Kubeainer

A Kubernetes container image and Docker Compose project to spin up a local cluster for development and experimentation purposes.

It uses upstream Kubernetes as well as CRI-O and initializes the cluster using kubeadm.

Build and run from source

Clone the repo, build and run the container:

git clone https://github.com/mgoltzsche/kubeainer.git
make apps image compose-up

Set the NODES parameter to scale.

Usage

Docker

Run a single-node cluster:

docker run -d --name mykube --privileged -v "`pwd`:/output" mgoltzsche/kubeainer:latest

Wait for the cluster to initialize:

docker exec mykube kubeainer install
export KUBECONFIG="`pwd`/kubeconfig.yaml

You can provide additional apps to the kubeainer install command as shown below.

Complete example with ingress:

docker run -d --name mykube --privileged -p 80:80 -v "`pwd`:/output" mgoltzsche/kubeainer:latest
docker exec mykube kubeainer install ingress-nginx sample-app
docker exec mykube kubeainer retry 90 curl -fsS -H 'Host: sample-app.kubeainer.example.org' http://localhost
curl -fsS -H 'Host: sample-app.kubeainer.example.org' http://localhost

Docker Compose

Run a single-node cluster:

docker-compose up -d --scale kube-node=0

You can run a multi-node cluster by scaling the kube-node service.

Wait for the cluster to initialize:

docker-compose exec -T kube-master kubeainer install

You can provide additional apps to the kubeainer install command as shown below.

Once the cluster is initialized the Kubernetes client configuration is written to $PWD/kubeconfig.yaml ($PWD is the compose directory) and can be used as follows:

export KUBECONFIG="$PWD/kubeconfig.yaml"

Init processes

entrypoint.sh
└── exec systemd
    ├── crio
    ├── kubelet
    └── kubeadm-bootstrap.sh
        └── kubeadm

Apps

The kubeainer script within the container can be used to install additional apps. An app can be provided as directory that contains Kubernetes manifests. The image already contains some apps within the /etc/kubeainer/apps directory. By default the flannel app is installed. To install additional apps, run e.g.:

docker-compose exec -T kube-master kubeainer install local-path-provisioner ingress-nginx cert-manager metallb external-dns

You can also mount your own Kubernetes manifests into the kubeainer container and use them as apps.