I want to build a Docker container from a Dockerfile. It contains a private project.
My question is quite simple, and I don't find a clear answer: after having built my image, will it be automatically sent as a public one on Docker repository?
I want to build this container for private use and it's not intended to be retrieved on the public Internet.
docker build -f Dockerfile is a local operation.
You can docker push an image onto Dockerhub, but that is a separate operation and requires a Dockerhub account.
No, it will not automatically be published anywhere.
If you push the image onto Docker Hub, then it would be public unless you marked that repository private. (You get one private repository for free, though you can have more than one if you pay for an account.)
Related
While trying to signup with docker hub by selecting a suitable plan, I see pricing is based on Private Repositories Required and Parallel Builds desired.
What is a PARALLEL BUILD in this context?
PS:
After a bit of an internet search, I found that docker hub can pull up my source code from external repositories and build an image by itself and later publish the same into Hub. If this is true and I don't want to use docker hub build service, can I ignore the PARALLEL BUILD part entirely?
Dockerhub is a service provided by Docker for finding and sharing container images with your team. It provides the following major features:
Repositories: Push and pull container images.
Teams & Organizations: Manage access to private repositories of
container images.
Official Images: Pull and use high-quality container images provided
by Docker.
Publisher Images: Pull and use high-quality container images provided
by external vendors. Certified images also include support and
guarantee compatibility with Docker Enterprise.
Builds: Automatically build container images from GitHub and
Bitbucket and push them to Docker Hub
Webhooks: Trigger actions after a successful push to a repository to
integrate Docker Hub with other services.
More info here.
If you see the pricing page of dockerhub. There are two things you should know:
PARALLEL BUILD specifies the number of images that you can build
parallelly (con-currently). The parallelism is across all of the
repos owned by you.
Private Repository specify the number of repository that are private and not exposed publicly.
If you're new to docker and trying out it first time then its ok to go with dockerhub free plan where you can have max 1 private repository and 1 parallel build count.
If you want to store docker images of your project privately that is hosted somewhere on public cloud like AWS then I suggest to use docker registry provided by those cloud providers like AWS ECR, Azure ACR, Google container registry and so on.
Or else you can host docker image privately by running docker registry inside container. Check this.
Hope this helps.
I have few docker images composed together in the stack using docker-compose.yml.
Now I want to transfer whole docker compose stack to the other host machine without uploading to the dockerhub,
And deploy it on the docker swarm.
I saw there is a thing called docker compose bundle, would that help?
If you’re deploying on a multi-host swarm (or something similar like Kubernetes or Nomad) you all but need a Docker registry. It doesn’t specifically have to be Docker Hub — quay.io, Amazon’s ECR, Google’s GCR, and self-hosted registries all work fine — but you do need to have pushed the built images somewhere where the orchestrator can retrieve them by name.
I’ve never used docker-compose bundle myself, but its documentation also notes that its operation “requires interaction with a Docker registry”.
The only real alternative is using docker save and docker load to manually move images between machines, but as a manual process it will get tedious very quickly, and you need to make sure an identical set of images are on every machine for consistency. Using a registry will be vastly easier.
The easyest way to do it is to use a Docker registry. The problem with Docker Hub is that you can only have one private registry, the rest must be public or paid.
Thankfully, there are other (free) alternatives:
Deploy your own private registry. Here is a nice tutorial where you can try it in the browser.
Use a free private registry. I personnaly use Codefresh. It can automatically build your image from a private repo (like bitbucket who has free plan too), but you can also just use it like a "simple" docker registry and push and pull your Docker images there.
Aim: to deploy a private registry
Discussion
private repository
I have read multiple posts and now I am confused. I have tried to run a docker container that should serve a private docker registry, but it returns an empty UI. Some posts indicate that it has been deprecated, but some other do not.
images
I used to navigate to dockerhub, but now there is https://store.docker.com?
Questions
Has docker registry been phased out?
Should one now use https://store.docker.com in stead of docker hub?
Docker hub still exists and will remain for the open source projects as it always has.
Docker store is a new offering for commercial images.
The standalone registry does not have a UI, don't believe it ever has. It's intended to be accessed with docker push and docker pull commands.
I'm confused as to the difference between docker registries and repositories. It seems like the Docker documentation uses the two words interchangeably. Also, repositories are sometimes referred to as images, such as this from their docs:
In order to push a repository to its registry, you need to have named
an image or committed your container to a named image as we saw here.
Now you can push this repository to the registry designated by its
name or tag.
How can you push a repository to a registry? Aren't you pushing the image to the repository?
Docker registry is a service that is storing your docker images.
Docker registry could be hosted by a third party, as public or private registry, like one of the following registries:
Docker Hub,
Quay,
Google Container Registry,
AWS Container Registry
or you can host the docker registry by yourself
(see https://docs.docker.com/ee/dtr/ for more details).
Docker repository is a collection of different docker images with same name, that have different tags. Tag is alphanumeric identifier of the image within a repository.
For example see https://hub.docker.com/r/library/python/tags/. There are many different tags for the official python image, these tags are all members of the official python repository on the Docker Hub. Docker Hub is a Docker Registry hosted by Docker.
To find out more read:
https://docs.docker.com/registry/
https://github.com/docker/distribution
From the book Using Docker, Developing and deploying Software with Containers
Registries, Repositories, Images, and Tags
There is a hierarchical system for storing images.
The following terminology is used:
Registry
A service responsible for hosting and distributing images. The default registry is the Docker Hub.
Repository
A collection of related images (usually providing different versions of the same application or service).
Tag
An alphanumeric identifier attached to images within a repository (e.g., 14.04 or stable ).
So the command docker pull amouat/revealjs:latest will download the image tagged latest within the amouat/revealjs repository from the Docker Hub registry.
Complementing the information:
You usually push a repository to a registry (and all images that are part of it). But you can push a single image to a registry. In all cases, you use docker push.
An image has a 12-hex-digit Image ID, but is also identified by: namespace/repo-name:tag
The image full name can be optionally prefixed by the registry host name and port: myregistryhost:5000/namespace/repo-name:tag
A common naming convention is to use your registry user-name as what I called "namespace".
A docker repository is a cute combination of registry and image.
docker tag foo <registry>/<image>:<tag>
is the same as
docker tag foo <repository>:<tag>
Docker Registry is a service, which you can either host yourself (Trusted and Private) or you can let docker hub be the host for this service. Usually, if your software is commercial, you will have hosted this as a "Private and Trusted" registry. For Java Developers, this is somewhat analogous to Maven Artifactory setup.
Docker Repository is a set of "Tagged" images. An example is that you might have tagged 5 of ubuntu:latest images:
a) Nano editor (image1_tag:v1)
b) A specific software 1 (image1_tag:v2)
c) Sudo (image1_tag:v3)
d) apache http daemon (image1_tag:v4)
e) tomcat (image1_tag:v5)
You can use docker push command to push each of the above images to your repository. As long as the repository names match, they will be pushed successfully, and appear under your chosen repository and correctly tagged.
Now, your question is, "So where is this repository hosted/who is managing the service"? That is where Docker Registry comes into picture. By default you will get a docker hub registry (Open Source) which you can use to keep your private/public repository. So without any modification, your images will be pushed to your private repository in docker hub. An example output when you pushing your image tags are the following:
docker#my-docker-vm:/$ docker push mydockerhub/my-helloworld-repo:my_tag
The push refers to repository [docker.io/mydockerhub/my-helloworld-repo]
bf41e934d39d: Pushed
70d93396f87f: Pushed
6ec525dfd060: Pushed
705419d10b13: Pushed
a4aaef726d02: Pushed
04964fddc946: Pushed
latest: digest: sha256:eb93c92351bce785aa3ec0de489cfeeaafd55b7d90adf95ecea02629b376e577 size: 1571
docker#my-docker-vm:/$
And if you type immediately docker images --digests -a you can confirm that your pushed image tags are now showing new signature against the private repository managed by docker hub registry.
A Docker image registry is the place to store all your Docker images. The image registry allows you to push and pull the container images as needed.
Registries can be private or public. When the registry is public, the images are shared with the whole world whereas in the private registry the images are shared only amongst the members of an enterprise or a team.
A registry makes it possible for the Docker daemon to easily pull and run your Docker images.
Docker Hub and other third party repository hosting services are called “registries”. A registry stores a collection of repositories.
As a registry can have many repositories and a repository can have many different versions of the same image which are individually versioned with tags.
The confusion starts with this definition of a tag: "An alphanumeric identifier attached to images in a repository"
I'd rather call that alphanumeric identifier that you append with a ':' a tag-suffix for now. When somebody says "'latest' is the default tag", then this kind of tag-suffix is meant.
In reality, the :latest' suffix is technically part of the tag. The entire name is a tag. All these are tags (possibly referring to the same image):
myimagename
myimagename:latest
username/theirimagename:1.0
myrepo:5000/username/imagename:1.0
(I say imagename here, just to illustrate the other main source of confusion. That's the repositoryname, of course. Sorry.)
Examples:
a) When you want to name your image while building, you use docker build -t thisname ... -- that is -t for tag, (not -n for name).
b) When you want to push that image to a registry, you need to have the full URL (starting with registryname and ending with a tag-suffix) as a tag:
docker tag thisname mylocalregistry:5000/username/repoimagething:1.0
Now you push the image known as thisname by saying:
docker push mylocalregistry:5000/username/repoimagething:1.0
Naming things is hard.
Alas! A repository is not a "container" (aaargh...) where you put things in, that is what muggles think...
I am using docker-registry to pull my own docker images, but I want to do so without the need to specify the host. meanning:
instead of writing:
docker pull <host>:<port>/<dockerImage>
I want to write:
docker pull <dockerImage>
and first it will try to pull the docker from my private registry, before trying to pull it from the public docker registry.
Is it possible?
I tried to change the DOCKER_INDEX_URL to [my_docker_registry_host]:[port], but it doesn't work.
You can modify or add your /etc/sysconfig/docker
ADD_REGISTRY='--add-registry 192.168.0.169:5000'
INSECURE_REGISTRY='--insecure-registry 192.168.0.169:5000'
then modify /etc/systemd/system/docker.service or /usr/lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd --registry-mirror=http://192.168.0.169:5000
when you pull a image,docker will pull it from your private registry first,and then docker hub if not found in your private registry.I am working on CentOS 7 Docker 1.12.
No, I think it is not supported yet (1.1.2 as write). I guess main reasons is
The local private registry is not the mirror from the public registry, therefore the logical is not that if it can't be found locally, then it goes to public. They are totally different.
Therefore if we setup own private docker repository but keep the same naming, it will mess up.
When you do docker images, and you see ubuntu, how do you know it is from your local private registry or public.
UPDATE: add one sample case
Also if we have a Dockerfile, put the tomcatit use tomcat7 as base
FROM tomcat7
How do you know this build comes from ?
If we want to have strict process or control on the mapping between the private repo and public repo, it will be complicated.
Technically it is possible, but gain less. It loose the power of docker (community)
It is similar case for other package system which demands the unique name for the package.