github.com/endocode/docker@v1.4.2-0.20160113120958-46eb4700391e/man/docker-run.1.md (about) 1 % DOCKER(1) Docker User Manuals 2 % Docker Community 3 % JUNE 2014 4 # NAME 5 docker-run - Run a command in a new container 6 7 # SYNOPSIS 8 **docker run** 9 [**-a**|**--attach**[=*[]*]] 10 [**--add-host**[=*[]*]] 11 [**--blkio-weight**[=*[BLKIO-WEIGHT]*]] 12 [**--blkio-weight-device**[=*[]*]] 13 [**--cpu-shares**[=*0*]] 14 [**--cap-add**[=*[]*]] 15 [**--cap-drop**[=*[]*]] 16 [**--cgroup-parent**[=*CGROUP-PATH*]] 17 [**--cidfile**[=*CIDFILE*]] 18 [**--cpu-period**[=*0*]] 19 [**--cpu-quota**[=*0*]] 20 [**--cpuset-cpus**[=*CPUSET-CPUS*]] 21 [**--cpuset-mems**[=*CPUSET-MEMS*]] 22 [**-d**|**--detach**] 23 [**--detach-keys**[=*[]*]] 24 [**--device**[=*[]*]] 25 [**--device-read-bps**[=*[]*]] 26 [**--device-read-iops**[=*[]*]] 27 [**--device-write-bps**[=*[]*]] 28 [**--device-write-iops**[=*[]*]] 29 [**--dns**[=*[]*]] 30 [**--dns-opt**[=*[]*]] 31 [**--dns-search**[=*[]*]] 32 [**-e**|**--env**[=*[]*]] 33 [**--entrypoint**[=*ENTRYPOINT*]] 34 [**--env-file**[=*[]*]] 35 [**--expose**[=*[]*]] 36 [**--group-add**[=*[]*]] 37 [**-h**|**--hostname**[=*HOSTNAME*]] 38 [**--help**] 39 [**-i**|**--interactive**] 40 [**--ipc**[=*IPC*]] 41 [**--isolation**[=*default*]] 42 [**--kernel-memory**[=*KERNEL-MEMORY*]] 43 [**-l**|**--label**[=*[]*]] 44 [**--label-file**[=*[]*]] 45 [**--link**[=*[]*]] 46 [**--log-driver**[=*[]*]] 47 [**--log-opt**[=*[]*]] 48 [**-m**|**--memory**[=*MEMORY*]] 49 [**--mac-address**[=*MAC-ADDRESS*]] 50 [**--memory-reservation**[=*MEMORY-RESERVATION*]] 51 [**--memory-swap**[=*LIMIT*]] 52 [**--memory-swappiness**[=*MEMORY-SWAPPINESS*]] 53 [**--name**[=*NAME*]] 54 [**--net**[=*"bridge"*]] 55 [**--oom-kill-disable**] 56 [**--oom-score-adj**[=*0*]] 57 [**-P**|**--publish-all**] 58 [**-p**|**--publish**[=*[]*]] 59 [**--pid**[=*[]*]] 60 [**--privileged**] 61 [**--read-only**] 62 [**--restart**[=*RESTART*]] 63 [**--rm**] 64 [**--security-opt**[=*[]*]] 65 [**--stop-signal**[=*SIGNAL*]] 66 [**--shm-size**[=*[]*]] 67 [**--sig-proxy**[=*true*]] 68 [**-t**|**--tty**] 69 [**--tmpfs**[=*[CONTAINER-DIR[:<OPTIONS>]*]] 70 [**-u**|**--user**[=*USER*]] 71 [**--ulimit**[=*[]*]] 72 [**--uts**[=*[]*]] 73 [**-v**|**--volume**[=*[[HOST-DIR:]CONTAINER-DIR[:OPTIONS]]*]] 74 [**--volume-driver**[=*DRIVER*]] 75 [**--volumes-from**[=*[]*]] 76 [**-w**|**--workdir**[=*WORKDIR*]] 77 IMAGE [COMMAND] [ARG...] 78 79 # DESCRIPTION 80 81 Run a process in a new container. **docker run** starts a process with its own 82 file system, its own networking, and its own isolated process tree. The IMAGE 83 which starts the process may define defaults related to the process that will be 84 run in the container, the networking to expose, and more, but **docker run** 85 gives final control to the operator or administrator who starts the container 86 from the image. For that reason **docker run** has more options than any other 87 Docker command. 88 89 If the IMAGE is not already loaded then **docker run** will pull the IMAGE, and 90 all image dependencies, from the repository in the same way running **docker 91 pull** IMAGE, before it starts the container from that image. 92 93 # OPTIONS 94 **-a**, **--attach**=[] 95 Attach to STDIN, STDOUT or STDERR. 96 97 In foreground mode (the default when **-d** 98 is not specified), **docker run** can start the process in the container 99 and attach the console to the process’s standard input, output, and standard 100 error. It can even pretend to be a TTY (this is what most commandline 101 executables expect) and pass along signals. The **-a** option can be set for 102 each of stdin, stdout, and stderr. 103 104 **--add-host**=[] 105 Add a custom host-to-IP mapping (host:ip) 106 107 Add a line to /etc/hosts. The format is hostname:ip. The **--add-host** 108 option can be set multiple times. 109 110 **--blkio-weight**=*0* 111 Block IO weight (relative weight) accepts a weight value between 10 and 1000. 112 113 **--blkio-weight-device**=[] 114 Block IO weight (relative device weight, format: `DEVICE_NAME:WEIGHT`). 115 116 **--cpu-shares**=*0* 117 CPU shares (relative weight) 118 119 By default, all containers get the same proportion of CPU cycles. This proportion 120 can be modified by changing the container's CPU share weighting relative 121 to the weighting of all other running containers. 122 123 To modify the proportion from the default of 1024, use the **--cpu-shares** 124 flag to set the weighting to 2 or higher. 125 126 The proportion will only apply when CPU-intensive processes are running. 127 When tasks in one container are idle, other containers can use the 128 left-over CPU time. The actual amount of CPU time will vary depending on 129 the number of containers running on the system. 130 131 For example, consider three containers, one has a cpu-share of 1024 and 132 two others have a cpu-share setting of 512. When processes in all three 133 containers attempt to use 100% of CPU, the first container would receive 134 50% of the total CPU time. If you add a fourth container with a cpu-share 135 of 1024, the first container only gets 33% of the CPU. The remaining containers 136 receive 16.5%, 16.5% and 33% of the CPU. 137 138 On a multi-core system, the shares of CPU time are distributed over all CPU 139 cores. Even if a container is limited to less than 100% of CPU time, it can 140 use 100% of each individual CPU core. 141 142 For example, consider a system with more than three cores. If you start one 143 container **{C0}** with **-c=512** running one process, and another container 144 **{C1}** with **-c=1024** running two processes, this can result in the following 145 division of CPU shares: 146 147 PID container CPU CPU share 148 100 {C0} 0 100% of CPU0 149 101 {C1} 1 100% of CPU1 150 102 {C1} 2 100% of CPU2 151 152 **--cap-add**=[] 153 Add Linux capabilities 154 155 **--cap-drop**=[] 156 Drop Linux capabilities 157 158 **--cgroup-parent**="" 159 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. 160 161 **--cidfile**="" 162 Write the container ID to the file 163 164 **--cpu-period**=*0* 165 Limit the CPU CFS (Completely Fair Scheduler) period 166 167 Limit the container's CPU usage. This flag tell the kernel to restrict the container's CPU usage to the period you specify. 168 169 **--cpuset-cpus**="" 170 CPUs in which to allow execution (0-3, 0,1) 171 172 **--cpuset-mems**="" 173 Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effective on NUMA systems. 174 175 If you have four memory nodes on your system (0-3), use `--cpuset-mems=0,1` 176 then processes in your Docker container will only use memory from the first 177 two memory nodes. 178 179 **--cpu-quota**=*0* 180 Limit the CPU CFS (Completely Fair Scheduler) quota 181 182 Limit the container's CPU usage. By default, containers run with the full 183 CPU resource. This flag tell the kernel to restrict the container's CPU usage 184 to the quota you specify. 185 186 **-d**, **--detach**=*true*|*false* 187 Detached mode: run the container in the background and print the new container ID. The default is *false*. 188 189 At any time you can run **docker ps** in 190 the other shell to view a list of the running containers. You can reattach to a 191 detached container with **docker attach**. If you choose to run a container in 192 the detached mode, then you cannot use the **-rm** option. 193 194 When attached in the tty mode, you can detach from the container (and leave it 195 running) using a configurable key sequence. The default sequence is `CTRL-p CTRL-q`. 196 You configure the key sequence using the **--detach-keys** option or a configuration file. 197 See **config-json(5)** for documentation on using a configuration file. 198 199 **--detach-keys**="" 200 Override the key sequence for detaching a container. Format is a single character `[a-Z]` or `ctrl-<value>` where `<value>` is one of: `a-z`, `@`, `^`, `[`, `,` or `_`. 201 202 **--device**=[] 203 Add a host device to the container (e.g. --device=/dev/sdc:/dev/xvdc:rwm) 204 205 **--device-read-bps**=[] 206 Limit read rate from a device (e.g. --device-read-bps=/dev/sda:1mb) 207 208 **--device-read-iops**=[] 209 Limit read rate from a device (e.g. --device-read-iops=/dev/sda:1000) 210 211 **--device-write-bps**=[] 212 Limit write rate to a device (e.g. --device-write-bps=/dev/sda:1mb) 213 214 **--device-write-iops**=[] 215 Limit write rate a a device (e.g. --device-write-iops=/dev/sda:1000) 216 217 **--dns-search**=[] 218 Set custom DNS search domains (Use --dns-search=. if you don't wish to set the search domain) 219 220 **--dns-opt**=[] 221 Set custom DNS options 222 223 **--dns**=[] 224 Set custom DNS servers 225 226 This option can be used to override the DNS 227 configuration passed to the container. Typically this is necessary when the 228 host DNS configuration is invalid for the container (e.g., 127.0.0.1). When this 229 is the case the **--dns** flags is necessary for every run. 230 231 **-e**, **--env**=[] 232 Set environment variables 233 234 This option allows you to specify arbitrary 235 environment variables that are available for the process that will be launched 236 inside of the container. 237 238 **--entrypoint**="" 239 Overwrite the default ENTRYPOINT of the image 240 241 This option allows you to overwrite the default entrypoint of the image that 242 is set in the Dockerfile. The ENTRYPOINT of an image is similar to a COMMAND 243 because it specifies what executable to run when the container starts, but it is 244 (purposely) more difficult to override. The ENTRYPOINT gives a container its 245 default nature or behavior, so that when you set an ENTRYPOINT you can run the 246 container as if it were that binary, complete with default options, and you can 247 pass in more options via the COMMAND. But, sometimes an operator may want to run 248 something else inside the container, so you can override the default ENTRYPOINT 249 at runtime by using a **--entrypoint** and a string to specify the new 250 ENTRYPOINT. 251 252 **--env-file**=[] 253 Read in a line delimited file of environment variables 254 255 **--expose**=[] 256 Expose a port, or a range of ports (e.g. --expose=3300-3310) informs Docker 257 that the container listens on the specified network ports at runtime. Docker 258 uses this information to interconnect containers using links and to set up port 259 redirection on the host system. 260 261 **--group-add**=[] 262 Add additional groups to run as 263 264 **-h**, **--hostname**="" 265 Container host name 266 267 Sets the container host name that is available inside the container. 268 269 **--help** 270 Print usage statement 271 272 **-i**, **--interactive**=*true*|*false* 273 Keep STDIN open even if not attached. The default is *false*. 274 275 When set to true, keep stdin open even if not attached. The default is false. 276 277 **--ipc**="" 278 Default is to create a private IPC namespace (POSIX SysV IPC) for the container 279 'container:<name|id>': reuses another container shared memory, semaphores and message queues 280 'host': use the host shared memory,semaphores and message queues inside the container. Note: the host mode gives the container full access to local shared memory and is therefore considered insecure. 281 282 **--isolation**="*default*" 283 Isolation specifies the type of isolation technology used by containers. 284 285 **-l**, **--label**=[] 286 Set metadata on the container (e.g., --label com.example.key=value) 287 288 **--kernel-memory**="" 289 Kernel memory limit (format: `<number>[<unit>]`, where unit = b, k, m or g) 290 291 Constrains the kernel memory available to a container. If a limit of 0 292 is specified (not using `--kernel-memory`), the container's kernel memory 293 is not limited. If you specify a limit, it may be rounded up to a multiple 294 of the operating system's page size and the value can be very large, 295 millions of trillions. 296 297 **--label-file**=[] 298 Read in a line delimited file of labels 299 300 **--link**=[] 301 Add link to another container in the form of <name or id>:alias or just <name or id> 302 in which case the alias will match the name 303 304 If the operator 305 uses **--link** when starting the new client container, then the client 306 container can access the exposed port via a private networking interface. Docker 307 will set some environment variables in the client container to help indicate 308 which interface and port to use. 309 310 **--log-driver**="*json-file*|*syslog*|*journald*|*gelf*|*fluentd*|*awslogs*|*splunk*|*none*" 311 Logging driver for container. Default is defined by daemon `--log-driver` flag. 312 **Warning**: the `docker logs` command works only for the `json-file` and 313 `journald` logging drivers. 314 315 **--log-opt**=[] 316 Logging driver specific options. 317 318 **-m**, **--memory**="" 319 Memory limit (format: <number>[<unit>], where unit = b, k, m or g) 320 321 Allows you to constrain the memory available to a container. If the host 322 supports swap memory, then the **-m** memory setting can be larger than physical 323 RAM. If a limit of 0 is specified (not using **-m**), the container's memory is 324 not limited. The actual limit may be rounded up to a multiple of the operating 325 system's page size (the value would be very large, that's millions of trillions). 326 327 **--memory-reservation**="" 328 Memory soft limit (format: <number>[<unit>], where unit = b, k, m or g) 329 330 After setting memory reservation, when the system detects memory contention 331 or low memory, containers are forced to restrict their consumption to their 332 reservation. So you should always set the value below **--memory**, otherwise the 333 hard limit will take precedence. By default, memory reservation will be the same 334 as memory limit. 335 336 **--memory-swap**="LIMIT" 337 A limit value equal to memory plus swap. Must be used with the **-m** 338 (**--memory**) flag. The swap `LIMIT` should always be larger than **-m** 339 (**--memory**) value. 340 341 The format of `LIMIT` is `<number>[<unit>]`. Unit can be `b` (bytes), 342 `k` (kilobytes), `m` (megabytes), or `g` (gigabytes). If you don't specify a 343 unit, `b` is used. Set LIMIT to `-1` to enable unlimited swap. 344 345 **--mac-address**="" 346 Container MAC address (e.g. 92:d0:c6:0a:29:33) 347 348 Remember that the MAC address in an Ethernet network must be unique. 349 The IPv6 link-local address will be based on the device's MAC address 350 according to RFC4862. 351 352 **--name**="" 353 Assign a name to the container 354 355 The operator can identify a container in three ways: 356 UUID long identifier (“f78375b1c487e03c9438c729345e54db9d20cfa2ac1fc3494b6eb60872e74778”) 357 UUID short identifier (“f78375b1c487”) 358 Name (“jonah”) 359 360 The UUID identifiers come from the Docker daemon, and if a name is not assigned 361 to the container with **--name** then the daemon will also generate a random 362 string name. The name is useful when defining links (see **--link**) (or any 363 other place you need to identify a container). This works for both background 364 and foreground Docker containers. 365 366 **--net**="*bridge*" 367 Set the Network mode for the container 368 'bridge': create a network stack on the default Docker bridge 369 'none': no networking 370 'container:<name|id>': reuse another container's network stack 371 'host': use the Docker 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. 372 '<network-name>|<network-id>': connect to a user-defined network 373 374 **--oom-kill-disable**=*true*|*false* 375 Whether to disable OOM Killer for the container or not. 376 377 **--oom-score-adj**="" 378 Tune the host's OOM preferences for containers (accepts -1000 to 1000) 379 380 **-P**, **--publish-all**=*true*|*false* 381 Publish all exposed ports to random ports on the host interfaces. The default is *false*. 382 383 When set to true publish all exposed ports to the host interfaces. The 384 default is false. If the operator uses -P (or -p) then Docker will make the 385 exposed port accessible on the host and the ports will be available to any 386 client that can reach the host. When using -P, Docker will bind any exposed 387 port to a random port on the host within an *ephemeral port range* defined by 388 `/proc/sys/net/ipv4/ip_local_port_range`. To find the mapping between the host 389 ports and the exposed ports, use `docker port`. 390 391 **-p**, **--publish**=[] 392 Publish a container's port, or range of ports, to the host. 393 394 Format: `ip:hostPort:containerPort | ip::containerPort | hostPort:containerPort | containerPort` 395 Both hostPort and containerPort can be specified as a range of ports. 396 When specifying ranges for both, the number of container ports in the range must match the number of host ports in the range. 397 (e.g., `docker run -p 1234-1236:1222-1224 --name thisWorks -t busybox` 398 but not `docker run -p 1230-1236:1230-1240 --name RangeContainerPortsBiggerThanRangeHostPorts -t busybox`) 399 With ip: `docker run -p 127.0.0.1:$HOSTPORT:$CONTAINERPORT --name CONTAINER -t someimage` 400 Use `docker port` to see the actual mapping: `docker port CONTAINER $CONTAINERPORT` 401 402 **--pid**=*host* 403 Set the PID mode for the container 404 **host**: use the host's PID namespace inside the container. 405 Note: the host mode gives the container full access to local PID and is therefore considered insecure. 406 407 **--uts**=*host* 408 Set the UTS mode for the container 409 **host**: use the host's UTS namespace inside the container. 410 Note: the host mode gives the container access to changing the host's hostname and is therefore considered insecure. 411 412 **--privileged**=*true*|*false* 413 Give extended privileges to this container. The default is *false*. 414 415 By default, Docker containers are 416 “unprivileged” (=false) and cannot, for example, run a Docker daemon inside the 417 Docker container. This is because by default a container is not allowed to 418 access any devices. A “privileged” container is given access to all devices. 419 420 When the operator executes **docker run --privileged**, Docker will enable access 421 to all devices on the host as well as set some configuration in AppArmor to 422 allow the container nearly all the same access to the host as processes running 423 outside of a container on the host. 424 425 **--read-only**=*true*|*false* 426 Mount the container's root filesystem as read only. 427 428 By default a container will have its root filesystem writable allowing processes 429 to write files anywhere. By specifying the `--read-only` flag the container will have 430 its root filesystem mounted as read only prohibiting any writes. 431 432 **--restart**="*no*" 433 Restart policy to apply when a container exits (no, on-failure[:max-retry], always, unless-stopped). 434 435 **--rm**=*true*|*false* 436 Automatically remove the container when it exits (incompatible with -d). The default is *false*. 437 438 **--security-opt**=[] 439 Security Options 440 441 "label:user:USER" : Set the label user for the container 442 "label:role:ROLE" : Set the label role for the container 443 "label:type:TYPE" : Set the label type for the container 444 "label:level:LEVEL" : Set the label level for the container 445 "label:disable" : Turn off label confinement for the container 446 447 **--stop-signal**=*SIGTERM* 448 Signal to stop a container. Default is SIGTERM. 449 450 **--shm-size**="" 451 Size of `/dev/shm`. The format is `<number><unit>`. 452 `number` must be greater than `0`. Unit is optional and can be `b` (bytes), `k` (kilobytes), `m`(megabytes), or `g` (gigabytes). 453 If you omit the unit, the system uses bytes. If you omit the size entirely, the system uses `64m`. 454 455 **--sig-proxy**=*true*|*false* 456 Proxy received signals to the process (non-TTY mode only). SIGCHLD, SIGSTOP, and SIGKILL are not proxied. The default is *true*. 457 458 **--memory-swappiness**="" 459 Tune a container's memory swappiness behavior. Accepts an integer between 0 and 100. 460 461 **-t**, **--tty**=*true*|*false* 462 Allocate a pseudo-TTY. The default is *false*. 463 464 When set to true Docker can allocate a pseudo-tty and attach to the standard 465 input of any container. This can be used, for example, to run a throwaway 466 interactive shell. The default is false. 467 468 The **-t** option is incompatible with a redirection of the docker client 469 standard input. 470 471 **--tmpfs**=[] Create a tmpfs mount 472 473 Mount a temporary filesystem (`tmpfs`) mount into a container, for example: 474 475 $ docker run -d --tmpfs /tmp:rw,size=787448k,mode=1777 my_image 476 477 This command mounts a `tmpfs` at `/tmp` within the container. The mount copies 478 the underlying content of `my_image` into `/tmp`. For example if there was a 479 directory `/tmp/content` in the base image, docker will copy this directory and 480 all of its content on top of the tmpfs mounted on `/tmp`. The supported mount 481 options are the same as the Linux default `mount` flags. If you do not specify 482 any options, the systems uses the following options: 483 `rw,noexec,nosuid,nodev,size=65536k`. 484 485 **-u**, **--user**="" 486 Sets the username or UID used and optionally the groupname or GID for the specified command. 487 488 The followings examples are all valid: 489 --user [user | user:group | uid | uid:gid | user:gid | uid:group ] 490 491 Without this argument the command will be run as root in the container. 492 493 **--ulimit**=[] 494 Ulimit options 495 496 **-v**|**--volume**[=*[[HOST-DIR:]CONTAINER-DIR[:OPTIONS]]*] 497 Create a bind mount. If you specify, ` -v /HOST-DIR:/CONTAINER-DIR`, Docker 498 bind mounts `/HOST-DIR` in the host to `/CONTAINER-DIR` in the Docker 499 container. If 'HOST-DIR' is omitted, Docker automatically creates the new 500 volume on the host. The `OPTIONS` are a comma delimited list and can be: 501 502 * [rw|ro] 503 * [z|Z] 504 * [`[r]shared`|`[r]slave`|`[r]private`] 505 506 The `CONTAINER-DIR` must be an absolute path such as `/src/docs`. The `HOST-DIR` 507 can be an absolute path or a `name` value. A `name` value must start with an 508 alphanumeric character, followed by `a-z0-9`, `_` (underscore), `.` (period) or 509 `-` (hyphen). An absolute path starts with a `/` (forward slash). 510 511 If you supply a `HOST-DIR` that is an absolute path, Docker bind-mounts to the 512 path you specify. If you supply a `name`, Docker creates a named volume by that 513 `name`. For example, you can specify either `/foo` or `foo` for a `HOST-DIR` 514 value. If you supply the `/foo` value, Docker creates a bind-mount. If you 515 supply the `foo` specification, Docker creates a named volume. 516 517 You can specify multiple **-v** options to mount one or more mounts to a 518 container. To use these same mounts in other containers, specify the 519 **--volumes-from** option also. 520 521 You can add `:ro` or `:rw` suffix to a volume to mount it read-only or 522 read-write mode, respectively. By default, the volumes are mounted read-write. 523 See examples. 524 525 Labeling systems like SELinux require that proper labels are placed on volume 526 content mounted into a container. Without a label, the security system might 527 prevent the processes running inside the container from using the content. By 528 default, Docker does not change the labels set by the OS. 529 530 To change a label in the container context, you can add either of two suffixes 531 `:z` or `:Z` to the volume mount. These suffixes tell Docker to relabel file 532 objects on the shared volumes. The `z` option tells Docker that two containers 533 share the volume content. As a result, Docker labels the content with a shared 534 content label. Shared volume labels allow all containers to read/write content. 535 The `Z` option tells Docker to label the content with a private unshared label. 536 Only the current container can use a private volume. 537 538 By default bind mounted volumes are `private`. That means any mounts done 539 inside container will not be visible on host and vice-a-versa. One can change 540 this behavior by specifying a volume mount propagation property. Making a 541 volume `shared` mounts done under that volume inside container will be 542 visible on host and vice-a-versa. Making a volume `slave` enables only one 543 way mount propagation and that is mounts done on host under that volume 544 will be visible inside container but not the other way around. 545 546 To control mount propagation property of volume one can use `:[r]shared`, 547 `:[r]slave` or `:[r]private` propagation flag. Propagation property can 548 be specified only for bind mounted volumes and not for internal volumes or 549 named volumes. For mount propagation to work source mount point (mount point 550 where source dir is mounted on) has to have right propagation properties. For 551 shared volumes, source mount point has to be shared. And for slave volumes, 552 source mount has to be either shared or slave. 553 554 Use `df <source-dir>` to figure out the source mount and then use 555 `findmnt -o TARGET,PROPAGATION <source-mount-dir>` to figure out propagation 556 properties of source mount. If `findmnt` utility is not available, then one 557 can look at mount entry for source mount point in `/proc/self/mountinfo`. Look 558 at `optional fields` and see if any propagaion properties are specified. 559 `shared:X` means mount is `shared`, `master:X` means mount is `slave` and if 560 nothing is there that means mount is `private`. 561 562 To change propagation properties of a mount point use `mount` command. For 563 example, if one wants to bind mount source directory `/foo` one can do 564 `mount --bind /foo /foo` and `mount --make-private --make-shared /foo`. This 565 will convert /foo into a `shared` mount point. Alternatively one can directly 566 change propagation properties of source mount. Say `/` is source mount for 567 `/foo`, then use `mount --make-shared /` to convert `/` into a `shared` mount. 568 569 **--volume-driver**="" 570 Container's volume driver. This driver creates volumes specified either from 571 a Dockerfile's `VOLUME` instruction or from the `docker run -v` flag. 572 See **docker-volume-create(1)** for full details. 573 574 **--volumes-from**=[] 575 Mount volumes from the specified container(s) 576 577 Mounts already mounted volumes from a source container onto another 578 container. You must supply the source's container-id. To share 579 a volume, use the **--volumes-from** option when running 580 the target container. You can share volumes even if the source container 581 is not running. 582 583 By default, Docker mounts the volumes in the same mode (read-write or 584 read-only) as it is mounted in the source container. Optionally, you 585 can change this by suffixing the container-id with either the `:ro` or 586 `:rw ` keyword. 587 588 If the location of the volume from the source container overlaps with 589 data residing on a target container, then the volume hides 590 that data on the target. 591 592 **-w**, **--workdir**="" 593 Working directory inside the container 594 595 The default working directory for 596 running binaries within a container is the root directory (/). The developer can 597 set a different default with the Dockerfile WORKDIR instruction. The operator 598 can override the working directory by using the **-w** option. 599 600 # Exit Status 601 602 The exit code from `docker run` gives information about why the container 603 failed to run or why it exited. When `docker run` exits with a non-zero code, 604 the exit codes follow the `chroot` standard, see below: 605 606 **_125_** if the error is with Docker daemon **_itself_** 607 608 $ docker run --foo busybox; echo $? 609 # flag provided but not defined: --foo 610 See 'docker run --help'. 611 125 612 613 **_126_** if the **_contained command_** cannot be invoked 614 615 $ docker run busybox /etc; echo $? 616 # exec: "/etc": permission denied 617 docker: Error response from daemon: Contained command could not be invoked 618 126 619 620 **_127_** if the **_contained command_** cannot be found 621 622 $ docker run busybox foo; echo $? 623 # exec: "foo": executable file not found in $PATH 624 docker: Error response from daemon: Contained command not found or does not exist 625 127 626 627 **_Exit code_** of **_contained command_** otherwise 628 629 $ docker run busybox /bin/sh -c 'exit 3' 630 # 3 631 632 # EXAMPLES 633 634 ## Running container in read-only mode 635 636 During container image development, containers often need to write to the image 637 content. Installing packages into /usr, for example. In production, 638 applications seldom need to write to the image. Container applications write 639 to volumes if they need to write to file systems at all. Applications can be 640 made more secure by running them in read-only mode using the --read-only switch. 641 This protects the containers image from modification. Read only containers may 642 still need to write temporary data. The best way to handle this is to mount 643 tmpfs directories on /run and /tmp. 644 645 # docker run --read-only --tmpfs /run --tmpfs /tmp -i -t fedora /bin/bash 646 647 ## Exposing log messages from the container to the host's log 648 649 If you want messages that are logged in your container to show up in the host's 650 syslog/journal then you should bind mount the /dev/log directory as follows. 651 652 # docker run -v /dev/log:/dev/log -i -t fedora /bin/bash 653 654 From inside the container you can test this by sending a message to the log. 655 656 (bash)# logger "Hello from my container" 657 658 Then exit and check the journal. 659 660 # exit 661 662 # journalctl -b | grep Hello 663 664 This should list the message sent to logger. 665 666 ## Attaching to one or more from STDIN, STDOUT, STDERR 667 668 If you do not specify -a then Docker will attach everything (stdin,stdout,stderr) 669 . You can specify to which of the three standard streams (stdin, stdout, stderr) 670 you’d like to connect instead, as in: 671 672 # docker run -a stdin -a stdout -i -t fedora /bin/bash 673 674 ## Sharing IPC between containers 675 676 Using shm_server.c available here: https://www.cs.cf.ac.uk/Dave/C/node27.html 677 678 Testing `--ipc=host` mode: 679 680 Host shows a shared memory segment with 7 pids attached, happens to be from httpd: 681 682 ``` 683 $ sudo ipcs -m 684 685 ------ Shared Memory Segments -------- 686 key shmid owner perms bytes nattch status 687 0x01128e25 0 root 600 1000 7 688 ``` 689 690 Now run a regular container, and it correctly does NOT see the shared memory segment from the host: 691 692 ``` 693 $ docker run -it shm ipcs -m 694 695 ------ Shared Memory Segments -------- 696 key shmid owner perms bytes nattch status 697 ``` 698 699 Run a container with the new `--ipc=host` option, and it now sees the shared memory segment from the host httpd: 700 701 ``` 702 $ docker run -it --ipc=host shm ipcs -m 703 704 ------ Shared Memory Segments -------- 705 key shmid owner perms bytes nattch status 706 0x01128e25 0 root 600 1000 7 707 ``` 708 Testing `--ipc=container:CONTAINERID` mode: 709 710 Start a container with a program to create a shared memory segment: 711 ``` 712 $ docker run -it shm bash 713 $ sudo shm/shm_server & 714 $ sudo ipcs -m 715 716 ------ Shared Memory Segments -------- 717 key shmid owner perms bytes nattch status 718 0x0000162e 0 root 666 27 1 719 ``` 720 Create a 2nd container correctly shows no shared memory segment from 1st container: 721 ``` 722 $ docker run shm ipcs -m 723 724 ------ Shared Memory Segments -------- 725 key shmid owner perms bytes nattch status 726 ``` 727 728 Create a 3rd container using the new --ipc=container:CONTAINERID option, now it shows the shared memory segment from the first: 729 730 ``` 731 $ docker run -it --ipc=container:ed735b2264ac shm ipcs -m 732 $ sudo ipcs -m 733 734 ------ Shared Memory Segments -------- 735 key shmid owner perms bytes nattch status 736 0x0000162e 0 root 666 27 1 737 ``` 738 739 ## Linking Containers 740 741 The link feature allows multiple containers to communicate with each other. For 742 example, a container whose Dockerfile has exposed port 80 can be run and named 743 as follows: 744 745 # docker run --name=link-test -d -i -t fedora/httpd 746 747 A second container, in this case called linker, can communicate with the httpd 748 container, named link-test, by running with the **--link=<name>:<alias>** 749 750 # docker run -t -i --link=link-test:lt --name=linker fedora /bin/bash 751 752 Now the container linker is linked to container link-test with the alias lt. 753 Running the **env** command in the linker container shows environment variables 754 with the LT (alias) context (**LT_**) 755 756 # env 757 HOSTNAME=668231cb0978 758 TERM=xterm 759 LT_PORT_80_TCP=tcp://172.17.0.3:80 760 LT_PORT_80_TCP_PORT=80 761 LT_PORT_80_TCP_PROTO=tcp 762 LT_PORT=tcp://172.17.0.3:80 763 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin 764 PWD=/ 765 LT_NAME=/linker/lt 766 SHLVL=1 767 HOME=/ 768 LT_PORT_80_TCP_ADDR=172.17.0.3 769 _=/usr/bin/env 770 771 When linking two containers Docker will use the exposed ports of the container 772 to create a secure tunnel for the parent to access. 773 774 If a container is connected to the default bridge network and `linked` 775 with other containers, then the container's `/etc/hosts` file is updated 776 with the linked container's name. 777 778 > **Note** Since Docker may live update the container’s `/etc/hosts` file, there 779 may be situations when processes inside the container can end up reading an 780 empty or incomplete `/etc/hosts` file. In most cases, retrying the read again 781 should fix the problem. 782 783 784 ## Mapping Ports for External Usage 785 786 The exposed port of an application can be mapped to a host port using the **-p** 787 flag. For example, a httpd port 80 can be mapped to the host port 8080 using the 788 following: 789 790 # docker run -p 8080:80 -d -i -t fedora/httpd 791 792 ## Creating and Mounting a Data Volume Container 793 794 Many applications require the sharing of persistent data across several 795 containers. Docker allows you to create a Data Volume Container that other 796 containers can mount from. For example, create a named container that contains 797 directories /var/volume1 and /tmp/volume2. The image will need to contain these 798 directories so a couple of RUN mkdir instructions might be required for you 799 fedora-data image: 800 801 # docker run --name=data -v /var/volume1 -v /tmp/volume2 -i -t fedora-data true 802 # docker run --volumes-from=data --name=fedora-container1 -i -t fedora bash 803 804 Multiple --volumes-from parameters will bring together multiple data volumes from 805 multiple containers. And it's possible to mount the volumes that came from the 806 DATA container in yet another container via the fedora-container1 intermediary 807 container, allowing to abstract the actual data source from users of that data: 808 809 # docker run --volumes-from=fedora-container1 --name=fedora-container2 -i -t fedora bash 810 811 ## Mounting External Volumes 812 813 To mount a host directory as a container volume, specify the absolute path to 814 the directory and the absolute path for the container directory separated by a 815 colon: 816 817 # docker run -v /var/db:/data1 -i -t fedora bash 818 819 When using SELinux, be aware that the host has no knowledge of container SELinux 820 policy. Therefore, in the above example, if SELinux policy is enforced, the 821 `/var/db` directory is not writable to the container. A "Permission Denied" 822 message will occur and an avc: message in the host's syslog. 823 824 825 To work around this, at time of writing this man page, the following command 826 needs to be run in order for the proper SELinux policy type label to be attached 827 to the host directory: 828 829 # chcon -Rt svirt_sandbox_file_t /var/db 830 831 832 Now, writing to the /data1 volume in the container will be allowed and the 833 changes will also be reflected on the host in /var/db. 834 835 ## Using alternative security labeling 836 837 You can override the default labeling scheme for each container by specifying 838 the `--security-opt` flag. For example, you can specify the MCS/MLS level, a 839 requirement for MLS systems. Specifying the level in the following command 840 allows you to share the same content between containers. 841 842 # docker run --security-opt label:level:s0:c100,c200 -i -t fedora bash 843 844 An MLS example might be: 845 846 # docker run --security-opt label:level:TopSecret -i -t rhel7 bash 847 848 To disable the security labeling for this container versus running with the 849 `--permissive` flag, use the following command: 850 851 # docker run --security-opt label:disable -i -t fedora bash 852 853 If you want a tighter security policy on the processes within a container, 854 you can specify an alternate type for the container. You could run a container 855 that is only allowed to listen on Apache ports by executing the following 856 command: 857 858 # docker run --security-opt label:type:svirt_apache_t -i -t centos bash 859 860 Note: 861 862 You would have to write policy defining a `svirt_apache_t` type. 863 864 ## Setting device weight 865 866 If you want to set `/dev/sda` device weight to `200`, you can specify the device 867 weight by `--blkio-weight-device` flag. Use the following command: 868 869 # docker run -it --blkio-weight-device "/dev/sda:200" ubuntu 870 871 ## Specify isolation technology for container (--isolation) 872 873 This option is useful in situations where you are running Docker containers on 874 Microsoft Windows. The `--isolation <value>` option sets a container's isolation 875 technology. On Linux, the only supported is the `default` option which uses 876 Linux namespaces. These two commands are equivalent on Linux: 877 878 ``` 879 $ docker run -d busybox top 880 $ docker run -d --isolation default busybox top 881 ``` 882 883 On Microsoft Windows, can take any of these values: 884 885 * `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. 886 * `process`: Namespace isolation only. 887 * `hyperv`: Hyper-V hypervisor partition-based isolation. 888 889 In practice, when running on Microsoft Windows without a `daemon` option set, these two commands are equivalent: 890 891 ``` 892 $ docker run -d --isolation default busybox top 893 $ docker run -d --isolation process busybox top 894 ``` 895 896 If you have set the `--exec-opt isolation=hyperv` option on the Docker `daemon`, any of these commands also result in `hyperv` isolation: 897 898 ``` 899 $ docker run -d --isolation default busybox top 900 $ docker run -d --isolation hyperv busybox top 901 ``` 902 903 # HISTORY 904 April 2014, Originally compiled by William Henry (whenry at redhat dot com) 905 based on docker.com source material and internal work. 906 June 2014, updated by Sven Dowideit <SvenDowideit@home.org.au> 907 July 2014, updated by Sven Dowideit <SvenDowideit@home.org.au> 908 November 2015, updated by Sally O'Malley <somalley@redhat.com>