Strimzi Quick Start guide (0.18.0)

1. Overview of Strimzi

Strimzi simplifies the process of running Apache Kafka in a Kubernetes cluster.

Before trying Strimzi, it is useful to understand its capabilities and how you might wish to use it. This chapter introduces some of the key concepts behind Kafka, and also provides a brief overview of the Strimzi Operators.

Operators are a method of packaging, deploying, and managing a Kubernetes application. Strimzi Operators extend Kubernetes functionality, automating common and complex tasks related to a Kafka deployment. By implementing knowledge of Kafka operations in code, Kafka administration tasks are simplified and require less manual intervention.

1.1. Kafka capabilities

The underlying data stream-processing capabilities and component architecture of Kafka can deliver:

Microservices and other applications to share data with extremely high throughput and low latency
Message ordering guarantees
Message rewind/replay from data storage to reconstruct an application state
Message compaction to remove old records when using a key-value log
Horizontal scalability in a cluster configuration
Replication of data to control fault tolerance
Retention of high volumes of data for immediate access

1.2. Kafka use cases

Kafka’s capabilities make it suitable for:

Event-driven architectures
Event sourcing to capture changes to the state of an application as a log of events
Message brokering
Website activity tracking
Operational monitoring through metrics
Log collection and aggregation
Commit logs for distributed systems
Stream processing so that applications can respond to data in real time

1.3. How Strimzi supports Kafka

Strimzi provides container images and Operators for running Kafka on Kubernetes. Strimzi Operators are fundamental to the running of Strimzi. The Operators provided with Strimzi are purpose-built with specialist operational knowledge to effectively manage Kafka.

Operators simplify the process of:

Deploying and running Kafka clusters
Deploying and running Kafka components
Configuring access to Kafka
Securing access to Kafka
Upgrading Kafka
Managing brokers
Creating and managing topics
Creating and managing users

1.4. Operators

Strimzi provides Operators for managing a Kafka cluster running within a Kubernetes cluster.

Cluster Operator: Deploys and manages Apache Kafka clusters, Kafka Connect, Kafka MirrorMaker, Kafka Bridge, Kafka Exporter, and the Entity Operator
Entity Operator: Comprises the Topic Operator and User Operator
Topic Operator: Manages Kafka topics
User Operator: Manages Kafka users

The Cluster Operator can deploy the Topic Operator and User Operator as part of an Entity Operator configuration at the same time as a Kafka cluster.

Operators within the Strimzi architecture

Operators

1.5. Document Conventions

Replaceables

In this document, replaceable text is styled in monospace and italics.

For example, in the following code, you will want to replace my-namespace with the name of your namespace:

sed -i 's/namespace: .*/namespace: my-namespace/' install/cluster-operator/*RoleBinding*.yaml

2. Evaluate Strimzi

The procedures in this chapter provide a quick way to evaluate the functionality of Strimzi.

Follow the steps in the order provided to install Strimzi, and start sending and receiving messages from a topic:

Ensure you have the required prerequisites
Install and start Minikube
Install Strimzi
Create a Kafka cluster
Access the Kafka cluster to send and receive messages

2.1. Prerequisites

Install and start Minikube.
You need to be able to access Strimzi GitHub.

2.2. Downloading Strimzi

The resources and artifacts required to install Strimzi, along with examples for configuration, are provided in a ZIP file.

Procedure

Download the strimzi-x.y.z.zip file from GitHub.
Unzip the file to any destination.
- Windows or Mac: Extract the contents of the ZIP archive by double-clicking on the ZIP file.
- Linux: Open a terminal window in the target machine and navigate to where the ZIP file was downloaded.
Extract the ZIP file with this command:
```
unzip strimzi-xyz.zip
```

2.3. Installing Strimzi

Using the download files, install Strimzi with the Custom Resource Definitions (CRDs) and RBAC configuration required for deployment.

In this task you create namespaces in the cluster for your deployment. Use namespaces to separate functions.

Prerequisites

Installation requires a Kubernetes account with cluster admin credentials.

Procedure

Log in to the Kubernetes cluster using an account that has cluster admin privileges.
Create a new kafka namespace for the Strimzi Kafka Cluster Operator.
```
kubectl create ns kafka
```
Modify the installation files to reference the kafka namespace where you will install the Strimzi Kafka Cluster Operator.

Note
By default, the files work in the myproject namespace.
- On Linux, use:
  sed -i 's/namespace: .*/namespace: kafka/' install/cluster-operator/*RoleBinding*.yaml
- On Mac, use:
  sed -i '' 's/namespace: .*/namespace: kafka/' install/cluster-operator/*RoleBinding*.yaml
Create a new my-kafka-project namespace where you will deploy your Kafka cluster.
```
kubectl create ns my-kafka-project
```
Edit the install/cluster-operator/050-Deployment-strimzi-cluster-operator.yaml file and set the STRIMZI_NAMESPACE environment variable to the namespace my-kafka-project.
```
# ...
env:
- name: STRIMZI_NAMESPACE
  value: my-kafka-project
# ...
```
Deploy the CRDs and role-based access control (RBAC) resources to manage the CRDs.
```
kubectl apply -f install/cluster-operator/ -n kafka
```

Give permission to the Cluster Operator to watch the my-kafka-project namespace.

kubectl apply -f install/cluster-operator/020-RoleBinding-strimzi-cluster-operator.yaml -n my-kafka-project

kubectl apply -f install/cluster-operator/032-RoleBinding-strimzi-cluster-operator-topic-operator-delegation.yaml -n my-kafka-project

kubectl apply -f install/cluster-operator/031-RoleBinding-strimzi-cluster-operator-entity-operator-delegation.yaml -n my-kafka-project

The commands create role bindings that grant permission for the Cluster Operator to access the Kafka cluster.

2.4. Creating a cluster

With Strimzi installed, you create a Kafka cluster, then a topic within the cluster.

When you create a cluster, the Cluster Operator you deployed when installing Strimzi watches for new Kafka resources.

Prerequisites

For the Kafka cluster, ensure a Cluster Operator is deployed.
For the topic, you must have a running Kafka cluster.

Procedure

Create a new my-cluster Kafka cluster with one ZooKeeper and one Kafka broker.

Use persistent-claim storage

Expose the Kafka cluster outside of the Kubernetes cluster using an external listener configured to use a nodeport.

cat << EOF | kubectl create -n my-kafka-project -f -
apiVersion: kafka.strimzi.io/v1beta1
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    replicas: 1
    listeners:
      plain: {}
      tls: {}
      external:
        type: nodeport
        tls: false
    storage:
      type: jbod
      volumes:
      - id: 0
        type: persistent-claim
        size: 100Gi
        deleteClaim: false
    config:
      offsets.topic.replication.factor: 1
      transaction.state.log.replication.factor: 1
      transaction.state.log.min.isr: 1
  zookeeper:
    replicas: 1
    storage:
      type: persistent-claim
      size: 100Gi
      deleteClaim: false
  entityOperator:
    topicOperator: {}
    userOperator: {}
EOF

Wait for the cluster to be deployed:

kubectl wait kafka/my-cluster --for=condition=Ready --timeout=300s -n my-kafka-project

When your cluster is ready, create a topic to publish and subscribe from your external client.

Create the following my-topic custom resource definition with 3 partitions and replication factor 1 in the my-cluster Kafka cluster:
```
cat << EOF | kubectl create -n my-kafka-project -f -
apiVersion: kafka.strimzi.io/v1beta1
kind: KafkaTopic
metadata:
  name: my-topic
  labels:
    strimzi.io/cluster: "my-cluster"
spec:
  partitions: 3
  replicas: 1
EOF
```

2.5. Sending and receiving messages from a topic

You can test your Strimzi installation by sending and receiving messages to my-topic from outside the cluster.

Use a terminal to run a Kafka producer and consumer on a local machine.

Prerequisites

Ensure Strimzi is installed on the Kubernetes cluster.
ZooKeeper and Kafka must be running to be able to send and receive messages.

Procedure

Download the latest Kafka binaries and install Kafka on your local machine.

Apache Kafka download

Find the port of the bootstrap service:

kubectl get service my-cluster-kafka-external-bootstrap -n my-kafka-project -o=jsonpath='{.spec.ports[0].nodePort}{"\n"}'

Find the IP address of the Minikube node:

kubectl get nodes --output=jsonpath='{range .items[*]}{.status.addresses[?(@.type=="InternalIP")].address}{"\n"}{end}'

Open a terminal, and start the Kafka console producer with the topic my-topic:

bin/kafka-console-producer.sh --broker-list <node-address>:_<node-port>_ --topic my-topic

Type your message into the console where the producer is running.

Open a new terminal tab or window, and start the consumer to receive the messages:

bin/kafka-console-consumer.sh --bootstrap-server <node-address>:_<node-port>_ --topic my-topic --from-beginning

Verify that you see the incoming messages in the consumer console.
Press Crtl+C to exit the Kafka console producer and consumer.