A Kubernetes cluster with Heat

These Heat templates will deploy an N-node Kubernetes cluster, where N is the value of the number_of_minions parameter you specify when creating the stack.

The cluster uses Flannel to provide an overlay network connecting pods deployed on different minions.

Requirements

OpenStack

These templates will work with the Juno version of Heat.

Guest image

These templates will work with either CentOS Atomic Host or Fedora 21 Atomic. You will need an image dated later than 2015-01-20 in order to have both the flannel package installed and the appropriately configured docker.service unit.

You can enable the VXLAN backend for flannel by setting the "flannel_use_vxlan" parameter to "true", but I have run into kernel crashes using that backend with CentOS 7. It seems to work fine with Fedora 21.

Creating the stack

Creating an environment file local.yaml with parameters specific to your environment:

parameters:
  ssh_key_name: lars
  external_network_id: 028d70dd-67b8-4901-8bdd-0c62b06cce2d
  dns_nameserver: 192.168.200.1
  server_image: centos-7-atomic-20150101

And then create the stack, referencing that environment file:

heat stack-create -f kubecluster.yaml -e local.yaml my-kube-cluster

You must provide values for:

• ssh_key_name
• external_network_id
• server_image

Interacting with Kubernetes

You can get the ip address of the Kubernetes master using the heat output-show command:

$ heat output-show my-kube-cluster kube_master
"192.168.200.86"

You can ssh into that server as the minion user:

$ ssh minion@192.168.200.86

And once logged in you can run kubectl, etc:

$ kubectl get minions
NAME                LABELS
10.0.0.4            <none>

You can log into your minions using the minion user as well. You can get a list of minion addresses by running:

$ heat output-show my-kube-cluster kube_minions_external
[
  "192.168.200.182"
]

Testing

The templates install an example Pod and Service description into /etc/kubernetes/examples. You can deploy this with the following commands:

$ kubectl create -f /etc/kubernetes/examples/web.service
$ kubectl create -f /etc/kubernetes/examples/web.pod

This will deploy a minimal webserver and a service. You can use kubectl get pods and kubectl get services to see the results of these commands.

License

Copyright 2014 Lars Kellogg-Stedman lars@redhat.com

Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Contact

Please report bugs using the GitHub issue tracker at https://github.com/larsks/heat-kubernetes/issues.