Install using k0sctl#
k0sctl is a command-line tool for bootstrapping and managing k0s clusters. k0sctl connects to the provided hosts using SSH and gathers information on the hosts, with which it forms a cluster by configuring the hosts, deploying k0s, and then connecting the k0s nodes together.
With k0sctl, you can create multi-node clusters in a manner that is automatic and easily repeatable. This method is recommended for production cluster installation.
Note: The k0sctl install method is necessary for automatic upgrade.
You can execute k0sctl on any system that supports the Go language. Pre-compiled k0sctl binaries are availble on the k0sctl releases page).
Note: For target host prerequisites information, refer to the k0s System Requirements.
1. Install k0sctl tool#
k0sctl is a single binary, the instructions for downloading and installing of which are available in the k0sctl github repository.
2. Configure the cluster#
Run the following command to create a k0sctl configuration file:
k0sctl init > k0sctl.yaml
This action creates a
k0sctl.yamlfile in the current directory:
apiVersion: k0sctl.k0sproject.io/v1beta1 kind: Cluster metadata: name: k0s-cluster spec: hosts: - role: controller ssh: address: 10.0.0.1 # replace with the controller's IP address user: root keyPath: ~/.ssh/id_rsa - role: worker ssh: address: 10.0.0.2 # replace with the worker's IP address user: root keyPath: ~/.ssh/id_rsa
Provide each host with a valid IP address that is reachable by k0ctl, and the connection details for an SSH connection.
Note: Refer to the k0sctl documentation for k0sctl configuration specifications.
3. Deploy the cluster#
k0sctl apply to perform the cluster deployment:
$ k0sctl apply --config k0sctl.yaml ⠀⣿⣿⡇⠀⠀⢀⣴⣾⣿⠟⠁⢸⣿⣿⣿⣿⣿⣿⣿⡿⠛⠁⠀⢸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠀█████████ █████████ ███ ⠀⣿⣿⡇⣠⣶⣿⡿⠋⠀⠀⠀⢸⣿⡇⠀⠀⠀⣠⠀⠀⢀⣠⡆⢸⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀███ ███ ███ ⠀⣿⣿⣿⣿⣟⠋⠀⠀⠀⠀⠀⢸⣿⡇⠀⢰⣾⣿⠀⠀⣿⣿⡇⢸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠀███ ███ ███ ⠀⣿⣿⡏⠻⣿⣷⣤⡀⠀⠀⠀⠸⠛⠁⠀⠸⠋⠁⠀⠀⣿⣿⡇⠈⠉⠉⠉⠉⠉⠉⠉⠉⢹⣿⣿⠀███ ███ ███ ⠀⣿⣿⡇⠀⠀⠙⢿⣿⣦⣀⠀⠀⠀⣠⣶⣶⣶⣶⣶⣶⣿⣿⡇⢰⣶⣶⣶⣶⣶⣶⣶⣶⣾⣿⣿⠀█████████ ███ ██████████ INFO k0sctl 0.0.0 Copyright 2021, Mirantis Inc. INFO Anonymized telemetry will be sent to Mirantis. INFO By continuing to use k0sctl you agree to these terms: INFO https://k0sproject.io/licenses/eula INFO ==> Running phase: Connect to hosts INFO [ssh] 10.0.0.1:22: connected INFO [ssh] 10.0.0.2:22: connected INFO ==> Running phase: Detect host operating systems INFO [ssh] 10.0.0.1:22: is running Ubuntu 20.10 INFO [ssh] 10.0.0.2:22: is running Ubuntu 20.10 INFO ==> Running phase: Prepare hosts INFO [ssh] 10.0.0.1:22: installing kubectl INFO ==> Running phase: Gather host facts INFO [ssh] 10.0.0.1:22: discovered 10.12.18.133 as private address INFO ==> Running phase: Validate hosts INFO ==> Running phase: Gather k0s facts INFO ==> Running phase: Download K0s on the hosts INFO [ssh] 10.0.0.2:22: downloading k0s 0.11.0 INFO [ssh] 10.0.0.1:22: downloading k0s 0.11.0 INFO ==> Running phase: Configure K0s WARN [ssh] 10.0.0.1:22: generating default configuration INFO [ssh] 10.0.0.1:22: validating configuration INFO [ssh] 10.0.0.1:22: configuration was changed INFO ==> Running phase: Initialize K0s Cluster INFO [ssh] 10.0.0.1:22: installing k0s controller INFO [ssh] 10.0.0.1:22: waiting for the k0s service to start INFO [ssh] 10.0.0.1:22: waiting for kubernetes api to respond INFO ==> Running phase: Install workers INFO [ssh] 10.0.0.1:22: generating token INFO [ssh] 10.0.0.2:22: writing join token INFO [ssh] 10.0.0.2:22: installing k0s worker INFO [ssh] 10.0.0.2:22: starting service INFO [ssh] 10.0.0.2:22: waiting for node to become ready INFO ==> Running phase: Disconnect from hosts INFO ==> Finished in 2m2s INFO k0s cluster version 0.11.0 is now installed INFO Tip: To access the cluster you can now fetch the admin kubeconfig using: INFO k0sctl kubeconfig
4. Access the cluster#
To access your k0s cluster, use k0sctl to generate a
kubeconfig for the purpose.
k0sctl kubeconfig > kubeconfig
kubeconfig, you can access your cluster using either kubectl or Lens.
$ kubectl get pods --kubeconfig kubeconfig -A NAMESPACE NAME READY STATUS RESTARTS AGE kube-system calico-kube-controllers-5f6546844f-w8x27 1/1 Running 0 3m50s kube-system calico-node-vd7lx 1/1 Running 0 3m44s kube-system coredns-5c98d7d4d8-tmrwv 1/1 Running 0 4m10s kube-system konnectivity-agent-d9xv2 1/1 Running 0 3m31s kube-system kube-proxy-xp9r9 1/1 Running 0 4m4s kube-system metrics-server-6fbcd86f7b-5frtn 1/1 Running 0 3m51s
- k0sctl does not perform any discovery of hosts, and thus it only operates on the hosts listed in the provided configuration.
- k0sctl can only add more nodes to the cluster. It cannot remove existing nodes.