Yesterday I've been asked about how to make a docker images with dockerfile
This time I want to add a question
If I want to make the OS ubuntu 14:04 on images docker, which it is installed, postgresql-9.3.10, install Java JDK 6, copy the file (significant location), and create a user on the images.
Whether I can combine of several dockerfile as needed for images? (dockerfile of postgresql, java, copyfile, and create a user so one dockerfile)
Example. I made one dockerfile "ubuntu"
which contains the command
top line
# Create dockerfile
# get OS ubuntu to images
FROM ubuntu: 14:04
# !!further adding a command on the following link, below the line per-dockerfile(intends command in dockerfile on the link)
# command on dockerfile postgresql-9.3
https://github.com/docker-library/postgres/blob/ed23320582f4ec5b0e5e35c99d98966dacbc6ed8/9.3/Dockerfile
# command on dockerfile java
https://github.com/docker-library/java/blob/master/openjdk-6-jdk/Dockerfile
# create a user on images ubuntu
RUN adduser myuser
# copy file/directory on images ubuntu
COPY /home/myuser/test /home/userimagedockerubuntu/test
# ?
CMD ["ubuntu:14.04"]
Please help me
No, you cannot combine multiple Dockerfile.
The best practice is to:
start from an imabe already included what you need, like this postgresql image already based on ubuntu.
That means that if your Dockerfile starts with:
FROM orchardup/postgresql
You would be building an image which already contains ubuntu and postgresql.
COPY or RUN what you need in your dockerfile, like for openjdk6:
RUN \
apt-get update && \
apt-get install -y openjdk-6-jdk && \
rm -rf /var/lib/apt/lists/*
ENV JAVA_HOME /usr/lib/jvm/java-6-openjdk-amd64
Finally, your default command should run the service you want:
# Set the default command to run when starting the container
CMD ["/usr/lib/postgresql/9.3/bin/postgres", "-D", "/var/lib/postgresql/9.3/main", "-c", "config_file=/etc/postgresql/9.3/main/postgresql.conf"]
But since the Dockerfile of orchardup/postgresql already contains a CMD, you don't even have to specify one: you will inherit from the CMD defined in your base image.
I think nesting multiple Dockerfiles is not possible due to the layer system. You may however outsource tasks into shell scripts and run those in your Dockerfile.
In your Dockerfile please fix the base image:
FROM ubuntu:14.04
Further your CMD is invalid. You may want to execute a bash with CMD ["bash"] that you can work with.
I would suggest you to start with the doc on Dockerfile as you clearly missed this and it contains all the answers to your questions, and even questions you don't even think to ask yet.
Related
I have entered into the WSL terminal the following command:
docker compose build --no-cache && docker compose up
This is what happened:
I have not downloaded anything outside of Docker on this computer and I have cloned this "backend" from the repository.
I have no experience in Docker or Laravel.
What methods should I start with to fix this?
The option -g in the groupadd command needs to be numerical, you can't use use the word sail.
See Ubuntu's documentation about that command and option here.
I want add shell or bash to my image to execute installation command.
I have copied the /bin/bash on my VM on to my image on Dockerfile:
COPY /bin/bash /bin/
But when I execute the docker command:
docker run -it --entrypoint "/bin/bash" <my_image>
Then I get the following error :
/bin/bash: error while loading shared libraries: libtinfo.so.5: cannot open shared object file: No such file or directory
Thanks for your help
You can do it by copying the statically compiled shell from official busybox image in a multi-stage build in your Dockerfile. Or just COPY --from it.
The static shell doesn't have so many dependencies, so it will work for a range of different base images. It may not work for some very advanced cases, but otherwise it gets the job done.
The statically compiled shell is tagged with uclibc. Depending on your base image you may have success with other flavours of busybox as well.
Example:
FROM busybox:1.35.0-uclibc as busybox
FROM gcr.io/distroless/base-debian11
# Now copy the static shell into base image.
COPY --from=busybox /bin/sh /bin/sh
# You may also copy all necessary executables into distroless image.
COPY --from=busybox /bin/mkdir /bin/mkdir
COPY --from=busybox /bin/cat /bin/cat
ENTRYPOINT ["/bin/sh", "/entrypoint.sh"]
The single-line COPY --from directly from image would also work:
FROM gcr.io/distroless/base-debian11
COPY --from=busybox:1.35.0-uclibc /bin/sh /bin/sh
ENTRYPOINT ["/bin/sh", "/entrypoint.sh"]
Google's distroless images have versions tagged debug, which contain busybox executable (with sh bundled in).
If you have to, you can arguably use them even in production (which defeats the purpose of increased security - such as hiding environment variables and protecting scripted apps code).
Usage example of the distroless/base image with debug tag:
$ docker run -it --rm --name base -u 0 gcr.io/distroless/base:debug
/ # id
uid=0(root) gid=0(root)
That's because you're trying to use dynamic-compiled bash in in docker without glibc support.
TL;DR
... either use bash-static instead of classic bash
You may download it or run ./build.sh
or add bash for alpine: add this line to your Dockerfile: RUN apk add --no-cache bash
Alpine is a musl-based distro
Many docker images are built with alpine as base image:
alpine (usually) is small & fast:
Here are the sizes of the images of popular operating systems.
source: A Breakdown of Operating Systems of Dockerhub
The difference in image size is striking: the range goes from BusyBox at 1MB all the way up to Fedora at 230MB. It’s interesting to see the clustering happening. Alpine and BusyBox are lightweight and right near 0MB, then the midweights like Debian and Ubuntu are around 100MB, and largest are heavyweights such as CentOS and Oracle Linux up by 200MB.
musl doesn't contain libtinfo
See more about difference between glibc and musl Functional differences from glibc
P.S. you can run bash-static even in empty container from scratch
FROM scratch
ADD bash
ENTRYPOINT ['/bash']
You could probably add busybox in now.
I'm following this part of the Docker tutorial (on a Mac): https://docs.docker.com/mac/step_four/. I'm getting an error when I try to run the docker-whalesay image because it can't find fortunes.
I started off in the Dockerfile using /user/games/fortunes. Then I changed to just fortunes. Neither work.
How do I specify in the Dockerfile to use the current folder (mydockerbuild)?
The Dockerfile in that example does not rely on files that are present on your computer, basically, the only steps needed are;
Create an empty directory (you named it mydockerbuild)
mkdir mydockerbuild
Change to that directory
cd mydockerbuild
Create a Dockerfile
Edit the Dockerfile to look like this;
FROM docker/whalesay:latest
RUN apt-get -y update && apt-get install -y fortunes
CMD /usr/games/fortune -a | cowsay
Build the Dockerfile, and name the built image "docker-whale"
docker build -t docker-whale .
Run the image you just built
docker run --rm docker-whale
The /usr/games/fortunes path in the Dockerfile is referring to a path inside the container. In this case, the /usr/games/fortunes is created by the fortune package that it's installed by apt-get install -y fortunes.
I trying to create Dockerfile file from scratch on Windows7. However, currently have trouble on very first step. My Dockerfile is placed under C:\Users\Arturas\Docker\Jenkins. Virtual Box shared folder path on c:\Users and folder name on c/Users (defaults from boot2docker was not changed).
When I run (on git bash):
$ docker build --file Docker/Jenkins/ .
I get:
unable to process Dockerfile: read C:\Users\Arturas\Docker\Jenkins:
The handle is invalid.
Dockerfile content is just one line:
FROM jenkins
I just started learning Docker so my experience is very limited yet. However from tools like boot2docker I expect basic commands to work out of the box so I must be missing something.
Try instead:
cd /C/Users/Arturas/Docker/Jenkins
docker build -t myimage .
I assume here that you have a file named Dockerfile under the Jenkins folder.
The -f option of a docker build is for referencing the Dockerfile (if it is named differently for instance)
Don't forget to use the latest docker-machine (the 0.5.4 one: an auto-extractible exe docker-machine_windows-amd64.exe): it uses a VM named boot2docker.iso through VirtualBox.
Try to specify the "Dockerfile" name
$ docker build --file Docker/Jenkins/Dockerfile .
I have Docker Toolbox installed on my Mac, but I'm having issues adding a file to a container during build. I'm using the ADD command in the Dockerfile. I can't seem to add any local files. I understand that Docker Toolbox uses VirtualBox under the hood, but I am not sure how to get those files into the VM to build the container. Is there a way I can do it that allows me to keep a clean OS-agnostic Dockerfile without any absolute paths?
Here is my Dockerfile. It's built from the Node.js container with some additional dependencies.
FROM node:4.2.2
RUN apt-get update
RUN apt-get install -y libvips-dev libgsf-1-dev libkrb5-dev
RUN apt-get clean
ADD app/ /app
RUN cd /app && npm install --production
RUN npm install forever -g
Turns out this does work, but only for my current directory. My Dockerfile and the files I wanted to add were not in the same directory. Moving the shell to the files I wanted, and then manually specifying the Dockerfile worked.
docker build -f my/other/Dockerfile .
Since docker will use a VirtualBox VM on Mac (with boot2docker or with docker-machine), it will use VirtualBox Guest Additions, which is there for the express purpose of using VirtualBox folder sharing.
Make sure to be in such a shared path, typically in /Users/....
If app/ is in /Users/path/to/app, then ADD should work.
You can mount other paths with boot2docker, but it can be problematic with docker machine (see issue 13).
Of course, for ADD app ... to work, you need to be in the parent folder of app/.
From docker ADD:
The <src> path must be inside the context of the build; you cannot ADD ../something /something