Docker Files And Directories How To Handle This

You can then attach as many containers to that host directory as needed; each container (as well as the host) will have access to the same data.

Docker Files And Directories How To Handle This

Heres how to handle this task with the help of Docker volumes.

But how does that container save data Or how do you work with that data or share it between containers.

Its a very complex system (called a Union File System) that doesnt work with data in the standard fashion.

This file system does an outstanding job when you dont need to retain data.

But what about when you need to stop and redeploy a container, and retain the data To be able to save data (or share data between containers), you have to take advantage of volumes.

A Docker volume is a directory (or files) that exists on the host file system (outside the Union File System).

I will be working with the latest release of Docker on the Ubuntu Server 16.04 platform.

The process for using volumes will be the same, regardless of host OS.

This is done with the command: docker volume create --name volume1.

You can get more details about the volume by issuing the command docker volume inspect volume1.

The output of that command ( Figure B ) will display the name, options, mountpoint, and more.

Lets create a volume that will go a long way to making your Docker containers even more flexible.

SEE: Cloud computing is the new normal: Is it time to use it for everything (TechRepublic) Creating a host data volume Now what we are going to do is deploy a new container (based on the latest Ubuntu image) that contains a volume attached to a directory on the host.

This means you can work within that container and save data into a container directory, that will be in sync with a host directory.

The first thing you must do is make sure to create the host directory.

Well create a directory called container-data with the command: mkdir container-data.

You can actually create that directory anywhere on your system (so long as the user has read-write permission).

With that directory in place, the command to deploy the container (attaching the host directory to the container volume located at the data directory within the container) would be: docker run -d -P --name test-container -v homejackcontainer-data:data ubuntu.

Gain shell access to the running container with the command: docker attach ID.

You should now find yourself at the bash prompt of the running container.

If you issue the command ls you should see the data directory we added at container run-time.

Now go back to the terminal of the host and issue the command ls container-data.

From within that same terminal, issue the command touch container-datatest2.

Go back to our container shell and issue the command ls data and both test and test2 should appear.

Docker For Mac Files And Directories