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Version: 22.3

Get Started with Redpanda in Kubernetes

In this tutorial, you learn how to deploy Redpanda on Kubernetes using the Helm chart. You'll deploy a Redpanda cluster and an instance of Redpanda Console. You'll explore the Kubernetes components that the Helm chart deploys. Then, you'll use rpk both as an internal client and an external client to interact with your Redpanda cluster from the command line.

Looking for the Redpanda Operator?

If you're an existing user of the Redpanda Operator, see the Redpanda Operator documentation.

warning

Redpanda does not recommend the Redpanda Operator for new deployments. The Redpanda Operator was built for Redpanda Cloud and has unique features and workflows for that specific use case. If you're not already using the Redpanda Operator, continue with this tutorial to get started with the Redpanda Helm chart.

Prerequisites​

Before you begin, make sure that you have the correct software for your chosen Kubernetes platform:

  • kubectl. Minimum required Kubernetes version: 1.21

    kubectl version

  • Helm. Minimum required Helm version: 3.6.0

    helm version

Create a Kubernetes cluster​

Redpanda brokers are designed to have access to all resources, such as CPU and memory, on their host machine. As a result, in a Kubernetes environment, it's recommended to run each Redpanda broker on its own Kubernetes node.

Redpanda recommends at least three Redpanda brokers to use as seed servers. Seed servers are used to bootstrap the gossip process for new brokers joining a cluster. When a new broker joins, it connects to the seed servers to find out the topology of the Redpanda cluster. A larger number of seed servers makes consensus more robust and minimizes the chance of unwanted clusters forming when brokers are restarted without any data.

In this step, you create the Kubernetes nodes to host the Pods for the Redpanda brokers.

  1. Define a cluster in the kind.yaml configuration file:

    cat <<EOF >kind.yaml
    ---
    apiVersion: kind.x-k8s.io/v1alpha4
    kind: Cluster
    nodes:
      - role: control-plane
      - role: worker
      - role: worker
      - role: worker
    EOF

  2. Create the Kubernetes cluster from the configuration file:

    kind create cluster --config kind.yaml

Deploy Redpanda​

  1. Install Redpanda using Helm:

    helm repo add redpanda https://charts.redpanda.com/
    helm repo update
    helm install redpanda redpanda/redpanda \
      --namespace redpanda \
      --create-namespace

    The installation displays some tips for getting started.

  2. Wait for the Redpanda cluster to be ready:

    kubectl -n redpanda rollout status statefulset redpanda --watch

    When the Redpanda cluster is ready, the output should look similar to the following:

    statefulset rolling update complete 3 pods at revision redpanda-8654f645b4...

    If your cluster remains in a pending state, see Troubleshooting

  3. Verify that each Redpanda broker is scheduled on only one Kubernetes node:

    kubectl get pod -n redpanda \
    -o=custom-columns=NODE:.spec.nodeName,NAME:.metadata.name \
    | grep 'redpanda-[0-9]'
    Example output
    example-worker3   redpanda-0
    example-worker2   redpanda-1
    example-worker    redpanda-2

Explore the Kubernetes components​

Your deployment includes the following components by default:

StatefulSet​

Redpanda is a stateful application. Each Redpanda broker needs to store its own state (topic partitions) in its own storage volume. As a result, the Helm chart deploys a StatefulSet to manage the Pods in which the Redpanda brokers are running.

kubectl get statefulset -n redpanda
Example output
NAME       READY   AGE
redpanda   3/3     3m11s

StatefulSets ensure that the state associated with a particular Pod replica is always the same, no matter how often the Pod is recreated. Each Pod is also given a unique ordinal number in its name such as redpanda-0. A Pod with a particular ordinal number is always associated with a PersistentVolumeClaim with the same number. When a Pod in the StatefulSet is deleted and recreated, it is given the same ordinal number and so it mounts the same storage volume as the deleted Pod that it replaced.

kubectl get pod -n redpanda
Example output
NAME                          READY   STATUS      RESTARTS        AGE
redpanda-0                    1/1     Running     0               6m9s
redpanda-1                    1/1     Running     0               6m9s
redpanda-2                    1/1     Running     0               6m9s
redpanda-post-install-9t5qr   0/1     Completed   0               6m9s
important

The post-install Job updates the Redpanda runtime configuration.

PersistentVolumeClaim​

Redpanda brokers must be able to store their data on disk. By default, the Helm chart uses the default StorageClass in the Kubernetes cluster to create a PersistentVolumeClaim for each Pod. The default StorageClass in your Kubernetes cluster depends on the Kubernetes platform that you are using.

kubectl get persistentvolumeclaims -n redpanda
Example output
NAME                 STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-redpanda-0   Bound    pvc-3311ade3-de84-4027-80c6-3d8347302962   20Gi       RWO            standard       75s
datadir-redpanda-1   Bound    pvc-4ea8bc03-89a6-41e4-b985-99f074995f08   20Gi       RWO            standard       75s
datadir-redpanda-2   Bound    pvc-45c3555f-43bc-48c2-b209-c284c8091c45   20Gi       RWO            standard       75s

Service​

The clients writing to or reading from a given partition have to connect directly to the leader broker that hosts the partition. As a result, clients needs to be able to connect directly to each Pod. To allow internal and external clients to connect to each Pod that hosts a Redpanda broker, the Helm chart configures two Services:

kubectl get service -n redpanda
Example output
NAME                TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                                                       AGE
redpanda            ClusterIP   None            <none>        <none>                                                        5m37s
redpanda-external   NodePort    10.96.137.220   <none>        9644:31644/TCP,9094:31092/TCP,8083:30082/TCP,8080:30081/TCP   5m37s

Headless ClusterIP Service​

The headless Service associated with a StatefulSet gives the Pods their network identity in the form of a fully qualified domain name (FQDN). Both Redpanda brokers in the same Redpanda cluster and clients within the same Kubernetes cluster use this FQDN to communicate with each other.

When you created your first topic in the previous section, the address in the --brokers parameter used the internal FQDN to connect rpk to the Redpanda brokers:

redpanda-0.redpanda.redpanda.svc.cluster.local.

note

An important requirement of distributed applications such as Redpanda is peer discovery: The ability for each broker to find other brokers in the same cluster. When each Pod is rolled out, its seed_servers field is updated with the FQDN of each Pod in the cluster so that they can discover each other.

kubectl -n redpanda exec redpanda-0 -c redpanda -- cat etc/redpanda/redpanda.yaml
redpanda:
    data_directory: /var/lib/redpanda/data
    empty_seed_starts_cluster: false
    
    seed_servers:
        - host:
            address: redpanda-0.redpanda.redpanda.svc.cluster.local.
            port: 33145
        - host:
            address: redpanda-1.redpanda.redpanda.svc.cluster.local.
            port: 33145
        - host:
            address: redpanda-2.redpanda.redpanda.svc.cluster.local.
            port: 33145

NodePort Service​

External access is made available by a NodePort service that opens the following ports by default:

Node portPod portPurpose
300818080Schema registry
300828083HTTP proxy
310929094Kafka API
316449644Admin API

Deploy Redpanda Console​

Redpanda Console is a developer-friendly web UI for managing and debugging your Redpanda cluster and your applications.

Install Redpanda Console using Helm:

helm repo add redpanda 'https://charts.redpanda.com/'
helm repo update
helm install redpanda-console redpanda/console \
  --namespace redpanda \
  --create-namespace \
  --set console.config.kafka.brokers=redpanda-0.redpanda.redpanda.svc.cluster.local.:9093 \
  --set service.type=NodePort \
  --set service.targetPort=8080
  • --namespace redpanda: Deploy Redpanda Console in the same namespace as your Redpanda cluster so that it can access the brokers using their internal FQDNs.
  • --set console.config.kafka.brokers=redpanda-0.redpanda.redpanda.svc.cluster.local.:9093: The Redpanda broker to which Redpanda Console connects to get information from the Redpanda cluster.
  • --set service.type=NodePort: The Service that Redpanda Console should be exposed to. A NodePort Service allows you to access Redpand Console from outside Kubernetes.
  • --set service.targetPort=8080 The port on which the Redpanda Console container expects traffic.

Start streaming​

Each Redpanda broker comes with rpk, which is a CLI tool for connecting to and interacting with Redpanda brokers. You can use rpk inside one of the Redpanda broker's Docker containers to create a topic, produce messages to it, and consume messages from it.

  1. Create an alias to simplify the rpk commands:

    alias rpk="  kubectl -n redpanda exec -ti redpanda-0 -c redpanda -- rpk --brokers redpanda-0.redpanda.redpanda.svc.cluster.local.:9093,redpanda-1.redpanda.redpanda.svc.cluster.local.:9093,redpanda-2.redpanda.redpanda.svc.cluster.local.:9093"

  2. Create a topic called twitch_chat:

    rpk topic create twitch_chat
    Example output
    TOPIC       STATUS
    twitch_chat  OK

  3. Describe the topic:

    rpk topic describe twitch_chat
    Example output
    SUMMARY
    =======
    NAME        twitch_chat
    PARTITIONS  1
    REPLICAS    1

    CONFIGS
    =======
    KEY                     VALUE                          SOURCE
    cleanup.policy          delete                         DYNAMIC_TOPIC_CONFIG
    compression.type        producer                       DEFAULT_CONFIG
    message.timestamp.type  CreateTime                     DEFAULT_CONFIG
    partition_count         1                              DYNAMIC_TOPIC_CONFIG
    redpanda.datapolicy     function_name:  script_name:   DEFAULT_CONFIG
    redpanda.remote.read    false                          DEFAULT_CONFIG
    redpanda.remote.write   false                          DEFAULT_CONFIG
    replication_factor      1                              DYNAMIC_TOPIC_CONFIG
    retention.bytes         -1                             DEFAULT_CONFIG
    retention.ms            604800000                      DEFAULT_CONFIG
    segment.bytes           1073741824                     DEFAULT_CONFIG

  4. Produce a message to the topic:

    rpk topic produce twitch_chat

  5. Type a message, then press Enter:

    Pandas are fabulous!
    Example output
    Produced to partition 0 at offset 0 with timestamp 1663282629789.

  6. Press Ctrl+C to finish producing messages to the topic.

  7. Consume one message from the topic:

    rpk topic consume twitch_chat --num 1
    Example output

    Your message is displayed along with its metadata,:

    {
      "topic": "twitch_chat",
      "value": "Pandas are fabulous!",
      "timestamp": 1663282629789,
      "partition": 0,
      "offset": 0
    }

Explore your topic in Redpanda Console​

  1. Find the node port of the Redpanda Console's NodePort Service:

    kubectl get svc redpanda-console -n redpanda
    Example output

    Here, the node port is 30858.

    NAME               TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
    redpanda-console   NodePort   10.111.229.17   <none>        8080:30858/TCP   2d19h

  2. Find out on which worker node Redpanda Console is running:

    kubectl get pod -n redpanda -o=custom-columns=NODE:.spec.nodeName,NAME:.metadata.name | grep 'redpanda-console'
    Example output
    worker3   redpanda-console-7bcb56f5f7-56w2h

  3. Open Redpanda Console in a web browser:

    Replace <node-ip> with the IP address of the worker node that's running Redpanda Console. Replace <node-port with the node port you found in the previous step.

    http://<node-ip>:<node-port>/brokers

    All your Redpanda brokers are listed along with their IP addresses and IDs.

  4. Go to Topics > twitch_chat.

    The message that you produced to the topic is displayed along with some other details about the topic.

Configure external access to the Redpanda brokers​

Since external clients are not in the Kubernetes cluster where the Redpanda brokers are running, they cannot resolve the internal address of the headless ClusterIP Service. Instead, external clients must connect to the external addresses that the Redpanda brokers advertise. By default, each Redpanda broker advertises the redpanda-<ordinal-number>.local hostname, where .local is set in the redpanda.external.domain field of the values.yaml file. For example, redpanda-0.local. To connect an external client to the Redpanda cluster, you must ensure that these external addresses being advertised by Redpanda brokers are resolvable on your system.

The simplest option for development is to configure the Redpanda brokers to advertise the IP addresses of the Kubernetes nodes on which they are running, instead of the redpanda-<ordinal-number>.local hostname.

Only for development and testing

IP addresses can change. If the IP addresses of your Kubernetes nodes change, you must reconfigure the Redpanda brokers and all your external clients with the new IP addresses.

In production environments, it's best to customize the domain in the redpanda.external.domain field of the values.yaml file to point to something resolvable through DNS.

  1. Find the internal IP addresses of all Kubernetes nodes in the cluster:

    kubectl get nodes -o wide
    Example output
    NAME                 STATUS   ROLES           AGE     VERSION   INTERNAL-IP   EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
    kind-control-plane   Ready    control-plane   4m52s   v1.25.3   172.18.0.4    <none>        Ubuntu 22.04.1 LTS   5.15.0-47-generic   containerd://1.6.9
    kind-worker          Ready    <none>          4m28s   v1.25.3   172.18.0.2    <none>        Ubuntu 22.04.1 LTS   5.15.0-47-generic   containerd://1.6.9
    kind-worker2         Ready    <none>          4m28s   v1.25.3   172.18.0.3    <none>        Ubuntu 22.04.1 LTS   5.15.0-47-generic   containerd://1.6.9
    kind-worker3         Ready    <none>          4m29s   v1.25.3   172.18.0.5    <none>        Ubuntu 22.04.1 LTS   5.15.0-47-generic   containerd://1.6.9

    This example shows three Kubernetes nodes with the internal IP addresses 172.18.0.2, 172.18.0.3, and 172.18.0.5.

  2. Find out on which Kubernetes node each Pod is running:

    kubectl get pods -o wide -n redpanda
    Example output
    NAME                          READY   STATUS      RESTARTS   AGE     IP           NODE           NOMINATED NODE   READINESS GATES
    redpanda-0                    1/1     Running     0          2m39s   10.244.2.3   kind-worker2   <none>           <none>
    redpanda-1                    1/1     Running     0          2m39s   10.244.3.3   kind-worker    <none>           <none>
    redpanda-2                    1/1     Running     0          2m39s   10.244.1.4   kind-worker3   <none>           <none>

    This example shows that the redpanda-0 Pod is running on the minikube-m02 Kubernetes node.

  3. Use the node names to find the internal IP address of the Kubernetes node that runs each Pod. For these examples, the result is the following:

    Redpanda brokerInternal IP
    redpanda-0172.18.0.3
    redpanda-1172.18.0.2
    redpanda-2172.18.0.5
    note

    Make sure that the internal IP address of the Kubernetes node matches the correct Redpanda broker. The Kubernetes nodes are not always displayed in the same order as the Pods.

  4. Add entries to /etc/hosts file on your local machine for each Kubernetes node that's running a Redpanda broker. For example:

    172.18.0.3 redpanda-0.local # kind-worker2
    172.18.0.2 redpanda-1.local # kind-worker
    172.18.0.5 redpanda-2.local # kind-worker3

  5. Install rpk on your local machine, not on a Pod.

  6. Set the REDPANDA_BROKERS environment variable to the IP addresses of your Kubernetes nodes:

    export REDPANDA_BROKERS=172.18.0.3:31092,172.18.0.2:31092,172.18.0.5:31092
    note

    31092 is the Kafka API port that's exposed by the NodePort Service.

  7. Get the cluster info:

    rpk cluster info
    Example output
    BROKERS
    =======
    ID    HOST              PORT
    0*    redpanda-0.local  31092
    1     redpanda-1.local  31092
    2     redpanda-2.local  31092

Troubleshooting​

StatefulSet never rolls out​

If the StatefulSet Pods remain in a pending state, they are waiting for resources to become available:

  • Make sure that you have a default StorageClass available in your Kubernetes cluster and that the underlying volumes have at least 20Gi of storage capacity.

  • If you're running on EKS, make sure that you installed the Amazon EBS CSI driver. This driver is required to allow EKS to create PersistentVolumes.

dig not defined​

Error: parse error at (redpanda/templates/statefulset.yaml:203): function "dig" not defined

If you see this error, make sure that you are using the correct version of Helm. See the prerequisites.

Next steps​

Suggested reading​

Explore the Redpanda Helm chart's values.yaml file to learn what else you can configure.

Explore the Redpanda Console Helm chart's values.yaml file to learn what else you can configure.

Learn more about advertised listeners.

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