Kubernetes

Kubernetes is an open source implementation of container cluster management.

Kubernetes Design Document - Kubernetes @ Google I/O 2014

Kubernetes can run anywhere!

However, initial development was done on GCE and so our instructions and scripts are built around that. If you make it work on other infrastructure please let us know and contribute instructions/code.

Kubernetes is in pre-production beta!

While the concepts and architecture in Kubernetes represent years of experience designing and building large scale cluster manager at Google, the Kubernetes project is still under heavy development. Expect bugs, design and API changes as we bring it to a stable, production product over the coming year.

Contents

• Getting started on Google Compute Engine
• Running a local cluster
• Running on CoreOS
• Discussion and Community Support
• Hacking on Kubernetes

Getting started on Google Compute Engine

Prerequisites

1. You need a Google Cloud Platform account with billing enabled. Visit http://cloud.google.com/console for more details.

2. Make sure you can start up a GCE VM. At least make sure you can do the Create an instance part of the GCE Quickstart.

3. You need to have the Google Storage API, and the Google Storage JSON API enabled.

4. You must have Go (version 1.2 or later) installed: www.golang.org.

5. You must have the gcloud components installed.

6. Ensure that your gcloud components are up-to-date by running gcloud components update.

7. Get the Kubernetes source:

    git clone https://github.com/GoogleCloudPlatform/kubernetes.git
   

Setup

The setup script builds Kubernetes, then creates Google Compute Engine instances, firewall rules, and routes:

cd kubernetes
hack/dev-build-and-up.sh

The script above relies on Google Storage to deploy the software to instances running in GCE. It uses the Google Storage APIs so the "Google Cloud Storage JSON API" setting must be enabled for the project in the Google Developers Console (https://cloud.google.com/console#/project).

The instances must also be able to connect to each other using their private IP. The script uses the "default" network which should have a firewall rule called "default-allow-internal" which allows traffic on any port on the private IPs. If this rule is missing from the default network or if you change the network being used in cluster/config-default.sh create a new rule with the following field values:

• Source Ranges: 10.0.0.0/8
• Allowed Protocols or Port: tcp:1-65535;udp:1-65535;icmp

Running a container (simple version)

Once you have your instances up and running, the build-go.sh script sets up your Go workspace and builds the Go components.

The kubecfg.sh script spins up two containers, running Nginx and with port 80 mapped to 8080:

cd kubernetes
hack/build-go.sh
cluster/kubecfg.sh -p 8080:80 run dockerfile/nginx 2 myNginx

To stop the containers:

cluster/kubecfg.sh stop myNginx

To delete the containers:

cluster/kubecfg.sh rm myNginx

Running a container (more complete version)

Assuming you've run hack/dev-build-and-up.sh and hack/build-go.sh:

cd kubernetes
cluster/kubecfg.sh -c api/examples/pod.json create /pods

Where pod.json contains something like:

{
  "ID": "nginx",
  "desiredState": {
    "image": "dockerfile/nginx",
    "networkPorts": [{
      "containerPort": 80,
      "hostPort": 8080
    }]
  },
  "labels": {
    "name": "foo"
  }
}

Look in api/examples/ for more examples

Tearing down the cluster

cd kubernetes
cluster/kube-down.sh

Running locally

In a separate tab of your terminal, run:

cd kubernetes
hack/local-up-cluster.sh

This will build and start a lightweight local cluster, consisting of a master and a single minion. Type Control-C to shut it down.

If you are running both a remote kubernetes cluster and the local cluster, you can determine which you talk to using the KUBERNETES_MASTER environment variable.

Running on CoreOS

The folks at CoreOS have instructions for running Kubernetes on CoreOS

Where to go next?

Detailed example application

Example of dynamic updates

Or fork and start hacking!

Community, discussion and support

If you have questions or want to start contributing please reach out. We don't bite!

The Kubernetes team is hanging out on IRC on the #google-containers room on freenode.net. We also have the google-containers Google Groups mailing list.

If you are a company and are looking for a more formal engagement with Google around Kubernetes and containers at Google as a whole, please fill out this form. and we'll be in touch.

Development

Hooks

# Before committing any changes, please link/copy these hooks into your .git
# directory. This will keep you from accidentally committing non-gofmt'd
# go code.
#
# NOTE: The "../.." part seems odd but is correct, since the newly created
# links will be 2 levels down the tree.
cd kubernetes
ln -s ../../hooks/prepare-commit-msg .git/hooks/prepare-commit-msg
ln -s ../../hooks/commit-msg .git/hooks/commit-msg

Unit tests

cd kubernetes
hack/test-go.sh

Coverage

cd kubernetes
go tool cover -html=target/c.out

Integration tests

# You need an etcd somewhere in your path.
# To get from head:
go get github.com/coreos/etcd
go install github.com/coreos/etcd
sudo ln -s "$GOPATH/bin/etcd" /usr/bin/etcd
# Or just use the packaged one:
sudo ln -s "$REPO_ROOT/target/bin/etcd" /usr/bin/etcd

cd kubernetes
hack/integration-test.sh

Keeping your development fork in sync

One time after cloning your forked repo:

git remote add upstream https://github.com/GoogleCloudPlatform/kubernetes.git

Then each time you want to sync to upstream:

git fetch upstream
git rebase upstream/master

Regenerating the documentation

cd kubernetes/api
sudo docker build -t kubernetes/raml2html .
sudo docker run --name="docgen" kubernetes/raml2html
sudo docker cp docgen:/data/kubernetes.html .