A command-line bootstrapping and management tool for k0s zero friction kubernetes clusters.
Example output of k0sctl deploying a k0s cluster:
$ k0sctl apply
⠀⣿⣿⡇⠀⠀⢀⣴⣾⣿⠟⠁⢸⣿⣿⣿⣿⣿⣿⣿⡿⠛⠁⠀⢸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠀█████████ █████████ ███
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⠀⣿⣿⣿⣿⣟⠋⠀⠀⠀⠀⠀⢸⣿⡇⠀⢰⣾⣿⠀⠀⣿⣿⡇⢸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠀███ ███ ███
⠀⣿⣿⡏⠻⣿⣷⣤⡀⠀⠀⠀⠸⠛⠁⠀⠸⠋⠁⠀⠀⣿⣿⡇⠈⠉⠉⠉⠉⠉⠉⠉⠉⢹⣿⣿⠀███ ███ ███
⠀⣿⣿⡇⠀⠀⠙⢿⣿⣦⣀⠀⠀⠀⣠⣶⣶⣶⣶⣶⣶⣿⣿⡇⢰⣶⣶⣶⣶⣶⣶⣶⣶⣾⣿⣿⠀█████████ ███ ██████████
INFO By continuing to use k0sctl you agree to these terms:
INFO https://k0sproject.io/licenses/eula
INFO ==> Running phase: Connect to hosts
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 ==> 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 binaries on hosts
INFO ==> Running phase: Configure k0s
INFO [ssh] 10.0.0.1:22: validating configuration
INFO ==> Running phase: Initialize the k0s cluster
INFO [ssh] 10.0.0.1:22: installing k0s controller
INFO ==> Running phase: Install workers
INFO [ssh] 10.0.0.1:22: generating token
INFO [ssh] 10.0.0.2:22: installing k0s worker
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 kubeconfigDownload the desired version for your operating system and processor architecture from the k0sctl releases page. Make the file executable and place it in a directory available in your $PATH.
As the released binaries aren't signed yet, on macOS and Windows, you must first run the executable via "Open" in the context menu and allow running it.
If you have a working Go toolchain, you can use go get to install k0sctl to your $GOPATH/bin.
GO111MODULE=on go get github.com/k0sproject/k0sctlScripts for installation via popular package managers such as Homebrew, Scoop or SnapCraft will be added later.
K0sctl is still in an early stage of development. Missing major features include at least:
- Windows targets are not yet supported
- The released binaries have not been signed
- Nodes can't be removed
The main function of k0sctl is the k0sctl apply subcommand. Provided a configuration file describing the desired cluster state, k0sctl will connect to the listed hosts, determines the current state of the hosts and configures them as needed to form a k0s cluster.
The default location for the configuration file is k0sctl.yaml in the current working directory. To load a configuration from a different location, use:
k0sctl apply --config path/to/k0sctl.yamlIf the configuration cluster version spec.k0s.version is greater than the version detected on the cluster, a cluster upgrade will be performed. If the configuration lists hosts that are not part of the cluster, they will be configured to run k0s and will be joined to the cluster.
Generate a configuration template. Use --k0s to include an example spec.k0s.config k0s configuration block. You can also supply a list of host addresses via arguments or stdin.
Output a minimal configuration template:
k0sctl init > k0sctl.yamlOutput an example configuration with a default k0s config:
k0sctl init --k0s > k0sctl.yamlCreate a configuration from a list of host addresses and pipe it to k0sctl apply:
k0sctl init 10.0.0.1 10.0.0.2 [email protected]:8022 | k0sctl apply --config -Takes a backup of the cluster control plane state into the current working directory.
The files are currently named with a running (unix epoch) timestamp, e.g. k0s_backup_1623220591.tar.gz.
Restoring a backup can be done as part of the k0sctl apply command using --restore-from k0s_backup_1623220591.tar.gz flag.
Restoring the cluster state is a full restoration of the cluster control plane state, including:
- Etcd datastore content
- Certificates
- Keys
In general restore is intended to be used as a disaster recovery mechanism and thus it expects that no k0s components actually exist on the controllers.
Known limitations in the current restore process:
- The control plane address (
externalAddress) needs to remain the same between backup and restore. This is caused by the fact that all worker node components connect to this address and cannot currently be re-configured.
Uninstall k0s from the hosts listed in the configuration.
Connects to the cluster and outputs a kubeconfig file that can be used with kubectl or kubeadm to manage the kubernetes cluster.
Example:
$ k0sctl kubeconfig --config path/to/k0sctl.yaml > k0s.config
$ kubectl get node --kubeconfig k0s.config
NAME STATUS ROLES AGE VERSION
worker0 NotReady <none> 10s v1.20.2-k0s1The configuration file is in YAML format and loosely resembles the syntax used in Kubernetes. YAML anchors and aliases can be used.
To generate a simple skeleton configuration file, you can use the k0sctl init subcommand.
Configuration example:
apiVersion: k0sctl.k0sproject.io/v1beta1
kind: Cluster
metadata:
name: my-k0s-cluster
spec:
hosts:
- role: controller
installFlags:
- --debug
ssh:
address: 10.0.0.1
user: root
port: 22
keyPath: ~/.ssh/id_rsa
- role: worker
installFlags:
- --debug
ssh:
address: 10.0.0.2
k0s:
version: 0.10.0
config:
apiVersion: k0s.k0sproject.io/v1beta1
kind: Cluster
metadata:
name: my-k0s-cluster
images:
calico:
cni:
image: calico/cni
version: v3.16.2The configuration file syntax version. Currently the only supported version is k0sctl.k0sproject.io/v1beta1.
In the future, some of the configuration APIs can support multiple types of objects. For now, the only supported kind is Cluster.
The main object definition, see below
Information that can be used to uniquely identify the object.
Example:
metadata:
name: k0s-cluster-nameA list of cluster hosts. Host requirements:
- Currently only linux targets are supported
- The user must either be root or have passwordless
sudoaccess. - The host must fulfill the k0s system requirements
See host object documentation below.
Settings related to the k0s cluster.
See k0s object documentation below.
One of controller, worker or to set up a controller that can also run workloads, use controller+worker.
When true, the k0s binaries for target host will be downloaded and cached on the local host and uploaded to the target.
When false, the k0s binary downloading is performed on the target host itself
A path to a file on the local host that contains a k0s binary to be uploaded to the host. Can be used to test drive a custom development build of k0s.
Override host's hostname. When not set, the hostname reported by the operating system is used.
Extra flags passed to the k0s install command on the target host. See k0s install --help for a list of options.
List of key-value pairs to set to the target host's environment variables.
Example:
environment:
HTTP_PROXY: 10.0.0.1:443List of files to be uploaded to the host.
Example:
- name: image-bundle
src: airgap-images.tgz
dstDir: /var/lib/k0s/images/
perm: 0700name: name of the file "bundle", used only for logging purposes (optional)src: Glob pattern to match files to be uploadeddstDir: Destination directory for the file(s).k0sctlwill create full directory structure if it does not already exist on the host.perm: File permission mode for uploaded file(s) and created directories
Run a set of commands on the remote host during k0sctl operations.
Example:
hooks:
apply:
before:
- date > k0sctl-apply.log
after:
- echo "apply success" > k0sctl-apply.logThe currently available "hook points" are:
apply: Runs duringk0sctl applybefore: Runs after configuration and host validation, right before configuring k0s on the hostafter: Runs before disconnecting from the hosts after a successful apply operation
backup: Runs duringk0s backupbefore: Runs before k0sctl runs thek0s backupcommandafter: Runs before disconnecting from the hosts after successfully taking a backup
reset: Runs duringk0sctl resetbefore: Runs after gathering information about the cluster, right before starting to remove the k0s installation.after: Runs before disconnecting from the hosts after a successful reset operation
Override OS distribution auto-detection. By default k0sctl detects the OS by reading /etc/os-release or /usr/lib/os-release files. In case your system is based on e.g. Debian but the OS release info has something else configured you can override k0sctl to use Debian based functionality for the node with:
- role: worker
os: debian
ssh:
address: 10.0.0.2SSH connection options.
Example:
spec:
hosts:
- role: controller
ssh:
address: 10.0.0.2
user: ubuntu
keyPath: ~/.ssh/id_rsaIt's also possible to tunnel connections through a bastion host. The bastion configuration has all the same fields as any SSH connection:
spec:
hosts:
- role: controller
ssh:
address: 10.0.0.2
user: ubuntu
keyPath: ~/.ssh/id_rsa
bastion:
address: 10.0.0.1
user: root
keyPath: ~/.ssh/id_rsa2SSH agent and auth forwarding are also supported, a host without a keyfile:
spec:
hosts:
- role: controller
ssh:
address: 10.0.0.2
user: ubuntu$ ssh-add ~/.ssh/aws.pem
$ ssh -A user@jumphost
user@jumphost ~ $ k0sctl apply
IP address of the host
Username to log in as.
TCP port of the SSH service on the host.
Path to a SSH private key file.
Localhost connection options. Can be used to use the local host running k0sctl as a node in the cluster.
This must be set true to enable the localhost connection.
The version of k0s to deploy. When left out, k0sctl will default to using the latest released version of k0s or the version already running on the cluster.
Embedded k0s cluster configuration. See k0s configuration documentation for details.
When left out, the output of k0s default-config will be used.