I had docker 18 when I pulled some docker images. Then I upgraded docker to docker 20, but it seems there are no images left (docker images) list nothing. Can I somehow retrieve them or I should pull them again?
A Docker container consists of network settings, volumes, and images. The location of Docker files depends on your operating system. Here is an overview for the most used operating systems:
Linux: /var/lib/docker/
Windows: C:\ProgramData\DockerDesktop
MacOS: ~/Library/Containers/com.docker.docker/Data/vms/0/
If you use the default storage driver in overlay2, Linux, then your Docker images are stored in /var/lib/docker/overlay2. There, you can find different files that represent read-only layers of a Docker image and a layer on top of it that contains your changes.
If the update overwrote the folder .... you'll have to pull again.
Related
Now that Docker released an upgrade to version 23.0.0 I got an unfriendly reminder that three old Ubuntu installations were still configured to use aufs with Docker.
I had to revert to version 20.10.23 in order to be able to start my containers.
According to a chatbot, I can use docker save to export the content of the image, then upgrade the system to 23.0.0, and use docker load in order to recreate the image for use with the overlay2 driver.
Now my question is:
Is it possible to push the old, original, unsaved aufs images of the 20.10.23 version into a private registry, then upgrade the system to Docker version 23.0.0, and have docker run pull those old images for use with the overlay2 driver?
Could this cause an undefined behavior because the images in the registry were created with aufs, or is this a working migration path?
The Docker registry protocols and the docker save tar file formats are independent of any particular storage backend. If you (or your CI system) have an aufs Docker installation and push images to a registry, you shouldn't have any trouble pulling them on to an overlay2 setup.
Also consider that the registry protocol has only really had two major versions, but at various times devicemapper, aufs, overlay, and overlay2 have all been "the best" storage backend, and Docker Hub itself hasn't needed to do anything special to support this. Also of note is the appearance of alternate container runtimes like Podman, and Kubernetes's announcement that Docker proper is no longer a recommended container runtime, but these alternate systems still work file with existing image registries.
I had a corrupted OS of Ubuntu 16, and I wanted to backup all the docker things. Starting docker daemon outside fakeroot with --data-dir= didn't help, so I made a full backup of /var/lib/docker (with tar --xattrs --xattrs-include='*' --acls).
And in the fresh system (upgraded to Ubuntu 22.04), I extracted the tar, but found docker ps having empty output. I have the whole overlay2 filesystem and /var/lib/docker/image/overlay2/repositories.json, so there may be a way to extract the images and containers, but I couldn't find one.
Is there any way to restore them?
The backup worked actually, it was due to the docker installed during Ubuntu Server 22.04 installation process was ported by snap. After removing snap and installing a systemd version, the docker did recognize all the images and containers in overlayfs. Thanks for everyone!
For those who cannot start docker daemon for backup, you can try cp -a or tar --xattrs-include='*' --acls --selinux to copy the whole /var/lib/docker directory.
Probably not , as far as I have learned about docker it has stored your image in form different layers with different sha256 chunks.
Even when you try to transfer the images from one machine to another you would require online public/private repository to store and retrieve images or you have to zip the files from command line and then you can copy and paste it another location as single file.
Maybe from next time make sure you store all your important images to any of the online repository.
You can also refer different answers from this thread : How to copy Docker images from one host to another without using a repository
I am using a machine with os ubuntu-18.05 in arm platform. It has some space issue and I want to work with docker images.
Usually, when I work on this machine I mount a directory and perform memory expensive operations there.
Is there any way I can pull image in host machine and make it work?
Example: I have mounted directory /home/test-mount, now instead of storing docker image and it's graph in location mentioned here Where are Docker images stored on the host machine? I want to efficiently pull, store and use image at path /home/test-mount, such that it can be easily switched to actual path.
Stop docker and make sure the following can be found in in /etc/docker/daemon.json:
{
"data-root": "/home/test-mount"
}
Now restart docker
I am running windows 10 and the most recent version of docker. I am trying to run a docker image and transfer files to and from the image.
I have tried using the "docker cp" command, but from what I've seen online, this does not appear to work for docker images. It only works for containers.
When searching for info on this topic, I have only seen responses dealing with containers, not for images.
A docker image is basically a template used for containers. If you add something to the image it will show up in all of the containers. So if you just want to share a single set of files that don't change you can add the copy command to your docker file, and then run the new image and you'll find the container.
Another option is to use shared volumes. Shared volumes are basically folders that exist on both the host machine and the running docker container. If you move a file on the host system into that folder it will be available on the container (and if you put something from the container into the folder on the container side you can access it from the host side).
I have a compute cluster of 16 nodes running centos 6.7, with each node having a local disk and a shared storage between all nodes which is FhGFS based. the shared path is '/cluster'.
How to install Docker so that the image repository is allocated on /cluster, and any node could run containers from that repo. Is there a way to allocate the image repo in the shared area, while installing only the docker engine on each of the nodes? or even better, installing both the image repo and the engine on the shared area and making this installation usable by all nodes?
You can just modify your docker daemon configs to have the runtime root be /cluster
docker daemon --graph="/cluster"
or
docker daemon -g "/cluster"
Say you are using CentOS or RHEL you could add these options under
/etc/sysconfig/docker
If you are using Debian or Ubuntu you would change:
/etc/defaults/docker
So this way all the pulls that you do for images will be stored under /cluster also all your container runtimes will be under /cluster. So if you mount /cluster on all your machines then all of them will be able to see them.
If you want to share the binary, just put it under say /cluster/bin and then add it to your $PATH.
You might also want to look at Docker Swarm which is Docker's native clustering support. Although not ready for primetime as of Today, it's worth looking at.