I downloaded an image of ubuntu os in my system and after about committing 3 images from it(every image has an incremental change from before image), I now have my final image. Now I want the Dockerfile of this final image so that I can include commands like starting service at the start of container.
I have used this command,
sudo docker commit --change='CMD service apache2 start' 172d6dc34471 server_startup
to make the apache service start when the container is run. This starts the service in the container but doesn't go inside the container. It just starts the apache and exits to my local environment.
I would like to know how to get the Dockerfile for my final image so that I can include startup commands.
I have also tried this dockerfile from image, but its not working. It just throws error that .sock file is missing. I have tried this with both the new image and the parent image that I first downloaded.
Any help is much appreciated. Thanks.
you can use
docker history --no-trunc your_image
it will show you (in reverse order) what has been done
It is less user friendly than dockerfile from image, but it is basically the same thing.
I have somewhere a Python script that does that cleanly, I will check and post it.
Edit: Just this should show a lot
docker history your_image | docker inspect $(awk ' NR>1 {print $1}')
As CMD you need to provide a no-daemon program that keeps in foreground. That is not accomplished by service.
You should try:
sudo docker commit --change='CMD apache2 -DFOREGROUND' 172d6dc34471 server_startup
Sorry for the late reply, I used the --change argument while committing the image to point to the custom script(which I added within the container with the list of commands to be run at the start) that I want to run when the image is run for the first time.
sudo docker commit --change='ENTRYPOINT ["/test.sh"]' containerId autostart
I didn't know much about the dockerfile that everyone is suggesting but it is also a very good solution.
Related
I wanted to install CVAT for training an Object Detection AI using Docker. The install failed for some reason in the middle and it wasn't installed. But all the files were still occupying space on my machine. I tried reinstalling the CVAT and the files keep adding to the occupied space. How do I remove all of these files? I am using a MacBook Pro with MacOS Big Sur Beta 4.
Edit: https://github.com/opencv/cvat/blob/develop/cvat/apps/documentation/installation.md#mac-os-mojave
These are the commands I am running to install CVAT.
docker-compose build output: https://pastebin.com/7EkeQ289
docker-compose up -d output: https://pastebin.com/hF3GFDkX
docker exec -it cvat bash -ic 'python3 ~/manage.py createsuperuser output: https://pastebin.com/Mfh8CivL
If you are trying to remove the containers, attempt the following:
1. docker ps -a - lists all containers
2. docker stop [label or SHA of the containers you want to remove]
docker-compose down [YAML configuration file you targeted with docker-compose up] - this should stop all containers, teardown networks, etc. that docker-compose started with 'up'
docker container prune - removes all stopped containers
NOTE: If you have other stopped containers that you want to keep, do not run this, but remove them individually, as I suggested in the stricken-through step two above, or Konrad Botor's comment
https://docs.docker.com/compose/reference/down/
https://docs.docker.com/engine/reference/commandline/container_prune/
If you want to remove the images:
docker images
docker rmi [label or SHA] (RMI is the remove image command)
https://docs.docker.com/engine/reference/commandline/images/
https://docs.docker.com/engine/reference/commandline/rmi/
To speed up this process, analyze the YAML configuration file being targeted for your docker-compose build command, and/or reference the documentation for that specific project (CVAT) if available, to determine what containers (software) it is initializing (and how it is doing so, if necessary). It might help to paste its contents in the question.
Note: what is taking up space may be volumes which are not cleaned up properly by the docker build scripts for this project. See the following documentation on how to remove those:
https://docs.docker.com/engine/reference/commandline/volume_rm/
I might be missing some context, as I cannot access your pastebin links (behind a firewall at the moment).
I was following this post - the reference code is on GitHub. I have cloned the repository on my local.
The project has got a react app inside it. I'm trying to run it on my local following step 7 on the same post:
docker run -p 8080:80 shakyshane/cra-docker
This returns:
Unable to find image 'shakyshane/cra-docker:latest' locally
docker: Error response from daemon: pull access denied for shakyshane/cra-docker, repository does not exist or may require 'docker login'.
See 'docker run --help'.
I tried login to docker again but looks like since it belongs to #shakyShane I cannot access it.
I idiotically tried npm start too but it's not a simple react app running on node - it's in the container and containers are not controlled by npm
Looks like docker pull shakyshane/cra-docker:latest throws this:
Error response from daemon: pull access denied for shakyshane/cra-docker, repository does not exist or may require 'docker login'
So the question is how do I run this docker image on my local mac machine?
Well this is illogical but still sharing so future people like me don't get stuck.
The problem was that I was trying to run a docker image which doesn't exist.
I needed to build the image:
docker build . -t xameeramir/cra-docker
And then run it:
docker run -p 8080:80 xameeramir/cra-docker
In my case, my image had TAG specified with it and I was not using it.
REPOSITORY TAG IMAGE ID CREATED SIZE
testimage testtag 189b7354c60a 13 hours ago 88.3MB
Unable to find image 'testimage:latest' locally for this command docker run testimage
So specifying tag like this - docker run testimage:testtag worked for me
Posting my solution since non of the above worked.
Working on macbook M1 pro.
The issue I had is that the image was built as arm/64. And I was running the command:
docker run --platform=linux/amd64 ...
So I had to build the image for amd/64 platform in order to run it.
Command below:
docker buildx build --platform=linux/amd64 ...
In conclusion your docker image platform and docker run platform needs to be the same from what I experienced.
In my case, the docker image did exist on the system and still I couldn't run the container locally, so I used the exact image ID instead of image name and tag, like this:
docker run myContainer c29150c8588e
I received this error message when I typed the name/character wrong. That is, "name1\name2" instead of "name1/name2" (wrong slash).
In my case, I saw this error when I had logged in to the dockerhub in my docker desktop. The repo I was pulling was local to my enterprise. Once i logged out of dockerhub, the pull worked.
This just happened to me because my local docker vm on macos ran out of disk space.
I just deleted some old images using docker image prune and it started working correctly again.
shakyshane/cra-docker Does not exist in that user's repo https://hub.docker.com/u/shakyshane/
The problem is you are trying to run an imagen that does not exists. If you are executing a Dockerfile, the image was not created until Dockerfile pass with no errors; so when Dockerfile tries to run the image, it can't find it. Be sure you have no errors in the execution of your scripts.
The simplest answer can be the correct one!.. make sure you have permissions to execute the command, use:
sudo docker run -p 8080:80 shakyshane/cra-docker
In my case, I didn't realise there was a difference between docker run and docker start, and I kept using the run command when I should've been using the start command.
FYI, run is for building and creating the docker container, start is to just start a stopped container
Use -d
sudo docker run -d -p 8000:8000 rasa/duckling
learn about -d here
sudo docker run --help
At first, i build image on mac-m1-pro with this command docker build -t hello_k8s_world:0.0.1 ., when is run this image the issue appear.
After read Master Yi's answer, i realize the crux of the matter and rebuild my images like this docker build --platform=arm64 -t hello_k8s_world:0.0.1 .
Finally，it worked.
I create a docker container using
docker-machine.exe create -d virtualbox --virtualbox-memory 2048 default
and I logged into the bash using
docker run -ti ubuntu /bin/bash
and I got something like root#ae78cd536ddf:/# where I did a couple of apt-get installs.
Then, I exited from the bash and when I again logged back in I could not find what I had installed. I wanted to do a docker commit, but I somehow can't figure where my installed stuff is?
UPDATE
Based on the answers I tried creating an image of the container. I have compiled all commands in a gist.
With docker run, you create a container from the ubuntu image. The container has the name ae78cd536ddf (in your case). You can inspect images and containers with docker ps -a and docker images respectively.
Each time you run docker run, a new container is created. When using docker run --name Somename, you force the container to be named Somename which prevents you from creating another container with the same name.
Images are immutable which means you can not change them. So when you modify something in the running container, the image stays the same and this you can create more containers from the same image.
So after you stopped a container (docker stop, exit the containerized bash or just reboot), you can run docker start ae78cd536ddf to restart it. But it will be running in background and you won't have a bash (check docker ps to see it's running). Now you just need a bash: docker exec -it ae78cd536ddf /bin/bash will execute a bash in the container you started before.
Just a note about creating images. You might want to install the software you always need (I personally love vim, htop, ...) and then docker commit the container. This will create a new image which you can see in docker images. Now you can run containers from this image by replacing ubuntu with your image name.
To get more reproducable builds (when using a CI for example), you can create a Dockerfile and run docker build.
Every docker run command creates a new container. The id in the hostname of the bash shell is the container ID. You can commit that.
To see all containers (including stopped containers), do docker ps -a.
I'm trying to create my own docker image in a ubuntu-14 system.
My docker file is like the following:
FROM scratch
RUN /bin/bash -c 'echo "hello"'
I got the error message when I run docker build .:
exec: "/bin/sh": stat /bin/sh: no such file or directory
I guess it is because /bin/sh doesn't exist in the base image "scratch". How should I solve this problem?
Docker is basically a containerising tool that helps to build systems and bring them up and running in a flash without a lot of resource utilisation as compared to Virtual Machines.
A Docker container is basically a layered container. In case you happen to read a Dockerfile, each and every command in that file will lead to a creation of a new layer in container and the final layer is what your container actually is after all the commands in the Dockerfile has been executed.
The images available on the Dockerhub are specially optimised for this sort of environment and are very easy to setup and build. In case you are building a container right from scratch i.e. without any base image, then what you basically have is an empty container. An empty container does not understand what /bin/bash actually is and hence it won't work for you.
The Docker container does not use any specifics from your underlying OS. Multiple docker containers will make use of the same underlying kernel in an effective manner. That's it. Nothing else.
( There is however a concept of volumes wherein the container shares a specific volume on the local underlying system )
So in case you want to use /bin/bash, you need a base image which will setup the nitty gritties of this command for your container and then you can successfully execute it.
However, it is recommended that you use official Docker images for say Ubuntu and then install your custom stuff on top of it. The official images are right from the makers and are highly optimised for this environment.
Base image scratch does not use /bin/bash. So you should change to:
FROM ubuntu:14.04
RUN /bin/sh -c 'echo "hello"'
Trying to fix errors and debug problems with my application that is split over several containers, I frequently edit files in containers:
either I am totally lazy and install nano and edit directly in container or
I docker cp the file out of the container, edit it, copy it back and restart the container
Those are intermediate steps before coming to new content for container build, which takes a lot longer than doing the above (which of course is only intermediate/fiddling around).
Now I frequently break the starting program of the container, which in the breaking cases is either a node script or a python webserver script, both typically fail from syntax errors.
Is there any way to save those containers? Since they do not start, I cannot docker exec into them, and thus they are lost to me. I then go the rm/rmi/build/run route after fixing the offending file in the build input.
How can I either edit files in a stopped container, or cp them in or start a shell in a stopped container - anything that allows me to fix this container?
(It seems a bit like working on a remote computer and breaking the networking configuration - connection is lost "forever" this way and one has to use a fallback, if that exists.)
How to edit Docker container files from the host? looks relevant but is outdated.
I had a problem with a container which wouldn't start due to a bad config change I made.
I was able to copy the file out of the stopped container and edit it. something like:
docker cp docker_web_1:/etc/apache2/sites-enabled/apache2.conf .
(correct the file)
docker cp apache.conf docker_web_1:/etc/apache2/sites-enabled/apache2.conf
Answering my own question.. still hoping for a better answer from a more knowledgable person!!
There are 2 possibilities.
1) Editing file system on host directly. This is somewhat dangerous and has a chance of completely breaking the container, possibly other data depending on what goes wrong.
2) Changing the startup script to something that never fails like starting a bash, doing the fixes/edits and then changing the startup program again to the desired one (like node or whatever it was before).
More details:
1) Using
docker ps
to find the running containers or
docker ps -a
to find all containers (including stopped ones) and
docker inspect (containername)
look for the "Id", one of the first values.
This is the part that contains implementation detail and might change, be aware that you may lose your container this way.
Go to
/var/lib/docker/aufs/diff/9bc343a9..(long container id)/
and there you will find all files that are changed towards the image the container is based upon. You can overwrite files, add or edit files.
Again, I would not recommend this.
2) As is described at https://stackoverflow.com/a/32353134/586754 you can find the configuration json config.json at a path like
/var/lib/docker/containers/9bc343a99..(long container id)/config.json
There you can change the args from e. g. "nodejs app.js" to "/bin/bash". Now restart the docker service and start the container (you should see that it now correctly starts up). You should use
docker start -i (containername)
to make sure it does not quit straight away. You can now work with the container and/or later attach with
docker exec -ti (containername) /bin/bash
Also, docker cp is rather useful for copying files that were edited outside of the container.
Also, one should only fall back to those measures if the container is more or less "lost" anyway, so any change would be an improvement.
You can edit container file-system directly, but I don't know if it is a good idea.
First you need to find the path of directory which is used as runtime root for container.
Run docker container inspect id/name.
Look for the key UpperDir in JSON output.
That is your directory.
If you are trying to restart an stopped container and need to alter the container because of misconfiguration but the container isn't starting you can do the following which works using the "docker cp" command (similar to previous suggestion). This procedure lets you remove files and do any other changes needed. With luck you can skip a lot of the steps below.
Use docker inspect to find entrypoint, (named Path in some versions)
Create a clone of the using docker run
Enter clone using docker exec -ti bash (if *nix container)
Locate entrypoint file location by looking though the clone to find
Copy the old entrypoint script using docker cp : ./
Modify or create a new entrypoint script for instance
#!/bin/bash
tail -f /etc/hosts
ensure the script has execution rights
Replace the old entrypoint using docker cp ./ :
start the old container using start
redo steps 6-9 until the starts
Fix issues in container
Restore entrypoint if needed and redo steps 6-9 as required
Remove clone if needed