I have a docker-compose.yaml file with details on how to build and use 10 containers.
I ran docker-compose build which built 5 images successfully, but failed on the 6th.
After I corrected the problem, I re-ran docker-compose build hoping that docker-compose would only build missing images. But it started building images from the beginning!
Why?
Can I get docker-compose to continue, without re-building existing images?
Note: The answer to the question below didn't really resolve my problem, because I'm not trying to pull the images from anywhere:
Can docker compose skip build if the image is present?
Related
This question already has answers here:
how to get docker-compose to use the latest image from repository
(17 answers)
Closed 6 months ago.
I've a system running on docker, my system has an specific test environment which might need to update the image version several times on a day...
So every time a new version need to be placed, i need to open the compose.yml file, look the container and edit the image version, then re-run docker compose up -d
So to skip this boring process of edit the compose.yml file, I had one idea: in the pipeline which builds and publishes the docker image, i create a new tag $image_name:latest-test and a new step which publishes the image to this tag
so on any image update in my pipeline two tags are created, one with the version number and other with the latest-test... both are published to dockerhub and this process works like a charm
but even when a new image is published to dockerhub and i run docker compose up -d no matter if the container is running or not, docker doesn't check if the image we have cached is really the one on dockerhub... it assumes the cache is the latest one and dont update
THE QUESTION IS:
1 - is there any way to force docker to check if the cached image has been updated on dockerhub?
2 - is there any other workaround i can do to keep a specific tag on my compose.yml file and update the image when needed without needing to edit the file 1000 times a day?
thanks
is there any way to force docker to check if the cached image has been updated on dockerhub?
No.
is there any other workaround i can do to keep a specific tag on my compose.yml file and update the image when needed without needing to edit the file 1000 times a day?
Just use latest and use docker-compose pull to pull the images.
I'm new to docker and have been dabbling with it for the past few days. I've managed to successfully use docker-compose for a multi-container deployment involving an app server (flask + gunicorn) and web server (nginx).
Now, I'd like to recreate the deployment on an offline machine. After doing research, it seems that most have mentioned use docker save and docker load to transfer over the base images. However, I'm wondering whether its possible to recreate the deployment from the image created by docker-compose build? Reason being I would like to skip the entire process of wheeling my python package dependencies for offline use, which I would have to do for the method starting from the base images.
I've tried to save that particular image (output of docker-compose build) and load it on the offline machine, and then tried docker run and docker-compose up but both don't seem to work. Would like to check with the community whether this method is even possible, and if so what's the right way to go about it?
Thanks!
To solve my issue, I ended up making an image of each individual container post pip install, then using docker-compose.yml simply to spin them up. As David mentioned, it doesn't seem possible to spin up the container from the single image output by docker-compose build.
Simple question: After using Docker for about a week, my docker build command gets bogged down and hangs (before anything executes) for about a minute. After staying in this hanging state, it will execute the docker build command with no issues at all and at at the expected speed.
Other Docker commands (like docker run) do not suffer from this "hanging" issue.
Docker Installation info:
Version 18.06.1-ce-win73
Channel: stable
Things I have tried:
docker system prune - This does clear up space, but doesn't speed up my docker build command
Reinstalling Docker on my machine - This does fix the issue, but it reappeared after about a week of using Docker again.
Does anyone else suffer from this issue?
I had the same issue. I solved it moving the Dockerfile to an empty folder, then I executed the docker build command and worked perfectly.
On some other forums people created a .dockerignore file including the any call to git and many other files, but that approach didn't work for me.
Here was the the issue:
The very first line of my Dockerfile (the FROM command) was failing. The "hanging" was caused by a timeout during the attempt to download the base image. I was attempting to download the base image from a location that I needed to set a proxy on my machine for.
So I was mistaken in my original post: The Docker build command wasn't running as expected. It was failing to download the base image due to a missing proxy setting.
2 reasons:
1.If you are building many dockers for hours ..please restart your router if possible as sometimes due to heavy data packets movement the router collapses.
2.Increase RAM ,CPU and Swap of docker engine and restart docker and try to build again.
I am new to docker container. I met a problem about how to catch changes of my code. Some lines in my local style.css file have been changed. Then I built docker image again, but actually nothing changed when I browsed my app.
Here are some methods I found online and tried, but didn't work.
remove image and build again
--no-cache=true
add a comment in Dockerfile to make it different
docker system prune
--pull
(I also used git pull to get code on my cloud instance, these files were checked to be the latest.)
I know little about docker mechanism, could anyone tell me what the problem is?
Extra info I found:
After stopping container and removing image, I restart my instance, then build image, run container again. Only in this way, can I catch those changes. Does anyone know the problem?
Many thanks!
There appears to be a disconnect on the difference between a container and an image. The container is the running instance of your application. It is based on an image that you have already built. That image has a tag for easier referencing, but the real reference to the image is a sha256 hash and building a new image will change the hash that the tag points to without impacting any of your running containers.
Therefore, the workflow to update your running application in docker is to:
Build a new image
Stop the running container
Start a new container pointing to that image
Cleanup any old images or stopped containers
If you are using docker-compose, it automates the middle two steps with a docker-compose up command, and that even deletes the old container. Most users keep a few copies of older images to allow easy rollback.
I'm playing with docker by creating a Dockerfile with some nodejs instructions. Right now, every time I make changes to the dockerfile I recreate the image by running sudo docker build -t nodejstest . in my project folder however, this creates a new image each time and swallows my ssd pretty soon.
Is there a way I can update an existing image when I change the dockerfile or I'm forced to create a new one each time I make changes to the file?
Sorry if it's a dumb question
Docker build support caching as long as there is no ADD instruction. If you are actively developing and changing files, only what is after the ADD will be rebuilt.
Since 0.6.2 (scheduled today), you can do docker build --rm . and it will remove the temporary containers. It will keep the images though.
In order to remove the orphan images, you can check them out with docker images, and perform a docker rmi <id> on one of them. As of now, there is an auto-prune and all untagged images (orphans, previous builds) will be removed.
According to this best practices guide if you keep the first lines of your dockerfile the same it'll also cache them and reuse the same images for future builds
During development, it makes less sense to re-build a whole container for every commit. Later, you can automate building a Docker container with your latest code as part of your QA/deployment process.
Basically, you can choose to make a minimal container that pulls in code (using git when starting the container, or using -v /home/myuser/mynode:/home/myuser/mynode with ENTRYPOINT to run node).
See my answer to this question:
Docker rails app and git