docker -v should return Docker version 17.12.0-ce, ...
docker run hello-world
Show daemon running on host.
docker run -it ubuntu /bin/bash will start a shell running inside an Ubuntu container.
Notice how the image is downloaded automatically, layer by layer.
ps -fe will show the namespaced process tree inside the container. How long do you expect the output to be?
docker exec -it $container /bin/bash will open another shell in the same container.
What happens if I run vim /tmp/new_file.txt?
What happens if I run touch /tmp/new_file.txt, exit the container and start a new one?
docker build -f Dockerfile.hello -t elifesciences/hello . will build a local image tagged elifesciences/hello. Take a look at the [Dockerfile.
docker run elifesciences/hello will run the default command of the image, which is a cat command.
What do I have to do if I want to run this code on another laptop?
docker run -it -u 33 elifesciences/hello /bin/bash runs a shell for the www-data standard user, which is unprivileged.
What happens when I run echo "IMPACT FACTOR" > message.txt?
docker run -it -v $(pwd):/code elifesciences/hello /bin/bash will run a container where the current folder is mounted as a volume. Incidentally, it also means the volume's content will persist beyond the lifetime of the container.
mount | grep /code will show the mount point.
What does ls -ld /code shows? What does that 1000 (or other number) mean?
Can I touch /code/42.txt?
docker build -f Dockerfile.derived -t elifesciences/hello . will create an image derived from our own base PHP CLI image.
docker run elifesciences/hello will now use the new image, try it.
But what if we want to use local modifications? Without rebuilding the container every time we save a file?
Make a local change. What happens when I run docker run -v $(pwd)/hello.php:/srv/hello/hello.php elifesciences/hello?
Run docker run -p 8003:8003 elifesciences/hello php -S 0.0.0.0:8003 -t . to start a PHP container listening on port 8003 for HTTP connections, and forward the host's 8003 port to it.
This is a blocking command, so won't exit until Ctrl-C is pressed.
Now curl -v localhost:8003/hello.php should answer with 200 OK.
Do Docker containers have their own port space? What happens if while the first command is running, I start another identical one? What do I have to change to make them coexist?
Build a sample heavy image (taking more than 60 seconds to build) with docker build -f Dockerfile.heavy -t elifesciences/heavy .
Now change after.txt by adding a line or similar, and rebuild. What happens?
Change before.txt instead, and rebuild. What happens?
Run docker build -f Dockerfile.heavy -t elifesciences/heavy --no-cache . to skip the layer cache.