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Juju

Juju encapsulates the operational knowledge of provisioning, installing, and securing a Kubernetes cluster into one step. Juju allows you to deploy a Kubernetes cluster on different cloud providers with a consistent, repeatable user experience. Once deployed the cluster can easily scale up with one command.

The Juju Kubernetes work is curated by a dedicated team of community members, let us know how we are doing. If you find any problems please open an issue on the kubernetes project and tag the issue with “juju” so we can find them.

• Prerequisites
  • On Ubuntu
  • With Docker
  • Configure Juju to your favorite cloud provider
• Launch a Kubernetes cluster
• Exploring the cluster
• Run some containers!
• Scale up cluster
• Scale out cluster
• Tear down cluster
• More Info
  • Cloud compatibility
• 支持级别

Prerequisites

Note: If you’re running kube-up, on Ubuntu - all of the dependencies will be handled for you. You may safely skip to the section: Launch a Kubernetes Cluster

On Ubuntu

Install the Juju client

This documentation focuses on the Juju 2.0 release which will be promoted to stable during the April 2016 release cycle.

To paraphrase, on your local Ubuntu system:

sudo add-apt-repository ppa:juju/devel
sudo apt-get update
sudo apt-get install juju

If you are using another distro/platform - please consult the getting started guide to install the Juju dependencies for your platform.

With Docker

If you prefer the isolation of Docker, you can run the Juju client in a container. Create a local directory to store the Juju configuration, then volume mount the container:

mkdir -p $HOME/.local/share/juju
docker run --rm -ti \
  -v $HOME/.local/share/juju:/home/ubuntu/.local/share/juju \
  jujusolutions/charmbox:devel

While this is a common target, the charmbox flavors of images are unofficial, and should be treated as experimental. If you encounter any issues turning up the Kubernetes cluster with charmbox, please file a bug on the charmbox issue tracker.

Configure Juju to your favorite cloud provider

At this point you have access to the Juju client. Before you can deploy a cluster you have to configure Juju with the cloud credentials for each cloud provider you would like to use.

Juju supports a wide variety of public clouds to set up the credentials for your chosen cloud see the cloud setup page.

After configuration is complete test your setup with a juju bootstrap command: juju bootstrap $controllername $cloudtype you are ready to launch the Kubernetes cluster.

Launch a Kubernetes cluster

You can deploy a Kubernetes cluster with Juju from the kubernetes directory of the kubernetes github project. Clone the repository on your local system. Export the KUBERNETES_PROVIDER environment variable before bringing up the cluster.

cd kubernetes
export KUBERNETES_PROVIDER=juju
cluster/kube-up.sh

If this is your first time running the kube-up.sh script, it will attempt to install the required dependencies to get started with Juju.

The script will deploy two nodes of Kubernetes, 1 unit of etcd, and network the units so containers on different hosts can communicate with each other.

Exploring the cluster

The juju status command provides information about each unit in the cluster:

$ juju status
MODEL    CONTROLLER  CLOUD/REGION     VERSION
default  windows     azure/centralus  2.0-beta13

APP         VERSION  STATUS  EXPOSED  ORIGIN      CHARM       REV  OS
etcd                 active  false    jujucharms  etcd        3    ubuntu
kubernetes           active  true     jujucharms  kubernetes  5    ubuntu

RELATION      PROVIDES    CONSUMES    TYPE
cluster       etcd        etcd        peer
etcd          etcd        kubernetes  regular
certificates  kubernetes  kubernetes  peer

UNIT          WORKLOAD  AGENT  MACHINE  PORTS     PUBLIC-ADDRESS  MESSAGE
etcd/0        active    idle   0        2379/tcp  13.67.217.11    (leader) cluster is healthy
kubernetes/0  active    idle   1        8088/tcp  13.67.219.76    Kubernetes running.
kubernetes/1  active    idle   2        6443/tcp  13.67.219.182   (master) Kubernetes running.

MACHINE  STATE    DNS            INS-ID     SERIES  AZ
0        started  13.67.217.11   machine-0  trusty  
1        started  13.67.219.76   machine-1  trusty  
2        started  13.67.219.182  machine-2  trusty 

Run some containers!

The kubectl file, and the TLS certificates along with the configuration are all available on the Kubernetes master unit. Fetch the kubectl package so you can run commands on the new Kuberntetes cluster.

Use the juju status command to figure out which unit is the master. In the example above the “kubernetes/1” unit is the master. Use the juju scp command to copy the file from the unit:

juju scp kubernetes/1:kubectl_package.tar.gz .
tar xvfz kubectl_package.tar.gz
./kubectl --kubeconfig kubeconfig get pods

If you are not on a Linux amd64 host system, you will need to find or build a kubectl binary package for your architecture.

Copy the kubeconfig file to the home directory so you don’t have to specify it on the command line each time. The default location is ${HOME}/.kube/config.

No pods will be available before starting a container:

kubectl get pods
NAME READY STATUSRESTARTS   AGE

kubectl get replicationcontrollers
CONTROLLER  CONTAINER(S)  IMAGE(S)  SELECTOR  REPLICAS

We’ll follow the aws-coreos example. Create a pod manifest: pod.json

{
  "apiVersion": "v1",
  "kind": "Pod",
  "metadata": {
"name": "hello",
"labels": {
  "name": "hello",
  "environment": "testing"
}
  },
  "spec": {
"containers": [{
  "name": "hello",
  "image": "quay.io/kelseyhightower/hello",
  "ports": [{
"containerPort": 80,
"hostPort": 80
  }]
}]
  }
}

Create the pod with kubectl:

kubectl create -f pod.json

Get info on the pod:

kubectl get pods

To test the hello app, we need to locate which node is hosting the container. We can use juju run and juju status commands to find our hello app.

Exit out of our ssh session and run:

juju run --unit kubernetes/0 "docker ps -n=1"
...
juju run --unit kubernetes/1 "docker ps -n=1"
CONTAINER IDIMAGE  COMMAND CREATED STATUS  PORTS   NAMES
02beb61339d8quay.io/kelseyhightower/hello:latest   /hello  About an hour ago   Up About an hourk8s_hello....

We see “kubernetes/1” has our container, expose the kubernetes charm and open port 80:

juju run --unit kubernetes/1 "open-port 80"
juju expose kubernetes
sudo apt-get install curl
curl $(juju status --format=oneline kubernetes/1 | cut -d' ' -f3)

Finally delete the pod:

juju ssh kubernetes/0
kubectl delete pods hello

Scale up cluster

Want larger Kubernetes nodes? It is easy to request different sizes of cloud resources from Juju by using constraints. You can increase the amount of CPU or memory (RAM) in any of the systems requested by Juju. This allows you to fine tune th Kubernetes cluster to fit your workload. Use flags on the bootstrap command or as a separate juju constraints command. Look to the Juju documentation for machine details.

Scale out cluster

Need more workers? Juju makes it easy to add units of a charm:

juju add-unit kubernetes

Or multiple units at one time:

juju add-unit -n3 kubernetes

You can also scale the etcd charm for more fault tolerant key/value storage:

juju add-unit -n2 etcd

Tear down cluster

We recommend that you use the kube-down.sh script when you are done using the cluster, as it properly brings down the cloud and removes some of the build directories.

./cluster/kube-down.sh

Alternately if you want stop the servers you can destroy the Juju model or the controller. Use the juju switch command to get the current controller name:

juju switch
juju destroy-controller $controllername --destroy-all-models

More Info

Juju works with charms and bundles to deploy solutions. The code that stands up a Kubernetes cluster is done in the charm code. The charm is built from using a layered approach to keep the code smaller and more focused on the operations of Kubernetes.

The Kubernetes layer and bundles can be found in the kubernetes project on github.com:

• Bundle location
• Kubernetes charm layer location
• More about Juju

Cloud compatibility

Juju is cloud agnostic and gives you a consistent experience across different cloud providers. Juju supports a variety of public cloud providers: Amazon Web Service, Microsoft Azure, Google Compute Engine, Joyent, Rackspace, any OpenStack cloud, and Vmware vSphere.

If you do not see your favorite cloud provider listed many clouds with ssh access can be configured for manual provisioning.

To change to a different cloud you can use the juju switch command and set up the credentials for that cloud provider and continue to use the kubeup.sh script.

支持级别

For support level information on all solutions, see the Table of solutions chart.