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=PATH Path to the OCI bundle, by default it is the current di‐
141 rectory.
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 --cgroup=PATH Specify a sub-cgroup path inside the container cgroup.
223 The path must already exist in the container cgroup.
224 --env=ENV Specify an environment variable.
227 --no-new-privs Set the no new privileges value for the process.
230 --preserve-fds=N Additional number of FDs to pass into the container.
233 --process=FILE Path to a file containing the process JSON configura‐
236 tion.
237 --process-label=VALUE Set the asm process label for the process com‐
240 monly used with selinux.
241 --pid-file=PATH Path to the file that will contain the new process PID.
244 -t --tty Allocate a pseudo TTY.
247 **-u USERSPEC --user=USERSPEC Specify the user in the form UID[:GID].
250
253 crun [global options] list [options]
254 -q --quiet Show only the container ID.
257
260 crun [global options] kill [options] CONTAINER SIGNAL
261 --all Kill all the processes in the container.
264 --regex=REGEX Kill all the containers that satisfy the specified regex.
267
270 crun [global options] ps [options]
271 --format=FORMAT Specify the output format. It must be either table or
274 json. By default table is used.
275
278 crun [global options] spec [options]
279 -b DIR --bundle=DIR Path to the root of the bundle dir (default ".").
282 --rootless Generate a config.json file that is usable by an unprivi‐
285 leged user.
286
289 crun [global options] update [options] CONTAINER
290 --blkio-weight=VALUE Specifies per cgroup weight.
293 --cpu-period=VALUE CPU CFS period to be used for hardcapping.
296 --cpu-quota=VALUE CPU CFS hardcap limit.
299 --cpu-rt-period=VALUE CPU realtime period to be used for hardcapping.
302 --cpu-rt-runtime=VALUE CPU realtime hardcap limit.
305 --cpu-share=VALUE CPU shares.
308 --cpuset-cpus=VALUE CPU(s) to use.
311 --cpuset-mems=VALUE Memory node(s) to use.
314 --kernel-memory=VALUE Kernel memory limit.
317 --kernel-memory-tcp=VALUE Kernel memory limit for TCP buffer.
320 --memory=VALUE Memory limit.
323 --memory-reservation=VALUE Memory reservation or soft_limit.
326 --memory-swap=VALUE Total memory usage.
329 --pids-limit=VALUE Maximum number of pids allowed in the container.
332 -r, --resources=FILE Path to the file containing the resources to up‐
335 date.
336
339 crun [global options] checkpoint [options] CONTAINER
340 --image-path=DIR Path for saving CRIU image files
343 --work-path=DIR Path for saving work files and logs
346 --leave-running Leave the process running after checkpointing
349 --tcp-established Allow open TCP connections
352 --ext-unix-sk Allow external UNIX sockets
355 --shell-job Allow shell jobs
358
361 crun [global options] restore [options] CONTAINER
362 -b DIR --bundle=DIR Container bundle directory (default ".")
365 --image-path=DIR Path for saving CRIU image files
368 --work-path=DIR Path for saving work files and logs
371 --tcp-established Allow open TCP connections
374 --ext-unix Allow external UNIX sockets
377 --shell-job Allow shell jobs
380 --detach Detach from the container's process
383 --pid-file=FILE Where to write the PID of the container
386
391 If the annotation run.oci.seccomp.receiver=PATH is specified, the sec‐
392 comp listener is sent to the UNIX socket listening on the specified
393 path. It can also set with the RUN_OCI_SECCOMP_RECEIVER environment
394 variable. It is an experimental feature, and the annotation will be
395 removed once it is supported in the OCI runtime specs. It must be an
396 absolute path.
397
400 If the annotation run.oci.seccomp.plugins=PLUGIN1[:PLUGIN2]... is spec‐
401 ified, the seccomp listener fd is handled through the specified plug‐
402 ins. The plugin must either be an absolute path or a file name that is
403 looked up by ldopen(3). More information on how the lookup is per‐
404 formed are available on the ld.so(8) man page.
405
408 If the annotation run.oci.seccomp_fail_unknown_syscall is present, then
409 crun will fail when an unknown syscall is encountered in the seccomp
410 configuration.
411
414 If the annotation run.oci.seccomp_bpf_data is present, then crun ig‐
415 nores the seccomp section in the OCI configuration file and use the
416 specified data as the raw data to the seccomp(SECCOMP_SET_MODE_FILTER)
417 syscall. The data must be encoded in base64.
418 It is an experimental feature, and the annotation will be removed once
421 it is supported in the OCI runtime specs.
422
425 If the annotation run.oci.keep_original_groups is present, then crun
426 will skip the setgroups syscall that is used to either set the addi‐
427 tional groups specified in the OCI configuration, or to reset the list
428 of additional groups if none is specified.
429
432 If the annotation run.oci.systemd.force_cgroup_v1=/PATH is present,
433 then crun will override the specified mount point /PATH with a cgroup
434 v1 mount made of a single hierarchy none,name=systemd. It is useful to
435 run on a cgroup v2 system containers using older versions of systemd
436 that lack support for cgroup v2.
437 Note: Your container host has to have the cgroup v1 mount already
440 present, otherwise this will not work. If you want to run the container
441 rootless, the user it runs under has to have permissions to this mount‐
442 point.
443 For example, as root:
446 mkdir /sys/fs/cgroup/systemd
449 mount cgroup -t cgroup /sys/fs/cgroup/systemd -o none,name=systemd,xattr
450 chown -R the_user.the_user /sys/fs/cgroup/systemd
451
455 Specify the offset to be written to /proc/self/timens_offsets when cre‐
456 ating a time namespace.
457
460 Override the name for the systemd sub cgroup created under the systemd
461 scope, so the final cgroup will be like:
462 /sys/fs/cgroup/$PATH/$SUBGROUP
465 When it is set to the empty string, a sub cgroup is not created.
469 If not specified, it defaults to container on cgroup v2, and to "" on
472 cgroup v1.
473 e.g.
476 /sys/fs/cgroup//system.slice/foo-352700.scope/container
479
483 If the run.oci.systemd.subgroup annotation is specified, yet another
484 sub-cgroup is created and the container process is moved here.
485 /sys/fs/cgroup/$PATH/$SUBGROUP/$DELEGATED-CGROUP
488 The runtime doesn't apply any limit to the $DELEGATED-CGROUP sub-
492 cgroup, the runtime uses only $PATH/$SUBGROUP.
493 The container payload fully manages $DELEGATE-CGROUP, the limits ap‐
496 plied to $PATH/$SUBGROUP still applies to $DELEGATE-CGROUP.
497 Since cgroup delegation is not safe on cgroup v1, this option is sup‐
500 ported only on cgroup v2.
501
504 If the annotation run.oci.hooks.stdout is present, then crun will open
505 the specified file and use it as the stdout for the hook processes.
506 The file is opened in append mode and it is created if it doesn't al‐
507 ready exist.
508
511 If the annotation run.oci.hooks.stderr is present, then crun will open
512 the specified file and use it as the stderr for the hook processes.
513 The file is opened in append mode and it is created if it doesn't al‐
514 ready exist.
515
518 It is an experimental feature.
519 If specified, run the specified handler for execing the container. The
522 only supported value is krun. When krun is specified, the libkrun.so
523 shared object is loaded and it is used to launch the container using
524 libkrun.
525
528 If specified, run the wasm handler for container. Allows running wasm
529 workload natively. Accepts a .wasm binary as input and if .wat is pro‐
530 vided it will automatically compiled into a wasm module. Stdout of
531 wasm module is relayed back via crun.
532
535 If the tmpcopyup option is specified for a tmpfs, then the path that is
536 shadowed by the tmpfs mount is recursively copied up to the tmpfs it‐
537 self.
538
541 When running as user different than root, an user namespace is automat‐
542 ically created even if it is not specified in the config file. The
543 current user is mapped to the ID 0 in the container, and any additional
544 id specified in the files /etc/subuid and /etc/subgid is automatically
545 added starting with ID 1.
546
549 If the configuration specifies a new user namespace made of a single
550 mapping to the root user, but either the UID or the GID are set as non‐
551 zero then crun automatically creates another user namespace to map the
552 root user to the specified UID and GID.
553 It enables running unprivileged containers with UID and GID different
556 than zero, even when a single UID and GID are available, e.g. rootless
557 users on a system without newuidmap/newgidmap.
558
562 Note: cgroup v2 does not yet support control of realtime processes and
563 the cpu controller can only be enabled when all RT processes are in the
564 root cgroup. This will make crun fail while running alongside RT pro‐
565 cesses.
566 If the cgroup configuration found is for cgroup v1, crun attempts a
569 conversion when running on a cgroup v2 system.
570 These are the OCI resources currently supported with cgroup v2 and how
573 they are converted when needed from the cgroup v1 configuration.
574
577 ┌────────────┬────────────────────┬──────────────────────┬──────────────────┐
578 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
579 ├────────────┼────────────────────┼──────────────────────┼──────────────────┤
580 │limit │ memory.max │ y = x │ │
581 ├────────────┼────────────────────┼──────────────────────┼──────────────────┤
582 │swap │ memory.swap.max │ y = x - memory_limit │ the swap limit │
583 │ │ │ │ on cgroup v1 in‐ │
584 │ │ │ │ cludes the mem‐ │
585 │ │ │ │ ory usage too │
586 ├────────────┼────────────────────┼──────────────────────┼──────────────────┤
587 │reservation │ memory.low │ y = x │ │
588 └────────────┴────────────────────┴──────────────────────┴──────────────────┘
589
591 ┌────────┬────────────────────┬────────────┬─────────┐
592 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
593 ├────────┼────────────────────┼────────────┼─────────┤
594 │limit │ pids.max │ y = x │ │
595 └────────┴────────────────────┴────────────┴─────────┘
596
598 ┌────────┬────────────────────┬──────────────────┬──────────────────┐
599 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
600 ├────────┼────────────────────┼──────────────────┼──────────────────┤
601 │shares │ cpu.weight │ y = (1 + ((x - │ │
602 │ │ │ 2) * 9999) / │ │
603 │ │ │ 262142) │ │
604 ├────────┼────────────────────┼──────────────────┼──────────────────┤
605 │ │ convert from │ │ │
606 │ │ [2-262144] to │ │ │
607 │ │ [1-10000] │ │ │
608 ├────────┼────────────────────┼──────────────────┼──────────────────┤
609 │period │ cpu.max │ y = x │ period and quota │
610 │ │ │ │ are written to‐ │
611 │ │ │ │ gether │
612 ├────────┼────────────────────┼──────────────────┼──────────────────┤
613 │quota │ cpu.max │ y = x │ period and quota │
614 │ │ │ │ are written to‐ │
615 │ │ │ │ gether │
616 └────────┴────────────────────┴──────────────────┴──────────────────┘
617
619 ┌──────────────┬────────────────────┬────────────┬─────────┐
620 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
621 ├──────────────┼────────────────────┼────────────┼─────────┤
622 │weight │ io.bfq.weight │ y = x │ │
623 ├──────────────┼────────────────────┼────────────┼─────────┤
624 │weight_device │ io.bfq.weight │ y = x │ │
625 ├──────────────┼────────────────────┼────────────┼─────────┤
626 │rbps │ io.max │ y=x │ │
627 ├──────────────┼────────────────────┼────────────┼─────────┤
628 │wbps │ io.max │ y=x │ │
629 ├──────────────┼────────────────────┼────────────┼─────────┤
630 │riops │ io.max │ y=x │ │
631 ├──────────────┼────────────────────┼────────────┼─────────┤
632 │wiops │ io.max │ y=x │ │
633 └──────────────┴────────────────────┴────────────┴─────────┘
634
636 ┌────────┬────────────────────┬────────────┬─────────┐
637 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
638 ├────────┼────────────────────┼────────────┼─────────┤
639 │cpus │ cpuset.cpus │ y = x │ │
640 ├────────┼────────────────────┼────────────┼─────────┤
641 │mems │ cpuset.mems │ y = x │ │
642 └────────┴────────────────────┴────────────┴─────────┘
643
645 ┌────────────────┬────────────────────┬────────────┬─────────┐
646 │OCI (x) │ cgroup 2 value (y) │ conversion │ comment │
647 ├────────────────┼────────────────────┼────────────┼─────────┤
648 │.limit_in_bytes │ hugetlb..max │ y = x │ │
649 └────────────────┴────────────────────┴────────────┴─────────┘
650 User Commands crun(1)