Kubernetes

Table of Contents

1. Description
2. Setup - The basics of getting started with kubernetes
   • Setup requirements
   • Beginning with kubernetes
3. Reference - An under-the-hood peek at what the module is doing and how
4. Limitations - OS compatibility, etc.
5. Development - Guide for contributing to the module

Overview

The Puppet kubernetes module installs and configures the Kubernetes system which arranges containers into logical units to improve management and discovery.

Description

This module installs and configures Kubernetes. Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications.

It groups containers that make up an application into logical units for easy management and discovery.

Setup

Setup Requirements

The included configuration tool kube_tools auto generates all the security parameters, the bootstrap token, and other configurations for your cluster into a file. The kube_tool requires Ruby 2.3 and above.

1. cfssl is a requirement, so we recommend you install the module on a local machine and not a Puppet server by running this command:

puppet module install puppetlabs-kubernetes --version 0.2.0

2. Install cfssl. See Cloudflare's cfssl documentation.

3. Change directory into the root of the module, and run the bundle install command.

4. Change directory into the tools directory, and run the kube_tool command.

5. To view the help menu, run the ./kube_tool.rb -h command.

The kube_tools help menu:

Usage: kube_tool [options]
    -o, --os-type os-type            the os that kubernetes will run on
    -v, --version version            the kubernetes version to install
    -r container runtime,            the container runtime to use. this can only be docker or cri_containerd
        --container_runtime
    -f, --fqdn fqdn                  fqdn
    -i, --ip ip                      ip
    -b bootstrap,                    the bootstrap controller ip address
        --bootstrap-controller-ip
    -e etcd_initial_cluster,         members of the initial etcd cluster
        --etcd-initial-cluster
    -t, --etcd-ip etcd_ip            ip address of etcd
    -a, --api-address api_address    the ip address that kube api will listen on
    -d dashboard,                    install the kube dashboard
        --install-dashboard
    -h, --help                       Displays Help

So to generate the hiera file for my cluster I use:

./kube_tool.rb -o debian -v 1.8.4 -r docker -f kubernetes -i 172.17.10.101 -b 172.17.10.101 -e "etcd-kube-master=http://172.17.10.101:2380,etcd-kube-replica-master-01=http://172.17.10.210:2380,etcd-kube-replica-master-02=http://172.17.10.220:2380" -t "%{::ipaddress_enp0s8}" -a "%{::ipaddress_enp0s8}" -d true

The parameters are:

• OS: the os kubernetes will run on.
• VERSION: the version of kubernetes you want to deploy
• CONTAINER_RUNTIME: the container runtime kubernetes will use, this can only be set to docker or cri_containerd
• FQDN: the cluster fqdn.
• BOOTSTRAP_CONTROLLER_IP: the ip address of the controller puppet will use to create things like cluster role bindings, kube dns, and the Kubernetes dashboard.
• ETCD_INITIAL_CLUSTER: the server addresses. When in production, include three, five, or seven nodes for etcd.
• ETCD_IP and ETCD_IP KUBE_API_ADVERTISE_ADDRESS: we recommend passing the fact for the interface to be used by the cluster.
• INSTALL_DASHBOARD: a boolean to install the dashboard or not.

The tool creates a kubernetes.yaml file. To view the file contents on screen, run the cat command.

6. Add the kubernetes.yaml file to the Hiera directory on your Puppet server.

The tool also creates a bootstrap token and base64 encodes any values that need to be encoded for Kubernetes. If you run the cat command again, all the values are re-generated, including the certificates and tokens. You can then use Jenkins or Bamboo to add the Hiera file to your control repository or version control application.

If you don't want to use the kube_tools configuration tool and want to manually configure the module, all of the parameters are listed in the Reference section and in the init.pp file.

If you don't want to install the dependencies in your local environment, a Dockerfile is included. To build, change directory into the tooling directory, and run the docker build -t puppet/kubetool command.

The docker image takes each of the parameters as environment variables. When run as follows it will output a kubernetes.yaml file in your current working directory:

docker run -v $(pwd):/mnt -e FQDN=kubernetes -e IP=172.17.10.101 -e BOOTSTRAP_CONTROLLER_IP=172.17.10.101 -e ETCD_INITIAL_CLUSTER="etcd-kube-master=http://172.17.10.101:2380" -e ETCD_IP="%{::ipaddress_enp0s8}" -e KUBE_API_ADVERTISE_ADDRESS="%{::ipaddress_enp0s8}" -e INSTALL_DASHBOARD=true puppetlabs/kubetool

Begininning with kubernetes

After your kubernetes.yaml file has been added to the Hiera directory on your Puppet server, configure your node with one of the following parameters:

• bootstrap controller
• controller
• worker

Bootstrap Controller

A bootstrap controller is the node a cluster uses to add cluster addons (such as kube dns, cluster role bindings etc). After the cluster is bootstrapped, the bootstrap controller becomes a normal controller.

To make a node a bootstrap controller, add the following code to the manifest:

class {'kubernetes':
  controller           => true,
  bootstrap_controller => true,
}

Controller

A controller in Kubernetes contains the control plane and etcd. In a production cluster you should have three, five, or seven controllers.

To make a node a controller, add the following code to the manifest:

class {'kubernetes':
  controller => true,
}

Worker

A worker node runs your applications. You can add as many of these as Kubernetes can handle. For information about nodes in Kubernetes, see the Kubernetes docs.

To make a node a worker node, add the following code to the manifest:

class {'kubernetes':
  worker => true,
}

Please note that a node can not be a controller and a worker. It must be one or the other.

Reference

Parameters

kubernetes_version

The version of the Kubernetes containers to install.

Defaults to 1.7.3.

kubernetes_package_version

The version the Kubernetes OS packages to install, such as kubectl and kubelet.

Defaults to 1.7.3.

cni_version

The version of the cni package to install.

Defaults to 0.5.1.

kube_dns_version

The version of kube DNS to install.

Defaults to 1.14.2.

container_runtime

Choose between docker or cri_containerd

Defaults to docker

controller

Specifies whether to set the node as a Kubernetes controller.

Valid values are true, false.

Defaults to false.

bootstrap_controller

Specifies whether to set the node as the bootstrap controller.

The bootstrap controller is used only for creating the initial cluster.

Valid values are true, false.

Defaults to false.

bootstrap_controller_ip

The IP address of the bootstrap controller.

Defaults to undef.

worker

Specifies whether to set a node as a worker.

Defaults to undef.

manage_epel

Specifies whether you to manage epel for a RHEL box.

Valid values are true, false.

Defaults to false.

kube_api_advertise_address

The IP address you want exposed by the API server.

An example with hiera would be kubernetes::kube_api_advertise_address:"%{::ipaddress_enp0s8}".

Defaults to undef.

etcd_version

The version of etcd to use.

Defaults to 3.0.17.

etcd_ip

The IP address you want etcd to use for communications.

An example with hiera would be kubernetes::etcd_ip:"%{::ipaddress_enp0s8}".

Defaults to undef.

etcd_initial_cluster

This will tell etcd how many nodes will be in the cluster and is passed as a string.

A Hiera example is kubernetes::etcd_initial_cluster: etcd-kube-master=http://172.17.10.101:2380,etcd-kube-replica-master-01=http://172.17.10.210:2380,etcd-kube-replica-master-02=http://172.17.10.220:2380.

Defaults to undef.

bootstrap_token

The token Kubernetes uses to start components.

For information on bootstrap tokens, see https://kubernetes.io/docs/admin/bootstrap-tokens/

Defaults to undef.

bootstrap_token_name

The name of the bootstrap token.

An example with hiera would be kubernetes::bootstrap_token_name: bootstrap-token-95e1e0.

Defaults to undef.

bootstrap_token_description

The base64 encoded description of the bootstrap token.

A Hiera example is kubernetes::bootstrap_token_description: VGhlIGRlZmF1bHQgYm9vdHN0cmFwIHRva2VuIHBhc3NlZCB0byB0aGUgY2x1c3RlciB2aWEgUHVwcGV0Lg== # lint:ignore:140chars.

bootstrap_token_id

The base64 encoded ID the cluster uses to point to the token.

A Hiera example is kubernetes::bootstrap_token_id: OTVlMWUwDQo=.

Defaults to undef.

bootstrap_token_secret

The base64 encoded secret which validates the bootstrap token.

An example with hiera would be kubernetes::bootstrap_token_secret: OTVlMWUwLmFlMmUzYjkwYTdmYjlkMzYNCg==.

Defaults to undef.

bootstrap_token_usage_bootstrap_authentication

The base64 encoded bool which uses the bootstrap token. (true = dHJ1ZQ==)

An example with hiera would be kubernetes::bootstrap_token_usage_bootstrap_authentication: dHJ1ZQ==.

Defaults to undef.

bootstrap_token_usage_bootstrap_signing

The base64 encoded bool which uses the bootstrap signing. (true = dHJ1ZQ==)

An example with hiera would be kubernetes::bootstrap_token_usage_bootstrap_signing: dHJ1ZQ==.

Defaults to undef.

certificate_authority_data

The string value for the cluster ca certificate data.

Defaults to undef.

client_certificate_data_controller

The client certificate for the controller. Must be a string value.

Defaults to undef.

client_certificate_data_controller_manager

The client certificate for the controller manager. Must be a string value.

Defaults to undef.

client_certificate_data_scheduler

The client certificate for the scheduler. Must be a string value.

Defaults to undef.

client_certificate_data_worker

The client certificate for the kubernetes worker. Must be a string value.

Defaults to undef.

client_key_data_controller

The client certificate key for the controller. Must be a string value.

Defaults to undef.

client_key_data_controller_manager

The client certificate key for the controller manager. Must be a string value.

Defaults to undef.

client_key_data_scheduler

The client certificate key for the scheduler. Must be a string value.

Defaults to undef.

client_key_data_worker

The client certificate key for the kubernetes worker. Must be a string value.

Defaults to undef.

apiserver_kubelet_client_crt

The certificate for the kubelet api server. Must be a certificate value and not a file.

Defaults to undef.

apiserver_kubelet_client_key

The client key for the kubelet api server. Must be a certificate value and not a file.

Defaults to undef.

apiserver_crt

The certificate for the api server. Must be a certificate value and not a file.

Defaults to undef.

apiserver_key

The key for the api server. Must be a certificate value and not a file.

Defaults to undef.

ca_crt

The ca certificate for the cluster. Must be a certificate value and not a file.

Defaults to undef.

ca_key

The ca key for the cluster. Must be a certificate value and not a file.

Defaults to undef.

front_proxy_ca_crt

The ca certificate for the front proxy. Must be a certificate value and not a file.

Defaults to undef.

front_proxy_ca_key

The ca key for the front proxy. Must be a certificate value and not a file.

Defaults to undef.

front_proxy_client_crt

The client certificate for the front proxy. Must be a certificate value and not a file.

Defaults to undef.

front_proxy_client_key

The client key for front proxy. Must be a certificate value and not a file.

Defaults to undef.

sa_key

The key for the service account. Must be a certificate value and not a file.

Defaults to undef.

sa_pub

The public key for the service account. Must be a certificate value and not a file.

Defaults to undef.

cni_network_provider

The network deployment URL that kubectl can locate.

We support networking providers that supports cni.

This defaults to https://git.io/weave-kube-1.6.

install_dashboard

Specifies whether the kubernetes dashboard is installed.

Valid values are true, false.

Defaults to false.

Limitations

This module supports Kubernetes 1.6 and above.

This module supports only Puppet 4 and above.

This module has been tested on the following OS

RedHat 7.x CentOS 7.x Ubuntu 16.04

Development

If you would like to contribute to this module please follow the rules in the CONTRIBUTING.md.