The docker-compose file https://docs.docker.com/compose/compose-file/#/volumes-volume-driver shows various ways to mount host sub-directories relative to the compose file.
For example:
volumes: # Just specify a path and let the Engine create a volume - /var/lib/mysql
# Specify an absolute path mapping - /opt/data:/var/lib/mysql
# Path on the host, relative to the Compose file - ./cache:/tmp/cache
# User-relative path - ~/configs:/etc/configs/:ro
# Named volume - datavolume:/var/lib/mysql
Is is possible to mount a sub-directory of a named volume at a specific location? For example something like below, which I tried, but does not seem to work.
# Named volume
- datavolume/sql_data:/var/lib/mysql
I am assuming I might be able to manage this by mounting the data volume to a location like /data and then in the Dockerfiles for each container, create symbolic links from the sub-directories to the locations.
for example in a docker-compose.yml file
volumes:
- datavolume:/data
and then in the container Dockerfile
RUN ln -s /data/sql_data /var/lib/mysql
I started going down this path but it was getting messy and was not working. Before I either abandon that approach or invest the time debugging it, I wanted to make sure there was no way to just specify sub-directories of a named vollume.