Installing K3s and Knative on ARM

January 16, 2022

Installation

This past week I wanted to try out Knative, a “Kubernetes-based platform to deploy and manage modern serverless workloads”. In essence, what I’m looking forward is a higher level abstration for running applications/microservices without worrying with Kubernetes inherent complexities.

I’ve been using K3s, a light-weight Kubernetes distribution built by the team behind Rancher for all of my deployments for a while. It’s easy and fast to install, highly scalable and has a minimal footprint, perfect for on-premises and self-managed deployments.

K3s comes with it’s own network layer, provided by Traefik. However, since Knative needs to takeover the networking layer in order to successfully run applications as Knative Services, Traefik needs to be disabled. It’s possible to install K3s without Traefik by running the following command:

curl -sfL https://get.k3s.io | sh -s - --disable traefik

After this, to install Knative, just follow the Knative installation guide.

Finally, to try out and “smoke test” the installation, I’ve created the following Knative Service definition (which deploys Nginx as a Knative Service)…

# hello.yaml
---
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: hello
spec:
  template:
    metadata:
      # This is the name of our new "Revision," it must follow the convention {service-name}-{revision-name}
      name: hello-nginx
    spec:
      containers:
        - image: nginx
          ports:
            - containerPort: 80

…and applied it with the the following command:

sudo kubectl apply -f hello.world

You can then get the application URL by listing the Knative Services (note that you’ll need the Knative CLI, kn, installed):

kn service list

Automation

I’ve created a set of Ansible playbooks to deploy K3s, Knative (and a “smoke test” application) on ARM and made them available in this GitHub repo. Hope it makes your life easier, when testing Knative.