Docker shops downloaded photographs, operating containers, and chronic quantity information in a single shared listing root in your system drive. You possibly can customise your configuration to make use of an exterior drive, community share, or second inside disc if it’s worthwhile to add storage to your set up.
Preparation
The primary a part of this information applies to Docker Engine for Linux and Docker Desktop on Home windows and Mac. You’ll want to seek out your Docker daemon.json file on all three platforms. This might be in one of many following areas:
/and so forth/docker/daemon.jsonon Linux.%programdatapercentdockerconfigdaemon.jsonon Home windows.~/Library/Containers/com.docker.docker/Information/database/com.docker.driver.amd64-linux/and so forth/docker/daemon.jsonon Mac.
Docker advises that Home windows and Mac customers replace the config file through the UI, as an alternative of manually making use of modifications in a textual content editor. You possibly can entry the settings display by heading to Preferences > Docker Engine > Edit file within the Docker Desktop interface.
Altering Your Information Listing
The situation of Docker’s information listing is managed by the data-root setting in your config file. Previous Docker variations launched previous to 17.06 used graph as an alternative. You possibly can test the model you’ve received by operating the docker model command.
$ docker model
...
Server: Docker Engine - Neighborhood
Engine:
Model: 20.10.17
Discover or add the related key contained in the config file. Set your required listing path as its worth. Right here’s a Linux instance that’ll retailer Docker information to an exterior drive mounted within the filesystem:
{
"data-root": "/mnt/docker-data"
}
You need to restart the Docker daemon after you make the change:
$ sudo service docker restart
Docker Desktop might be restarted on Home windows and Mac by exiting it after which launching a brand new occasion.
You must copy the contents of your present information listing to the brand new path if you wish to retain your present content material. In any other case you’ll begin with a clear slate, unable to entry beforehand created containers and pictures.
$ sudo rsync -aSv /var/lib/docker/ /mnt/docker-data
Altering the Information Listing With out a Restart
You possibly can transfer your information listing with out restarting the daemon by making a symlink from /var/lib/docker to your new location. This may very well be helpful should you’re operating out of area on a number the place an unscheduled Docker service restart isn’t a viable possibility.
Copy your present Docker information to your new listing:
$ sudo rsync -aSv /var/lib/docker/ /mnt/docker-data
Then create a symlink that resolves /var/lib/docker to the goal location:
$ sudo ln -s /mnt/docker-data/ /var/lib/docker
Don’t use this method for workloads that quickly modify filesystem information. There’s a threat of inconsistencies occurring if information will get written within the time between you copying the prevailing listing and creating the symlink.
What Truly Modifications?
Altering Docker’s root listing impacts all of the totally different information varieties that the daemon shops. This consists of your photographs, containers, put in plugins, Swarm configuration, and volumes, in addition to the Docker construct cache.
Modifying the trail will write all this information to your new location. You possibly can’t selectively transfer particular varieties to separate mount factors. This implies it’s vital to pick out a storage location that can provide good general efficiency. Utilizing a sluggish exterior drive may hurt the responsiveness of docker CLI operations, even when it will swimsuit sure forms of information reminiscent of long-term picture storage.
Within the absence of per-type information path assist, pruning unused sources could be a higher strategy to handle Docker’s storage necessities. As a substitute of allocating Docker more room, clear up redundant belongings and push unused photographs to a separate central registry. This may unencumber appreciable area in your host.
One-Time Use of a Completely different Information Listing
You possibly can manually begin Docker Engine with a selected information listing by passing the --data-root flag while you begin the daemon. This can be utilized to modify between information directories or run a clear occasion with out your present information.
$ sudo /usr/bin/dockerd --data-root /mnt/docker-data
The flag will override the listing path specified by the daemon.json file. The configured listing will stay intact so you possibly can revert to that occasion sooner or later.
Abstract
Docker shops all its information together with constructed and pulled photographs, created containers, and volumes inside a single listing tree. The foundation is often /var/lib/docker however you possibly can customise it by including a setting to your config file or supplying the --data-root flag while you begin the daemon.
Altering the information listing means your present information received’t seem in Docker until you copy it to the brand new path. You should utilize this characteristic to keep up a number of unbiased Docker storage repositories, reminiscent of one for private tasks and one other for work. You’ll must restart the daemon earlier than you turn contexts although, as just one occasion can run concurrently.
