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How to get started, and achieve tasks, using Kubernetes

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Cloudstack

CloudStack is a software to build public and private clouds based on hardware virtualization principles (traditional IaaS). To deploy Kubernetes on CloudStack there are several possibilities depending on the Cloud being used and what images are made available. Exoscale for instance makes a CoreOS template available, therefore instructions to deploy Kubernetes on coreOS can be used. CloudStack also has a vagrant plugin available, hence Vagrant could be used to deploy Kubernetes either using the existing shell provisioner or using new Salt based recipes.

CoreOS templates for CloudStack are built nightly. CloudStack operators need to register this template in their cloud before proceeding with these Kubernetes deployment instructions.

This guide uses an Ansible playbook. This is a completely automated, a single playbook deploys Kubernetes based on the coreOS instructions.

This Ansible playbook deploys Kubernetes on a CloudStack based Cloud using CoreOS images. The playbook, creates an ssh key pair, creates a security group and associated rules and finally starts coreOS instances configured via cloud-init.

Prerequisites

$ sudo apt-get install -y python-pip
$ sudo pip install ansible
$ sudo pip install cs

cs is a python module for the CloudStack API.

Set your CloudStack endpoint, API keys and HTTP method used.

You can define them as environment variables: CLOUDSTACK_ENDPOINT, CLOUDSTACK_KEY, CLOUDSTACK_SECRET and CLOUDSTACK_METHOD.

Or create a ~/.cloudstack.ini file:

[cloudstack]
endpoint = <your cloudstack api endpoint>
key = <your api access key>
secret = <your api secret key>
method = post

We need to use the http POST method to pass the large userdata to the coreOS instances.

Clone the playbook

$ git clone --recursive https://github.com/runseb/ansible-kubernetes.git
$ cd ansible-kubernetes

The ansible-cloudstack module is setup in this repository as a submodule, hence the --recursive.

Create a Kubernetes cluster

You simply need to run the playbook.

$ ansible-playbook k8s.yml

Some variables can be edited in the k8s.yml file.

vars:
  ssh_key: k8s
  k8s_num_nodes: 2
  k8s_security_group_name: k8s
  k8s_node_prefix: k8s2
  k8s_template: Linux CoreOS alpha 435 64-bit 10GB Disk
  k8s_instance_type: Tiny

This will start a Kubernetes master node and a number of compute nodes (by default 2). The instance_type and template by default are specific to exoscale, edit them to specify your CloudStack cloud specific template and instance type (i.e service offering).

Check the tasks and templates in roles/k8s if you want to modify anything.

Once the playbook as finished, it will print out the IP of the Kubernetes master:

TASK: [k8s | debug msg='k8s master IP is {{ k8s_master.default_ip }}'] ********

SSH to it using the key that was created and using the core user and you can list the machines in your cluster:

$ ssh -i ~/.ssh/id_rsa_k8s core@<master IP>
$ fleetctl list-machines
MACHINE		IP		       METADATA
a017c422...	<node #1 IP>   role=node
ad13bf84...	<master IP>	   role=master
e9af8293...	<node #2 IP>   role=node

Support Level

IaaS Provider Config. Mgmt OS Networking Docs Conforms Support Level
CloudStack Ansible CoreOS flannel docs   Community (@runseb)

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

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