that of --memory. Default is double the
value of --memory. Set to -1 to enable unlimited swap.
--mac-address=""
Container MAC address (e.g., 92:d0:c6:0a:29:33)
Remember that the MAC address in an Ethernet network must be unique.
The IPv6 link-local address will be based on the device's MAC address
according to RFC4862.
--mount type=TYPE,TYPE-SPECIFIC-OPTION[,...]
Attach a filesystem mount to the container
Current supported mount TYPES are bind, volume, and tmpfs.
e.g.
type=bind,source=/path/on/host,destination=/path/in/container
type=volume,source=my-volume,destination=/path/in/container,volume-la-
bel="color=red",volume-label="shape=round"
type=tmpfs,tmpfs-size=512M,destination=/path/in/container
Common Options:
• src, source: mount source spec for bind and volume. Mandatory for
bind.
• dst, destination, target: mount destination spec.
• ro, readonly: true or false (default).
Note: setting readonly for a bind mount may not make its submounts
read-only depending on the kernel version. See also bind-recursive.
Options specific to bind:
• bind-propagation: shared, slave, private, rshared, rslave, or rpri-
vate(default). See also mount(2).
• consistency: consistent(default), cached, or delegated. Currently,
only effective for Docker for Mac.
• bind-recursive: enabled (default), disabled, writable, or readonly:
If set to enabled, submounts are recursively bind-mounted and at-
tempted to be made recursively read-only.
If set to disabled, submounts are not recursively bind-mounted.
If set to writable, submounts are recursively bind-mounted but not
made recursively read-only.
If set to readonly, submounts are recursively bind-mounted and
forcibly made recursively read-only.
Options specific to volume:
• volume-driver: Name of the volume-driver plugin.
• volume-label: Custom metadata.
• volume-nocopy: true(default) or false. If set to false, the Engine
copies existing files and directories under the mount-path into the
volume, allowing the host to access them.
• volume-opt: specific to a given volume driver.
Options specific to tmpfs:
• tmpfs-size: Size of the tmpfs mount in bytes. Unlimited by default in
Linux.
• tmpfs-mode: File mode of the tmpfs in octal. (e.g. 700 or 0700.) De-
faults to 1777 in Linux.
--name=""
Assign a name to the container
The operator can identify a container in three ways:
┌──────────────────────┬────────────────────────────────────────────────────────────────────┐
│Identifier type │ Example value │
├──────────────────────┼────────────────────────────────────────────────────────────────────┤
│UUID long identifier │ "f78375b1c487e03c9438c729345e54db9d20cfa2ac1fc3494b6eb60872e74778" │
├──────────────────────┼────────────────────────────────────────────────────────────────────┤
│UUID short identifier │ "f78375b1c487" │
├──────────────────────┼────────────────────────────────────────────────────────────────────┤
│Name │ "evil_ptolemy" │
└──────────────────────┴────────────────────────────────────────────────────────────────────┘
The UUID identifiers come from the Docker daemon, and if a name is not
assigned to the container with --name then the daemon will also gener-
ate a random string name. The name is useful when defining links (see
--link) (or any other place you need to identify a container). This
works for both background and foreground Docker containers.
--network=type
Set the Network mode for the container. Supported values are:
┌────────────────────────┬────────────────────────────┐
│Value │ Description │
├────────────────────────┼────────────────────────────┤
│none │ No networking in the con- │
│ │ tainer. │
├────────────────────────┼────────────────────────────┤
│bridge │ Connect the container to │
│ │ the default Docker bridge │
│ │ via veth interfaces. │
├────────────────────────┼────────────────────────────┤
│host │ Use the host's network │
│ │ stack inside the con- │
│ │ tainer. │
├────────────────────────┼────────────────────────────┤
│container:name|id │ Use the network stack of │
│ │ another container, speci- │
│ │ fied via its name or id. │
├────────────────────────┼────────────────────────────┤
│network-name|network-id │ Connects the container to │
│ │ a user created network │
│ │ (using docker network cre- │
│ │ ate command) │
└────────────────────────┴────────────────────────────┘
Default is bridge.
--network-alias=[]
Add network-scoped alias for the container
--oom-kill-disable=true|false
Whether to disable OOM Killer for the container or not.
--oom-score-adj=""
Tune the host's OOM preferences for containers (accepts -1000 to
1000)
-P, --publish-all=true|false
Publish all exposed ports to random ports on the host interfaces.
The default is false.
When set to true publish all exposed ports to the host interfaces. The
default is false. If the operator uses -P (or -p) then Docker will make
the exposed port accessible on the host and the ports will be available
to any client that can reach the host. When using -P, Docker will bind
any exposed port to a random port on the host within an ephemeral port
range defined by /proc/sys/net/ipv4/ip_local_port_range. To find the
mapping between the host ports and the exposed ports, use docker
port(1).
-p, --publish ip:[hostPort]:containerPort | [hostPort:]containerPort
Publish a container's port, or range of ports, to the host.
Both hostPort and containerPort can be specified as a range. When
specifying ranges for both, the number of ports in ranges should be
equal.
Examples: -p 1234-1236:1222-1224, -p 127.0.0.1:$HOSTPORT:$CONTAINER-
PORT.
Use docker port(1) to see the actual mapping, e.g. docker port CON-
TAINER $CONTAINERPORT.
--pid=""
Set the PID mode for the container
Default is to create a private PID namespace for the container
'container:': join another container's
PID namespace
'host': use the host's PID namespace for
the container. Note: the host mode gives the container full access to
local PID and is therefore considered insecure.
--userns=""
Set the usernamespace mode for the container when userns-remap op-
tion is enabled.
host: use the host usernamespace and enable all privileged options
(e.g., pid=host or --privileged).
--pids-limit=""
Tune the container's pids (process IDs) limit. Set to -1 to have un-
limited pids for the container.
--uts=type
Set the UTS mode for the container. The only possible type is host,
meaning to use the host's UTS namespace inside the container.
Note: the host mode gives the container access to changing the
host's hostname and is therefore considered insecure.
--privileged [true|false]
Give extended privileges to this container. A "privileged" container
is given access to all devices.
When the operator executes docker run --privileged, Docker will enable
access to all devices on the host as well as set some configuration in
AppArmor to allow the container nearly all the same access to the host
as processes running outside of a container on the host.
--read-only=true|false
Mount the container's root filesystem as read only.
By default a container will have its root filesystem writable allowing
processes to write files anywhere. By specifying the --read-only flag
the container will have its root filesystem mounted as read only pro-
hibiting any writes.
--restart policy
Restart policy to apply when a container exits. Supported values
are:
┌─────────────────────────┬────────────────────────────┐
│Policy │ Result │
├─────────────────────────┼────────────────────────────┤
│no │ Do not automatically │
│ │ restart the container when │
│ │ it exits. │
├─────────────────────────┼────────────────────────────┤
│on-failure[:max-retries] │ Restart only if the con- │
│ │ tainer exits with a non- │
│ │ zero exit status. Option- │
│ │ ally, limit the number of │
│ │ restart retries the Docker │
│ │ daemon attempts. │
├─────────────────────────┼────────────────────────────┤
│always │ Always restart the con- │
│ │ tainer regardless of the │
│ │ exit status. When you │
│ │ specify always, the Docker │
│ │ daemon will try to restart │
│ │ the container indefi- │
│ │ nitely. The container will │
│ │ also always start on dae- │
│ │ mon startup, regardless of │
│ │ the current state of the │
│ │ container. │
├─────────────────────────┼────────────────────────────┤
│unless-stopped │ Always restart the con- │
│ │ tainer regardless of the │
│ │ exit status, but do not │
│ │ start it on daemon startup │
│ │ if the container has been │
│ │ put to a stopped state be- │
│ │ fore. │
└─────────────────────────┴────────────────────────────┘
Default is no.
--rm true|false
Automatically remove the container when it exits. The default is
false.
--rm flag can work together with -d, and auto-removal will be done
on daemon side. Note that it's incompatible with any restart policy
other than none.
--security-opt value[,...]
Security Options for the container. The following options can be
given:
"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" : Disable container processes from gaining additional privileges
"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
--storage-opt
Storage driver options per container
$ docker run -it --storage-opt size=120G fedora /bin/bash
This (size) will allow to set the container rootfs size to 120G at cre-
ation time.
This option is only available for the btrfs, overlay2 and zfs graph
drivers.
For the btrfs and zfs storage drivers, user cannot pass a size less
than the Default BaseFS Size.
For the overlay2 storage driver, the size option is only available
if the backing fs is xfs and mounted with the pquota mount option.
Under these conditions, user can pass any size less than the backing
fs size.
--stop-signal=""
Signal to stop the container.
The --stop-signal flag sets the system call signal that will be sent to
the
container to exit. This signal can be a signal name in the format
SIG<NAME>,
for instance SIGKILL, or an unsigned number that matches a position
in the
kernel's syscall table, for instance 9.
The default is defined by STOPSIGNAL in the image, or SIGTERM if the
image
has no STOPSIGNAL defined.
--stop-timeout
Timeout (in seconds) to stop a container, or -1 to disable timeout.
The --stop-timeout flag sets the number of seconds to wait for the con-
tainer
to stop after sending the pre-defined (see --stop-signal) system call
signal.
If the container does not exit after the timeout elapses, it is
forcibly killed
with a SIGKILL signal.
If --stop-timeout is set to -1, no timeout is applied, and the daemon
will
wait indefinitely for the container to exit.
The default is determined by the daemon, and 10 seconds for Linux con-
tainers,
and 30 seconds for Windows containers.
--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.
--sysctl=SYSCTL
Configure namespaced kernel parameters at runtime
IPC Namespace - current sysctls allowed:
kernel.msgmax, kernel.msgmnb, kernel.msgmni, kernel.sem, kernel.shmall,
kernel.shmmax, kernel.shmmni, kernel.shm_rmid_forced
Sysctls beginning with fs.mqueue.*
If you use the --ipc=host option these sysctls will not be allowed.
Network Namespace - current sysctls allowed:
Sysctls beginning with net.*
If you use the --network=host option these sysctls will not be allowed.
--sig-proxy=true|false
Proxy received signals to the process (non-TTY mode only). SIGCHLD,
SIGSTOP, and SIGKILL are not proxied. The default is true.
--memory-swappiness=""
Tune a container's memory swappiness behavior. Accepts an integer
between 0 and 100.
-t, --tty=true|false
Allocate a pseudo-TTY. The default is false.
When set to true Docker can allocate a pseudo-tty and attach to the
standard input of any container. This can be used, for example, to run
a throwaway interactive shell. The default is false.
The -t option is incompatible with a redirection of the docker client
standard input.
--tmpfs=[] Create a tmpfs mount
Mount a temporary filesystem (tmpfs) mount into a container, for exam-
ple:
$ docker run -d --tmpfs /tmp:rw,size=787448k,mode=1777 my_image
This command mounts a tmpfs at /tmp within the container. The sup-
ported mount options are the same as the Linux default mount flags. If
you do not specify any options, the systems uses the following options:
rw,noexec,nosuid,nodev,size=65536k.
See also --mount, which is the successor of --tmpfs and --volume.
Even though there is no plan to deprecate --tmpfs, usage of --mount
is recommended.
-u, --user=""
Sets the username or UID used and optionally the groupname or GID
for the specified command.
The followings examples are all valid:
--user [user | user:group | uid | uid:gid | user:gid | uid:group ]
Without this argument the command will be run as root in the container.
--ulimit=[]
Ulimit options
-v|--volume[=[[HOST-DIR:]CONTAINER-DIR[:OPTIONS]]]
Create a bind mount. If you specify, -v /HOST-DIR:/CONTAINER-DIR,
Docker
bind mounts /HOST-DIR in the host to /CONTAINER-DIR in the Docker
container. If 'HOST-DIR' is omitted, Docker automatically creates
the new
volume on the host. The OPTIONS are a comma delimited list and can
be:
• [rw|ro]
• [z|Z]
• [[r]shared|[r]slave|[r]private]
• [delegated|cached|consistent]
• [nocopy]
The CONTAINER-DIR must be an absolute path such as /src/docs. The HOST-
DIR can be an absolute path or a name value. A name value must start
with an alphanumeric character, followed by a-z0-9, _ (underscore), .
(period) or - (hyphen). An absolute path starts with a / (forward
slash).
If you supply a HOST-DIR that is an absolute path, Docker bind-mounts
to the path you specify. If you supply a name, Docker creates a named
volume by that name. For example, you can specify either /foo or foo
for a HOST-DIR value. If you supply the /foo value, Docker creates a
bind mount. If you supply the foo specification, Docker creates a named
volume.
You can specify multiple -v options to mount one or more mounts to a
container. To use these same mounts in other containers, specify the
--volumes-from option also.
You can supply additional options for each bind mount following an ad-
ditional colon. A :ro or :rw suffix mounts a volume in read-only or
read-write mode, respectively. By default, volumes are mounted in read-
write mode. You can also specify the consistency requirement for the
mount, either :consistent (the default), :cached, or :delegated. Mul-
tiple options are separated by commas, e.g. :ro,cached.
Labeling systems like SELinux require that proper labels are placed on
volume 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, Docker does not change the labels set by
the OS.
To change a label in the container context, you can add either of two
suffixes :z or :Z to the volume mount. These suffixes tell Docker to
relabel file objects on the shared volumes. The z option tells Docker
that two containers share the volume content. As a result, Docker la-
bels the content with a shared content label. Shared volume labels al-
low all containers to read/write content. The Z option tells Docker to
label the content with a private unshared label. Only the current con-
tainer can use a private volume.
By default bind mounted volumes are private. That means any mounts done
inside container will not be visible on host and vice versa. One can
change this behavior by specifying a volume mount propagation property.
Making a volume shared mounts done under that volume inside container
will be visible on host and vice versa. Making a volume slave enables
only one way mount propagation and that is mounts done on host under
that volume will be visible inside container but not the other way
around.
To control mount propagation property of volume one can use :[r]shared,
:[r]slave or :[r]private propagation flag. Propagation property can be
specified only for bind mounted volumes and not for internal volumes or
named volumes. For mount propagation to work source mount point (mount
point where source dir is mounted on) has to have right propagation
properties. For shared volumes, source mount point has to be shared.
And for slave volumes, source mount has to be either shared or slave.
Use df <source-dir> to figure out the source mount and then use findmnt
-o TARGET,PROPAGATION <source-mount-dir> to figure out propagation
properties of source mount. If findmnt utility is not available, then
one can look at mount entry for source mount point in
/proc/self/mountinfo. Look at optional fields and see if any propaga-
tion properties are specified. shared:X means mount is shared, mas-
ter:X means mount is slave and if nothing is there that means mount is
private.
To change propagation properties of a mount point use mount command.
For example, if one wants to bind mount source directory /foo one can
do mount --bind /foo /foo and mount --make-private --make-shared /foo.
This will convert /foo into a shared mount point. Alternatively one can
directly change propagation properties of source mount. Say / is source
mount for /foo, then use mount --make-shared / to convert / into a
shared mount.
Note: When using systemd to manage the Docker daemon's start and
stop, in the systemd unit file there is an option to control
mount propagation for the Docker daemon itself, called Mount-
Flags. The value of this setting may cause Docker to not see
mount propagation changes made on the mount point. For example,
if this value is slave, you may not be able to use the shared or
rshared propagation on a volume.
To disable automatic copying of data from the container path to the
volume, use the nocopy flag. The nocopy flag can be set on bind mounts
and named volumes.
See also --mount, which is the successor of --tmpfs and --volume. Even
though there is no plan to deprecate --volume, usage of --mount is rec-
ommended.
--volume-driver=""
Container's volume driver. This driver creates volumes specified ei-
ther from
a Dockerfile's VOLUME instruction or from the docker run -v flag.
See docker-volume-create(1) for full details.
--volumes-from=[]
Mount volumes from the specified container(s)
Mounts already mounted volumes from a source container onto another
container. You must supply the source's container-id. To share
a volume, use the --volumes-from option when running
the target container. You can share volumes even if the source con-
tainer
is not running.
By default, Docker mounts the volumes in the same mode (read-write or
read-only) as it is mounted in the source container. Optionally, you
can change this by suffixing the container-id with either the :ro or
:rw keyword.
If the location of the volume from the source container overlaps with
data residing on a target container, then the volume hides
that data on the target.
-w, --workdir=""
Working directory inside the container
The default working directory for running binaries within a container
is the root directory (/). The developer can set a different default
with the Dockerfile WORKDIR instruction. The operator can override the
working directory by using the -w option.
Exit Status
The exit code from docker run gives information about why the container
failed to run or why it exited. When docker run exits with a non-zero
code, the exit codes follow the chroot standard, see below:
125 if the error is with Docker daemon itself
$ docker run --foo busybox; echo $?
# flag provided but not defined: --foo
See 'docker run --help'.
125
126 if the contained command cannot be invoked
$ docker run busybox /etc; echo $?
# exec: "/etc": permission denied
docker: Error response from daemon: Contained command could not be invoked
126
127 if the contained command cannot be found
$ docker run busybox foo; echo $?
# exec: "foo": executable file not found in $PATH
docker: Error response from daemon: Contained command not found or does not exist
127
Exit code of contained command otherwise
$ docker run busybox /bin/sh -c 'exit 3'
# 3
EXAMPLES
Running container in read-only mode
During container image development, containers often need to write to
the image content. Installing packages into /usr, for example. In
production, applications seldom need to write to the image. Container
applications write to volumes if they need to write to file systems at
all. Applications can be made more secure by running them in read-only
mode using the --read-only switch. This protects the containers image
from modification. Read only containers may still need to write tempo-
rary data. The best way to handle this is to mount tmpfs directories
on /run and /tmp.
# docker run --read-only --tmpfs /run --tmpfs /tmp -i -t fedora /bin/bash
Exposing log messages from the container to the host's log
If you want messages that are logged in your container to show up in
the host's syslog/journal then you should bind mount the /dev/log di-
rectory as follows.
# docker run -v /dev/log:/dev/log -i -t fedora /bin/bash
From inside the container you can test this by sending a message to the
log.
(bash)# logger "Hello from my container"
Then exit and check the journal.
# exit
# journalctl -b | grep Hello
This should list the message sent to logger.
Attaching to one or more from STDIN, STDOUT, STDERR
If you do not specify -a then Docker will attach everything (stdin,std-
out,stderr) . You can specify to which of the three standard streams
(stdin, stdout, stderr) you'd like to connect instead, as in:
# docker run -a stdin -a stdout -i -t fedora /bin/bash
Sharing IPC between containers
Using shm_server.c available here:
https://www.cs.cf.ac.uk/Dave/C/node27.html
Testing --ipc=host mode:
Host shows a shared memory segment with 7 pids attached, happens to be
from httpd:
$ sudo ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x01128e25 0 root 600 1000 7
Now run a regular container, and it correctly does NOT see the shared
memory segment from the host:
$ docker run -it shm ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
Run a container with the new --ipc=host option, and it now sees the
shared memory segment from the host httpd:
$ docker run -it --ipc=host shm ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x01128e25 0 root 600 1000 7
Testing --ipc=container:CONTAINERID mode:
Start a container with a program to create a shared memory segment:
$ docker run -it shm bash
$ sudo shm/shm_server &
$ sudo ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x0000162e 0 root 666 27 1
Create a 2nd container correctly shows no shared memory segment from
1st container:
$ docker run shm ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
Create a 3rd container using the new --ipc=container:CONTAINERID op-
tion, now it shows the shared memory segment from the first:
$ docker run -it --ipc=container:ed735b2264ac shm ipcs -m
$ sudo ipcs -m
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x0000162e 0 root 666 27 1
Linking Containers
Note: This section describes linking between containers on the
default (bridge) network, also known as "legacy links". Using
--link on user-defined networks uses the DNS-based discovery,
which does not add entries to /etc/hosts, and does not set envi-
ronment variables for discovery.
The link feature allows multiple containers to communicate with each
other. For example, a container whose Dockerfile has exposed port 80
can be run and named as follows:
# docker run --name=link-test -d -i -t fedora/httpd
A second container, in this case called linker, can communicate with
the httpd container, named link-test, by running with the --link=:
# docker run -t -i --link=link-test:lt --name=linker fedora /bin/bash
Now the container linker is linked to container link-test with the
alias lt. Running the env command in the linker container shows envi-
ronment variables
with the LT (alias) context (LT_)
# env
HOSTNAME=668231cb0978
TERM=xterm
LT_PORT_80_TCP=tcp://172.17.0.3:80
LT_PORT_80_TCP_PORT=80
LT_PORT_80_TCP_PROTO=tcp
LT_PORT=tcp://172.17.0.3:80
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
LT_NAME=/linker/lt
SHLVL=1
HOME=/
LT_PORT_80_TCP_ADDR=172.17.0.3
_=/usr/bin/env
When linking two containers Docker will use the exposed ports of the
container to create a secure tunnel for the parent to access.
If a container is connected to the default bridge network and linked
with other containers, then the container's /etc/hosts file is updated
with the linked container's name.
Note Since Docker may live update the container's /etc/hosts
file, there may be situations when processes inside the con-
tainer can end up reading an empty or incomplete /etc/hosts
file. In most cases, retrying the read again should fix the
problem.
Mapping Ports for External Usage
The exposed port of an application can be mapped to a host port using
the -p flag. For example, an httpd port 80 can be mapped to the host
port 8080 using the following:
# docker run -p 8080:80 -d -i -t fedora/httpd
Creating and Mounting a Data Volume Container
Many applications require the sharing of persistent data across several
containers. Docker allows you to create a Data Volume Container that
other containers can mount from. For example, create a named container
that contains directories /var/volume1 and /tmp/volume2. The image will
need to contain these directories so a couple of RUN mkdir instructions
might be required for you fedora-data image:
# docker run --name=data -v /var/volume1 -v /tmp/volume2 -i -t fedora-data true
# docker run --volumes-from=data --name=fedora-container1 -i -t fedora bash
Multiple --volumes-from parameters will bring together multiple data
volumes from multiple containers. And it's possible to mount the vol-
umes that came from the DATA container in yet another container via the
fedora-container1 intermediary container, allowing to abstract the ac-
tual data source from users of that data:
# docker run --volumes-from=fedora-container1 --name=fedora-container2 -i -t fedora bash
Mounting External Volumes
To mount a host directory as a container volume, specify the absolute
path to the directory and the absolute path for the container directory
separated by a colon:
# docker run -v /var/db:/data1 -i -t fedora bash
When using SELinux, be aware that the host has no knowledge of con-
tainer SELinux policy. Therefore, in the above example, if SELinux pol-
icy is enforced, the /var/db directory is not writable to the con-
tainer. A "Permission Denied" message will occur and an avc: message in
the host's syslog.
To work around this, at time of writing this man page, the following
command needs to be run in order for the proper SELinux policy type la-
bel to be attached to the host directory:
# chcon -Rt svirt_sandbox_file_t /var/db
Now, writing to the /data1 volume in the container will be allowed and
the changes will also be reflected on the host in /var/db.
Using alternative security labeling
You can override the default labeling scheme for each container by
specifying the --security-opt flag. For example, you can specify the
MCS/MLS level, a requirement for MLS systems. Specifying the level in
the following command allows you to share the same content between con-
tainers.
# docker run --security-opt label=level:s0:c100,c200 -i -t fedora bash
An MLS example might be:
# docker run --security-opt label=level:TopSecret -i -t rhel7 bash
To disable the security labeling for this container versus running with
the --permissive flag, use the following command:
# docker run --security-opt label=disable -i -t fedora bash
If you want a tighter security policy on the processes within a con-
tainer, you can specify an alternate type for the container. You could
run a container that is only allowed to listen on Apache ports by exe-
cuting the following command:
# docker run --security-opt label=type:svirt_apache_t -i -t centos bash
Note:
You would have to write policy defining a svirt_apache_t type.
Setting device weight
If you want to set /dev/sda device weight to 200, you can specify the
device weight by --blkio-weight-device flag. Use the following command:
# docker run -it --blkio-weight-device "/dev/sda:200" ubuntu
Specify isolation technology for container (--isolation)
This option is useful in situations where you are running Docker con-
tainers on Microsoft Windows. The --isolation <value> option sets a
container's isolation technology. On Linux, the only supported is the
default option which uses Linux namespaces. These two commands are
equivalent on Linux:
$ docker run -d busybox top
$ docker run -d --isolation default busybox top
On Microsoft Windows, can take any of these values:
• default: Use the value specified by the Docker daemon's --exec-opt .
If the daemon does not specify an isolation technology, Microsoft
Windows uses process as its default value.
• process: Namespace isolation only.
• hyperv: Hyper-V hypervisor partition-based isolation.
In practice, when running on Microsoft Windows without a daemon option
set, these two commands are equivalent:
$ docker run -d --isolation default busybox top
$ docker run -d --isolation process busybox top
If you have set the --exec-opt isolation=hyperv option on the Docker
daemon, any of these commands also result in hyperv isolation:
$ docker run -d --isolation default busybox top
$ docker run -d --isolation hyperv busybox top
Setting Namespaced Kernel Parameters (Sysctls)
The --sysctl sets namespaced kernel parameters (sysctls) in the con-
tainer. For example, to turn on IP forwarding in the containers network
namespace, run this command:
$ docker run --sysctl net.ipv4.ip_forward=1 someimage
Note:
Not all sysctls are namespaced. Docker does not support changing
sysctls inside of a container that also modify the host system. As the
kernel evolves we expect to see more sysctls become namespaced.
See the definition of the --sysctl option above for the current list of
supported sysctls.
HISTORY
April 2014, Originally compiled by William Henry (whenry at redhat dot
com) based on docker.com source material and internal work. June 2014,
updated by Sven Dowideit SvenDowideit@home.org.au ⟨mailto:Sven-
Dowideit@home.org.au⟩ July 2014, updated by Sven Dowideit Sven-
Dowideit@home.org.au ⟨mailto:SvenDowideit@home.org.au⟩ November 2015,
updated by Sally O'Malley somalley@redhat.com ⟨mailto:somalley@red-
hat.com⟩
Docker Community JUNE 2014 DOCKER(1)
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