11 KiB
Ansible Role: k3s
Ansible role for installing Racher Labs k3s ("Lightweight Kubernetes") as either a standalone server or cluster.
Requirements
The control host requires the following Python dependencies:
jmespath >= 0.9.0
This role has been tested on Ansible 2.7.0+ against the following Linux Distributions:
- Amazon Linux 2
- CentOS 8
- CentOS 7
- Debian 9
- Debian 10
- Fedora 29
- Fedora 30
- Fedora 31
- openSUSE Leap 15
- Ubuntu 18.04 LTS
Disclaimer
⚠️ May not be suitable for production use!
Rancher Labs is awesome and has released k3s as v1.0.0, however at the time of creating this role I do not have a k3s cluster in production nor am I unlikely to ever have one. Please ensure you practice extreme caution and operational rigor before using this role for any serious workloads.
If you have any problems please create a GitHub issue, I maintain this role in my spare time so I cannot promise a speedy fix delivery.
Role Variables
Group Variables
Below are variables that are set against all of the play hosts for environment consistency.
| Variable | Description | Default Value |
|---|---|---|
k3s_cluster_state |
State of cluster: installed, started, stopped, restarted, downloaded. | installed |
k3s_release_version |
Use a specific version of k3s, eg. v0.2.0. Specify false for latest. |
false |
k3s_github_url |
Set the GitHub URL to install k3s from. | https://github.com/rancher/k3s |
k3s_install_dir |
Installation directory for k3s. | /usr/local/bin |
k3s_use_experimental |
Allow the use of experimental features in k3s. | false |
k3s_non_root |
Install k3s as non-root user. See notes below. | false |
k3s_control_workers |
Are control hosts also workers? | true |
k3s_cluster_cidr |
Network CIDR to use for pod IPs | 10.42.0.0/16 |
k3s_service_cidr |
Network CIDR to use for service IPs | 10.43.0.0/16 |
k3s_control_node_address |
Use a specific control node address. IP or FQDN. | NULL |
k3s_control_token |
Use a specific control token, please read notes below. | NULL |
k3s_https_port |
HTTPS port listening port. | 6443 |
k3s_use_docker |
Use Docker rather than Containerd? | false |
k3s_no_flannel |
Do not use Flannel | false |
k3s_flannel_backend |
Flannel backend ('none', 'vxlan', 'ipsec', or 'wireguard') | vxlan |
k3s_no_coredns |
Do not use CoreDNS | false |
k3s_cluster_dns |
Cluster IP for CoreDNS service. Should be in your service-cidr range. | NULL |
k3s_cluster_domain |
Cluster Domain. | cluster.local |
k3s_resolv_conf |
Kubelet resolv.conf file | NULL |
k3s_no_traefik |
Do not use Traefik | false |
k3s_no_servicelb |
Do not use ServiceLB, necessary for using something like MetalLB. | false |
k3s_no_local_storage |
Do not use Local Storage | false |
k3s_no_metrics_server |
Do not deploy metrics server | false |
k3s_disable_scheduler |
Disable Kubernetes default scheduler | false |
k3s_disable_cloud_controller |
Disable k3s default cloud controller manager. | false |
k3s_disable_network_policy |
Disable k3s default network policy controller. | false |
k3s_write_kubeconfig_mode |
Define the file mode from the generated KubeConfig, eg. 644 |
NULL |
k3s_datastore_endpoint |
Define the database or etcd cluster endpoint for HA. | NULL |
k3s_datastore_cafile |
Define the database TLS CA file. | NULL |
k3s_datastore_certfile |
Define the database TLS Cert file. | NULL |
k3s_datastore_keyfile |
Define the database TLS Key file. | NULL |
k3s_dqlite_datastore |
Use DQLite as the database backend for HA. (EXPERIMENTAL) | false |
Important note about k3s_release_version
If you do not set a k3s_release_version the latest version of k3s will be
installed. If you are developing against a specific version of k3s you must
ensure this is set in your Ansible configuration, eg:
k3s_release_version: v0.2.0
Important note about k3s_non_root
To install k3s as non root you must not use become: true. The intention of
this variable is to run a single node development environment. At the time
of release v1.0.1, rootless is still experimental.
You must also ensure that you set k3s_use_experimental to true.
Additionally k3s_install_dir must be writable by your user.
Important notes about k3s_control_node_address and k3s_control_token
If you set this, you are explicitly specifying the control host that agents should connect to, the value should be an IP address or FQDN.
If the control host is not configured by this role, then you need to also
specify the k3s_control_token.
Please note that this may potentially break setting up agents.
Host Variables
Below are variables that are set against specific hosts in your inventory.
| Variable | Description | Default Value |
|---|---|---|
k3s_control_node |
Define the host as a control plane node, (True/False). | false |
k3s_node_name |
Define the name of this node. | $(hostname) |
k3s_node_id |
Define the ID of this node. | NULL |
k3s_flannel_interface |
Define the flannel proxy interface for this node. | NULL |
k3s_bind_address |
Define the bind address for this node. | localhost |
k3s_node_ip_address |
IP Address to advertise for this node. | NULL |
k3s_node_external_address |
External IP Address to advertise for this node. | NULL |
k3s_node_labels |
List of node labels. | NULL |
k3s_node_taints |
List of node taints. | NULL |
k3s_node_data_dir |
Folder to hold state. | /var/lib/rancher/k3s |
k3s_tls_san |
Add additional hosname or IP as Subject Alternate Name in the TLS cert. | NULL |
Important note about k3s_control_node and High Availability (HA)
By default only one host will be defined as a control node by Ansible, If you do not set a host as a control node, the role will automatically delegate the first play host as a control node (master). This is not suitable for use in a Production workload.
If multiple hosts have k3s_control_node set to true, you must also set
k3s_datastore_endpoint as the connection string to a MySQL or PostgreSQL
database, or etcd cluster else the play will fail.
If using TLS, the CA, Certificate and Key need to already be available on the play hosts.
See: High Availability with an External DB
Since K3s v1.0.0 it is possible to use DQLite as the backend database, and this
is done by setting k3s_dqlite_datastore to true. As this is an experimental
feature you will also need to set k3s_use_experimental to true.
Important note about k3s_flannel_interface
If you are running k3s on systems with multiple network interfaces, it is necessary to have the flannel interface on a network interface that is routable to the master node(s).
Notes about k3s_node_labels and k3s_node_taints
Both these variables are lists that will be iterated on. The below example will output the following:
YAML:
k3s_node_labels:
- foo: bar
- hello: world
k3s_node_taints:
- key1: value1:NoExecute
ARGS:
--node-label foo=bar \
--node-label hello=world \
--node-taint key1=value1:NoExecute
Dependencies
No dependencies on other roles.
Example Playbook
Example playbook:
- hosts: k3s_nodes
roles:
- { role: xanmanning.k3s, k3s_release_version: v0.10.2 }
License
BSD