puppet/kubetool repository overview

⁠Kubernetes

⁠Table of Contents

1. Description⁠
2. Setup - The basics of getting started with kubernetes⁠
   • Generating the module configuration⁠
   • Adding the OS and hostname yaml files to Hiera⁠
   • Configuring your node⁠
   • Validating and unit testing the module⁠
3. Reference - An under-the-hood peek at what the module is doing and how⁠
   • Classes⁠
   • Defined types⁠
   • Parameters⁠
4. Limitations - OS compatibility, etc.⁠
5. Development - Guide for contributing to the module⁠

⁠Description

This module installs and configures Kubernetes⁠ which is an open-source system for automating deployment, scaling, and management of containerized applications. For efficient management and discovery, containers that make up an application are grouped into logical units.

To bootstrap a Kubernetes cluster in a secure and extensible way, this module uses the kubeadm⁠ toolkit.

⁠Setup

Install⁠ this module, generate the configuration⁠, add the OS and hostname yaml files to Hiera⁠, and configure your node⁠.

Included in this module is Kubetool⁠, a configuration tool that auto-generates the Hiera security parameters, the discovery token hash, and other configurations for your Kubernetes cluster. To simplify installation and use, the tool is available as a Docker image.

⁠Generating the module configuration

If Docker is not installed on your workstation, install it from here⁠.

The Kubetool Docker image takes each parameter as an environment variable.

Note:: The version of Kubetool you use must match the version of the module on the Puppet Forge. For example, if using the module version 1.0.0, use puppet/kubetool:1.0.0.

To output a yaml file into your working directory that corresponds to the operating system you want Kubernetes to run on, and for each controller node, run either of these docker run commands:

docker run --rm -v $(pwd):/mnt --env-file env puppet/kubetool:{$module_version}

The docker run command above includes an env file which is included in the root folder of this repo.

docker run --rm -v $(pwd):/mnt -e OS=debian -e VERSION=1.10.2 -e CONTAINER_RUNTIME=docker -e CNI_PROVIDER=weave -e ETCD_INITIAL_CLUSTER=kube-master:172.17.10.101,kube-replica-master-01:172.17.10.210,kube-replica-master-02:172.17.10.220 -e ETCD_IP="%{::ipaddress_eth1}" -e KUBE_API_ADVERTISE_ADDRESS="%{::ipaddress_eth1}" -e INSTALL_DASHBOARD=true puppet/kubetool:{$module-version}

The above parameters are:

• OS: The operating system Kubernetes runs on.
• VERSION: The version of Kubernetes to deploy.
• CONTAINER_RUNTIME: The container runtime Kubernetes uses. Set this value to docker (officially supported) or cri_containerd. Advanced Kubernetes users can use cri_containerd, however this requires an increased understanding of Kubernetes, specifically when running applications in a HA cluster. To run a HA cluster and access your applications, an external load balancer is required in front of your cluster. Setting this up is beyond the scope of this module. For more information, see the Kubernetes documentation⁠.
• CNI_PROVIDER: The CNI network to install. Set this value to weave or flannel.
• ETCD_INITIAL_CLUSTER: The server hostnames and IPs in the form of hostname:ip. When in production, include three, five, or seven nodes for etcd.
• ETCD_IP: The IP each etcd member listens on. We recommend passing the fact for the interface to be used by the cluster.
• KUBE_API_ADVERTISE_ADDRESS: The IP each etcd/apiserver instance uses on each controller. We recommend passing the fact for the interface to be used by the cluster.
• INSTALL_DASHBOARD: A boolean which specifies whether to install the dashboard.

Kubetool creates:

• A yaml file that corresponds to the operating system specified by the OS parameter. To view the file contents, run cat Debian.yaml for a Debian system, or run cat RedHat.yaml for RedHat. The yaml files produced for each member of the etcd cluster contain certificate information to bootstrap an initial etcd cluster. Ensure these are also placed in your hieradata directory at the node level.

• A discovery token hash and encoded values required by Kubernetes. To regenerate the values, including certificates and tokens, run the kubetool command again.

⁠Adding the {$OS}.yaml and {$hostname}.yaml files to Hiera

Add the {$OS}.yaml file to the same control repo⁠ where your Hiera⁠ data is, usually the data directory. By leveraging location facts, such as the pp_datacenter⁠ trusted fact⁠, each cluster can be allocated its own configuration.

⁠Configuring your node

After the {$OS}.yaml and {$hostname}.yaml files have been added to the Hiera directory on your Puppet server, configure your node as the controller or worker.

A controller node contains the control plane and etcd. In a production cluster, you should have three, five, or seven controllers. A worker node runs your applications. You can add as many worker nodes as Kubernetes can handle. For information about nodes in Kubernetes, see the Kubernetes documentation⁠.

Note:: A node cannot be a controller and a worker. It must be one or the other.

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

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

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

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

⁠Validating and unit testing the module

This module is compliant with the Puppet Development Kit (PDK)⁠, which provides tools to help run unit tests on the module and validate the modules's metadata, syntax, and style.

Note: To run static validations and unit tests against this module using the pdk validate⁠ and pdk test unit⁠ commands, you must have Puppet 5 or higher installed. In the following examples we have specified Puppet 5.3.6.

To validate the metadata.json file, run the following command:

pdk validate metadata --puppet-version='5.3.6'

To validate the Puppet code and syntax, run the following command:

pdk validate puppet --puppet-version='5.3.6'

Note: The pdk validate ruby command ignores the excluded directories specified in the .rubocop.yml file. Therefore, to validate the Ruby code style and syntax you must specify the directory the code exists in.

In the following example we validate the Ruby code contained in the lib directory:

pdk validate ruby lib --puppet-version='5.3.6'

To unit test the module, run the following command:

pdk test unit --puppet-version='5.3.6'

⁠Reference

⁠Classes

⁠Public classes

• kubernetes

⁠Private classes

• kubernetes::cluster_roles
• kubernetes::config
• kubernetes::kube_addons
• kubernetes::packages
• kubernetes::repos
• kubernetes::service

⁠Defined types

• kubernetes::kubeadm_init
• kubernetes::kubeadm_join

⁠Parameters

The following parameters are available in the kubernetes class.

⁠apiserver_cert_extra_sans

A string array of Subject Alternative Names for the API server certificates.

Defaults to [].

⁠apiserver_extra_arguments

A string array of extra arguments passed to the API server.

Defaults to [].

⁠cloud_provider

The name of the cloud provider configured in /etc/kubernetes/cloud-config.

Note: This file is not managed within this module and must be present before bootstrapping the Kubernetes controller.

Defaults to undef.

⁠cloud_config

The location of the cloud config file used by cloud_provider. For use with v1.12 and above.

Note: This file is not managed within this module and must be present before bootstrapping the Kubernetes controller.

Defaults to undef.

⁠cni_network_provider

The URL to get the CNI providers yaml file. kube_tool sets this value.

Defaults to undef.

⁠cni_rbac_binding

The download URL for the cni providers rbac rules. Only for use with Calico.

Defaults to undef.

⁠cni_pod_cidr

Specifies the overlay (internal) network range to use. This value is set by kube_tool per CNI_PROVIDER.

Defaults to undef.

⁠container_runtime

Specifies the runtime that the Kubernetes cluster uses.

Valid values are cri_containerd or docker.

Defaults to docker.

⁠controller

Specifies whether to set the node as a Kubernetes controller.

Valid values are true, false.

Defaults to false.

⁠containerd_version

Specifies the version of the containerd runtime the module installs.

Defaults to 1.1.0.

⁠containerd_archive

The name of the containerd archive.

Defaults to containerd-${containerd_version}.linux-amd64.tar.gz.

⁠containerd_source

The download URL for the containerd archive.

Defaults to https://github.com/containerd/containerd/releases/download/v${containerd_version}/${containerd_archive}.

⁠controller_address

The IP address and port for the controller the worker node joins. For example 172.17.10.101:6443.

Defaults to undef.

⁠create_repos

Specifies whether to install the upstream Kubernetes and Docker repos.

Valid values are true, false.

Defaults to true.

⁠disable_swap

Specifies whether to turn off swap setting. This is required for kubeadm.

Valid values are true, false.

Defaults to true.

⁠manage_kernel_modules

Specifies whether to manage the kernel modules needed for kubernetes

Valid values are true, false.

Defaults to true

⁠manage_sysctl_settings

Specifies whether to manage the the sysctl settings needed for kubernetes

Valid values are true, false.

Defaults to true

⁠discovery_token_hash

The string used to validate to the root CA public key when joining a cluster. This value is created by kubetool.

Defaults to undef.

⁠docker_apt_location

The APT repo URL for the Docker packages.

Defaults to https://apt.dockerproject.org/repo.

⁠docker_apt_release

The release name for the APT repo for the Docker packages.

Defaults to 'ubuntu-${::lsbdistcodename}'.

⁠docker_apt_repos

The repos to install from the Docker APT url.

Defaults to main.

⁠docker_version

Specifies the version of the Docker runtime to install.

Defaults to:

• 17.03.0.ce-1.el7.centos on RedHat.
• 17.03.0~ce-0~ubuntu-xenial on Ubuntu.

⁠docker_package_name

The docker package name to download from an upstream repo.

Defaults to docker-engine.

⁠docker_key_id

The gpg key for the Docker APT repo.

Defaults to '58118E89F3A912897C070ADBF76221572C52609D'.

⁠docker_key_source

The URL for the Docker APT repo gpg key.

Defaults to https://apt.dockerproject.org/gpg.

⁠docker_yum_baseurl

The YUM repo URL for the Docker packages.

Defaults to https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64.

⁠docker_yum_gpgkey

The URL for the Docker yum repo gpg key.

Defaults to https://yum.dockerproject.org/gpg.

⁠etcd_version

Specifies the version of etcd.

Defaults to 3.1.12.

⁠etcd_archive

Specifies the name of the etcd archive.

Defaults to etcd-v${etcd_version}-linux-amd64.tar.gz.

⁠etcd_source

The download URL for the etcd archive.

Defaults to https://github.com/coreos/etcd/releases/download/v${etcd_version}/${etcd_archive}.

⁠etcd_ip

Specifies the IP address etcd uses for communications.

A Hiera is kubernetes::etcd_ip:"%{::ipaddress_enp0s8}".

Defaults to undef.

⁠etcd_initial_cluster

Informs etcd on how many nodes are in the cluster.

A Hiera example is kubernetes::etcd_initial_cluster: kube-master:172.17.10.101,kube-replica-master-01:172.17.10.210,kube-replica-master-02:172.17.10.220.

Defaults to undef.

⁠etcd_peers

Specifies how etcd lists the peers to connect to the cluster.

A Hiera example is kubernetes::etcd_peers:

• 172.17.10.101
• 172.17.10.102
• 172.17.10.103

Defaults to undef

⁠etcd_ca_key

The CA certificate key data for the etcd cluster. This value must be passed as string and not as a file.

Defaults to undef.

⁠etcd_ca_crt

The CA certificate data for the etcd cluster. This value must be passed as string and not as a file.

Defaults to undef.

⁠etcdclient_key

The client certificate key data for the etcd cluster. This value must be passed as string and not as a file.

Defaults to undef.

⁠etcdclient_crt

The client certificate data for the etcd cluster. This value must be passed as string not as a file.

Defaults to undef.

⁠etcdserver_key

The server certificate key data for the etcd cluster. This value must be passed as string not as a file.

Defaults to undef.

⁠etcdserver_crt

The server certificate data for the etcd cluster . This value must be passed as string not as a file.

Defaults to undef.

⁠etcdpeer_crt

The peer certificate data for the etcd cluster. This value must be passed as string not as a file.

Defaults to undef.

⁠etcdpeer_key

The peer certificate key data for the etcd cluster. This value must be passed as string not as a file.

Defaults to undef.

⁠image_repository

The container registry to pull control plane images from.

Defaults to k8s.gcr.io

⁠install_dashboard

Specifies whether the Kubernetes dashboard is installed.

Valid values are true, false.

Defaults to false.

⁠kubernetes_ca_crt

The cluster's CA certificate. Must be passed as a string and not a file.

Defaults to undef.

⁠kubernetes_ca_key

The clusters CA key. Must be passed as a string and not a file.

Defaults to undef.

⁠kube_api_advertise_address

The IP address you want exposed by the API server.

A Hiera example is kubernetes::kube_api_advertise_address:"%{::ipaddress_enp0s8}".

Defaults to undef.

⁠kubernetes_version

The version of the Kubernetes containers to install.

Defaults to 1.10.2.

⁠kubernetes_package_version

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

Defaults to 1.10.2.

⁠kubeadm_extra_config

A hash containing extra configuration data to be serialised with to_yaml and appended to the config.yaml file used by kubeadm.

Defaults to {}.

⁠kubelet_extra_config

A hash containing extra configuration data to be serialised with to_yaml and appended to Kubelet configuration file for the cluster. Requires DynamicKubeletConfig.

Defaults to {}.

⁠kubelet_extra_arguments

A string array to be appended to kubeletExtraArgs in the Kubelet's nodeRegistration configuration. It is applied to both masters and nodes. Use this for critical Kubelet settings such as pod-infra-container-image which may be problematic to configure via kubelet_extra_config and DynamicKubeletConfig.

Defaults to [].

⁠kubernetes_apt_location

The APT repo URL for the Kubernetes packages.

Defaults to https://apt.kubernetes.io.

⁠kubernetes_apt_release

The release name for the APT repo for the Kubernetes packages.

Defaults to 'kubernetes-${::lsbdistcodename}'.

⁠kubernetes_apt_repos

The repos to install using the Kubernetes APT URL.

Defaults to main.

⁠kubernetes_key_id

The gpg key for the Kubernetes APT repo.

Defaults to '54A647F9048D5688D7DA2ABE6A030B21BA07F4FB'.

⁠kubernetes_key_source

The URL for the APT repo gpg key.

Defaults to https://packages.cloud.google.com/apt/doc/apt-key.gpg.

⁠kubernetes_yum_baseurl

The YUM repo URL for the Kubernetes packages.

Defaults to https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64.

⁠kubernetes_yum_gpgkey

The URL for the Kubernetes yum repo gpg key.

Defaults to https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg.

⁠manage_docker

Specifies whether to install Docker repositories and packages via this module.

Valid values are true, false.

Defaults to true.

⁠manage_etcd

Specifies whether to install an external Etcd via this module.

Valid values are true, false.

Defaults to true.

⁠node_label

An override to the label of a node.

Defaults to hostname.

⁠runc_source

The download URL for runc.

Defaults to https://github.com/opencontainers/runc/releases/download/v${runc_version}/runc.amd64.

⁠runc_version

Specifies the version of runc to install.

Defaults to 1.0.0-rc5.

⁠sa_key

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

Defaults to undef.

⁠sa_pub

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

Defaults to undef.

⁠schedule_on_controller

Specifies whether to remove the master role and allow pod scheduling on controllers.

Valid values are true, false.

Defaults to false.

⁠service_cidr

The IP address range for service VIPs.

Defaults to 10.96.0.0/12.

⁠token

The string used to join nodes to the cluster. This value must be in the form of [a-z0-9]{6}.[a-z0-9]{16}.

Defaults to undef.

⁠worker

Specifies whether to set the node as a Kubernetes worker.

Valid values are true, false.

Defaults to false.

⁠Limitations

This module supports:

• Puppet 4 or higher.
• Kubernetes 1.10.x⁠ or higher.
• Ruby 2.3.0 or higher.

This module has been tested on the following operating systems:

• RedHat 7.x.
• CentOS 7.x.
• Ubuntu 16.04

Docker is the supported container runtime for this module.

⁠Development

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