bind mount

you can use bind mounts to mount a file or directory from the host machine into the container.

you can specify the bind mount while running a container like shown below. if your file path has spaces, use quotes.

docker run -v HOST-PATH:CONTAINER-PATH ... 

the --mount flag does the same thing.

# no space between src and target
docker run --mount src=HOST-PATH,target=CONTAINER-PATH

ports and expose

opening a connection from a container to the outside, requires two things:

• exposing a port → telling Docker that the container listens to a certain port.
• publishing a port → map host ports to the container ports.

expose

use EXPOSE PORT in the dockerfile.

publish

• map the host port to the container port → -p HOST-PORT:CONTAINER-PORT
• you can also specify a protocol → EXPORT 4000/udp and -p 3000:4000/udp
• if you ignore a host port, docker will assign any free port → -p 4000

security

while publishing a port by using -p 3000:4000, it will any host, anyone from the internet could come in and access what you’re running.

one way to avoid this is by specifying which hosts are allowed access.

• e.g. -p 127.0.0.1:3000:4000 → this will only allow requests from host 127.0.0.1, i.e., your computer only.

the short syntax, -p 3456:3000, will result in the same as -p 0.0.0.0:3000:4000, which truly is opening the port to everyone.

related

contents

• basic docker commands
• running docker containers
• dockerfile
• bind mount, ports and expose
• docker volumes
• docker-compose
• docker networking

creating container from scratch → https://youtu.be/8fi7uSYlOdc namespaces, cgroups, union filesystems

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