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!
Related
I want to run my Jenkins behind k8s. We can achieve that with any standard helm chart or our own manifest files. In this case, Jenkins (master only) will run inside a container (Pod).
Now I also want to have a pipeline job that uses docker agent as described here
I am getting confused, about
how and where this docker container will be run (on the same node where Jenkins is running? and suppose the node capacity is over then it needs to run docker agent on a different node)
how does Jenkins will authenticate to run containers on k8s nodes?
I saw the Kubernetes plugin/docker plugin. But those plugins create containers beforehand (or at least we need to set up a template, which decides how containers will start, which image will be used and many more) and connects Jenkins with help of JNLP / ssh. I lose the flexibility to have an image as an agent in that case.
going further, I also like to build custom images on the fly with help of Dockerfile shipped along with code. An example is available in the same link.
I believe this documentation is answering all of your questions: https://devopscube.com/jenkins-build-agents-kubernetes/
With this method, you are not losing your flexibility because your Jenkins master going to create a K8s pod on the fly. Yes, additionally you need JNLP authentication but you can think of that as a sidecar container.
About your first question: If you use exactly that way, your Jenkins jobs going to run under Jenkins master with the same Docker that your Jenkins Master is using.
New to Kubernetes, a little complex question needs help.
Background
Using Jenkins in GKE (Google Kubernetes Engine)
Want to use jenkins-docker plugin to provide the specific test environment for each type of tests
Don't want to mixin docker binary in the Jenkins image (because it is large)
Don't want docker-in-docker
More specifically, I don't want the Jenkins Pod be a new Docker Server
What I want
Each test environment can create a new pod in GKE Cluster, rather than creating containers inside the Jenkins Pod
P.S.
I have just read some articles, but half of them are telling about "how to use K8S to scale up the Jenkins (using jenkins-slave + jenkins-kubernates plugin)", another half are telling about how to "use docker plugin in a dockerized jenkins container on a bare metal machine (you can use /var/run/docker.sock to communicate between the host and the docker container)", but I cannot find **how to use docker plugin (to provide a specific environment) in a dockerized jenkins container inside K8S
According to the DataDog Docker Integration Docs:
There are two ways to run the [DataDog] Agent: directly on each host, or within a docker-dd-agent container. We recommend the latter.
Why is a Docker-based agent installation preferred over just installing the DataDog agent directly as a service on the box that's running the Docker containers?
One of Dockers main features is portability and it makes sense to bind datadog into that environment. That way they are packaged and deployed together and you don't have the overhead of installing datadog manually everywhere you choose to deploy.
What they are also implying is that you should use docker-compose and turn your application / docker container into an multi-container Docker application, running your image(s) alongside the docker agent. Thus you will not need to write/build/run/manage a container via Dockerfile, but rather add the agent image to your docker-compose.yml along with its configuration. Starting your multi-container application will still be easy via:
docker-compose up
Its really convenient and gives you additional features like their autodiscovery service.
I saw couple of tutorials on continuous deployment (on docker.com, on codecentric.de, on devopscube.com).
Overall I saw two approaches:
Set two types of jenkins server (master and slave). Master is in a docker container and slave on the host machine.
Jenkins server in docker container. They set up the link to the host and using that link the jenkins can create or recreate docker images.
In the first approach - I do not understand why they set up additional jenkins server residing inside the docker container. Is not it enough just to have jenkins server on host machine alongside with docker container?
The second approach seems to me a bit insecure because process from container is accessing host OS. Does it have any benefits?
Thanks for any useful info.
We are running jenkins in a docker container and we want to use the docker build step plugin. The documentation tells us:
You have to make sure that Docker service is running on slaves where you run the build. In Jenkins global configuration, you need to specify Docker REST API URL (typically somethig like http://127.0.0.1:2375)
But I see very often that people are using 0.0.0.0:2375
What is the difference and which do we have to use when we just want to use the docker daemon inside one docker container on one server (docker daemon is running on the same server)?
Regarding the differences between 0.0.0.0:2375 and 127.0.0.1:2375, according to this answer it's basically whether you want to open the host up to the outside or not.
If it's all on one server, I'm assuming both should work as it's all on the same host..