Files
runc/man/runc-update.8.md
T
Aleksa Sarai 24dff91a09 runtime-spec: update pids.limit handling to match new guidance
The main update is actually in github.com/opencontainers/cgroups, but we
need to also update runtime-spec to a newer pre-release version to get
the updates from there as well.

In short, the behaviour change is now that "0" is treated as a valid
value to set in "pids.max", "-1" means "max" and unset/nil means "do
nothing". As described in the opencontainers/cgroups PR, this change is
actually backwards compatible because our internal state.json stores
PidsLimit, and that entry is marked as "omitempty". So, an old runc
would omit PidsLimit=0 in state.json, and this will be parsed by a new
runc as being "nil" -- and both would treat this case as "do not set
anything".

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
(cherry picked from commit 3b75374cc7)
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
2025-11-12 20:07:00 +11:00

2.3 KiB

% runc-update "8"

NAME

runc-update - update running container resource constraints

SYNOPSIS

runc update [option ...] container-id

runc update -r resources.json|- container-id

DESCRIPTION

The update command change the resource constraints of a running container instance.

The resources can be set using options, or, if -r is used, parsed from JSON provided as a file or from stdin.

In case -r is used, the JSON format is like this:

{
	"memory": {
		"limit": 0,
			"reservation": 0,
			"swap": 0,
			"kernel": 0,
			"kernelTCP": 0
	},
		"cpu": {
			"shares": 0,
			"quota": 0,
			"burst": 0,
			"period": 0,
			"realtimeRuntime": 0,
			"realtimePeriod": 0,
			"cpus": "",
			"mems": ""
		},
		"blockIO": {
			"blkioWeight": 0
		}
}

OPTIONS

--resources|-r resources.json
Read the new resource limits from resources.json. Use - to read from stdin. If this option is used, all other options are ignored.
--blkio-weight weight
Set a new io weight.
--cpu-period num
Set CPU CFS period to be used for hardcapping (in microseconds)
--cpu-quota num
Set CPU usage limit within a given period (in microseconds).
--cpu-burst num
Set CPU burst limit within a given period (in microseconds).
--cpu-rt-period num
Set CPU realtime period to be used for hardcapping (in microseconds).
--cpu-rt-runtime num
Set CPU realtime hardcap limit (in usecs). Allowed cpu time in a given period.
--cpu-share num
Set CPU shares (relative weight vs. other containers).
--cpuset-cpus list
Set CPU(s) to use. The list can contain commas and ranges. For example: 0-3,7.
--cpuset-mems list
Set memory node(s) to use. The list format is the same as for --cpuset-cpus.
--memory num
Set memory limit to num bytes.
--memory-reservation num
Set memory reservation, or soft limit, to num bytes.
--memory-swap num
Set total memory + swap usage to num bytes. Use -1 to unset the limit (i.e. use unlimited swap).
--pids-limit num
Set the maximum number of processes allowed in the container. Use -1 to unset the limit.
--l3-cache-schema value
Set the value for Intel RDT/CAT L3 cache schema.
--mem-bw-schema value
Set the Intel RDT/MBA memory bandwidth schema.

SEE ALSO

runc(8).