Looking at https://github.com/nginxinc/docker-nginx/blob/f8fad321cf58d5cbcafa3d9fa15314b8a77b5e65/mainline/alpine/Dockerfile it's clear that the official nginx repo doesn't use the nginx that's available in alpine's repositories, but instead seems to compile from scratch. You can install nginx on any container using apk add --update --no-cache nginx. Why wouldn't nginx juse utilize this and maintain the official alpine repo?
Typically the maintainer wants more control over the install of the main component of the image. That control lets them:
Install a specific version
Install with container specific options
Avoid including packaging values that do not apply to containers, like startup scripts
One of the bigger reasons I can think of is to install a version immediately after it's release and before the package maintainers have had a chance to create a package for that release.
This act has some answer.like:
probably! nginx package in apk is not official and they want to configure and compile their self nginx
Or they add additional configure option to nginx image!
Related
I've got a repository that has a series of documents (multimarkdown files, PDFs, GSN arguments, etc.) that need to use our internal (currently) proprietary tool to assemble those documents into a HTML-like document. The internal tool is quite complicated to use and isn't (yet) deployable.
What I tried doing was compiling the internal tool on the Ubuntu VM that I knew would be used for this job and then not tell GitLab (we're using self-hosted GitLab) to use any docker image when it tried to assemble the documents. Alas, when the CI job was run, I saw:
Pulling docker image alpine:latest ...
And then, of course, none of the stuff I installed on the VM itself was available.
Is there a way to have GitLab run the CI job without any Docker image?
If not (or if this alternative is just plain "better"), what is a good resource for reading how to install this complicated internal tool into a Docker image?
NB: The current methodology for "installing" the complicated internal tool, in addition to a lot of installing packages via apt-get, etc., (which I already have examples of how to do in Docker), is to clone the repository, and then run npm install and rake install in the cloned directory.
This is controlled by your GitLab-runner configuration. When the runner uses the docker executor it will always use a docker image for the build. If you want to run a GitLab job without using docker, you will need to configure a GitLab runner with the "shell" executor on your VM.
However, using image: ubuntu:focal or similar is likely enough. You usually don't have to be concerned about the fact that an executor happens to run your job inside of a container. This is also beneficial, as it means your build environment is reproducible and that process will be defined in your job.
myjob:
image: ubuntu:focal
script:
- apt update && apt install -y nodejs ruby # or whatever else
# - npm install
# - gem install
# - rake install
# etc...
-
Or better yet, if you can produce a docker image with your core dependencies installed you can just use image: my-special-image in your GitLab job to use that image as your build environment.
I need to build a Docker container (feeling as a N00b about it) that runs a Java application fronted by an nginx Web server. For reasons not subject to discussion I need to put them into one container.
I'd like to use Alpine for that. I found both images that contain Alpine with an installed nginx and Alpine with an installed JDK. I need to combine both.
What's my best course of action? Start with the nginx container and add a jdk or start with the jdk containing container and add nginx?
Or is there an option to combine 2 images (and would that be a good idea).
Insights are appreciated.
For creating a combined image, you could follow either of the suggested paths:
Creating a merged Dockerfile with the setup steps for both images, and building your own custom image.
Creating a Dockerfile pulling from image 1 (the more "complex" one), and adding the commands needed for image 2.
The second approach is preferred, since you start off a known-good image, not having to start from scrach. Plus, you may need only minimal changes. For this to work, both images should share a common base image, such as alpine for example.
Examining both Nginx and Java OpenJDK Dockerfiles, you could see that Nginx Dockerfile is fairly more complex, with many prerequisite packages and setup steps, so it would make a better fit for the base image. My suggestion is, start from the Nginx base image, and add Java on top.
If you're happy with the versions of JDK available in Alpile repositories, your combined Dockerfile may be as simple as:
FROM nginx:alpine
RUN apk add openjdk17
If you need a specific Java version, which isn't available in Alpine repositories, it's usually a matter of downloading the zipped Alpine Java distribution and unpacking it and setting JAVA_HOME accordingly. For example, see the OpenJDK 13 Alpine Dockerfile.
I have a totally empty debian9 on which I installed docker-ce and nothing else.
My client wants me to run a website (already done locally on my PC) that he can migrate/move rapidly from one server to another moving docker images.
My idea is to install some empty docker image, and then install on it manually all dependencies (ngingrtmp, apache2, nodejs, mysql, phpmyadmin, php, etc...)
I need to install all these dependencies MANUALLY (to keep control) - not using a ready to go docker images from dockerhub, and then to create an IMAGE of ALL things I have done (including these dependencies, but also files I will upload).
Problem is : I have no idea how to start a blank image, connect to it and then save a modified image with components and dependencies I will run.
I am aware that the SIZE may be bigger with a simple dockerfile, but I need to customize lots of things such as using php5.6, apache2.2, edit some php.ini etc etc..
regards
if you don't want to define you're dependencies on the docker file then you can have an approach like this, spin up a linux container with a base image and go inside the docker
sudo docker exec -it <Container ID> /bin/bash
install your dependencies as you install on any other linux server.
sudo apt-get install -y ngingrtmp apache2 nodejs mysql phpmyadmin php
then exit the container by ctrl+p and ctrl+q and now commit the changes you made
sudo docker commit CONTAINER_ID new-image-name
run docker images command and you will see the new image you have created, then you can use/move that image
You can try with a Dockerfile with the following content
FROM SCRATCH
But then you will need to build and add the operating system yourself.
For instance, alpine linux does this in the following way:
FROM scratch
ADD rootfs.tar.xz /
CMD ["/bin/sh"]
Where rootfs.tar.xz is a file of less of 2MB available on alpine's github repository (version 3.7 for x86_64 arch):
https://github.com/gliderlabs/docker-alpine/tree/61c3181ad3127c5bedd098271ac05f49119c9915/versions/library-3.7/x86_64
Or you can begin with alpine itself, but you said that you don't want to depend on ready to go docker images.
A good start point for you (if you decide to use alpnie linux), could look like the one available at https://github.com/docker-library/httpd/blob/eaf4c70fb21f167f77e0c9d4b6f8b8635b1cb4b6/2.4/alpine/Dockerfile
As you can see, A Dockerfile can became very big and complex because within it you provision all the software you need for running your image.
Once you have your Dockerfile, you can build the image with:
docker build .
You can give it a name:
docker build -t mycompany/myimage:1.0
Then you can run your image with:
docker run mycompany/myimage:1.0
Hope this helps.
For work purpose, I have an ova file which I need to convert it to DockerFile.
Does someone know how to do it?
Thanks in advance
There are a few different ways to do this. They all involve getting at the disk image of the VM. One is to mount the VDI, then create Docker image from that (see other Stackoverflow answers). Another is to boot the VM and copy the complete disk contents, starting at root, to a shared folder. And so on. We have succeeded with multiple approaches. As long as the disk in the VM is compatible with the kernel underlying the running container, creating Docker image that has the complete VM disk has worked.
Yes it is possible to use a VM image and run it in a container. Many our customers have been using this project successfully: https://github.com/rancher/vm.git.
RancherVM allows you to create VMs that run inside of Kubernetes pods,
called VM Pods. A VM pod looks and feels like a regular pod. Inside of
each VM pod, however, is a container running a virtual machine
instance. You can package any QEMU/KVM image as a Docker image,
distribute it using any Docker registry such as DockerHub, and run it
on RancherVM.
Recently this project has been made compatible for kubernetes as well. For more information: https://rancher.com/blog/2018/2018-04-27-ranchervm-now-available-on-kubernetes
Step 1
Install ShutIt as root:
sudo su -
(apt-get update && apt-get install -y python-pip git docker) || (yum update && yum install -y python-pip git docker which)
pip install shutit
The pre-requisites are python-pip, git and docker. The exact names of these in your package manager may vary slightly (eg docker-io or docker.io) depending on your distro.
You may need to make sure the docker server is running too, eg with ‘systemctl start docker’ or ‘service docker start’.
Step 2
Check out the copyserver script:
git clone https://github.com/ianmiell/shutit_copyserver.git
Step 3
Run the copy_server script:
cd shutit_copyserver/bin
./copy_server.sh
There are a couple of prompts – one to correct perms on a config file, and another to ask what docker base image you want to use. Make sure you use one as close to the original server as possible.
Note that this requires a version of docker that has the ‘docker exec’ option.
Step 4
Run the build server:
docker run -ti copyserver /bin/bash
You are now in a practical facsimile of your server within a docker container!
Source
https://zwischenzugs.com/2015/05/24/convert-any-server-to-a-docker-container/
in my opinon it's totally impossible. But you can create a dockerfile with same OS and mount your datas.
I want to create development environment for all our programmers so I want to install jdk, jdeveloper, maven and svn in one docker container.
How can I do that?
First of all, you need to go to the docker site and learn how to create a Dockerfile. The file will run and create a container with whatever you want to install in it. For example:
FROM debian
RUN apt-get update -qq && DEBIAN_FRONTEND=noninteractive apt-get install -yqq\
openjdk-8-jre\
maven\
svn\
....
RUN ... (to run commands inside the container when it's created)
EXPOSE 80 8080... (whatever ports you want to expose)
This is a very simple example, you have to read the docs and see what is available. I would recommend looking at the Dockerfile for from the github repo that has all the library docker files and get an idea of what's happening so you know how to create your container.
On a side note, I would not install svn in the same container, it would be better to have it in a separate container so that you never have more than one service per container since each container runs in a separate process. You can link containers, but that would require reading the docs to see how that is done.
Why using jdeveloper? For eclipse you can find several examples in the docker hub.
Agree with #Hatem-Jaber seperate svn from the dev environment.