> ## Documentation Index
> Fetch the complete documentation index at: https://docs.streamnative.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Manually scale a Pulsar cluster using the Pulsar Operators

When the traffic handled by your Pulsar cluster increases or decreases, you can scale out or scale in the cluster accordingly. Depending on the specific use case, you may choose to increase or decrease the number of nodes for different components, including Pulsar brokers, Pulsar proxies, bookies, and ZooKeeper.

When resizing the Pulsar cluster on Kubernetes created by the Pulsar Operators, you need to perform the scaling action on [Custom Resources (CRs)](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/) instead of the individual workloads deployed through them. For example, when deploying Pulsar broker workloads, the Pulsar Operators create a broker [StatefulSet](https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/) with 2 Pod replicas by default. To scale the StatefulSet, you should adjust the broker CR instead of manually changing the StatefulSet.

This document describes how to manually scale Pulsar components on Kubernetes.

## Prerequisites

You have deployed a Pulsar cluster using the Pulsar Operators.

## Scale Pulsar brokers

If you use the default broker CR, you should have 2 broker replicas running in the `pulsar` namespace. This example scales the number of Pods from 2 to 5.

1. View the existing broker CR.

   ```bash theme={null}
   kubectl get pb -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME     REPLICAS   READY REPLICAS   DESIRED IMAGE                            ENDPOINT   AGE
   brokers  2          2                streamnative/sn-platform-slim:2.10.3.4              10m
   ```

2. Run the following command to scale brokers.

   ```bash theme={null}
   kubectl scale pb brokers --replicas=5 -n pulsar
   ```

3. View the newly-created Pods.

   ```bash theme={null}
   kubectl get pods -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME                         READY   STATUS    RESTARTS   AGE
   bookies-bk-0                 1/1     Running   0          10m
   bookies-bk-1                 1/1     Running   0          10m
   bookies-bk-2                 1/1     Running   0          10m
   bookies-bk-auto-recovery-0   1/1     Running   0          10m
   brokers-broker-0             1/1     Running   0          10m
   brokers-broker-1             1/1     Running   0          10m
   brokers-broker-2             1/1     Running   0          10s
   brokers-broker-3             1/1     Running   0          10s
   brokers-broker-4             1/1     Running   0          10s
   proxys-proxy-0               1/1     Running   0          10m
   proxys-proxy-1               1/1     Running   0          10m
   zookeepers-zk-0              1/1     Running   0          10m
   zookeepers-zk-1              1/1     Running   0          10m
   zookeepers-zk-2              1/1     Running   0          10m
   ```

4. Alternatively, you can create a broker YAML file with the following configuration and use the `kubectl apply -f` command to apply the file.

   ```yaml theme={null}
   apiVersion: pulsar.streamnative.io/v1alpha1
   kind: PulsarBroker
   metadata:
   name: brokers
   namespace: pulsar
   spec:
   image: streamnative/sn-platform-slim:2.10.3.4
   pod:
     resources:
       requests:
       cpu: 200m
       memory: 512Mi
     securityContext:
       runAsNonRoot: true
   replicas: 5 # Change the replica count
   zkServers: zookeepers-zk:2181
   ```

## Scale Pulsar proxies

If you use the default proxy CR, you should have 2 proxy replicas running in the `pulsar` namespace. This example scales the number of Pods from 2 to 5.

1. View the existing proxy CR.

   ```bash theme={null}
   kubectl get pp -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME     REPLICAS   READY REPLICAS   DESIRED IMAGE                            ENDPOINT   AGE
   proxys   2          2                streamnative/sn-platform-slim:2.10.3.4              10m
   ```

2. Run the following command to scale Pulsar proxies.

   ```bash theme={null}
   kubectl scale pp proxys --replicas=5 -n pulsar
   ```

3. View the newly created Pods.

   ```bash theme={null}
   kubectl get pods -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME                         READY   STATUS    RESTARTS   AGE
   bookies-bk-0                 1/1     Running   0          10m
   bookies-bk-1                 1/1     Running   0          10m
   bookies-bk-2                 1/1     Running   0          10m
   bookies-bk-auto-recovery-0   1/1     Running   0          10m
   brokers-broker-0             1/1     Running   0          10m
   brokers-broker-1             1/1     Running   0          10m
   proxys-proxy-0               1/1     Running   0          10m
   proxys-proxy-1               1/1     Running   0          10m
   proxys-proxy-2               1/1     Running   0          42s
   proxys-proxy-3               1/1     Running   0          42s
   proxys-proxy-4               1/1     Running   0          42s
   zookeepers-zk-0              1/1     Running   0          10m
   zookeepers-zk-1              1/1     Running   0          10m
   zookeepers-zk-2              1/1     Running   0          10m
   ```

4. Alternatively, you can create a proxy YAML file with the following configuration and use the `kubectl apply -f` command to apply the file.

   ```yaml theme={null}
   apiVersion: pulsar.streamnative.io/v1alpha1
   kind: PulsarProxy
   metadata:
   name: proxys
   namespace: pulsar
   spec:
   image: 'streamnative/sn-platform-slim:2.10.3.4'
   pod:
     resources:
       requests:
       cpu: 200m
       memory: 512Mi
     securityContext:
       runAsNonRoot: true
   brokerAddress: brokers-broker
   replicas: 5 # Change the replica count
   config:
     tls:
       enabled: false
   dnsNames: []
   issuerRef:
     name: ''
   ```

## Scale bookies

If you use the default BookKeeper CR, you should have 3 bookie replicas running in the `pulsar` namespace. This example scales the number of bookie Pods from 3 to 7.

1. View the existing BookKeeper CR.

   ```bash theme={null}
   kubectl get bk -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME      REPLICAS   READY REPLICAS   ZKSERVERS            DESIRED IMAGE                            AGE
   bookies   3          3                zookeepers-zk:2181   streamnative/sn-platform-slim:2.10.3.4   13m
   ```

2. Run the following command to scale bookies.

   ```bash theme={null}
   kubectl scale bk bookies --replicas=7 -n pulsar
   ```

3. View the newly-created Pods.

   ```bash theme={null}
   kubectl get pods -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME                         READY   STATUS    RESTARTS   AGE
   bookies-bk-0                 1/1     Running   0          10m
   bookies-bk-1                 1/1     Running   0          10m
   bookies-bk-2                 1/1     Running   0          10m
   bookies-bk-3                 1/1     Running   0          40s
   bookies-bk-4                 1/1     Running   0          40s
   bookies-bk-5                 1/1     Running   0          40s
   bookies-bk-6                 1/1     Running   0          40s
   bookies-bk-auto-recovery-0   1/1     Running   0          10m
   brokers-broker-0             1/1     Running   0          10m
   brokers-broker-1             1/1     Running   0          10m
   proxys-proxy-0               1/1     Running   0          10m
   proxys-proxy-1               1/1     Running   0          10m
   zookeepers-zk-0              1/1     Running   0          10m
   zookeepers-zk-1              1/1     Running   0          10m
   zookeepers-zk-2              1/1     Running   0          10m
   ```

4. Alternatively, you can create a BookKeeper YAML file with the following configuration and use the `kubectl apply -f` command to apply the file.

   ```yaml theme={null}
   apiVersion: bookkeeper.streamnative.io/v1alpha1
   kind: BookKeeperCluster
   metadata:
   name: bookies
   namespace: pulsar
   spec:
   image: streamnative/sn-platform-slim:2.10.3.4
   replicas: 7 # Change the replica count
   pod:
     resources:
       requests:
       cpu: 200m
       memory: 512Mi
     securityContext:
       runAsNonRoot: true
   storage:
     journal:
       numDirsPerVolume: 1
       numVolumes: 1
       volumeClaimTemplate:
       accessModes:
         - ReadWriteOnce
       resources:
         requests:
           storage: 8Gi
     ledger:
       numDirsPerVolume: 1
       numVolumes: 1
       volumeClaimTemplate:
       accessModes:
         - ReadWriteOnce
       resources:
         requests:
           storage: 16Gi
     reclaimPolicy: Delete
   zkServers: zookeepers-zk:2181
   ```

## Scale ZooKeeper

If you use the default ZooKeeper CR, you should have 3 ZooKeeper replicas running in the `pulsar` namespace. This example scales the number of Pods from 3 to 5.

1. View the existing ZooKeeper CR.

   ```bash theme={null}
   kubectl get zk -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME         REPLICAS   READY REPLICAS   DESIRED IMAGE                            AGE
   zookeepers   3          3                streamnative/sn-platform-slim:2.10.3.4   16m
   ```

2. Run the following command to scale ZooKeeper.

   ```bash theme={null}
   kubectl scale zk zookeepers --replicas=5 -n pulsar
   ```

3. View the newly-created Pods.

   ```bash theme={null}
   kubectl get pods -n pulsar
   ```

   You should see the following output:

   ```bash theme={null}
   NAME                         READY   STATUS    RESTARTS   AGE
   bookies-bk-0                 1/1     Running   0          10m
   bookies-bk-1                 1/1     Running   0          10m
   bookies-bk-2                 1/1     Running   0          10m
   bookies-bk-auto-recovery-0   1/1     Running   0          10m
   brokers-broker-0             1/1     Running   0          10m
   brokers-broker-1             1/1     Running   0          10m
   proxys-proxy-0               1/1     Running   0          10m
   proxys-proxy-1               1/1     Running   0          10m
   zookeepers-zk-0              1/1     Running   0          54s
   zookeepers-zk-1              1/1     Running   0          31s
   zookeepers-zk-2              1/1     Running   0          71s
   zookeepers-zk-3              1/1     Running   0          98s
   zookeepers-zk-4              1/1     Running   0          98s
   ```

4. Alternatively, you can create a ZooKeeper YAML file with the following configuration and use the `kubectl apply -f` command to apply the file.

   ```yaml theme={null}
   apiVersion: zookeeper.streamnative.io/v1alpha1
   kind: ZooKeeperCluster
   metadata:
   name: zookeepers
   namespace: pulsar
   spec:
   image: streamnative/sn-platform-slim:2.10.3.4
   pod:
     resources:
       requests:
       cpu: 50m
       memory: 256Mi
     securityContext:
       runAsNonRoot: true
   persistence:
     data:
       accessModes:
         - ReadWriteOnce
       resources:
       requests:
         storage: 8Gi
     dataLog:
       accessModes:
         - ReadWriteOnce
       resources:
       requests:
         storage: 2Gi
     reclaimPolicy: Delete
   replicas: 5 # Change the replica count
   ```