Getting Started

Deploy kaas onto a Kubernetes cluster with the Helm chart, or run a single broker locally in dev mode with in-memory storage.

Deploy on Kubernetes

Prerequisites: Kubernetes ≥ 1.27, Helm ≥ 3.8, and — for more than one broker — a ReadWriteMany StorageClass with NFSv4-class semantics (what "NFSv4-class" means precisely, and which providers qualify, is Storage substrate requirements). A single-broker cluster can run on a plain ReadWriteOnce local-path class.

helm install my-kaas oci://ghcr.io/kaas-rs/charts/kaas \
  --version 0.3.1-preview \
  --namespace kafka --create-namespace \
  --set storage.className=<your-rwx-class> \
  --set broker.replicaCount=3

That deploys a broker StatefulSet, the operator, and the shared volume(s). The chart's defaults give you an anonymous in-cluster listener on 9092; TLS, SCRAM, OAuth (SASL/OAUTHBEARER against an OIDC issuer, disabled by default on 9096), and external access are chart values — see Helm chart & listener configuration.

Create a topic

Topics are Kubernetes resources:

apiVersion: kaas.rs/v1alpha1
kind: KafkaTopic
metadata:
  name: test
  namespace: kafka
spec:
  partitions: 3

If you'd rather stay in Kafka's own tooling, that works too — kafka-topics.sh --create (or any Admin-API client) creates the same KafkaTopic resource for you, so both routes end in one place and kubectl get kafkatopics always shows the truth.

Retention is enforced: a topic without an explicit retention config ages out after 7 days (Kafka's own default) — set retentionMs: -1 to keep data forever.

Talk to it

Any Kafka client, unchanged:

kubectl -n kafka port-forward svc/my-kaas-kaas 9092:9092 &
echo "hello" | kcat -b localhost:9092 -t test -P
kcat -b localhost:9092 -t test -C -o beginning -e

From here, the system overview explains what you just deployed — which pod does what, and where your bytes actually went.

Run locally in dev mode

The broker binary detects dev mode by the absence of the MY_POD_NAME env var (which the StatefulSet always sets): storage flips to in-memory, no Kubernetes API is needed, and the broker treats itself as leader of every partition.

cargo run -p kaas

Point any Kafka client at localhost:9092. Nothing is persisted and nothing is cluster-aware — it's a protocol-correct scratchpad for client development and codec work, not a single-node production mode.

Build the book and the code

cargo build --workspace          # toolchain is pinned; rustup auto-installs
cargo test  --workspace --all-features
cargo xtask docs --serve         # this book, live-reloading