After buying a mac on an m1 chip, I was faced with the problem of building images
I am working on a test that will check the relevance of the data in the database. After writing this test in Pycharm, I collect the image in docker with docker buildx build --platform linux/amd64 -t {IMAGE} . and push it to gitlab with docker push {IMAGE} and then test this image in dagster. My problem is that the image is being assembled, but my changes do not appear in the image, although I have committed and released the changes and I cannot test these changes in dagster. I’m already confused and don’t know what to do with it, so I’ll be glad of any help
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I'm trying here, after having posted the following on the Docker Forum.
I’ve tried the buildx command explained in the documentation (from my Intel-based Mac):
# This normally works with build, without buildx
git clone https://github.com/Rothamsted/knetminer
cd knetminer
# buildx is the new thing I'm trying, to have multi-arch support
docker buildx build --platform linux/amd64,linux/arm64 -t knetminer/knetminer -f docker/Dockerfile --push .
However, when I try the published image on an ARM64, I still get the usual:
standard_init_linux.go:211: exec user process caused “exec format error”
Is buildx enough to obtain multiple-architecture images? Or do I need more (eg, Linux images that actually support ARM)?
My image is based on another one, which is based on a Tomcat
+Linux image. Do I need to re-run buildx on all the parents?
For those interested in details, this is about building the image for our own application from its codebase, documentation here.
Thanks in advance.
standard_init_linux.go:211: exec user process caused “exec format error”
Does happen, when you try to run a image for another architecture on your devices.
Your base image must support the choosen architecture too. So you must build the parent by yourself for your architecture, if it does not support your architecture.
In dockerhub you can see supported architectures under tags.
Alternative you can use the docker image inspect command.
In 2019, I made a pull image of Python 3.6. After that, I was sure that the image was self-updating (I did not use it actively, I just hoped that the latest pushes themselves were pulled from the repository or something like that), but I was surprised when I accidentally noticed the download/creation date is 2019.
Q: How does image pull work? Are there flags so that the layer hash/its relevance* is checked every time the image is built? Perhaps there is a way to set this check through the docker daemon config file? Or do I have to delete the base image every time to get a new image?
What I want: So that every time I build my images, the base image is checked for the last push (publication of image) in the docker hub repository.
Note: I'm talking about images with an identical tag. Also, I'm not afraid to re-build my images, there is no purpose to preserve them.
Thanks.
You need to explicitly docker pull the image to get updates. For your custom images, there are docker build --pull and docker-compose build --pull options that will pull the base image (though there is not a "pull" option for docker-compose up --build).
Without this, Docker will never check for updates for an image it already has. If your Dockerfile starts FROM python:3.6 and you already have a local image with that name and tag, Docker just uses it without contacting Docker Hub. If you don't have it then Docker will pull it, once, and then you'll have it locally.
The other thing to watch for is that the updates do eventually stop. If you look at the Docker Hub python image page you'll notice that there are no longer rebuilds for Python 3.5. If you pin to a very specific patch version, the automated builds generally only build the latest patch version for each supported minor version; if your image is FROM python:3.6.11 it will never get updates because 3.6.12 is the latest 3.6.x version.
Is there a way to ensure that docker does not automatically attempt to download a container image if it doesn't exist locally? That is, a way to configure the docker daemon to avoid looking for FOO remotely if someone runs docker run FOO locally.
Update:
Docker released this feature on version 20.10.0 (2020-12-14):
Client:
Add --pull=missing|always|never to run and create commands docker/cli#1498
Old:
Currently, there is no way to do that, but there is an open Pull Request (#1498) to add this feature:
• This PR adds a new --pull flag to docker run and docker create,
following the proposal in moby/moby#34394.
• Per this proposal, the flag is tristate:
--pull=missing (this is the current behaviour and will be the default.)
--pull=never
--pull=always
• [...] pull the image if it
does not exist at all locally (--pull=missing), always try and update
the image (--pull=always), or never try and update the image, only using
images that already exist on the local machine (--pull=never)
Stay tuned to see when the merge will be accepted, and in which version the feature will be included.
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?
I have the following scenario:
A daemon_pulling running docker pull the last version of an image from a private registry.
E.g. docker pull localhost:5000/myimage:v1 # sha or image id: 1234
A daemon_pushing running docker push of the last version of a image.
E.g. docker commit container_stable localhost:5000/myimage:v1 && docker push localhost:5000/myimage:v1 # sha or image id: 6789
The code works fine to deploy images based on containers!
The problem is when a dameon_pushing (sha or image id: 6789) is running and run a daemon_pulling (sha or image id: 1234) at the same time, because the pushing (6789) is not finished when a docker pull (1234) is used and detect a local change (6789 != 1234) and try download the image (1234) again but my last stable image is pushing (6789)...
I'm looking for a way to push without affect a pull in progress, and vice versa.
What is a better way to manage this concurrency?
I tried using a different Docker image name as pivot and rename it directly on the registry server, but I didn't find a way to rename remotely (just local rename).
It looks like you have set up your CI build to pull an existing image, run a container from it and install the updates, commit the changes to the same image name and then push it back to the registry. Continuously updating images by running containers and committing to the same image is not a good practice, since it hides the changes, and makes it unnecessarily difficult to replicate the build.
A better way would be to build the image from a Dockerfile, where you define all build steps. Look at the Reference Architecture on Docker's official Continuous Integration use case for examples. If you want to shorten build times, you can make your own base image to start from.