README

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Installation

clk k8s expects docker to be up and available.

Hint curl -sSL https://get.docker.com | sh followed by sudo usermod -a -G docker $(id --user --name)

Now, to install clk k8s, you have two options:

1. either, install clk-project and the extension with

   curl -sSL https://clk-project.org/install.sh | env CLK_EXTENSIONS=k8s bash
       

2. or, if you already have clk, you can simply install this extension with

   clk extension install k8s
       

Usage

clk k8s flow all

Now, you have a local cluster running and ready to be used. It is that simple.

tilt extensions

This extension also provides some tilt functions. To use them, load the extension, like this

config.define_string("clk-k8s-local-path")
cfg = config.parse()

v1alpha1.extension_repo(
    name='clk-k8s',
    url=cfg.get(
        'clk-k8s-local-path',
        'https://github.com/clk-project/clk_extension_k8s',
    ),
)
v1alpha1.extension(
    name='clk-helpers',
    repo_name='clk-k8s',
    repo_path='tilt-extensions/helpers',
)
load('ext://clk-helpers', 'update_helm_chart')

shared host directory

When creating a kind cluster with clk k8s create-cluster, a shared directory is automatically set up between the host and the kind node:

• Host path: $(clk extension where-is global/k8s)/tmp/kind/shared
• Kind node path: /shared

This allows exchanging files between the host and pods running in the cluster. To use it in a deployment, mount a hostPath volume pointing to /shared:

cat <<'EOF' | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: shared-volume
spec:
  replicas: 1
  selector:
    matchLabels:
      app: shared-volume
  template:
    metadata:
      labels:
        app: shared-volume
    spec:
      containers:
      - name: alpine
        image: alpine:latest
        command: ['sleep', 'infinity']
        volumeMounts:
        - name: shared
          mountPath: /shared
      volumes:
      - name: shared
        hostPath:
          path: /shared
          type: DirectoryOrCreate
EOF

Data written to $(clk extension where-is global/k8s)/tmp/kind/shared on the host is immediately visible at /shared inside the pod, and vice versa. The data persists across deployment recreations since it lives on the host filesystem.

Note: If you use PersistentVolumes with hostPath outside of /tmp/, avoid using persistentVolumeReclaimPolicy: Delete as Kubernetes’ built-in host_path deleter only supports paths under /tmp/. Use Retain instead.

observability

You can install the opentelementry operator with clk k8s otel install-operator so that you only have to provide open telemetry collector custom resources depending on your need.

clk does not install any observability database like prometheus, loki, tempo, pyroscope etc. This is because they consume a lot of ram and in our experience it is enough to distract us from our job.

Because of this, clk is unable to create a collector without prior knowledge on where to send the data.

The command clk k8s otel create-collector is part of the clk k8s flow but does noting by default, to make it actually create a collector, you have to add a parameter that will set the option --log-endpoint to whatever endpoint you have at hand.

So in short, something like, clk k8s otel create-collector --log-endpoint http://mydatabase:4318 will do the trick.

That collector is configured to discover pods with the annotation io.opentelemetry.discovery.logs/enabled: "true" and send their log to the otlphttp database you configured.