I want to just print HOMEPATH variable from my machine:
This is my Dockerfile:
FROM python:3.8-slim
ARG some_path=$HOMEPATH
RUN echo "this is some_path: $some_path"
but receiving empty string, during image creation - docker build -t test_image . :
What I am doing wrong ?
Docker doesn't expose the builder to this sort of security risk. The build environment could have sensitive data in environment variables that they do not want exposed when the build arbitrary docker images. To inject a variables during build, you must explicitly pass it on the build command line with:
docker build --build-arg "some_path=$HOMEPATH" -t test_image .
Note that the path on the build server is typically not something you would want to inject in a build. The same build should work regardless of where you perform the build.
Dockerfile documentation states that there is possibility to pass --platform option in FROM instruction like this:
FROM [--platform=<platform>] <image> [AS <name>]
In my dockerfile I have following statements:
ARG arch
FROM --platform linux/${arch} bounz/hgbe.base
where bounz/hgbe.base image has two os/arch variants: linux/amd64 and linux/arm/v7.
But trying to build an image using this dockerfile I get an error:
$ docker build -f hgbe.dockerfile --build-arg arch=amd64 -t bounz/hgbetest:amd64-0.1 .
Sending build context to Docker daemon 12.29kB
Error response from daemon: Dockerfile parse error line 2: FROM requires either one or three arguments
What am I doing wrong?
And is there a way to reference specific platform of the base image if it has been built using docker buildx?
update your docker file, you are missing =
ARG arch
FROM --platform=linux/${arch} bounz/hgbe.base
Docker file:
# copy over system jboss configs
ARG SYSTEM_TYPE
COPY $SYSTEM_TYPE/AP/standalone.conf $JBOSS_HOME/bin/standalone.conf
COPY $SYSTEM_TYPE/AP/standalone-ha-bob.xml $JBOSS_HOME/bin/standalone-ha-bob.xml
Docker Command:
docker build --build-arg SERVER_TYPE=jbossconf/ENT-UAT/ -f /usr/etc/repos/docker-files/test-dockerfile-app -t appserver/test:1.0 .
Docker Build Result:
Step 15 : COPY $SYSTEM_TYPE/AP/standalone.conf $JBOSS_HOME/bin/standalone.conf
lstat AP/standalone.conf: no such file or directory
The --build-arg does not appear to be passing to the dockerfile. Where am I going wrong?
On your build args you are passing SERVER_TYPE and referencing $SYSTEM_TYPE on your dockerfile, that should fix it!
I can't seem to get docker build to run correctly:
wangyaos-MBP-3:~ wangyao$ cd /Users/wangyao/Ozintel/docker/flexcloud/
wangyaos-MBP-3:flexcloud wangyao$ ls
Dockerfile apache-tomcat-7.0.62 jdk1.8.0_45.jdk
wangyaos--3:flexcloud wangyao$ docker build -t="Users/wangyao/Ozintel/docker/flexcloud" .
Invalid namespace name (Users). Only [a-z0-9-_] are allowed.
wangyaos-MBP-3:flexcloud wangyao$ cd /Users/wangyao/
wangyaos-MBP-3:~ wangyao$ docker build -t="Users/wangyao/Ozintel/docker/flexcloud" .
Cannot locate Dockerfile: Dockerfile
wangyaos-MBP-3:~ wangyao$ docker build -t="Users/wangyao/Ozintel/docker/flexcloud"
docker: "build" requires 1 argument.
See 'docker build --help'.
Usage: docker build [OPTIONS] PATH | URL | -
Build a new image from the source code at PATH
How should I use docker build?
Slow down and take a look at the docs.
To use docker build, the easiest way is to cd into the directory with the Dockerfile then run something like:
$ docker build -t flexcloud .
The -t argument specifies the repository name and tag, not the directory with the Dockerfile. If you want to give a path to a different Dockerfile, you can use the -f argument. The . at the end specifies the "build context", in this case the current working directory.
Trying to follow the instructions for building a docker image from the docker website.
https://docs.docker.com/examples/running_redis_service/
this is the error I get will following the instructions on the doc and using this Dockerfile
FROM ubuntu:14.04
RUN apt-get update && apt-get install -y redis-server
EXPOSE 6379
ENTRYPOINT ["/usr/bin/redis-server"]
sudo docker build -t myrepo/redis
docker: "build" requires 1 argument. See 'docker build --help'.
How do resolve?
You need to add a dot, which means to use the Dockerfile in the local directory.
For example:
docker build -t mytag .
It means you use the Dockerfile in the local directory, and if you use docker 1.5 you can specify a Dockerfile elsewhere. Extract from the help output from docker build:
-f, --file="" Name of the Dockerfile(Default is 'Dockerfile' at context root)
In my case this error was happening in a Gitlab CI pipeline when I was passing multiple Gitlab env variables to docker build with --build-arg flags.
Turns out that one of the variables had a space in it which was causing the error. It was difficult to find since the pipeline logs just showed the $VARIABLE_NAME.
Make sure to quote the environment variables so that spaces get handled correctly.
Change from:
--build-arg VARIABLE_NAME=$VARIABLE_NAME
to:
--build-arg VARIABLE_NAME="$VARIABLE_NAME"
Did you copy the build command from somewhere else (webpage or some other file)? Try typing it in from scratch.
I copied a build command from an AWS tutorial and pasted it into my terminal and was getting this error. It was driving me crazy. After typing it in by hand, it worked! Looking closer and my previous failed commands, I noticed the "dash" character was different, it was a thinner, longer dash character than I got if I typed it myself using the "minus/dash" key.
Bad:
sudo docker build –t foo .
Good:
sudo docker build -t foo .
Can you see the difference?.. Cut and paste is hard.
In case anyone is running into this problem when trying to tag -t the image and also build it from a file that is NOT named Dockerfile (i.e. not using simply the . path), you can do it like this:
docker build -t my_image -f my_dockerfile .
Notice that docker expects a directory as the parameter and the filename as an option.
Use the following command
docker build -t mytag .
Note that mytag and dot has a space between them . This dot represents the present working directory .
Just provide dot (.) at the end of command including one space.
example:
command: docker build -t "blink:v1" .
Here you can see "blink:v1" then a space then dot(.)
Thats it.
You Need a DOT at the end...
So for example:
$ docker build -t <your username>/node-web-app .
It's a bit hidden, but if you pay attention to the . at the end...
From the command run:
sudo docker build -t myrepo/redis
there are no "arguments" passed to the docker build command, only a single flag -t and a value for that flag. After docker parses all of the flags for the command, there should be one argument left when you're running a build.
That argument is the build context. The standard command includes a trailing dot for the context:
sudo docker build -t myrepo/redis .
What's the build context?
Every docker build sends a directory to the build server. Docker is a client/server application, and the build runs on the server which isn't necessarily where the docker command is run. Docker uses the build context as the source for files used in COPY and ADD steps. When you are in the current directory to run the build, you would pass a . for the context, aka the current directory. You could pass a completely different directory, even a git repo, and docker will perform the build using that as the context, e.g.:
docker build -t sudobmitch/base:alpine --target alpine-base \
'https://github.com/sudo-bmitch/docker-base.git#main'
For more details on these options to the build command, see the docker build documentation.
What if you included an argument?
If you are including the value for the build context (typically the .) and still see this error message, you have likely passed more than one argument. Typically this is from failing to parse a flag, or passing a string with spaces without quotes. Possible causes for docker to see more than one argument include:
Missing quotes around a path or argument with spaces (take note using variables that may have spaces in them)
Incorrect dashes in the command: make sure to type these manually rather than copy and pasting
Incorrect quotes: smart quotes don't work on the command line, type them manually rather than copy and pasting.
Whitespace that isn't white space, or that doesn't appear to be a space.
Most all of these come from either a typo or copy and pasting from a source that modified the text to look pretty, breaking it for using as a command.
How do you figure out where the CLI error is?
The easiest way I have to debug this, run the command without any other flags:
docker build .
Once that works, add flags back in until you get the error, and then you'll know what flag is broken and needs the quotes to be fixed/added or dashes corrected, etc.
On older versions of Docker it seems you need to use this order:
docker build -t tag .
and not
docker build . -t tag
You can build docker image from a file called docker file and named Dockerfile by default. It has set of command/instruction that you need in your docker container.
Below command creates image with tag latest, Dockerfile should present on that location (. means present direcotry)
docker build . -t <image_name>:latest
You can specify the Dockerfile via -f if the file name in not default (Dockerfile)
Sameple Docker file contents.
FROM busybox
RUN echo "hello world"
Open PowerShelland and follow these istruction.
This type of error is tipically in Windows S.O.
When you use command build need an option and a path.
There is this type of error becouse you have not specified a path whit your Dockerfile.
Try this:
C:\Users\Daniele\app> docker build -t friendlyhello C:\Users\Daniele\app\
friendlyhello is the name who you assign to your conteiner
C:\Users\Daniele\app\ is the path who conteins your Dockerfile
if you want to add a tag
C:\Users\Daniele\app> docker build -t friendlyhello:3.0 C:\Users\Daniele\app\
The following command worked for me. Docker file was placed in my-app-master folder.
docker build -f my-app-master/Dockerfile -t my-app-master .
My problem was the Dockerfile.txt needed to be converted to a Unix executable file. Once I did that that error went away.
You may need to remove the .txt portion before doing this, but on a mac go to terminal and cd into the directory where your Dockerfile is and the type
chmod +x "Dockerfile"
And then it will convert your file to a Unix executable file which can then be executed by the Docker build command.
#Using a file other than Dockerfile instead.
#Supose my file is `Dockerfile-dev`
docker build -t mytag - < Dockerfile-dev
In my case I was using a dash (slightly longer hyphen) symbol – before the t option was the problem.
docker build –t simple-node .
Replace with a hyphen/ minus symbol.
docker build -t simple-node .
I got this error when using Docker with Jenkins pipeline within a pipeline script. The solution was to use this syntax in the pipeline script:
docker.build("[my_docker_image_tag]", "-f ./path/to/my/Dockerfile.jvm .")
Docker Build Command Format
In your powershell :
There is this type of error because you have not specified a path whith your Dockerfile.
Try this:
$ docker build -t friendlyhello:latest -f C:\\TestDockerApp\\Dockerfile.txt
friendlyhello is the name you assign to your container and add the version , just use the :latest
-f C:\TestDockerApp\Dockerfile.txt
- you want to add a tag because the build command needs a parameter or tag
- The DockerFile is a text document so explicitly add the extension .txt
**Try this format :
$ docker build -t friendlyhello:latest -f C:\\TestDockerApp\\Dockerfile.txt .**