# docker container update

**Description:** Update configuration of one or more containers

**Usage:** `docker container update [OPTIONS] CONTAINER [CONTAINER...]`

**Aliases:** `docker update`








## Description

The `docker update` command dynamically updates container configuration.
You can use this command to prevent containers from consuming too many
resources from their Docker host.  With a single command, you can place
limits on a single container or on many. To specify more than one container,
provide space-separated list of container names or IDs.

With the exception of the `--kernel-memory` option, you can specify these
options on a running or a stopped container. On kernel version older than
4.6, you can only update `--kernel-memory` on a stopped container or on
a running container with kernel memory initialized.

> [!WARNING]
> The `docker update` and `docker container update` commands are not supported
> for Windows containers.
{ .warning }


## Options

| Option | Default | Description |
|--------|---------|-------------|
| `--blkio-weight` |  |  Block IO (relative weight), between 10 and 1000, or 0 to disable (default 0)<br> |
| `--cpu-period` |  |  Limit CPU CFS (Completely Fair Scheduler) period |
| `--cpu-quota` |  |  Limit CPU CFS (Completely Fair Scheduler) quota |
| `--cpu-rt-period` |  | API 1.25+ Limit the CPU real-time period in microseconds |
| `--cpu-rt-runtime` |  | API 1.25+ Limit the CPU real-time runtime in microseconds |
| `-c`, `--cpu-shares` |  |  CPU shares (relative weight) |
| `--cpus` |  | API 1.29+ Number of CPUs |
| `--cpuset-cpus` |  |  CPUs in which to allow execution (0-3, 0,1) |
| `--cpuset-mems` |  |  MEMs in which to allow execution (0-3, 0,1) |
| `-m`, `--memory` |  |  Memory limit |
| `--memory-reservation` |  |  Memory soft limit |
| `--memory-swap` |  |  Swap limit equal to memory plus swap: -1 to enable unlimited swap |
| `--pids-limit` |  | API 1.40+ Tune container pids limit (set -1 for unlimited) |
| `--restart` |  |  Restart policy to apply when a container exits |



## Examples

The following sections illustrate ways to use this command.

### Update a container's cpu-shares (--cpu-shares) {#cpu-shares}

To limit a container's cpu-shares to 512, first identify the container
name or ID. You can use `docker ps` to find these values. You can also
use the ID returned from the `docker run` command.  Then, do the following:

```console
$ docker update --cpu-shares 512 abebf7571666
```

### Update a container with cpu-shares and memory (-m, --memory) {#memory}

To update multiple resource configurations for multiple containers:

```console
$ docker update --cpu-shares 512 -m 300M abebf7571666 hopeful_morse
```

### Update a container's kernel memory constraints (--kernel-memory) {#kernel-memory}

You can update a container's kernel memory limit using the `--kernel-memory`
option. On kernel version older than 4.6, this option can be updated on a
running container only if the container was started with `--kernel-memory`.
If the container was started without `--kernel-memory` you need to stop
the container before updating kernel memory.

> [!NOTE]
> The `--kernel-memory` option has been deprecated since Docker 20.10.

For example, if you started a container with this command:

```console
$ docker run -dit --name test --kernel-memory 50M ubuntu bash
```

You can update kernel memory while the container is running:

```console
$ docker update --kernel-memory 80M test
```

If you started a container without kernel memory initialized:

```console
$ docker run -dit --name test2 --memory 300M ubuntu bash
```

Update kernel memory of running container `test2` will fail. You need to stop
the container before updating the `--kernel-memory` setting. The next time you
start it, the container uses the new value.

Kernel version newer than (include) 4.6 does not have this limitation, you
can use `--kernel-memory` the same way as other options.

### Update a container's restart policy (--restart) {#restart}

You can change a container's restart policy on a running container. The new
restart policy takes effect instantly after you run `docker update` on a
container.

To update restart policy for one or more containers:

```console
$ docker update --restart=on-failure:3 abebf7571666 hopeful_morse
```

Note that if the container is started with `--rm` flag, you cannot update the restart
policy for it. The `AutoRemove` and `RestartPolicy` are mutually exclusive for the
container.