How to force Docker for a clean build of an image
There’s a –no-cache option: docker build –no-cache -t u12_core -f u12_core . In older versions of Docker you needed to pass –no-cache=true, but this is no longer the case.
docker
How to remove old Docker containers
Since Docker 1.13.x you can use Docker container prune: docker container prune This will remove all stopped containers and should work on all platforms the same way. There is also a Docker system prune: docker system prune which will clean up all unused containers, networks, images (both dangling and unreferenced), and optionally, volumes, in one … Read more
How do I get into a Docker container’s shell?
docker attach will let you connect to your Docker container, but this isn’t really the same thing as ssh. If your container is running a webserver, for example, docker attach will probably connect you to the stdout of the web server process. It won’t necessarily give you a shell. The docker exec command is probably … Read more
How to get a Docker container’s IP address from the host
The –format option of inspect comes to the rescue. Modern Docker client syntax is: docker inspect -f ‘{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}’ container_name_or_id Old Docker client syntax is: docker inspect –format ‘{{ .NetworkSettings.IPAddress }}’ container_name_or_id These commands will return the Docker container’s IP address. As mentioned in the comments: if you are on Windows, use double quotes ” instead … Read more
How to copy Docker images from one host to another without using a repository
You will need to save the Docker image as a tar file: docker save -o <path for generated tar file> <image name> Then copy your image to a new system with regular file transfer tools such as cp, scp or rsync(preferred for big files). After that you will have to load the image into Docker: … Read more
How to copy files from host to Docker container?
The cp command can be used to copy files. One specific file can be copied TO the container like: docker cp foo.txt container_id:/foo.txt One specific file can be copied FROM the container like: docker cp container_id:/foo.txt foo.txt For emphasis, container_id is a container ID, not an image ID. (Use docker ps to view listing which … Read more
What is the difference between CMD and ENTRYPOINT in a Dockerfile?
Docker has a default entrypoint which is /bin/sh -c but does not have a default command. When you run docker like this: docker run -i -t ubuntu bash the entrypoint is the default /bin/sh -c, the image is ubuntu and the command is bash. The command is run via the entrypoint. i.e., the actual thing … Read more
Docker: Copying files from Docker container to host
In order to copy a file from a container to the host, you can use the command docker cp <containerId>:/file/path/within/container /host/path/target Here’s an example: $ sudo docker cp goofy_roentgen:/out_read.jpg . Here goofy_roentgen is the container name I got from the following command: $ sudo docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 1b4ad9311e93 … Read more
From inside of a Docker container, how do I connect to the localhost of the machine?
Edit: If you are using Docker-for-mac or Docker-for-Windows 18.03+, just connect to your mysql service using the host host.docker.internal (instead of the 127.0.0.1 in your connection string). If you are using Docker-for-Linux 20.10.0+, you can also use the host host.docker.internal if you started your Docker container with the –add-host host.docker.internal:host-gateway option. Otherwise, read below TLDR … Read more
What is the difference between the ‘COPY’ and ‘ADD’ commands in a Dockerfile?
You should check the ADD and COPY documentation for a more detailed description of their behaviors, but in a nutshell, the major difference is that ADD can do more than COPY: ADD allows <src> to be a URL Referring to comments below, the ADD documentation states that: If is a local tar archive in a … Read more