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Reconfigure Kafka Combined Cluster
This guide will show you how to use KubeDB
Ops-manager operator to reconfigure a Kafka Combined cluster.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectl
command-line tool must be configured to communicate with your cluster.Install
KubeDB
Provisioner and Ops-manager operator in your cluster following the steps here.You should be familiar with the following
KubeDB
concepts:
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.
Now, we are going to deploy a Kafka
Combined cluster using a supported version by KubeDB
operator. Then we are going to apply KafkaOpsRequest
to reconfigure its configuration.
Prepare Kafka Combined Cluster
Now, we are going to deploy a Kafka
combined cluster with version 3.6.1
.
Deploy Kafka
At first, we will create a secret with the server.properties
file containing required configuration settings.
server.properties:
log.retention.hours=100
Here, log.retention.hours
is set to 100
, whereas the default value is 168
.
Let’s create a k8s secret containing the above configuration where the file name will be the key and the file-content as the value:
apiVersion: v1
kind: Secret
metadata:
name: kf-combined-custom-config
namespace: demo
stringData:
server.properties: |-
log.retention.hours=100
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/kafka/reconfigure/kafka-combined-custom-config.yaml
secret/kf-combined-custom-config created
In this section, we are going to create a Kafka object specifying spec.configSecret
field to apply this custom configuration. Below is the YAML of the Kafka
CR that we are going to create,
apiVersion: kubedb.com/v1
kind: Kafka
metadata:
name: kafka-dev
namespace: demo
spec:
replicas: 2
version: 3.6.1
configSecret:
name: kf-combined-custom-config
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/v2024.9.30/docs/examples/kafka/reconfigure/kafka-combined.yaml
kafka.kubedb.com/kafka-dev created
Now, wait until kafka-dev
has status Ready
. i.e,
$ kubectl get kf -n demo -w
NAME TYPE VERSION STATUS AGE
kafka-dev kubedb.com/v1 3.6.1 Provisioning 0s
kafka-dev kubedb.com/v1 3.6.1 Provisioning 24s
.
.
kafka-dev kubedb.com/v1 3.6.1 Ready 92s
Now, we will check if the kafka has started with the custom configuration we have provided.
Exec into the Kafka pod and execute the following commands to see the configurations:
$ kubectl exec -it -n demo kafka-dev-0 -- bash
kafka@kafka-dev-0:~$ kafka-configs.sh --bootstrap-server localhost:9092 --command-config /opt/kafka/config/clientauth.properties --describe --entity-type brokers --all | grep log.retention.hours
log.retention.hours=100 sensitive=false synonyms={STATIC_BROKER_CONFIG:log.retention.hours=100, DEFAULT_CONFIG:log.retention.hours=168}
log.retention.hours=100 sensitive=false synonyms={STATIC_BROKER_CONFIG:log.retention.hours=100, DEFAULT_CONFIG:log.retention.hours=168}
Here, we can see that our given configuration is applied to the Kafka cluster for all brokers. log.retention.hours
is set to 100
from the default value 168
.
Reconfigure using new config secret
Now we will reconfigure this cluster to set log.retention.hours
to 125
.
Now, update our server.properties
file with the new configuration.
server.properties:
log.retention.hours=125
Then, we will create a new secret with this configuration file.
apiVersion: v1
kind: Secret
metadata:
name: new-kf-combined-custom-config
namespace: demo
stringData:
server.properties: |-
log.retention.hours=125
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/kafka/reconfigure/new-kafka-combined-custom-config.yaml
secret/new-kf-combined-custom-config created
Create KafkaOpsRequest
Now, we will use this secret to replace the previous secret using a KafkaOpsRequest
CR. The KafkaOpsRequest
yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: KafkaOpsRequest
metadata:
name: kfops-reconfigure-combined
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: kafka-dev
configuration:
configSecret:
name: new-kf-combined-custom-config
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.name
specifies that we are reconfiguringkafka-dev
database.spec.type
specifies that we are performingReconfigure
on our database.spec.configSecret.name
specifies the name of the new secret.
Let’s create the KafkaOpsRequest
CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/kafka/reconfigure/kafka-reconfigure-update-combined.yaml
kafkaopsrequest.ops.kubedb.com/kfops-reconfigure-combined created
Verify the new configuration is working
If everything goes well, KubeDB
Ops-manager operator will update the configSecret
of Kafka
object.
Let’s wait for KafkaOpsRequest
to be Successful
. Run the following command to watch KafkaOpsRequest
CR,
$ kubectl get kafkaopsrequests -n demo
NAME TYPE STATUS AGE
kfops-reconfigure-combined Reconfigure Successful 4m55s
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 reconfigure the database.
$ kubectl describe kafkaopsrequest -n demo kfops-reconfigure-combined
Name: kfops-reconfigure-combined
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: KafkaOpsRequest
Metadata:
Creation Timestamp: 2024-08-01T09:14:46Z
Generation: 1
Resource Version: 258361
UID: ac2147ba-51cf-4ebf-8328-76253379108c
Spec:
Apply: IfReady
Configuration:
Config Secret:
Name: new-kf-combined-custom-config
Database Ref:
Name: kafka-dev
Timeout: 5m
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2024-08-01T09:14:46Z
Message: Kafka ops-request has started to reconfigure kafka nodes
Observed Generation: 1
Reason: Reconfigure
Status: True
Type: Reconfigure
Last Transition Time: 2024-08-01T09:14:55Z
Message: successfully reconciled the Kafka with new configure
Observed Generation: 1
Reason: UpdatePetSets
Status: True
Type: UpdatePetSets
Last Transition Time: 2024-08-01T09:15:00Z
Message: get pod; ConditionStatus:True; PodName:kafka-dev-0
Observed Generation: 1
Status: True
Type: GetPod--kafka-dev-0
Last Transition Time: 2024-08-01T09:15:00Z
Message: evict pod; ConditionStatus:True; PodName:kafka-dev-0
Observed Generation: 1
Status: True
Type: EvictPod--kafka-dev-0
Last Transition Time: 2024-08-01T09:16:15Z
Message: check pod running; ConditionStatus:True; PodName:kafka-dev-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-dev-0
Last Transition Time: 2024-08-01T09:16:20Z
Message: get pod; ConditionStatus:True; PodName:kafka-dev-1
Observed Generation: 1
Status: True
Type: GetPod--kafka-dev-1
Last Transition Time: 2024-08-01T09:16:20Z
Message: evict pod; ConditionStatus:True; PodName:kafka-dev-1
Observed Generation: 1
Status: True
Type: EvictPod--kafka-dev-1
Last Transition Time: 2024-08-01T09:17:20Z
Message: check pod running; ConditionStatus:True; PodName:kafka-dev-1
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-dev-1
Last Transition Time: 2024-08-01T09:17:25Z
Message: Successfully restarted all nodes
Observed Generation: 1
Reason: RestartNodes
Status: True
Type: RestartNodes
Last Transition Time: 2024-08-01T09:17:25Z
Message: Successfully completed reconfigure kafka
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 5m32s KubeDB Ops-manager Operator Start processing for KafkaOpsRequest: demo/kfops-reconfigure-combined
Normal Starting 5m32s KubeDB Ops-manager Operator Pausing Kafka databse: demo/kafka-dev
Normal Successful 5m32s KubeDB Ops-manager Operator Successfully paused Kafka database: demo/kafka-dev for KafkaOpsRequest: kfops-reconfigure-combined
Normal UpdatePetSets 5m23s KubeDB Ops-manager Operator successfully reconciled the Kafka with new configure
Warning get pod; ConditionStatus:True; PodName:kafka-dev-0 5m18s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-dev-0
Warning evict pod; ConditionStatus:True; PodName:kafka-dev-0 5m18s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-dev-0
Warning check pod running; ConditionStatus:False; PodName:kafka-dev-0 5m13s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-dev-0
Warning check pod running; ConditionStatus:True; PodName:kafka-dev-0 4m3s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-dev-0
Warning get pod; ConditionStatus:True; PodName:kafka-dev-1 3m58s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-dev-1
Warning evict pod; ConditionStatus:True; PodName:kafka-dev-1 3m58s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-dev-1
Warning check pod running; ConditionStatus:False; PodName:kafka-dev-1 3m53s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-dev-1
Warning check pod running; ConditionStatus:True; PodName:kafka-dev-1 2m58s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-dev-1
Normal RestartNodes 2m53s KubeDB Ops-manager Operator Successfully restarted all nodes
Normal Starting 2m53s KubeDB Ops-manager Operator Resuming Kafka database: demo/kafka-dev
Normal Successful 2m53s KubeDB Ops-manager Operator Successfully resumed Kafka database: demo/kafka-dev for KafkaOpsRequest: kfops-reconfigure-combined
Now let’s exec one of the instance and run a kafka-configs.sh command to check the new configuration we have provided.
$ kubectl exec -it -n demo kafka-dev-0 -- kafka-configs.sh --bootstrap-server localhost:9092 --command-config /opt/kafka/config/clientauth.properties --describe --entity-type brokers --all | grep 'log.retention.hours'
log.retention.hours=125 sensitive=false synonyms={STATIC_BROKER_CONFIG:log.retention.hours=125, DEFAULT_CONFIG:log.retention.hours=168}
log.retention.hours=125 sensitive=false synonyms={STATIC_BROKER_CONFIG:log.retention.hours=125, DEFAULT_CONFIG:log.retention.hours=168}
As we can see from the configuration of ready kafka, the value of log.retention.hours
has been changed from 100
to 125
. So the reconfiguration of the cluster is successful.
Reconfigure using apply config
Now we will reconfigure this cluster again to set log.retention.hours
to 150
. This time we won’t use a new secret. We will use the applyConfig
field of the KafkaOpsRequest
. This will merge the new config in the existing secret.
Create KafkaOpsRequest
Now, we will use the new configuration in the applyConfig
field in the KafkaOpsRequest
CR. The KafkaOpsRequest
yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: KafkaOpsRequest
metadata:
name: kfops-reconfigure-apply-combined
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: kafka-dev
configuration:
applyConfig:
server.properties: |-
log.retention.hours=150
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.name
specifies that we are reconfiguringkafka-dev
cluster.spec.type
specifies that we are performingReconfigure
on kafka.spec.configuration.applyConfig
specifies the new configuration that will be merged in the existing secret.
Let’s create the KafkaOpsRequest
CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/kafka/reconfigure/kafka-reconfigure-apply-combined.yaml
kafkaopsrequest.ops.kubedb.com/kfops-reconfigure-apply-combined created
Verify the new configuration is working
If everything goes well, KubeDB
Ops-manager operator will merge this new config with the existing configuration.
Let’s wait for KafkaOpsRequest
to be Successful
. Run the following command to watch KafkaOpsRequest
CR,
$ kubectl get kafkaopsrequests -n demo kfops-reconfigure-apply-combined
NAME TYPE STATUS AGE
kfops-reconfigure-apply-combined Reconfigure Successful 55s
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 reconfigure the cluster.
$ kubectl describe kafkaopsrequest -n demo kfops-reconfigure-apply-combined
Name: kfops-reconfigure-apply-combined
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: KafkaOpsRequest
Metadata:
Creation Timestamp: 2024-08-01T09:27:03Z
Generation: 1
Resource Version: 259123
UID: fdc46ef0-e2ae-490a-aab8-6a3380ec09d1
Spec:
Apply: IfReady
Configuration:
Apply Config:
server.properties: log.retention.hours=150
Database Ref:
Name: kafka-dev
Timeout: 5m
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2024-08-01T09:27:03Z
Message: Kafka ops-request has started to reconfigure kafka nodes
Observed Generation: 1
Reason: Reconfigure
Status: True
Type: Reconfigure
Last Transition Time: 2024-08-01T09:27:06Z
Message: Successfully prepared user provided custom config secret
Observed Generation: 1
Reason: PrepareCustomConfig
Status: True
Type: PrepareCustomConfig
Last Transition Time: 2024-08-01T09:27:12Z
Message: successfully reconciled the Kafka with new configure
Observed Generation: 1
Reason: UpdatePetSets
Status: True
Type: UpdatePetSets
Last Transition Time: 2024-08-01T09:27:17Z
Message: get pod; ConditionStatus:True; PodName:kafka-dev-0
Observed Generation: 1
Status: True
Type: GetPod--kafka-dev-0
Last Transition Time: 2024-08-01T09:27:17Z
Message: evict pod; ConditionStatus:True; PodName:kafka-dev-0
Observed Generation: 1
Status: True
Type: EvictPod--kafka-dev-0
Last Transition Time: 2024-08-01T09:27:27Z
Message: check pod running; ConditionStatus:True; PodName:kafka-dev-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-dev-0
Last Transition Time: 2024-08-01T09:27:32Z
Message: get pod; ConditionStatus:True; PodName:kafka-dev-1
Observed Generation: 1
Status: True
Type: GetPod--kafka-dev-1
Last Transition Time: 2024-08-01T09:27:32Z
Message: evict pod; ConditionStatus:True; PodName:kafka-dev-1
Observed Generation: 1
Status: True
Type: EvictPod--kafka-dev-1
Last Transition Time: 2024-08-01T09:27:52Z
Message: check pod running; ConditionStatus:True; PodName:kafka-dev-1
Observed Generation: 1
Status: True
Type: CheckPodRunning--kafka-dev-1
Last Transition Time: 2024-08-01T09:27:57Z
Message: Successfully restarted all nodes
Observed Generation: 1
Reason: RestartNodes
Status: True
Type: RestartNodes
Last Transition Time: 2024-08-01T09:27:57Z
Message: Successfully completed reconfigure kafka
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 2m7s KubeDB Ops-manager Operator Start processing for KafkaOpsRequest: demo/kfops-reconfigure-apply-combined
Normal Starting 2m7s KubeDB Ops-manager Operator Pausing Kafka databse: demo/kafka-dev
Normal Successful 2m7s KubeDB Ops-manager Operator Successfully paused Kafka database: demo/kafka-dev for KafkaOpsRequest: kfops-reconfigure-apply-combined
Normal UpdatePetSets 118s KubeDB Ops-manager Operator successfully reconciled the Kafka with new configure
Warning get pod; ConditionStatus:True; PodName:kafka-dev-0 113s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-dev-0
Warning evict pod; ConditionStatus:True; PodName:kafka-dev-0 113s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-dev-0
Warning check pod running; ConditionStatus:False; PodName:kafka-dev-0 108s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-dev-0
Warning check pod running; ConditionStatus:True; PodName:kafka-dev-0 103s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-dev-0
Warning get pod; ConditionStatus:True; PodName:kafka-dev-1 98s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:kafka-dev-1
Warning evict pod; ConditionStatus:True; PodName:kafka-dev-1 98s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:kafka-dev-1
Warning check pod running; ConditionStatus:False; PodName:kafka-dev-1 93s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:kafka-dev-1
Warning check pod running; ConditionStatus:True; PodName:kafka-dev-1 78s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:kafka-dev-1
Normal RestartNodes 73s KubeDB Ops-manager Operator Successfully restarted all nodes
Normal Starting 73s KubeDB Ops-manager Operator Resuming Kafka database: demo/kafka-dev
Normal Successful 73s KubeDB Ops-manager Operator Successfully resumed Kafka database: demo/kafka-dev for KafkaOpsRequest: kfops-reconfigure-apply-combined
Now let’s exec into one of the instance and run a kafka-configs.sh
command to check the new configuration we have provided.
$ kubectl exec -it -n demo kafka-dev-0 -- kafka-configs.sh --bootstrap-server localhost:9092 --command-config /opt/kafka/config/clientauth.properties --describe --entity-type brokers --all | grep 'log.retention.hours'
log.retention.hours=150 sensitive=false synonyms={STATIC_BROKER_CONFIG:log.retention.hours=150, DEFAULT_CONFIG:log.retention.hours=168}
log.retention.hours=150 sensitive=false synonyms={STATIC_BROKER_CONFIG:log.retention.hours=150, DEFAULT_CONFIG:log.retention.hours=168}
As we can see from the configuration of ready kafka, the value of log.retention.hours
has been changed from 125
to 150
. So the reconfiguration of the database using the applyConfig
field is successful.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete kf -n demo kafka-dev
kubectl delete kafkaopsrequest -n demo kfops-reconfigure-apply-combined kfops-reconfigure-combined
kubectl delete secret -n demo kf-combined-custom-config new-kf-combined-custom-config
kubectl delete namespace demo
Next Steps
- Detail concepts of Kafka object.
- Different Kafka topology clustering modes here.
- Monitor your Kafka database with KubeDB using out-of-the-box Prometheus operator.
- Want to hack on KubeDB? Check our contribution guidelines.