I am trying to use docker(dind) image for building an image. When I run docker info in the DockerFile, it complains dockerhost cannot be found. Is there any way when building a Docker image, can we use docker host in the build step ?
I don't think there is an effective way to run docker in DIND when building image via dockerfile. I ran a container version of DIND image and added all the config stuff and committed that to an image which solved the problem of me using dind
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I want to use a centos7.6 docker image, but I can't find centos7.6(arm) in docker hub.
Is there a way to build centos7.6 docker image match to arm(I am working on centos x86_64)? Thanks!
I have created a container using the following command: docker container run -i ubuntu. However, when I try to run a command within the container, such as cd, I get the following error: bash: line 1: cd: $'bin\r': No such file or directory. What could be the issue?
When you docker run an image, or use an image in a Dockerfile FROM line, or name an image: in a Docker Compose setup, Docker first checks to see if you have that image locally. If you have that image, Docker just uses it without checking Docker Hub or the other upstream registry.
Meanwhile, you can docker build or docker tag an image with any name you want...even a name that matches an official Docker Hub image.
You mention in a comment that you at some point did run docker build -t ubuntu .... That replaces the ubuntu image with what you built, so when you later docker run ubuntu, it's running your modified image and not the official Docker Hub Ubuntu image.
This is straightforward to fix. If you
docker rmi ubuntu
it will delete your local (modified) copy, and the next time you use it, Docker will automatically pull it from Docker Hub. It should also work to
# Explicitly get the Docker Hub copy of the image
docker pull ubuntu
# Build a custom image, pulling whatever's in the FROM line
docker build --pull -t my/image .
(You can also hit this in a Docker Compose setup if you specify both image: and build:; this instructs Compose on an explicit name to use for the built image. You do not need to repeat the FROM line in image:, and it causes trouble if you do. The resolution is the same as described above. I might leave image: out entirely unless you're planning to push the image to a registry.)
I am trying to create my custom docker image which I will use in my GitLab build pipeline. (Following this guide as I would like to configure my GitLab runners over AWS Fargate https://docs.gitlab.com/runner/configuration/runner_autoscale_aws_fargate/).
One of the prerequisites is to create your own custom docker image that has everything that's needed for the build pipeline to execute.
I would need to add a docker to my docker image.
I am able to install docker, however, I do not understand how to start the docker service as the error I am getting is
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
each time docker command is used.
I tried to add in my startup.sh script used as a docker entrypoint to start docker using rc-service(alpine-based image) or systemctl (amazon linux 2) but without any luck.
Any help is appreciated. Thanks.
For running docker in docker you need to configure docker image with docker-dind service to build docker. But it is limited and requires sudo priviledges, I do recommend to use kaniko, it is very easy to configure, does not require anything more than kaniko executor image.
https://docs.gitlab.com/ee/ci/docker/using_kaniko.html
If really need to use DinD (docker in docker), just go to:
https://docs.gitlab.com/ee/ci/docker/using_docker_build.html
Kaniko is simplest and safe way to run docker build
I'm learning about Docker Containers, so, I found this repo with a lot of images and references, can anyone help me in order to understand how can I use those images?
I know the docker run --rm command
With docker you first need a docker image. A docker image is a representation of an application that docker can understand and run.
The most common ways to get one is to use docker pull or to generate yours with docker build.
You can check the images you got with docker images
Once you got your image you can run it with docker run MyImage, this will create a container, a container is a running application.
According to the document, all configuration and stored application definitions will also be removed when a container is removed if openshift origin runs as a docker container.
My question is is there way to upgrade openshift without losing the configurations if I am running the container?
You can create a Dockerfile, use the original image as a base image an run your update statements.
FROM openshift/origin
RUN your-update-statement
ENTRYPOINT ["/usr/bin/openshift"]
After that just build and run your Docker image. For more info see https://docs.docker.com/engine/reference/builder/