What is Docker Update

The docker update command dynamically updates container configuration. You can use this command to prevent containers from consuming too many resources such as CPU and memory from their Docker host. With a single command, you can place limits on a single container or on many.

Notes

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.

The docker update command dynamically updates container configuration. You can use this command to prevent containers from consuming too many resources such as CPU and memory from their Docker host. With a single command, you can place limits on a single container or on many.

*Some Examples
*
Update a container’s cpu-shares
$ docker update --cpu-shares 512 abebf7571666

Update a container with cpu-shares and memory
$ docker update --cpu-shares 512 -m 300M abebf7571666 hopeful_morse

Update a new container’s kernel memory constraints
$ $ docker run -dit --name test --kernel-memory 50M ubuntu bash

Update kernel memory while the container is running:
$ docker update --kernel-memory 80M test

Started a container without kernel memory initialized:
docker run -dit --name test2 --memory 300M ubuntu bash

To update restart policy for one or more containers:
$ docker update --restart=on-failure:3 abebf7571666 hopeful_morse

Add a restart policy to a container that was already created
$ docker update --restart=always

Update the "RunningContainerNameOrId" to use 1g of memory and only use cpu core 1
$ docker update --memory "1g" --cpuset-cpu "1"

To up date all running containers to use core 1 and 1g of memory:
$ docker update --cpuset-cpus "1" --memory "1g" $(docker ps | awk 'NR>1 {print $1}')

Disable auto-restart on a container?
$ docker update --restart=no my-container