Menu
If I run a dockerfile where I have a command like
RUN curl -o file.txt http://X.X.X.X/path/to/file/file.txt
the build works, whereas if I use
ADD http://X.X.X.X/path/to/file/file.txt file.txt
The build fails and it complains about
Got HTTP status code >= 400: 503 Service Unavailable
Is there something about ADD that I'm not understanding?
Edit the file is also accessible through the docker host.
630
docker build builds a new image from the source code. docker create creates a writeable container from the image and prepares it for running. docker run creates the container (same as docker create ) and runs it.
COPY is a docker file command that copies files from a local source location to a destination in the Docker container. ADD command is used to copy files/directories into a Docker image. It only has only one assigned function. It can also copy files from a URL.
COPY takes in a src and destination. It only lets you copy in a local file or directory from your host (the machine building the Docker image) into the Docker image itself. ADD lets you do that too, but it also supports 2 other sources. First, you can use a URL instead of a local file / directory.
The ADD command is used to copy files/directories into a Docker image. It can copy data in three ways: Copy files from the local storage to a destination in the Docker image. Copy a tarball from the local storage and extract it automatically inside a destination in the Docker image.
ADD is executed in docker host.
The
ADDinstruction copies new files, directories or remote file URLs from<src>and adds them to the filesystem of the image at the path<dest>.
RUN is executed inside your container.
The
RUNinstruction will execute any commands in a new layer on top of the current image and commit the results. The resulting committed image will be used for the next step in theDockerfile.
Specifically the command RUN curl -o file.txt http://X.X.X.X/path/to/file/file.txt executes curl that must have already been installed in the image we are using. If the curl command has not been installed (and is not present in the base image) the entire RUN command fails.
Instead the command ADD url can be performed even without having installed curl (or analogues) inside the container just because it is executed by the host (it uses the Go libraries with which it is written docker) during the creation of our image.
Is http://X.X.X.X/path/to/file/file.txt accessible outside of your docker container?
Edit: as confirmed by the author of the question:
My docker host lives behind a firewall that has a proxy set in the
/etc/default/dockerfile. So while I wanted to grab a file internal to the network I'm on, the proxy caused it to look outside the network.
55
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
