1crun(1) General Commands Manual crun(1)
2
6 crun - a fast and lightweight OCI runtime
7
11 crun [global options] command [command options] [arguments...]
12
16 crun is a command line program for running Linux containers that follow
17 the Open Container Initiative (OCI) format.
18
22 create Create a container. The runtime detaches from the container
23 process once the container environment is created. It is necessary to
24 successively use start for starting the container.
25 delete Remove definition for a container.
28 exec Exec a command in a running container.
31 list List known containers.
34 kill Send the specified signal to the container init process. If no
37 signal is specified, SIGTERM is used.
38 ps Show the processes running in a container.
41 run Create and immediately start a container.
44 spec Generate a configuration file.
47 start Start a container that was previously created. A container can‐
50 not be started multiple times.
51 state Output the state of a container.
54 pause Pause all the processes in the container.
57 resume Resume the processes in the container.
60 update Update container resource constraints.
63 checkpoint Checkpoint a running container using CRIU
66 restore Restore a container from a checkpoint
69
73 By default, when running as root user, crun saves its state under the
74 /run/crun directory. As unprivileged user, instead the XDG_RUNTIME_DIR
75 environment variable is honored, and the directory $XDG_RUN‐
76 TIME_DIR/crun is used. The global option --root overrides this set‐
77 ting.
78
82 --debug Produce verbose output.
83 --log=LOG-DESTINATION Define the destination for the error and warning
86 messages generated by crun. If the error happens late in the container
87 init process, when crun already stopped watching it, then it will be
88 printed to the container stderr.
89 It is specified in the form BACKEND:SPECIFIER.
92 These following backends are supported:
95 • file:PATH
98 • journald:IDENTIFIER
100 • syslog:IDENTIFIER
102 If no backend is specified, then file: is used by default.
106 --log-format=FORMAT Define the format of the log messages. It can ei‐
109 ther be text, or json. The default is text.
110 --no-pivot Use chroot(2) instead of pivot_root(2) when creating the
113 container. This option is not safe, and should be avoided.
114 --root=DIR Defines where to store the state for crun containers.
117 --systemd-cgroup Use systemd for configuring cgroups. If not speci‐
120 fied, the cgroup is created directly using the cgroupfs backend.
121 --cgroup-manager=MANAGER Specify what cgroup manager must be used.
124 Permitted values are cgroupfs, systemd and disabled.
125 -?, --help Print a help list.
128 --usage Print a short usage message.
131 -V, --version Print program version
134
137 crun [global options] create [options] CONTAINER
138 --bundle=BUNDLE Path to the OCI bundle, by default it is the current
141 directory.
142 --config=FILE Override the configuration file to use. The default
145 value is config.json.
146 --console-socket=SOCKET Path to a UNIX socket that will receive the
149 ptmx end of the tty for the container.
150 --no-new-keyring Keep the same session key
153 --preserve-fds=N Additional number of FDs to pass into the container.
156 --pid-file=PATH Path to the file that will contain the container
159 process PID.
160
163 crun [global options] run [options] CONTAINER
164 --bundle=BUNDLE Path to the OCI bundle, by default it is the current
167 directory.
168 --config=FILE Override the configuration file to use. The default
171 value is config.json.
172 --console-socket=SOCKET Path to a UNIX socket that will receive the
175 ptmx end of the tty for the container.
176 --no-new-keyring Keep the same session key.
179 --preserve-fds=N Additional number of FDs to pass into the container.
182 --pid-file=PATH Path to the file that will contain the container
185 process PID.
186 --detach Detach the container process from the current session.
189
192 crun [global options] delete [options] CONTAINER
193 --force Delete the container even if it is still running.
196 --regex=REGEX Delete all the containers that satisfy the specified
199 regex.
200
203 crun [global options] exec [options] CONTAINER CMD
204 --apparmor=PROFILE Set the apparmor profile for the process.
207 --console-socket=SOCKET Path to a UNIX socket that will receive the
210 ptmx end of the tty for the container.
211 --cwd=PATH Set the working directory for the process to PATH.
214 --cap=CAP Specify an additional capability to add to the process.
217 --detach Detach the container process from the current session.
220 --env=ENV Specify an environment variable.
223 --no-new-privs Set the no new privileges value for the process.
226 --preserve-fds=N Additional number of FDs to pass into the container.
229 --process=FILE Path to a file containing the process JSON configura‐
232 tion.
233 --process-label=VALUE Set the asm process label for the process com‐
236 monly used with selinux.
237 --pid-file=PATH Path to the file that will contain the new process PID.
240 -t --tty Allocate a pseudo TTY.
243 -u USERSPEC --user=USERSPEC Specify the user in the form UID[:GID].
246
249 crun [global options] list [options]
250 -q --quiet Show only the container ID.
253
256 crun [global options] kill [options] CONTAINER SIGNAL
257 --all Kill all the processes in the container.
260 --regex=REGEX Kill all the containers that satisfy the specified regex.
263
266 crun [global options] ps [options]
267 --format=FORMAT Specify the output format. It must be either table or
270 json. By default table is used.
271
274 crun [global options] spec [options]
275 -b DIR --bundle=DIR Path to the root of the bundle dir (default ".").
278 --rootless Generate a config.json file that is usable by an unprivi‐
281 leged user.
282
285 crun [global options] update [options] CONTAINER
286 --blkio-weight=VALUE Specifies per cgroup weight.
289 --cpu-period=VALUE CPU CFS period to be used for hardcapping.
292 --cpu-quota=VALUE** CPU CFS hardcap limit.
295 --cpu-rt-period=VALUE CPU realtime period to be used for hardcapping.
298 --cpu-rt-runtime=VALUE CPU realtime hardcap limit.
301 --cpu-share=VALUE CPU shares.
304 --cpuset-cpus=VALUE CPU(s) to use.
307 --cpuset-mems=VALUE Memory node(s) to use.
310 --kernel-memory=VALUE Kernel memory limit.
313 --kernel-memory-tcp=VALUE Kernel memory limit for TCP buffer.
316 --memory=VALUE Memory limit.
319 --memory-reservation=VALUE Memory reservation or soft_limit.
322 --memory-swap=VALUE Total memory usage.
325 --pids-limit=VALUE Maximum number of pids allowed in the container.
328 -r, --resources=FILE Path to the file containing the resources to up‐
331 date.
332
335 crun [global options] checkpoint [options] CONTAINER
336 --image-path=DIR Path for saving CRIU image files
339 --work-path=DIR Path for saving work files and logs
342 --leave-running Leave the process running after checkpointing
345 --tcp-established Allow open TCP connections
348 --ext-unix-sk Allow external UNIX sockets
351 --shell-job Allow shell jobs
354
357 crun [global options] restore [options] CONTAINER
358 -b DIR --bundle=DIR Container bundle directory (default ".")
361 --image-path=DIR Path for saving CRIU image files
364 --work-path=DIR Path for saving work files and logs
367 --tcp-established Allow open TCP connections
370 --ext-unix Allow external UNIX sockets
373 --shell-job Allow shell jobs
376 --detach Detach from the container's process
379 --pid-file=FILE Where to write the PID of the container
382
387 If the annotation run.oci.seccomp.receiver=PATH is specified, the sec‐
388 comp listener is sent to the UNIX socket listening on the specified
389 path. It can also set with the RUN_OCI_SECCOMP_RECEIVER environment
390 variable. It is an experimental feature, and the annotation will be
391 removed once it is supported in the OCI runtime specs. It must be an
392 absolute path.
393
396 If the annotation run.oci.seccomp.plugins=PLUGIN1[:PLUGIN2]... is spec‐
397 ified, the seccomp listener fd is handled through the specified plug‐
398 ins. The plugin must either be an absolute path or a file name that is
399 looked up by ldopen(3). More information on how the lookup is per‐
400 formed are available on the ld.so(8) man page.
401
404 If the annotation run.oci.seccomp_fail_unknown_syscall is present, then
405 crun will fail when an unknown syscall is encountered in the seccomp
406 configuration.
407
410 If the annotation run.oci.seccomp_bpf_data is present, then crun ig‐
411 nores the seccomp section in the OCI configuration file and use the
412 specified data as the raw data to the seccomp(SECCOMP_SET_MODE_FILTER)
413 syscall. The data must be encoded in base64.
414 It is an experimental feature, and the annotation will be removed once
417 it is supported in the OCI runtime specs.
418
421 If the annotation run.oci.keep_original_groups is present, then crun
422 will skip the setgroups syscall that is used to either set the addi‐
423 tional groups specified in the OCI configuration, or to reset the list
424 of additional groups if none is specified.
425
428 If the annotation run.oci.systemd.force_cgroup_v1=/PATH is present,
429 then crun will override the specified mount point /PATH with a cgroup
430 v1 mount made of a single hierarchy none,name=systemd. It is useful to
431 run on a cgroup v2 system containers using older versions of systemd
432 that lack support for cgroup v2.
433
436 Specify the offset to be written to /proc/self/timens_offsets when cre‐
437 ating a time namespace.
438
441 Override the name for the systemd sub cgroup created under the systemd
442 scope, so the final cgroup will be like:
443 /sys/fs/cgroup/$PATH/$SUBGROUP
446 When it is set to the empty string, a sub cgroup is not created.
450 If not specified, it defaults to container on cgroup v2, and to "" on
453 cgroup v1.
454 e.g.
457 /sys/fs/cgroup//system.slice/foo-352700.scope/container
460
464 If the run.oci.systemd.subgroup annotation is specified, yet another
465 sub-cgroup is created and the container process is moved here.
466 /sys/fs/cgroup/$PATH/$SUBGROUP/$DELEGATED-CGROUP
469 The runtime doesn't apply any limit to the $DELEGATED-CGROUP
473 sub-cgroup, the runtime uses only $PATH/$SUBGROUP.
474 The container payload fully manages $DELEGATE-CGROUP, the limits ap‐
477 plied to $PATH/$SUBGROUP still applies to $DELEGATE-CGROUP.
478 Since cgroup delegation is not safe on cgroup v1, this option is sup‐
481 ported only on cgroup v2.
482
485 If the annotation run.oci.hooks.stdout is present, then crun will open
486 the specified file and use it as the stdout for the hook processes.
487 The file is opened in append mode and it is created if it doesn't al‐
488 ready exist.
489
492 If the annotation run.oci.hooks.stderr is present, then crun will open
493 the specified file and use it as the stderr for the hook processes.
494 The file is opened in append mode and it is created if it doesn't al‐
495 ready exist.
496
499 It is an experimental feature.
500 If specified, run the specified handler for execing the container. The
503 only supported value is krun. When krun is specified, the libkrun.so
504 shared object is loaded and it is used to launch the container using
505 libkrun.
506
509 If the tmpcopyup option is specified for a tmpfs, then the path that is
510 shadowed by the tmpfs mount is recursively copied up to the tmpfs it‐
511 self.
512
515 When running as user different than root, an user namespace is automat‐
516 ically created even if it is not specified in the config file. The
517 current user is mapped to the ID 0 in the container, and any additional
518 id specified in the files /etc/subuid and /etc/subgid is automatically
519 added starting with ID 1.
520
523 If the configuration specifies a new user namespace made of a single
524 mapping to the root user, but either the UID or the GID are set as non‐
525 zero then crun automatically creates another user namespace to map the
526 root user to the specified UID and GID.
527 It enables running unprivileged containers with UID and GID different
530 than zero, even when a single UID and GID are available, e.g. rootless
531 users on a system without newuidmap/newgidmap.
532
536 If the cgroup configuration found is for cgroup v1, crun attempts a
537 conversion when running on a cgroup v2 system.
538 These are the OCI resources currently supported with cgroup v2 and how
541 they are converted when needed from the cgroup v1 configuration.
542
545 ┌────────────┬────────────────────┬────────────┬─────────┐
546 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
547 ├────────────┼────────────────────┼────────────┼─────────┤
548 │limit │ memory.max │ y = x │ swap │
549 ├────────────┼────────────────────┼────────────┼─────────┤
550 │reservation │ memory.low │ y = x │ │
551 └────────────┴────────────────────┴────────────┴─────────┘
552
554 ┌────────┬────────────────────┬────────────┬─────────┐
555 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
556 ├────────┼────────────────────┼────────────┼─────────┤
557 │limit │ pids.max │ y = x │ │
558 └────────┴────────────────────┴────────────┴─────────┘
559
561 ┌────────┬────────────────────┬──────────────────┬──────────────────┐
562 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
563 ├────────┼────────────────────┼──────────────────┼──────────────────┤
564 │shares │ cpu.weight │ y = (1 + ((x - │ │
565 │ │ │ 2) * 9999) / │ │
566 │ │ │ 262142) │ │
567 ├────────┼────────────────────┼──────────────────┼──────────────────┤
568 │ │ convert from │ │ │
569 │ │ [2-262144] to │ │ │
570 │ │ [1-10000] │ │ │
571 ├────────┼────────────────────┼──────────────────┼──────────────────┤
572 │period │ cpu.max │ y = x │ period and quota │
573 │ │ │ │ are written to‐ │
574 │ │ │ │ gether │
575 ├────────┼────────────────────┼──────────────────┼──────────────────┤
576 │quota │ cpu.max │ y = x │ period and quota │
577 │ │ │ │ are written to‐ │
578 │ │ │ │ gether │
579 ├────────┼────────────────────┼──────────────────┼──────────────────┤
580 │ │ │ │ │
581 └────────┴────────────────────┴──────────────────┴──────────────────┘
582
584 ┌────────┬────────────────────┬────────────┬───────────────┐
585 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
586 ├────────┼────────────────────┼────────────┼───────────────┤
587 │weight │ io.bfq.weight │ y = x │ weight_device │
588 └────────┴────────────────────┴────────────┴───────────────┘
589
591 ┌────────┬────────────────────┬────────────┬─────────┐
592 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
593 ├────────┼────────────────────┼────────────┼─────────┤
594 │cpus │ cpuset.cpus │ y = x │ mems │
595 └────────┴────────────────────┴────────────┴─────────┘
596
598 ┌────────────────┬────────────────────┬────────────┬─────────┐
599 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
600 ├────────────────┼────────────────────┼────────────┼─────────┤
601 │.limit_in_bytes │ hugetlb..max │ y = x │ │
602 └────────────────┴────────────────────┴────────────┴─────────┘
603 User Commands crun(1)