Use T4 with k0s and kine

In this tutorial you will run a single-node k0s cluster with T4 as its datastore. k0s starts kine, kine embeds T4, and the Kubernetes API server continues to use kine’s local etcd-compatible endpoint.

This local-only setup is intended for learning and development. At the end, you can optionally add S3 durability.

Prerequisites

• k0s v1.36.1+k0s.0 or newer installed

1. Install k0s

Install k0s v1.36.1+k0s.0 or newer as /usr/local/bin/k0s. Follow the k0s installation guide if it is not installed yet.

k0s version

2. Configure kine to use T4

Create /etc/k0s/k0s.yaml:

apiVersion: k0s.k0sproject.io/v1beta1
kind: ClusterConfig
metadata:
  name: k0s
spec:
  storage:
    type: kine
    kine:
      dataSource: t4:///var/lib/k0s/t4

The t4:// scheme selects T4’s kine driver. The path after it is T4’s local data directory, where Pebble data and WAL segments are stored.

3. Install and start the controller

Install k0s as a single-node controller and worker, but do not start it yet:

sudo k0s install controller --single --config /etc/k0s/k0s.yaml

k0s runs kine as the kube-apiserver system user. Create a writable data directory for T4, then start k0s:

sudo install -d -o kube-apiserver -g root -m 0700 /var/lib/k0s/t4
sudo k0s start

Wait for the node to become ready:

sudo k0s status
sudo k0s kubectl get nodes

If startup fails, inspect the controller logs:

sudo journalctl -u k0scontroller --no-pager -n 100

4. Verify persistence

Create a Kubernetes object, restart k0s, and read the object back:

sudo k0s kubectl create namespace t4-tutorial
sudo k0s kubectl create configmap hello \
  --namespace t4-tutorial \
  --from-literal=message='Hello from T4'

sudo k0s stop
sudo k0s start

until sudo k0s kubectl get --raw=/readyz >/dev/null 2>&1; do
  sleep 2
done

sudo k0s kubectl get configmap hello \
  --namespace t4-tutorial \
  -o jsonpath='{.data.message}{"\n"}'

The final command should print:

Hello from T4

Your cluster state now lives in /var/lib/k0s/t4 instead of k0s-managed etcd.

Optional: add S3 durability

T4 can upload checkpoints and WAL segments to S3 or an S3-compatible object store. Add kine arguments to the same configuration:

spec:
  storage:
    type: kine
    kine:
      dataSource: t4:///var/lib/k0s/t4
      extraArgs:
        s3-bucket: my-k0s-state
        s3-folder: clusters/dev
        s3-region: us-east-1

Pass credentials into the k0s service when you install or reinstall it:

sudo k0s install controller --single \
  --config /etc/k0s/k0s.yaml \
  --force \
  -e AWS_ACCESS_KEY_ID="$AWS_ACCESS_KEY_ID" \
  -e AWS_SECRET_ACCESS_KEY="$AWS_SECRET_ACCESS_KEY"

sudo k0s stop
sudo k0s start

Use a unique s3-folder for every cluster that shares the bucket. For MinIO or another S3-compatible service, also set s3-endpoint under extraArgs.

This tutorial remains a single-controller setup. A multi-controller deployment also needs T4 peer addresses, shared S3 configuration, and peer TLS.