---
name: "runc-update"
section: "8"
platform: "linux"
package: "runc"
version: "1.5.2-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/runc-update"
---

# runc-update(8)

update running container resource constraints

## 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)](/runc/8.md).