moby--moby/man/docker-update.1.md

% DOCKER(1) Docker User Manuals % Docker Community % JUNE 2014

NAME

docker-update - Update configuration of one or more containers

SYNOPSIS

docker update [--blkio-weight[=[BLKIO-WEIGHT]]] [--cpu-shares[=0]] [--cpu-period[=0]] [--cpu-quota[=0]] [--cpuset-cpus[=CPUSET-CPUS]] [--cpuset-mems[=CPUSET-MEMS]] [--help] [--kernel-memory[=KERNEL-MEMORY]] [-m|--memory[=MEMORY]] [--memory-reservation[=MEMORY-RESERVATION]] [--memory-swap[=MEMORY-SWAP]] [--restart[=""]] CONTAINER [CONTAINER...]

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 value, you can specify these options on a running or a stopped container. You can only update --kernel-memory on a stopped container or on a running container with kernel memory initialized. For example, if you started a container with command:

# docker run -ti --name test --kernel-memory 50M ubuntu bash

You can update kernel memory of this running container:

# docker update --kernel-memory 80M test

If you started a container without kernel memory initialized:

# docker run -ti --name test2 --memory 300M ubuntu bash

Update kernel memory of running container test2 will fail, you can only stop the container and update kernel memory then. The next time you restart it, the container uses the new value.

Another configuration you can change with this command is restart policy, new restart policy will take effect instantly after you run docker update on a container.

OPTIONS

--blkio-weight=0 Block IO weight (relative weight) accepts a weight value between 10 and 1000.

--cpu-shares=0 CPU shares (relative weight)

--cpu-period=0 Limit the CPU CFS (Completely Fair Scheduler) period

--cpu-quota=0 Limit the CPU CFS (Completely Fair Scheduler) quota

--cpuset-cpus="" CPUs in which to allow execution (0-3, 0,1)

--cpuset-mems="" Memory nodes(MEMs) in which to allow execution (0-3, 0,1). Only effective on NUMA systems.

--help Print usage statement

--kernel-memory="" Kernel memory limit (format: <number>[<unit>], where unit = b, k, m or g)

Note that you can not update kernel memory to a running container if the container is started without kernel memory initialized, in this case, it can only be updated after it's stopped, and affect after it's started.

-m, --memory="" Memory limit (format: , where unit = b, k, m or g)

--memory-reservation="" Memory soft limit (format: [], where unit = b, k, m or g)

--memory-swap="" Total memory limit (memory + swap)

--restart="" Restart policy to apply when a container exits (no, on-failure[:max-retry], always, unless-stopped).

EXAMPLES

The following sections illustrate ways to use this command.

Update a container with cpu-shares=512

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

To update multiple resource configurations for multiple containers:

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

Update a container's restart policy

To update restart policy for one or more containers:

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