I need to copy images from Docker Hub into a private registry. For example, I need redislabs/rebloom:2.2.2. Then, can I name it my-private-registry.com/my-organization/redislabs/rebloom:2.2.2? (Notice there is my-organization which I cannot modify.)
In other words, is a.com/b/c/d:v1.0 ok or not?
I read this post and see Docker can parse it. However, will some tools reject this? Will Containerd reject this? I am afraid that they accept it but fails somewhere, which may be very difficult to debug.
Thank you very much!
My day job uses image names with a similar structure (hosted on Amazon ECR) and they work fine with plain Docker, Compose, and Kubernetes. I would not expect to run into any trouble with this, unless the specific image repository has stricter rules.
Related
I'm looking to be able to build docker containers on the fly given a docker file. That is, given a docker file, I want to be able to send the file to a remote "build service", which builds it for me programatically. Are there any hosted or open source services that provide this?
Note that I'm not looking to build images on CI, but rather do something in code like this:
def build_image(dockerfile_contents):
resp = docker_service.build(dockerfile_contents)
...
A simple rest API would be perfect. Any thoughts or ideas?
I don't think there are such service providers by now. But you can use Docker SDK to build images for you. You can use their official Python library.
Also, you can inspire how Docker CLI itself triggers the builds.
For the sake of remoteness and being cloudy, check out the way this article mentions using a Kubernetes cluster to build your images: You can use K8s API to trigger a job that its container builds your Docker image.
Seems like the best solution is to self-host something like kaniko. The post by #Ali Tou here seems like a more involved, but viable option.
I am new to Docker. Using Kitematic, how can I setup a Docker container containing the following?
Apache, Memcached, MySQL, Nginx, PHP FPM
Should I find one single image with all these? If so, how do I find that on https://hub.docker.com? It doesn't seem possible to filter by above requirements.
Or should I install these as separate containers?
Bart,
I don't know anything about kitematic but I can give you some general information though to clear things up.
General concensus is to run only a single process per container. There are lot's of discussions and information around why this would be good or bad, one such discussion for example: https://devops.stackexchange.com/questions/447/why-it-is-recommended-to-run-only-one-process-in-a-container.
That said, these are the images I would choose for an environment with the software you described above:
Memcache: https://hub.docker.com/_/memcached
MySql: https://hub.docker.com/_/mysql
Nginx: https://hub.docker.com/_/nginx
PHP FPM: https://hub.docker.com/_/php
How do I get these images? I go to hub.docker.com and search for the software I want, I then start with the official images and see if they suite my needs. If they do, great! Otherwise, I would look for non-official images and eventually if I don't find what I want I will extend the existing images by creating a custom image, based on one from hub.docker.com
Some more explanation about the last one, PHP. PHP is distributed with multiple tags. By going to the docker hub page ('description'-tab) you can see the supported tags. Clicking the tag you are interested in will lead you to a github repo where the Dockerfile is hosted. This file contains the commands, used to construct the image you are researching. You can check all the tags to see which one installs the software you need. For example, there are PHP tags where apache is installed (i.e. 7-apache) and there are tags where FPM is installed (i.e. 7-fpm).
Hope this will help you with the research about what images to use!
You need to run those images within the same docker network, tough a docker-compose (and is associated docker-compose.yml) such as this one.
The docker-compose support in Kinematic UI though... is still an open issue.
you cant find all of these containers as one image.. all you can do is create a docker-compose file and add all those independent images into the compose file.
This way you can handle all your containers as a service in a single with there dependencies too..
For further info refer to https://docs.docker.com/compose/
I cannot get the idea of connecting parts of a webapp via Dockerfile's.
Say, I need Postgres server, Golang compiler, nginx instance and something else.
I want to have a Dockerfile that describes all these dependencies and which I can deploy somewhere, then create an image and run a container from it.
Is it correct that I can put everything in one Dockerfile or should I create a separate Dockerfile for each dependency?
If I need to create a Dockerfile for each dependency, what's the correct way to create a merged image from them all and make all the parts work inside one container?
The current best practice is to have a single container perform one function. This means that you would have one container for ngnix and another for your app.. Each could be defined by their own dockerfile. Then to tie them all together, you would use docker-compose to define the dependencies between them.
A dockerfile is your docker image. One dockerfile for each image you build and push to a docker register. There are no rules as to how many images you manage, but it does take effort to manage an image.
You shouldn't need to build your own docker images for things like Postgres, Nginx, Golang, etc.. etc.. as there are many official images already published. They are configurable, easy to consume and can be often be run as just a CLI command.
Go to the page for a docker image and read the documentation. It often examples what mounts it supports, what ports it exposes and what you need to do to get it running.
Here's nginx:
https://hub.docker.com/_/nginx/
You use docker-compose to connect together multiple docker images. It makes it easy to docker-compose up an entire server stack with one command.
How to use docker-compose is like trying to explain how to use docker. It's a big topic, but I'll address the key point of your question.
Say, I need Postgres server, Golang compiler, nginx instance and something else. I want to have a Dockerfile that describes all these dependencies and which I can deploy somewhere, then create an image and run a container from it.
No, you don't describe those things with a dockerfile. Here's the problem in trying to answer your question. You might not need a dockerfile at all!.
Without knowing the specific details of what you're trying to build we can't tell you if you need your own docker images or how many.
You can for example; deploy a running LAMP server using nothing but published docker images from the docker hub. You would just mount the folder with your PHP source code and you're done.
So the key here is that you need to learn how to use docker-compose. Only after learning what it can not do will you know what work is left for you to do to fill in the gaps.
It's better to come back to stackoverflow with specific questions like "how do I run the Golang compiler on the command line via docker"
I'm using docker cloud at the moment. I'm trying to figure out a development to production workflow using docker with docker compose to pull application code for multiple applications of the same type, but simply changing the repository each pulls from. I understand the concept of mounting a volume, but all the examples show the source code in the same repo with the dockerfile and docker compose file. example. I want the app code from this example to come from a remote, dynamic repo. Would I set an environment variable in the docker image? If so how?
Any example or link to a workflow example is appreciated.
If done right, the code "baked" into Docker images should be immutable and the only thing that should change at runtime is configurable parameters like environment variables (e.g. to set the port the app will listen on).
Ideally, you should bake your code into the image. Otherwise you're losing a lot of the benefit of using Docker in the first place.
The problem is..
.. your use case does not match with the best practice. You want an image without any code embedded in it, but rather fetched at each update. If you browse the docker hub you'll find many image named as service:version. That's one of the benefit of Docker, offering different versions of the same service. If you want to always get the most up-to-date code your workflow may have some down sides.
One solution could be
Webhooks, especially if your code is versionned on GH. Or any tools of continuous integration.
I have two hosts and docker is installed in each.
As we know, each docker stores the images in local /var/lib/docker directory.
So If I want to use some image, such as ubuntu, I must execute the docker pull to download from internet in each host.
I think it's slow.
Can I store the images in a shared disk array? Then have some host pull the image once, allowing every host, with access to the shared disk, to use the image directly.
Is it possible or good practice? Why docker is not designed like this?
It may need to hack the docker's source code to implement this.
Have you looked at this article
Dockerizing an Apt-Cacher-ng Service
http://docs.docker.com/examples/apt-cacher-ng/
extract
This container makes the second download of any package almost instant.
At least one node will be very fast, and I think it should possible to tell the second node to use the cache of the first node.
Edit : you can run your own registry, with a command similar to
sudo docker run -p 5000:5000 registry
see
https://github.com/docker/docker-registry
What you are trying to do is not supposed to work as explained by cpuguy83 at this github/docker issue.
Indeed:
The underlying storage driver would need to synchronize access.
Sharing /var/lib/docker is far not enough and won't work!
According to the doc.docker.com/registry:
You should use the Registry if you want to:
tightly control where your images are being stored
fully own your images distribution pipeline
integrate image storage and distribution tightly into your in-house development workflow
So I guess that this is the (/your) best option to work this out (but I guess that you got that info -- I just add it here to update the details).
Good luck!
Update in 2016.1.25 docker mirror feature is deprecated
Therefore this answer is not applicable now, leave for reference
Old info
What you need is the mirror mode for docker registry, see https://docs.docker.com/v1.6/articles/registry_mirror/
It is supported directly from docker-registry
Surely you can use public mirror service locally.