- Getting Started with Kubernetes
- Usage - Configuration options and additional functionality
- Reference - An under-the-hood peek at what the module is doing and how
The garethr-kubernetes module allows you to use the Puppet DSL for managing Pods, ReplicationControllers, Services and more in Kubernetes. It doesn't install the various Kubernetes components.
The module allows for defining Kubernetes resources in Puppet, and then for Puppet to create or update those resources. This improves on the basic YAML file approach in a few ways:
- The Puppet language supports logic and abstractions, allowing for the crafting of business specific user interfaces and avoiding repetition
- Modifications can be made to the Puppet code and Puppet will handle updating the relevant resources, without having to describe the full state of the resource
- Puppet supports relationships between resources, so you can enforce ordering where necessary
The user interface of the Puppet code however follows the API/YAML format exactly. This allows for a familiar interface for anyone used to the Kubernetes API, at the same time as providing a low level building block for creating higher level types.
Note that the following assumes you have a Kubernetes cluster up and running.
- Kubeclient ruby gem
- Ruby 2.x, Kubeclient won't work with 1.8.7 or 1.9.x
Install the required gems with this command:
/opt/puppetlabs/puppet/bin/gem install activesupport -v 4.1.14
/opt/puppetlabs/puppet/bin/gem install kubeclient --no-ri --no-rdoc
You can provide the required information in a standard kubectl configuration
file. Store this as kubernetes.conf
in the relevant
confdir.
This should be:
- nix Systems:
/etc/puppetlabs/puppet
- Windows:
C:\ProgramData\PuppetLabs\puppet\etc
- non-root users:
~/.puppetlabs/etc/puppet
If you have a working kubectl setup you can export the file using the following command:
kubectl config view --raw=true
Finally install the module with:
puppet module install garethr-kubernetes
This module allows for describing resources in Kubernetes (like Pods, Services and ReplicationControllers) using the Puppet DSL. To create a new Pod for example:
kubernetes_pod { 'sample-pod':
ensure => present,
metadata => {
namespace => 'default',
},
spec => {
containers => [{
name => 'container-name',
image => 'nginx',
}]
},
}
In addition to creating and managing resources this module supports listing
and interactive management of resources via puppet resource
. For example:
puppet resource kubernetes_node
Or:
puppet resource kubernetes_service
You can use this to describe the state of your Kubernetes cluster and export the results to a file, which can then be used to maintain that state over time.
You can also delete the resources we created above by setting the ensure
property to absent
in the manifest or using puppet resouce
like so:
puppet resource kubernetes_pod sample-pod ensure=absent
The module examples folder contains additional usage examples:
You may already have YAML files describing your Kubernetes resources, or
be using Helm to download existing
Charts. The module includes an
experimental puppet kubernetes convert
command for just this
situation.
puppet kubernetes convert examples/guestbook.yaml
The above command will output to stdout the Puppet equivalent to the YAML description of Kubernetes resources, including correctly handling multi-document files like the example guestbook.
puppet kubernetes convert examples/guestbook.yaml > guestbook.pp
puppet apply --test guestbook.pp
If you want to then use that Puppet file the simplest way to do so is to redirect the output to a file and then run it with Puppet as shown above.
- kubernetes_pod
- kubernetes_service
- kubernetes_replication_controller
- kubernetes_node
- kubernetes_event
- kubernetes_endpoint
- kubernetes_namespace
- kubernetes_secret
- kubernetes_resource_quota
- kubernetes_limit_range
- kubernetes_peristent_volume
- kubernetes_persistent_volume_claim
- kubernetes_component_status
- kubernetes_service_account
This module is a proof of concept, demonstrating both the power of auto-generating Puppet types and providers from Swagger specifications and of managing higher level tools like Kubernetes with Puppet. It likely has several bugs and rough edges at the moment. Please report those on GitHub.
Much of the code for this module is auto-generated using the puppet-swagger-generator project. This means modifications to the types and providers should be done there, rather than within this project. Files which are auto-generated should have a suitable comment indicating as such.