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--- docker:share_data_between_docker_containers [2017/02/22 15:27] – created peter
+++ docker:share_data_between_docker_containers [2020/05/13 09:02] (current) – removed peter
@@ Line 1: / Line 1: @@
-====== Docker - Share data between docker containers ======
-Docker Volumes can be created and attached in the same command that creates a container, or they can be created independent of any containers and then attached later. There are a number of different ways to share data between containers.
-===== Creating an Independent Volume =====
-Docker's 1.9 onwards allows a volume to be created without it relating to any particular container:
-<code bash>
-docker volume create --name DataVolume1
-</code>
-The name is displayed, indicating that the command was successful.
-<code>
-Output
-DataVolume1
-</code>
-To make use of the volume, we'll create a new container from the Ubuntu image, using the **--rm** flag to automatically delete it when we exit.  We'll use **-v** to mount the new volume.  -v requires the name of the volume, a colon, then the absolute path to where the volume should appear inside the container.  If the directories in the path don't exist as part of the image, they'll be created when the command runs.  If they do exist, the mounted volume will hide the existing content.
-<code bash>
-docker run -ti --rm -v DataVolume1:/datavolume1 ubuntu
-</code>
-Write some data to the volume:
-<code bash>
-echo "Example1" > /datavolume1/Example1.txt
-</code>
-Because we used the **--rm** flag, the container will be automatically deleted when we exit.  The volume, however, will still be accessible.
-<code bash>
-exit
-</code>
-Verify the volume is present on the system with docker volume inspect:
-<code bash>
-docker volume inspect DataVolume1
-</code>
-Result
-<code>
-Output
-[
-    {
-        "Name": "DataVolume1",
-        "Driver": "local",
-        "Mountpoint": "/var/lib/docker/volumes/datavolume1/_data",
-        "Labels": null,
-        "Scope": "local"
-    }
-]
-</code>
-<WRAP warning>
-**WARNING**:  The data on the host can also be accessed at the path listed as the Mountpoint.  Avoid altering this as it can cause data corruption if applications or containers are unaware of changes.
-</WRAP>
-Start a new container and attach DataVolume1:
-<code bash>
-docker run --rm -ti -v DataVolume1:/datavolume1 ubuntu
-cat /datavolume1/Example1.txt
-</code>
-Displays:
-<code>
-Output
-Example1
-</code>
-Exit the container.
-<code bash>
-exit
-</code>
-In this example, we created a volume, attached it to a container, and verified its persistence.