Data Propagation & Updates

Another scenario that could be interesting to explore is when a container with a volume is running, and then we update the volume from the host. What happens to the container? Will the container see the changes?

# Create the volume if it doesn't exist
docker volume create my-other-vol || true

# Create a container
docker run -it -d --name my_container -v my-other-vol:/data busybox

# Write some data to /data from the container
docker exec my_container sh -c 'echo "Hello from container!" > /data/hello.txt'

# See the contents of the file on the host
cat /var/lib/docker/volumes/my-other-vol/_data/hello.txt

What you will see is Hello from container!. Now, if we update the file from the host:

# Write some data to /data from the host

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