docker container 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.

Options

Examples

The following sections illustrate ways to use this command.

Update a container's 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:

$ docker update --cpu-shares 512 abebf7571666

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

To update multiple resource configurations for multiple containers:

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

Update a container's kernel memory constraints (--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:

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

You can update kernel memory while the container is running:

$ docker update --kernel-memory 80M test

If you started a container without kernel memory initialized:

$ 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)

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:

$ 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.