Kubernetes is an open source system for managing containerized applications across multiple hosts. Kubernetes uses Docker to package, instantiate and run containerized applications.
The Kubernetes Juju charms enable you to run Kubernetes on all the cloud platforms that Juju supports.
A Kubernetes deployment consists of several independent charms that can be scaled to meet your needs
Etcd is a key value store for Kubernetes. All persistent master state
is stored in etcd.
Flannel is a software defined networking component that provides individual subnets for each machine in the cluster.
Docker is an open platform for distributing applications for system administrators.
The controlling unit in a Kubernetes cluster is called the master. It is the main management contact point providing many management services for the worker nodes.
The servers that perform the work are known as minions. Minions must be able to communicate with the master and run the workloads that are assigned to them.
To deploy a Kubernetes environment in Juju :
juju deploy cs:~kubernetes/trusty/etcd
juju deploy cs:trusty/flannel-docker
juju deploy cs:trusty/docker
juju deploy local:trusty/kubernetes-master
juju deploy local:trusty/kubernetes
juju add-relation etcd flannel-docker
juju add-relation flannel-docker:network docker:network
juju add-relation flannel-docker:docker-host docker
juju add-relation etcd kubernetes
juju add-relation etcd kubernetes-master
juju add-relation kubernetes kubernetes-master
Use the 'juju quickstart' command to deploy a Kubernetes cluster to any cloud supported by Juju.
The charm store version of the Kubernetes bundle can be deployed as follows:
juju quickstart u/kubernetes/kubernetes-cluster
Note: The charm store bundle may be locked to a specific Kubernetes release.
Alternately you could deploy a Kubernetes bundle straight from github or a file:
juju quickstart -i https://raw.githubusercontent.com/whitmo/bundle-kubernetes/master/bundles.yaml
The command above does few things for you:
- Starts a curses based gui for managing your cloud or MAAS credentials
- Looks for a bootstrapped deployment environment, and bootstraps if required. This will launch a bootstrap node in your chosen deployment environment (machine 0).
- Deploys the Juju GUI to your environment onto the bootstrap node.
- Provisions 4 machines, and deploys the Kubernetes services on top of them (Kubernetes-master, two Kubernetes minions using flannel, and etcd).
- Orchestrates the relations among the services, and exits.
Now you should have a running Kubernetes. Run juju status --format=oneline to see the address of your kubernetes-master unit.
For further reading on Juju Quickstart
Go to the Getting started with Juju guide for more information about deploying a development Kubernetes cluster.
To interact with the kubernetes environment, either build or download the kubectl binary (available in the releases binary tarball) and point it to the master with :
$ juju status kubernetes-master | grep public
public-address: 104.131.108.99
$ export KUBERNETES_MASTER="104.131.108.99"
For you convenience this charm supports changing the version of kubernetes binaries. This can be done through the Juju GUI or on the command line:
juju set kubernetes version=”v0.10.0”
If the charm does not already contain the tar file with the desired architecture and version it will attempt to download the kubernetes binaries using the gsutil command.
Congratulations you know have deployed a Kubernetes environment! Use the kubectl to interact with the environment.