I have installed CoreOS as my build environment. I installed Jenkins server as a docker container in CoreOS. And I created a free style project on the Jenkins server to build my project. How can I configure the build run on docker containers on the CoreOS?
So the structure is: CoreOS is my physical machine. Jenkins server is running in a docker container in the CoreOS. And I want to launch more docker containers to run my application. How can I achieve this? The hardest part I think is to launch a docker container in CoreOS from Jenkins JOB. I want to start a new docker container ever time for a build.
I'm not familiar with Jenkins, but I would suggest that you take a look at the docker-machine and docker-compose utilities.
You should be able to have Jenkins use one of those to have the host start your build container.
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I have Azure devops pipeline, building dockerfile on AKS, as AKS is deprecating docker with the latest release, kindly suggest best practice to have a dockerfile build without docker on AKS cluster.
Exploring on Kaniko, buildah to build without docker..
Nothing has changed. You can still use docker build and docker push on your developer or CI system to build and push the Docker image to a repository. The only difference is that using Docker proper as the container backend within your Kubernetes cluster isn't a supported option any more, but this is a low-level administrator-level decision that your application doesn't know or care about.
Unless you were somehow building using the host docker socket within your Kubernetes cluster, this change will not affect you. And if you were mounting the docker socket from the host in a kubernetes cluster, I'd consider that a security concern that you want to fix.
Docker Desktop runs a docker engine as a container on top of containerd, allowing developers to build and run containers in that environment. Similar can be done with DinD build patterns that run the docker engine inside a container, the difference is the underlying container management tooling is containerd instead of a full docker engine, but the containerized docker engine is indifferent to that.
As an alternative to building within the full docker engine, I'd recommend looking at buildkit which is the current default build tool in docker as of 20.10. It uses containerd and they ship a selection of manifests to run builds directly in kubernetes as a standalone builder.
Is it possible to use a cloud-init configuration file to define commands to be executed when a docker container is started?
I'd like to test the provisioning of an Ubuntu virtual machine using a docker container.
My idea is to provide the same cloud-init config file to an Ubuntu docker container.
No. If you want to test a VM setup, you need to use actual virtualization technology. The VM and Docker runtime environments are extremely different and you can't just substitute one technology for the other. A normal Linux VM startup will run a raft of daemons and startup scripts – systemd, crond, sshd, ifconfig, cloud-init, ... – but a Docker container will start none of these and will only run the single process in the container.
If your cloud-init script is ultimately running a docker run command, you can provide an alternate command to that container the same way you could docker run on your development system. But a Docker container won't look to places like the EC2 metadata service to find its own configuration usually, and it'd be unusual for a container to run cloud-init at all.
Right now I am setting up an application that has a deployment based upon docker images.
I use gitlab ci to:
Test each service
Build each service
Dockerize each image (create docker container)
Run integration tests (start docker compose that starts all services on special ports, run integration tests)
Stop prod images and run new images
I did this for each service, but I ran into an issue.
When I start my docker container for integration tests then it is setup within a gitlab ci task. For each task a docker based runner is used. I also mount my host docker socket to be able to use docker in docker.
So my gradle docker image is started by the gitlab runner. Then docker will be installed and all images will be started using docker compose.
One microservice listens to port 10004. Within the docker compose file there is a 11004:10004 port mapping.
My integration tests try to connect to port 11004. But this does not work right now.
When I attach to the image that run docker compose while it tries to execute the integration test then I am not able to do it manually by calling
wget ip: port
I just get the message connected and waiting for response. Either my tests can connect successfully. My service does not log any message about a new connection.
When I execute this wget command within my host shell then it works.
It's a public ip and within my container I can also connect to other ports using telnet and wget. Just one port of one service is broken when I try to connect from my docker in docker instance.
When I do not use docker compose then it works. Docker compose seems to setup a special default network that does something weird.
Setting network to host also works...
So did anyone also make such an experience when using docker compose?
The same setup works flawless in docker for mac, but my server runs on Debian 8.
My solution for now is to use a shell runner to avoid docker in docker issues. It works there as well.
So docker in docker combined with docker compose seems to have an ugly bug.
I'm writing while I am sitting in the subway but I hope describing my issue is also sufficient to talk about experiences. I don't think we need some sourcecode to find bad configurations because it works without docker in docker and on Mac.
I figured out that docker in docker has still some weird behaviors. I fixed my issue by adding a new gitlab ci runner that is a shell runner. Therefore docker-compose is run on my host and everything works flawless.
I can reuse the same runner for starting docker images in production as I do for integration testing. So the easy fix has another benefit for me.
The result is a best practice to avoid pitfalls:
Only use docker in docker when there is a real need.
For example to make sure fast io communication between your host docker image and your docker image of interest.
Have fun using docker (in docker (in docker)) :]
I have a docker Jenkins container running on RHEL host machine that pulls out code from TFS and builds a war using Ant scripts. After the build is complete we want to push the war to a JBoss running on our RHEL host. What is the best way to do this?
We have the Jenkins home mounted to a directory on the host system and I able to manually deploy the war from this directory onto the JBoss server using the jboss-cli deploy script.
When I am inside my Jenkins container running the build can I use the file system on the host to run the jboss-cli script?
No. You can not run scripts on the host from within a container.
One solution may be to share a volume between both Jenkins and JBoss containers. This way Jenkins can deploy the war to this directory and JBoss will be able to access it.
But you cannot use the Jenkins container to run a script on the host.
If you do need to execute a script, you could link the containers (ie. add them to the same docker network). You could build the JBoss container with SSH on it, and your Jenkins job could include a step to run a command on the JBoss container via SSH.
I wanted to be able to start multiple linked containers on demand, with a restrict where this build run tag like I do with docker plugin for one single container.
I'm currently running Jenkins inside a docker container and configured a slave cloud using docker plugin to provide a single slave container per job, this provisioning is done on demand by the plugin.
But now I have some new requirements, example:
Starting nodejs application container linked to selenium grid container for protractor e2e testing
Starting a container with a nodejs application linked to a redis server in another container.
Currently, docker plugin does not support linked containers so how should I approach those scenarios?
I know how to start multiple linked containers with docker-compose but there are currently no Jenkins plugins for compose.
I was able to get docker-in-docker working, and thought about having a DIND job with using compose in a pre-setup, but I'm finding this a quite inelegant solution.
Is there a plugin-wise solution?
Docker Slaves Plugin new version's side container feature solves that problem now!