dockerfile
Dockerfile define multiple ARG arguments in a single line
After testing this by creating the ARGs similar to ENV like this: ARG CDN_ENDPOINT \ AWS_S3_BUCKET I got this error: ARG requires exactly one argument definition So judging from that, the ARG command only allows one argument. So its impossible to define multiple ARGs in a single line inside dockerfile.
Docker: failed to export image: failed to create image: failed to get layer
This problem occurs with a specific sequence of COPY commands in a multistage build. More precisely, the bug triggers when there is a COPY instruction producing null effect (for example if the content copied is already present in the destination, with 0 diff), followed immediately by another COPY instruction. A workaround could be to add … Read more
How to measure Docker build steps duration?
BuildKit, which was experimental in 18.06 and generally available in 18.09, has this functionality built in. To configure the dockerd daemon with experimental mode, you can setup the daemon.json: $ cat /etc/docker/daemon.json { “experimental”: true } Then you can enable BuildKit from the client side with an environment variable: $ export DOCKER_BUILDKIT=1 $ docker build … Read more
Container command ‘/start.sh’ not found or does not exist, entrypoint to container is shell script
On windows, while building the docker image, i also used to get the same error after building the image, that shell script is missing.. the path and the shebang was also correct. Later on, i read some where that it may be due to the encoding issue. I just opened the file in sublime editor … Read more
How are intermediate containers formed?
Yes, Docker images are layered. When you build a new image, Docker does this for each instruction (RUN, COPY etc.) in your Dockerfile: create a temporary container from the previous image layer (or the base FROM image for the first command; run the Dockerfile instruction in the temporary “intermediate” container; save the temporary container as … Read more
How to Specify $docker build –network=”host” mode in docker-compose at the time of build
@dkanejs is right, and here is how you use it (the version number is important): version: ‘3.4’ services: my_image: build: context: . network: host
SSH agent forwarding during docker build
For Docker 18.09 and newer You can use new features of Docker to forward your existing SSH agent connection or a key to the builder. This enables for example to clone your private repositories during build. Steps: First set environment variable to use new BuildKit export DOCKER_BUILDKIT=1 Then create Dockerfile with new (experimental) syntax: # … Read more