Docker-registry image is started in local machine. Images that are built are able to be pushed to docker-registry. However, when we do the restart of the registry, the pushed images are lost and not retained.
Started the container with --always tag.
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Expected result would be to retain the images in the registry even after a restart of the docker-registry.
Pick a directory on the host file system to store the images during registry downtime, and bindmount that into the registry upon restart.
So in your docker run for the registry, you need this:
-v /registry-storage:/var/lib/registry
you can name the lefthand directory anything you like. You must call the righthand side of the colon /var/lib/registry
Related
I am aware that you can use curl <registry name>:5009/v2/_catalog to list images.
From this:
https://docs.docker.com/registry/deploying/#storage-customization
Is is stated "By default, the registry stores its data on the local filesystem", but where is that. -I am running Docker For Mac?
I just want an easy way to delete local images, and maybe it is a matter of finding this default host location - yes I looks like I could just use a custom volume.
I am still curious to where this default storage is located.
Is is stated "By default, the registry stores its data on the local filesystem", but where is that. -I am running Docker For Mac?
By default inside the container it's at /var/lib/registry. Each container gets its own read/write layer as part of the overlay filesystem (all of the image layers are read-only). This is stored within /var/lib/docker on the docker host, probably under a container or overlay sub directory, and then under a unique directory name per container. And then that, within Docker Desktop on Mac, is within a VM. You could probably exec into the container to see this path, but I wouldn't recommend modifying the contents directly for your request.
I just want an easy way to delete local images, and maybe it is a matter of finding this default host location - yes I looks like I could just use a custom volume.
First, just to verify you mean deleting images in the registry and not on the local docker engine. If the latter, you can run docker image prune.
Assuming you have a need to run a registry server, you'll want to pass the setting REGISTRY_STORAGE_DELETE_ENABLED=true to the registry (as an environment variable, or by setting the associated yaml config). Then you can call the manifest delete API. You'll want to get the digest and then call
curl -X DELETE http://<registry>:5000/v2/<repo>/manifests/<digest>
Once that's done, you need to run a garbage collection on the registry while no writes are occurring (by setting the server to read-only, picking an idle time, or stopping the registry and running a separate container against the same volume):
docker exec registry /bin/registry garbage-collect /etc/docker/registry/config.yml --delete-untagged
For simplifying the API calls, I've got a regclient project that includes regctl image delete ... and regctl tag delete ... (the latter only deleting one tag even if the manifest is referenced multiple times). And if you want to automate a cleanup policy, there's regclient/regbot in that same project that lets you define your own cleanup policy.
By default the registry container keep the data in /var/lib/registry within the container. You can bind mount a local directory on your host like the example did -v /mnt/registry:/var/lib/registry; which in this case the data will be kept on your host at /mnt/registry. You can also pre-create a volume like docker volume create registry and bind -v registry:/var/lib/registry; which in this case data will be stored at /var/lib/docker/volumes on your host.
I am trying to build a multi-arch image but would like to avoid pushing it to docker hub. I've had a lot of trouble finding out how to control the export options. is there a way to make "--push" push to a registry of my choosing?
Any help is appreciated
Docker provides a container image for a registry server that you may self run even on localhost, see: Deploying a registry server.
There are other servers|services that implement the registry API (see below) but this is a good place to start.
Conventionally, images pushed|pulled default to Docker registry; unless a registry is explicitly specifed, an image e.g. your-image:your-tag defaults to docker.io/my-image:my-tag. In my opinion, it's a good practice to always include this default to be more transparent about this.
If you run Docker's registry image on localhost on the default port 5000, you'll need to take your images with localhost:5000/your-image:your-tag to ensure that when you docker push localhost:5000/your-image:your-tag, the CLI is able to determine your local registry is the intended destination.
Similarly, if you use e.g. Quay registry, images must be prefixed quay.io, Google Artifact Registry, images are prefixed ${REGION}-docker.pkg.dev/${PROJECT}/${REPOSITORY} etc.
IIRC it's not possible to push to Docker's registry (aka dockerhub) without an account so, as long as you ensure you're not logged in, you should not accidentally push images to Docker's registry.
NOTE You only need to use a registry to ease distribution of container images between machines. If you're only interested in local(host) development, you can docker run ... immediately after a successful docker build without any pushing|pulling (beyond interim images, e.g. FROM).
I use minikube with Docker driver on Linux. For a manual workflow I can enable registry addon in minikube, push there my images and refer to them in deployment config file simply as localhost:5000/anything. Then they are pulled to a minikube's environment by its Docker daemon and deployments successfully start in here. As a result I get all the base images saved only on my local device (as I build my images using my local Docker daemon) and minikube's environment gets cluttered only by images that are pulled by its Docker daemon.
Can I implement the same workflow when use Skaffold? By default Skaffold uses minikube's environment for both building images and running containers out of them, and also it duplicates (sometimes even triplicates) my images inside minikube (don't know why).
Skaffold builds directly to Minikube's Docker daemon as an optimization so as to avoid the additional retrieve-and-unpack required when pushing to a registry.
I believe your duplicates are like the following:
$ (eval $(minikube docker-env); docker images node-example)
REPOSITORY TAG IMAGE ID CREATED SIZE
node-example bb9830940d8803b9ad60dfe92d4abcbaf3eb8701c5672c785ee0189178d815bf bb9830940d88 3 days ago 92.9MB
node-example v1.17.1-38-g1c6517887 bb9830940d88 3 days ago 92.9MB
Although these images have different tags, those tags are just pointers to the same Image ID so there is a single image being retained.
Skaffold normally cleans up left-over images from previous runs. So you shouldn't see the minikube daemon's space continuously growing.
An aside: even if those Image IDs were different, an image is made up of multiple layers, and those layers are shared across the images. So Docker's reported image sizes may not actually match the actual disk space consumed.
I followed this tutorial to enable gitlab as a repository of docker images, then I executed docker push of the image and it is loaded in gitlab correctly.
http://clusterfrak.com/sysops/app_installs/gitlab_container_registry/
If I go to the Project registry option in Gitlab, the image appears there, but the problem occurs when I restart the coupler engine or the container where gitlab is located and when I re-enter the option to register the project in gitlab, all the images they are eliminated
That could be happening.
the problem occurs when I restart the coupler engine or the container where gitlab is located and when I re-enter the option to register the project in gitlab, all the images they are eliminated
That means the path where GitLab is storing docker images is part of the container, and is not persistent, ie is not a volume or a bind mount.
From the tutorial, you have the configuration:
################
# Registry #
################
gitlab_rails['registry_enabled'] = true
gitlab_rails['gitlab_default_projects_features_container_registry'] = false
gitlab_rails['registry_path'] = "/mnt/docker_registry"
gitlab_rails['registry_api_url'] = "https://localhost:5000"
You need to make sure, when starting the GitLab container, that it mounts a volume or host local path (which is persistent) to the container internal path /mnt/docker_registry.
Then, restarting GitLab would allow you to find back all the images you might have stored in the GitLAb-managed Docker registry.
I have created the volume where the images are and now it works.
thank you very much
I'm wondering where Docker's images are exactly stored to in my local host machine.
Can I share my Docker-Image without using the Docker-Hub or a Dockerfile but the 'real' Docker-Image? And what is exactly happening when I 'push' my Docker-Image to Docker-Hub?
Docker images are stored as filesystem layers. Every command in the Dockerfile creates a layer. You can also create layers by using docker commit from the command line after making some changes (via docker run probably).
These layers are stored by default under /var/lib/docker. While you could (theoretically) cherry pick files from there and install it in a different docker server, is probably a bad idea to play with the internal representation used by Docker.
When you push your image, these layers are sent to the registry (the docker hub registry, by default… unless you tag your image with another registry prefix) and stored there. When pulling, the layer id is used to check if you already have the layer locally or it needs to be downloaded. You can use docker history to peek at which layers (other images) are used (and, to some extent, which command created the layer).
As for options to share an image without pushing to the docker hub registry, your best options are:
docker save an image or docker export a container. This will output a tar file to standard output, so you will like to do something like docker save 'dockerizeit/agent' > dk.agent.latest.tar. Then you can use docker load or docker import in a different host.
Host your own private registry. - Outdated, see comments See the docker registry image. We have built an s3 backed registry which you can start and stop as needed (all state is kept on the s3 bucket of your choice) which is trivial to setup. This is also an interesting way of watching what happens when pushing to a registry
Use another registry like quay.io (I haven't personally tried it), although whatever concerns you have with the docker hub will probably apply here too.
Based on this blog, one could share a docker image without a docker registry by executing:
docker save --output latestversion-1.0.0.tar dockerregistry/latestversion:1.0.0
Once this command has been completed, one could copy the image to a server and import it as follows:
docker load --input latestversion-1.0.0.tar
Sending a docker image to a remote server can be done in 3 simple steps:
Locally, save docker image as a .tar:
docker save -o <path for created tar file> <image name>
Locally, use scp to transfer .tar to remote
On remote server, load image into docker:
docker load -i <path to docker image tar file>
[Update]
More recently, there is Amazon AWS ECR (Elastic Container Registry), which provides a Docker image registry to which you can control access by means of the AWS IAM access management service. ECR can also run a CVE (vulnerabilities) check on your image when you push it.
Once you create your ECR, and obtain the "URL" you can push and pull as required, subject to the permissions you create: hence making it private or public as you wish.
Pricing is by amount of data stored, and data transfer costs.
https://aws.amazon.com/ecr/
[Original answer]
If you do not want to use the Docker Hub itself, you can host your own Docker repository under Artifactory by JFrog:
https://www.jfrog.com/confluence/display/RTF/Docker+Repositories
which will then run on your own server(s).
Other hosting suppliers are available, eg CoreOS:
http://www.theregister.co.uk/2014/10/30/coreos_enterprise_registry/
which bought quay.io