# Ansible Role: Kubernetes

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An Ansible Role that installs [Kubernetes](https://kubernetes.io) on Linux.

## Requirements

Requires Docker; recommended role for Docker installation: `geerlingguy.docker`.

## Role Variables

Available variables are listed below, along with default values (see `defaults/main.yml`):

    kubernetes_packages:
      - name: kubelet
        state: present
      - name: kubeadm
        state: present
      - name: kubernetes-cni
        state: present

Kubernetes packages to be installed on the server. You can either provide a list of package names, or set `name` and `state` to have more control over whether the package is `present`, `absent`, `latest`, etc.

    kubernetes_role: master

Whether the particular server will serve as a Kubernetes `master` (default) or `node`. The master will have `kubeadm init` run on it to intialize the entire K8s control plane, while `node`s will have `kubeadm join` run on them to join them to the `master`.

    kubernetes_kubelet_extra_args: ""
    kubernetes_kubelet_extra_args_config_file: /etc/default/kubelet

Extra args to pass to `kubelet` during startup. E.g. to allow `kubelet` to start up even if there is swap is enabled on your server, set this to: `"--fail-swap-on=false"`. Or to specify the node-ip advertised by `kubelet`, set this to `"--node-ip={{ ansible_host }}"`.

    kubernetes_allow_pods_on_master: True

Whether to remove the taint that denies pods from being deployed to the Kubernetes master. If you have a single-node cluster, this should definitely be `True`. Otherwise, set to `False` if you want a dedicated Kubernetes master which doesn't run any other pods.

    kubernetes_enable_web_ui: False

Whether to enable the Kubernetes web dashboard UI (only accessible on the master itself, or proxied).

    kuberenetes_debug: False

Whether to show extra debug info in Ansible's logs (e.g. the output of the `kubeadm init` command).

    kubernetes_pod_network_cidr: '10.0.1.0/16'
    kubernetes_apiserver_advertise_address: ''
    kubernetes_version: 'stable-1.11'
    kubernetes_ignore_preflight_errors: 'all'

Options passed to `kubeadm init` when initializing the Kubernetes master. The `apiserver_advertise_address` defaults to `ansible_default_ipv4.address` if it's left empty.

    kubernetes_apt_release_channel: main
    kubernetes_apt_repository: "deb http://apt.kubernetes.io/ kubernetes-xenial {{ kubernetes_apt_release_channel }}"
    kubernetes_apt_ignore_key_error: False

Apt repository options for Kubernetes installation.

    kubernetes_yum_arch: x86_64

Yum repository options for Kubernetes installation.

    kubernetes_flannel_manifest_file_rbac: https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml
    kubernetes_flannel_manifest_file: https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Flannel manifest files to apply to the Kubernetes cluster to enable networking. You can copy your own files to your server and apply them instead, if you need to customize the Flannel networking configuration.

## Dependencies

None.

## Example Playbooks

### Single node (master-only) cluster

```yaml
- hosts: all

  vars:
    kubernetes_allow_pods_on_master: True

  roles:
    - geerlingguy.docker
    - geerlingguy.kubernetes
```

### Two or more nodes (single master) cluster

Master inventory vars:

```yaml
kubernetes_role: "master"
```

Node(s) inventory vars:

```yaml
kubernetes_role: "node"
```

Playbook:

```yaml
- hosts: all

  vars:
    kubernetes_allow_pods_on_master: True

  roles:
    - geerlingguy.docker
    - geerlingguy.kubernetes
```

Then, log into the Kubernetes master, and run `kubectl get nodes` as root, and you should see a list of all the servers.

## License

MIT / BSD

## Author Information

This role was created in 2018 by [Jeff Geerling](https://www.jeffgeerling.com/), author of [Ansible for DevOps](https://www.ansiblefordevops.com/).