I currently run a Jenkins instance inside a Docker container. I've been doing some experimenting with Jenkins and their pipelines. I managed to make my Maven app build successful using a Jenkinsfile.
Right now I am trying to automatically deploy the app I built to a docker container that's a sibling to the Jenkins container. I did already mount the /var/run/docker.sock so I have access to the parent docker. But right now I can't seem to find any good information to guide me through the next part, which is modifying the Jenkinsfile to deploy my app in a new container.
How would I go over and run my Maven app inside a sibling docker container?
It might be more appropriate to spin up a slave node (a physical or virtual box) and then run something in there with docker.
If you check your instance URL: https://jenkins.address/job/myjob/pipeline-syntax/
You will find more information about what are the commands you need for this.
Anyway best way to do this is to actually create a dockerfile and as a step copy the artifact in it, push the image to a registry and then find somewhere to deploy the just built image
Related
I am trying to start a container using Jenkins and a Dockerfile in my SCM.
Jenkins uses the Dockerfile from my SCM repository and builds the image on a remote server having a Dockerfile. This is done using the "cloud bees docker build and publish plugin".
When I ssh to the server, I see that the image has been built with the tags I had defined in Jenkins.
# docker image ls
What I am not able to do is run a container for the image that has been built. How to get the image-id and start the container? Shouldn't it have been very simple given many plugins are provided?
Could your problem be related to how to refer to the recently created docker in order tu run it? Can you provide an extract of your pipeline and how you are trying to achieve this?
It that was the case, there are different solutions, one being specifying a tag during the Docker creation, so you can then refer to it to run it.
In reply to how to work with image-ids, the docker build process will return the image id of the docker it creates. You can capture that id, and then use to run the docker.
start the container yourself on the VM by using standard docker run command.
use a software like watchtower to restart the container with an updated version when available
I am currently running a Jenkins with Docker. When trying to build docker apps, i am facing some doubt on if i should use Docker in Docker (Dind) by binding the /var/run/docker.sock file or by installing another instance of docker in my Jenkins Docker. I actually saw that previously, it was discouraged to use something else than the docker.sock.
I don't actually understand why we should use something else than the docker daemon from the host apart from not polluting it.
sources : https://itnext.io/docker-in-docker-521958d34efd
Best solution for "jenkins in docker container needs docker" case is to add your host as a node(slave) in jenkins. This will make every build step (literally everything) run in your host machine. It took me a month to find perfect setup.
Mount docker socket in jenkins container: You will lose context. The files you want to COPY inside image is located inside workspace in jenkins container and your docker is running at host. COPY fails for sure.
Install docker client in jenkins container: You have to alter official jenkins image. Adds complexity. And you will lose context too.
Add your host as jenkins node: Perfect. You have the contex. No altering the official image.
Without completely understanding why you would need to use Docker in Docker - I suspect you need to meet some special requirements considering the environment in which you build the actual image, may I suggest you multistage building of docker images? You might find it useful as it enables you to first build the building environment and then build the actual image (hence the name 'multistage-building). Check it out here: https://docs.docker.com/develop/develop-images/multistage-build/
Basic example of what I want my Jenkinsfile to do:
node {
sh 'docker build -t foo/bar .'
}
It seems like I need to install docker onto the Jenkins slave image that's executing my Jenkinsfile. Is there an easy way of doing this? (That Jenkins slave image is itself a docker container)
Are my assumptions correct?
When running with Jenkins master/slaves, the Jenkinsfile is executed by a Jenkins slave
Jenkins plugins installed via the Manage Plugins section (e.g. the Docker Plugin, or Gcloud SDK plugin) are only installed on the Jenkins masters, therefore I would need to manually build my Jenkins slave docker image and install docker on the image?
Since I also need access to the 'gcloud' command (I'm running Jenkins via Kubernetes Helm/Charts), I've been using the gcr.io/cloud-solutions-images/jenkins-k8s-slave image for my Jenkins slave.
Currently it errors out saying "docker: not found"
My assumption is that you want to docker build inside the Jenkins slave (which is a Kubernetes pod, I assume created by the Kubernetes Jenkins Plugin)
To set the stage, when Kubernetes creates pod that will act as a Jenkins slave, all commands that you execute inside the node will be executed inside that Kubernetes pod, inside one of the containers there (by default there will only be one container, but more on this later).
So you are actually trying to run a Docker command inside a container based on gcr.io/cloud-solutions-images/jenkins-k8s-slave, which is most likely based on the official Jenkins JNLP Slave, which does not container Docker!
From this point forward, there are two approaches that you can take:
use a slightly modified image based on the JNLP slave that also contains the Docker client and mount the Docker socket (/var/run/docker.sock) inside the container.
(You can find details on this approach here).
Here is an image that contains the Docker client and kubectl.
Here is a complete view of how to configure the Jenkins Plugin:
Note that you use a different image (you can create your own and add any binary you want there) and that you mount the Docker socket inside the container.
the problem with the first approach is that you create a new image forked from the official JNLP slave and manually add the Docker client. This means that whenever Jenkins or Docker have updates, you need to manually update your image and entire configuration, which is not that desirable.
Using the second approach you always use official images, and you use the JNLP slave to start other containers in the same pod.
Here is the full file from the image below
Here is the Jenkins Plugin documentation for doing this
As I said, the JNLP image will start a container that you specify in the same pod. Note that in order to use Docker from a container you still need to mount the Docker sock.
These are the two ways I found to achieve building images inside a Jenkins JNLP slave running inside a container.
The example also shows how to push the image using credential bindings from Jenkins, and how to update a Kubernetes deployment as part of the build process.
Some more resources:
deploy Jenkins to Kubernetes as Helm chart, configure plugins to install
Thanks,
Radu M
I have just started Jenkins setup on docker. I started docker container and am planning to run the ANT script I have written, this is where problems started.
Jenkins kept on reporting
ERROR: Unable to find build script at /var/jenkins_home/workspace/SampleSCM/.SampleProject/build.xml
I am not sure how to access /var/Jenkins_home in my local host. Can someone please help ?
Thanks.
You won't find this location on your laptop, because it is not there. It is inside the docker container.
Normally you would checkout out the sources as part of your build. You do not put them there yourself.
If you want to see the files you can use the jenkins gui, or ssh/attach your container (docker attach) and look in there. The idea about docker is that it runs isolated, unless you tell it to map volumes (See here for a reference)
Is there a way to do automation with Jenkins to deploy and run containers? I heard we can use the Docker plugins for it. But there isn't any tutorials or info that explains how we can use Jenkins and Docker together. Anyone who uses them both care to share?
First off in my implementation of things Jenkins is actually a container in Docker.
Here's where it may seem things get bizarre: I actually install docker-ce inside of that container, not because I want to run Docker-in-Docker. I disable the Docker daemon from running (sysctl) but I want the command line.
I install docker-compose and docker-machine on the Jenkins host and add the "jenkins" userid to the docker group.
There's a bunch of other steps that I do but basically they are the same steps that a user is going to go through (except it's all in my Docker file) and I add the results of "docker-machine env" to the global variables in the Jenkins configuration.
head spinning yet?
Applications I have Jenkins deploying all have a "jenkins" subdirectory with a Jenkins file in it to perform the dirty work as a pipeline. (build/test/deploy)
Deployments for Java apps for instance involve copying the warfile for the application to the correct directory and when the container (or containers) start the application engine (tomcat, Jboss, whatever) picks it up and the application runs.
Have a look at
https://registry.hub.docker.com/search?q=jenkins&searchfield=
and at some Dockerfiles such as
https://registry.hub.docker.com/u/niaquinto/jenkins/dockerfile/
or
https://registry.hub.docker.com/u/aespinosa/jenkins/dockerfile/