New to KubeDB? Please start here.
Horizontal Scale Kafka Topology Cluster
This guide will show you how to use KubeDB Ops-manager operator to scale the Kafka topology cluster.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectlcommand-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.Install
KubeDBProvisioner and Ops-manager operator in your cluster following the steps here.You should be familiar with the following
KubeDBconcepts:
To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.
$ kubectl create ns demo
namespace/demo created
Note: YAML files used in this tutorial are stored in docs/examples/kafka directory of kubedb/docs repository.
Apply Horizontal Scaling on Topology Cluster
Here, we are going to deploy a Kafka topology cluster using a supported version by KubeDB operator. Then we are going to apply horizontal scaling on it.
Prepare Kafka Topology cluster
Now, we are going to deploy a Kafka topology cluster with version 3.6.1.
Deploy Kafka topology cluster
In this section, we are going to deploy a Kafka topology cluster. Then, in the next section we will scale the cluster using KafkaOpsRequest CRD. Below is the YAML of the Kafka CR that we are going to create,
apiVersion: kubedb.com/v1
kind: Kafka
metadata:
name: kafka-prod
namespace: demo
spec:
version: 3.6.1
topology:
broker:
replicas: 2
storage:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: standard
controller:
replicas: 2
storage:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: standard
storageType: Durable
deletionPolicy: WipeOut
Let’s create the Kafka CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/kafka/scaling/kafka-topology.yaml
kafka.kubedb.com/kafka-prod created
Now, wait until kafka-prod has status Ready. i.e,
$ kubectl get kf -n demo -w
NAME TYPE VERSION STATUS AGE
kafka-prod kubedb.com/v1 3.6.1 Provisioning 0s
kafka-prod kubedb.com/v1 3.6.1 Provisioning 24s
.
.
kafka-prod kubedb.com/v1 3.6.1 Ready 92s
Let’s check the number of replicas has from kafka object, number of pods the petset have,
Broker Replicas
$ kubectl get kafka -n demo kafka-prod -o json | jq '.spec.topology.broker.replicas'
2
$ kubectl get petset -n demo kafka-prod-broker -o json | jq '.spec.replicas'
2
Controller Replicas
$ kubectl get kafka -n demo kafka-prod -o json | jq '.spec.topology.controller.replicas'
2
$ kubectl get petset -n demo kafka-prod-controller -o json | jq '.spec.replicas'
2
We can see from commands that the cluster has 2 replicas for both broker and controller.
Also, we can verify the replicas of the topology from an internal kafka command by exec into a replica.
Now let’s exec to a broker instance and run a kafka internal command to check the number of replicas for broker and controller.,
Broker
$ kubectl exec -it -n demo kafka-prod-broker-0 -- kafka-broker-api-versions.sh --bootstrap-server localhost:9092 --command-config config/clientauth.properties
kafka-prod-broker-0.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 0 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
kafka-prod-broker-1.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 1 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
Controller
$ kubectl exec -it -n demo kafka-prod-broker-0 -- kafka-metadata-quorum.sh --bootstrap-server localhost:9092 --command-config config/clientauth.properties describe --status | grep CurrentObservers
CurrentObservers: [0,1]
We can see from the above output that the kafka has 2 nodes for broker and 2 nodes for controller.
We are now ready to apply the KafkaOpsRequest CR to scale this cluster.
Scale Up Replicas
Here, we are going to scale up the replicas of the topology cluster to meet the desired number of replicas after scaling.
Create KafkaOpsRequest
In order to scale up the replicas of the topology cluster, we have to create a KafkaOpsRequest CR with our desired replicas. Below is the YAML of the KafkaOpsRequest CR that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: KafkaOpsRequest
metadata:
name: kfops-hscale-up-topology
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: kafka-prod
horizontalScaling:
topology:
broker: 3
controller: 3
Here,
spec.databaseRef.namespecifies that we are performing horizontal scaling operation onkafka-prodcluster.spec.typespecifies that we are performingHorizontalScalingon kafka.spec.horizontalScaling.topology.brokerspecifies the desired replicas after scaling for broker.spec.horizontalScaling.topology.controllerspecifies the desired replicas after scaling for controller.
Let’s create the KafkaOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/kafka/scaling/horizontal-scaling/kafka-hscale-up-topology.yaml
kafkaopsrequest.ops.kubedb.com/kfops-hscale-up-topology created
Note: If you want to scale down only broker or controller, you can specify the desired replicas for only broker or controller in the
KafkaOpsRequestCR. You can specify one at a time. If you want to scale broker only, no node will need restart to apply the changes. But if you want to scale controller, all nodes will need restart to apply the changes.
Verify Topology cluster replicas scaled up successfully
If everything goes well, KubeDB Ops-manager operator will update the replicas of Kafka object and related PetSets and Pods.
Let’s wait for KafkaOpsRequest to be Successful. Run the following command to watch KafkaOpsRequest CR,
$ watch kubectl get kafkaopsrequest -n demo
NAME TYPE STATUS AGE
kfops-hscale-up-topology HorizontalScaling Successful 106s
We can see from the above output that the KafkaOpsRequest has succeeded. If we describe the KafkaOpsRequest we will get an overview of the steps that were followed to scale the cluster.
$ kubectl describe kafkaopsrequests -n demo kfops-hscale-up-topology
Name: kfops-hscale-up-topology
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: KafkaOpsRequest
Metadata:
Creation Timestamp: 2024-08-02T11:02:51Z
Generation: 1
Resource Version: 356503
UID: 44e0db0c-2094-4c13-a3be-9ca680888545
Spec:
Apply: IfReady
Database Ref:
Name: kafka-prod
Horizontal Scaling:
Topology:
Broker: 3
Controller: 3
Type: HorizontalScaling
Status:
Conditions:
Last Transition Time: 2024-08-02T11:02:51Z
Message: Kafka ops-request has started to horizontally scaling the nodes
Observed Generation: 1
Reason: HorizontalScaling
Status: True
Type: HorizontalScaling
Last Transition Time: 2024-08-02T11:02:59Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-controller-0
Last Transition Time: 2024-08-02T11:03:00Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-controller-0
Last Transition Time: 2024-08-02T11:03:09Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-controller-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-controller-0
Last Transition Time: 2024-08-02T11:03:14Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-controller-1
Last Transition Time: 2024-08-02T11:03:14Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-controller-1
Last Transition Time: 2024-08-02T11:03:24Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-controller-1
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-controller-1
Last Transition Time: 2024-08-02T11:03:29Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-broker-0
Last Transition Time: 2024-08-02T11:03:30Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-broker-0
Last Transition Time: 2024-08-02T11:03:59Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-broker-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-broker-0
Last Transition Time: 2024-08-02T11:04:04Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-broker-1
Last Transition Time: 2024-08-02T11:04:05Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-broker-1
Last Transition Time: 2024-08-02T11:04:19Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-broker-1
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-broker-1
Last Transition Time: 2024-08-02T11:04:24Z
Message: Successfully restarted all nodes
Observed Generation: 1
Reason: RestartNodes
Status: True
Type: RestartNodes
Last Transition Time: 2024-08-02T11:04:59Z
Message: Successfully Scaled Up Broker
Observed Generation: 1
Reason: ScaleUpBroker
Status: True
Type: ScaleUpBroker
Last Transition Time: 2024-08-02T11:04:30Z
Message: patch pet setkafka-prod-broker; ConditionStatus:True
Observed Generation: 1
Status: True
Type: PatchPetSetkafka-prod-broker
Last Transition Time: 2024-08-02T11:04:55Z
Message: node in cluster; ConditionStatus:True
Observed Generation: 1
Status: True
Type: NodeInCluster
Last Transition Time: 2024-08-02T11:05:15Z
Message: Successfully Scaled Up Controller
Observed Generation: 1
Reason: ScaleUpController
Status: True
Type: ScaleUpController
Last Transition Time: 2024-08-02T11:05:05Z
Message: patch pet setkafka-prod-controller; ConditionStatus:True
Observed Generation: 1
Status: True
Type: PatchPetSetkafka-prod-controller
Last Transition Time: 2024-08-02T11:05:15Z
Message: Successfully completed horizontally scale kafka cluster
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 4m19s KubeDB Ops-manager Operator Start processing for KafkaOpsRequest: demo/kfops-hscale-up-topology
Normal Starting 4m19s KubeDB Ops-manager Operator Pausing Kafka databse: demo/kafka-prod
Normal Successful 4m19s KubeDB Ops-manager Operator Successfully paused Kafka database: demo/kafka-prod for KafkaOpsRequest: kfops-hscale-up-topology
Warning get pod; ConditionStatus:True; PodName:kafka-prod-controller-0 4m11s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-controller-0 4m10s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-controller-0 4m6s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-controller-0
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-controller-0 4m1s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-controller-0
Warning get pod; ConditionStatus:True; PodName:kafka-prod-controller-1 3m56s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-controller-1 3m56s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-controller-1 3m50s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-controller-1
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-controller-1 3m46s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-controller-1
Warning get pod; ConditionStatus:True; PodName:kafka-prod-broker-0 3m41s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-broker-0 3m41s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-broker-0 3m36s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-broker-0
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-broker-0 3m11s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-broker-0
Warning get pod; ConditionStatus:True; PodName:kafka-prod-broker-1 3m6s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-broker-1 3m5s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-broker-1 3m1s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-broker-1
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-broker-1 2m51s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-broker-1
Normal RestartNodes 2m46s KubeDB Ops-manager Operator Successfully restarted all nodes
Warning patch pet setkafka-prod-broker; ConditionStatus:True 2m40s KubeDB Ops-manager Operator patch pet setkafka-prod-broker; ConditionStatus:True
Warning node in cluster; ConditionStatus:False 2m36s KubeDB Ops-manager Operator node in cluster; ConditionStatus:False
Warning node in cluster; ConditionStatus:True 2m15s KubeDB Ops-manager Operator node in cluster; ConditionStatus:True
Normal ScaleUpBroker 2m10s KubeDB Ops-manager Operator Successfully Scaled Up Broker
Warning patch pet setkafka-prod-controller; ConditionStatus:True 2m5s KubeDB Ops-manager Operator patch pet setkafka-prod-controller; ConditionStatus:True
Warning node in cluster; ConditionStatus:True 2m KubeDB Ops-manager Operator node in cluster; ConditionStatus:True
Normal ScaleUpController 115s KubeDB Ops-manager Operator Successfully Scaled Up Controller
Normal Starting 115s KubeDB Ops-manager Operator Resuming Kafka database: demo/kafka-prod
Normal Successful 115s KubeDB Ops-manager Operator Successfully resumed Kafka database: demo/kafka-prod for KafkaOpsRequest: kfops-hscale-up-topology
Now, we are going to verify the number of replicas this cluster has from the Kafka object, number of pods the petset have,
Broker Replicas
$ kubectl get kafka -n demo kafka-prod -o json | jq '.spec.topology.broker.replicas'
3
$ kubectl get petset -n demo kafka-prod-broker -o json | jq '.spec.replicas'
3
Now let’s connect to a kafka instance and run a kafka internal command to check the number of replicas of topology cluster for both broker and controller.,
Broker
$ kubectl exec -it -n demo kafka-prod-broker-0 -- kafka-broker-api-versions.sh --bootstrap-server localhost:9092 --command-config config/clientauth.properties
kafka-prod-broker-0.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 0 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
kafka-prod-broker-1.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 1 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
kafka-prod-broker-2.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 2 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
Controller
$ kubectl exec -it -n demo kafka-prod-broker-0 -- kafka-metadata-quorum.sh --bootstrap-server localhost:9092 --command-config config/clientauth.properties describe --status | grep CurrentObservers
CurrentObservers: [0,1,2]
From all the above outputs we can see that the both brokers and controller of the topology kafka is 3. That means we have successfully scaled up the replicas of the Kafka topology cluster.
Scale Down Replicas
Here, we are going to scale down the replicas of the kafka topology cluster to meet the desired number of replicas after scaling.
Create KafkaOpsRequest
In order to scale down the replicas of the kafka topology cluster, we have to create a KafkaOpsRequest CR with our desired replicas. Below is the YAML of the KafkaOpsRequest CR that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: KafkaOpsRequest
metadata:
name: kfops-hscale-down-topology
namespace: demo
spec:
type: HorizontalScaling
databaseRef:
name: kafka-prod
horizontalScaling:
topology:
broker: 2
controller: 2
Here,
spec.databaseRef.namespecifies that we are performing horizontal scaling down operation onkafka-prodcluster.spec.typespecifies that we are performingHorizontalScalingon kafka.spec.horizontalScaling.topology.brokerspecifies the desired replicas after scaling for the broker nodes.spec.horizontalScaling.topology.controllerspecifies the desired replicas after scaling for the controller nodes.
Let’s create the KafkaOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/kafka/scaling/horizontal-scaling/kafka-hscale-down-topology.yaml
kafkaopsrequest.ops.kubedb.com/kfops-hscale-down-topology created
Verify Topology cluster replicas scaled down successfully
If everything goes well, KubeDB Ops-manager operator will update the replicas of Kafka object and related PetSets and Pods.
Let’s wait for KafkaOpsRequest to be Successful. Run the following command to watch KafkaOpsRequest CR,
$ watch kubectl get kafkaopsrequest -n demo
NAME TYPE STATUS AGE
kfops-hscale-down-topology HorizontalScaling Successful 2m32s
We can see from the above output that the KafkaOpsRequest has succeeded. If we describe the KafkaOpsRequest we will get an overview of the steps that were followed to scale the cluster.
$ kubectl describe kafkaopsrequests -n demo kfops-hscale-down-topology
Name: kfops-hscale-down-topology
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: KafkaOpsRequest
Metadata:
Creation Timestamp: 2024-08-02T11:14:18Z
Generation: 1
Resource Version: 357545
UID: b786d791-6ba8-4f1c-ade8-9443e049cede
Spec:
Apply: IfReady
Database Ref:
Name: kafka-prod
Horizontal Scaling:
Topology:
Broker: 2
Controller: 2
Type: HorizontalScaling
Status:
Conditions:
Last Transition Time: 2024-08-02T11:14:18Z
Message: Kafka ops-request has started to horizontally scaling the nodes
Observed Generation: 1
Reason: HorizontalScaling
Status: True
Type: HorizontalScaling
Last Transition Time: 2024-08-02T11:14:46Z
Message: Successfully Scaled Down Broker
Observed Generation: 1
Reason: ScaleDownBroker
Status: True
Type: ScaleDownBroker
Last Transition Time: 2024-08-02T11:14:36Z
Message: reassign partitions; ConditionStatus:True
Observed Generation: 1
Status: True
Type: ReassignPartitions
Last Transition Time: 2024-08-02T11:14:36Z
Message: is pet set patched; ConditionStatus:True
Observed Generation: 1
Status: True
Type: IsPetSetPatched
Last Transition Time: 2024-08-02T11:14:37Z
Message: get pod; ConditionStatus:True
Observed Generation: 1
Status: True
Type: GetPod
Last Transition Time: 2024-08-02T11:14:37Z
Message: delete pvc; ConditionStatus:True
Observed Generation: 1
Status: True
Type: DeletePvc
Last Transition Time: 2024-08-02T11:15:26Z
Message: get pvc; ConditionStatus:True
Observed Generation: 1
Status: True
Type: GetPvc
Last Transition Time: 2024-08-02T11:15:31Z
Message: Successfully Scaled Down Controller
Observed Generation: 1
Reason: ScaleDownController
Status: True
Type: ScaleDownController
Last Transition Time: 2024-08-02T11:15:38Z
Message: successfully reconciled the Kafka with modified node
Observed Generation: 1
Reason: UpdatePetSets
Status: True
Type: UpdatePetSets
Last Transition Time: 2024-08-02T11:15:43Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-controller-0
Last Transition Time: 2024-08-02T11:15:44Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-controller-0
Last Transition Time: 2024-08-02T11:15:53Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-controller-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-controller-0
Last Transition Time: 2024-08-02T11:15:58Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-controller-1
Last Transition Time: 2024-08-02T11:15:58Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-controller-1
Last Transition Time: 2024-08-02T11:16:08Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-controller-1
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-controller-1
Last Transition Time: 2024-08-02T11:16:13Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-broker-0
Last Transition Time: 2024-08-02T11:16:13Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-broker-0
Last Transition Time: 2024-08-02T11:16:58Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-broker-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-broker-0
Last Transition Time: 2024-08-02T11:17:03Z
Message: get pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Observed Generation: 1
Status: True
Type: GetPod--kafka-prod-broker-1
Last Transition Time: 2024-08-02T11:17:03Z
Message: evict pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Observed Generation: 1
Status: True
Type: EvictPod--kafka-prod-broker-1
Last Transition Time: 2024-08-02T11:17:13Z
Message: check pod running; ConditionStatus:True; PodName:kafka-prod-broker-1
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-prod-broker-1
Last Transition Time: 2024-08-02T11:17:18Z
Message: Successfully restarted all nodes
Observed Generation: 1
Reason: RestartNodes
Status: True
Type: RestartNodes
Last Transition Time: 2024-08-02T11:17:19Z
Message: Successfully completed horizontally scale kafka cluster
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 8m35s KubeDB Ops-manager Operator Start processing for KafkaOpsRequest: demo/kfops-hscale-down-topology
Normal Starting 8m35s KubeDB Ops-manager Operator Pausing Kafka databse: demo/kafka-prod
Normal Successful 8m35s KubeDB Ops-manager Operator Successfully paused Kafka database: demo/kafka-prod for KafkaOpsRequest: kfops-hscale-down-topology
Warning reassign partitions; ConditionStatus:True 8m17s KubeDB Ops-manager Operator reassign partitions; ConditionStatus:True
Warning is pet set patched; ConditionStatus:True 8m17s KubeDB Ops-manager Operator is pet set patched; ConditionStatus:True
Warning get pod; ConditionStatus:True 8m16s KubeDB Ops-manager Operator get pod; ConditionStatus:True
Warning delete pvc; ConditionStatus:True 8m16s KubeDB Ops-manager Operator delete pvc; ConditionStatus:True
Warning get pvc; ConditionStatus:False 8m16s KubeDB Ops-manager Operator get pvc; ConditionStatus:False
Warning get pod; ConditionStatus:True 8m12s KubeDB Ops-manager Operator get pod; ConditionStatus:True
Warning delete pvc; ConditionStatus:True 8m12s KubeDB Ops-manager Operator delete pvc; ConditionStatus:True
Warning get pvc; ConditionStatus:True 8m12s KubeDB Ops-manager Operator get pvc; ConditionStatus:True
Normal ScaleDownBroker 8m7s KubeDB Ops-manager Operator Successfully Scaled Down Broker
Warning reassign partitions; ConditionStatus:True 7m31s KubeDB Ops-manager Operator reassign partitions; ConditionStatus:True
Warning is pet set patched; ConditionStatus:True 7m31s KubeDB Ops-manager Operator is pet set patched; ConditionStatus:True
Warning get pod; ConditionStatus:True 7m31s KubeDB Ops-manager Operator get pod; ConditionStatus:True
Warning delete pvc; ConditionStatus:True 7m31s KubeDB Ops-manager Operator delete pvc; ConditionStatus:True
Warning get pvc; ConditionStatus:False 7m31s KubeDB Ops-manager Operator get pvc; ConditionStatus:False
Warning get pod; ConditionStatus:True 7m27s KubeDB Ops-manager Operator get pod; ConditionStatus:True
Warning delete pvc; ConditionStatus:True 7m27s KubeDB Ops-manager Operator delete pvc; ConditionStatus:True
Warning get pvc; ConditionStatus:True 7m27s KubeDB Ops-manager Operator get pvc; ConditionStatus:True
Normal ScaleDownController 7m22s KubeDB Ops-manager Operator Successfully Scaled Down Controller
Normal UpdatePetSets 7m15s KubeDB Ops-manager Operator successfully reconciled the Kafka with modified node
Warning get pod; ConditionStatus:True; PodName:kafka-prod-controller-0 7m10s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-controller-0 7m9s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-controller-0
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-controller-0 7m5s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-controller-0
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-controller-0 7m KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-controller-0
Warning get pod; ConditionStatus:True; PodName:kafka-prod-controller-1 6m55s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-controller-1 6m55s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-controller-1
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-controller-1 6m50s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-controller-1
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-controller-1 6m45s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-controller-1
Warning get pod; ConditionStatus:True; PodName:kafka-prod-broker-0 6m40s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-broker-0 6m40s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-broker-0
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-broker-0 6m35s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-broker-0
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-broker-0 5m55s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-broker-0
Warning get pod; ConditionStatus:True; PodName:kafka-prod-broker-1 5m50s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Warning evict pod; ConditionStatus:True; PodName:kafka-prod-broker-1 5m50s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-prod-broker-1
Warning check pod running; ConditionStatus:False; PodName:kafka-prod-broker-1 5m45s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-prod-broker-1
Warning check pod running; ConditionStatus:True; PodName:kafka-prod-broker-1 5m40s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-prod-broker-1
Normal RestartNodes 5m35s KubeDB Ops-manager Operator Successfully restarted all nodes
Normal Starting 5m35s KubeDB Ops-manager Operator Resuming Kafka database: demo/kafka-prod
Normal Successful 5m34s KubeDB Ops-manager Operator Successfully resumed Kafka database: demo/kafka-prod for KafkaOpsRequest: kfops-hscale-down-topology
Now, we are going to verify the number of replicas this cluster has from the Kafka object, number of pods the petset have,
Broker Replicas
$ kubectl get kafka -n demo kafka-prod -o json | jq '.spec.topology.broker.replicas'
2
$ kubectl get petset -n demo kafka-prod-broker -o json | jq '.spec.replicas'
2
Controller Replicas
$ kubectl get kafka -n demo kafka-prod -o json | jq '.spec.topology.controller.replicas'
2
$ kubectl get petset -n demo kafka-prod-controller -o json | jq '.spec.replicas'
2
Now let’s connect to a kafka instance and run a kafka internal command to check the number of replicas for both broker and controller nodes,
Broker
$ kubectl exec -it -n demo kafka-prod-broker-0 -- kafka-broker-api-versions.sh --bootstrap-server localhost:9092 --command-config config/clientauth.properties
kafka-prod-broker-0.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 0 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
kafka-prod-broker-1.kafka-prod-pods.demo.svc.cluster.local:9092 (id: 1 rack: null) -> (
Produce(0): 0 to 9 [usable: 9],
Fetch(1): 0 to 15 [usable: 15],
ListOffsets(2): 0 to 8 [usable: 8],
Metadata(3): 0 to 12 [usable: 12],
LeaderAndIsr(4): UNSUPPORTED,
StopReplica(5): UNSUPPORTED,
UpdateMetadata(6): UNSUPPORTED,
ControlledShutdown(7): UNSUPPORTED,
OffsetCommit(8): 0 to 8 [usable: 8],
OffsetFetch(9): 0 to 8 [usable: 8],
FindCoordinator(10): 0 to 4 [usable: 4],
JoinGroup(11): 0 to 9 [usable: 9],
Heartbeat(12): 0 to 4 [usable: 4],
LeaveGroup(13): 0 to 5 [usable: 5],
SyncGroup(14): 0 to 5 [usable: 5],
DescribeGroups(15): 0 to 5 [usable: 5],
ListGroups(16): 0 to 4 [usable: 4],
SaslHandshake(17): 0 to 1 [usable: 1],
ApiVersions(18): 0 to 3 [usable: 3],
CreateTopics(19): 0 to 7 [usable: 7],
DeleteTopics(20): 0 to 6 [usable: 6],
DeleteRecords(21): 0 to 2 [usable: 2],
InitProducerId(22): 0 to 4 [usable: 4],
OffsetForLeaderEpoch(23): 0 to 4 [usable: 4],
AddPartitionsToTxn(24): 0 to 4 [usable: 4],
AddOffsetsToTxn(25): 0 to 3 [usable: 3],
EndTxn(26): 0 to 3 [usable: 3],
WriteTxnMarkers(27): 0 to 1 [usable: 1],
TxnOffsetCommit(28): 0 to 3 [usable: 3],
DescribeAcls(29): 0 to 3 [usable: 3],
CreateAcls(30): 0 to 3 [usable: 3],
DeleteAcls(31): 0 to 3 [usable: 3],
DescribeConfigs(32): 0 to 4 [usable: 4],
AlterConfigs(33): 0 to 2 [usable: 2],
AlterReplicaLogDirs(34): 0 to 2 [usable: 2],
DescribeLogDirs(35): 0 to 4 [usable: 4],
SaslAuthenticate(36): 0 to 2 [usable: 2],
CreatePartitions(37): 0 to 3 [usable: 3],
CreateDelegationToken(38): 0 to 3 [usable: 3],
RenewDelegationToken(39): 0 to 2 [usable: 2],
ExpireDelegationToken(40): 0 to 2 [usable: 2],
DescribeDelegationToken(41): 0 to 3 [usable: 3],
DeleteGroups(42): 0 to 2 [usable: 2],
ElectLeaders(43): 0 to 2 [usable: 2],
IncrementalAlterConfigs(44): 0 to 1 [usable: 1],
AlterPartitionReassignments(45): 0 [usable: 0],
ListPartitionReassignments(46): 0 [usable: 0],
OffsetDelete(47): 0 [usable: 0],
DescribeClientQuotas(48): 0 to 1 [usable: 1],
AlterClientQuotas(49): 0 to 1 [usable: 1],
DescribeUserScramCredentials(50): 0 [usable: 0],
AlterUserScramCredentials(51): 0 [usable: 0],
DescribeQuorum(55): 0 to 1 [usable: 1],
AlterPartition(56): UNSUPPORTED,
UpdateFeatures(57): 0 to 1 [usable: 1],
Envelope(58): UNSUPPORTED,
DescribeCluster(60): 0 [usable: 0],
DescribeProducers(61): 0 [usable: 0],
UnregisterBroker(64): 0 [usable: 0],
DescribeTransactions(65): 0 [usable: 0],
ListTransactions(66): 0 [usable: 0],
AllocateProducerIds(67): UNSUPPORTED,
ConsumerGroupHeartbeat(68): UNSUPPORTED
)
Controller
$ kubectl exec -it -n demo kafka-prod-controller-0 -- kafka-metadata-quorum.sh --bootstrap-server localhost:9092 --command-config config/clientauth.properties describe --status | grep CurrentObservers
CurrentObservers: [0,1]
From all the above outputs we can see that the replicas of both broker and controller of the topology cluster is 2. That means we have successfully scaled down the replicas of the Kafka topology cluster.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete kf -n demo kafka-prod
kubectl delete kafkaopsrequest -n demo kfops-hscale-up-topology kfops-hscale-down-topology
kubectl delete ns demo
Next Steps
- Detail concepts of Kafka object.
- Different Kafka topology clustering modes here.
- Monitor your Kafka with KubeDB using out-of-the-box Prometheus operator.
- Want to hack on KubeDB? Check our contribution guidelines.