Kafka-Operator

The Banzai Cloud Kafka operator is a Kubernetes operator to automate provisioning, management, autoscaling and operations of Apache Kafka clusters deployed to K8s.

Overview

Apache Kafka is an open-source distributed streaming platform, and some of the main features of the Kafka-operator are:

• the provisioning of secure and production ready Kafka clusters
• fine grained broker configuration support
• advanced and highly configurable External Access via LoadBalancers using Envoy
• graceful Kafka cluster scaling and rebalancing
• monitoring via Prometheus
• encrypted communication using SSL
• automatic reaction and self healing based on alerts (plugin system, with meaningful default alert plugins) using Cruise Control
• graceful rolling upgrade
• advanced topic and user management via CRD

We took a different approach to what's out there - we believe for a good reason - please read on to understand more about our design motivations and some of the scenarios which were driving us to create the Banzai Cloud Kafka operator.

Motivation

At Banzai Cloud we are building a Kubernetes distribution, PKE, and a hybrid-cloud container management platform, Pipeline, that operate Kafka clusters (among other types) for our customers. Apache Kafka predates Kubernetes and was designed mostly for static on-premise environments. State management, node identity, failover, etc all come part and parcel with Kafka, so making it work properly on Kubernetes and on an underlying dynamic environment can be a challenge.

There are already several approaches to operating Kafka on Kubernetes, however, we did not find them appropriate for use in a highly dynamic environment, nor capable of meeting our customers' needs. At the same time, there is substantial interest within the Kafka community for a solution which enables Kafka on Kubernetes, both in the open source and closed source space.

• Helm chart
• Yaml files
• Strimzi Kafka Operator
• Confluent operator

Join us as we take a deep dive into some of the details of the most popular pre-existing solutions, as well as our own:

	Banzai Cloud	Krallistic	Strimzi	Confluent
Open source	Apache 2	Apache 2	Apache 2	No
Fine grained broker config support	Yes (learn more)	Limited via StatefulSet	Limited via StatefulSet	Limited via StatefulSet
Fine grained broker volume support	Yes (learn more)	Limited via StatefulSet	Limited via StatefulSet	Limited via StatefulSet
Monitoring	Yes	Yes	Yes	Yes
Encryption using SSL	Yes	Yes	Yes	Yes
Rolling Update	Yes	No	No	Yes
Cluster external accesses	Envoy (single LB)	Nodeport	Nodeport or LB/broker	Yes (N/A)
User Management via CRD	Yes	No	Yes	No
Topic management via CRD	Yes	No	Yes	No
Reacting to Alerts	Yes (Prometheus + Cruise Control	No	No	No
Graceful Cluster Scaling (up and down)	Yes (using Cruise Control)	No	No	Yes

-if you find any of this information inaccurate, please let us know, and we'll fix it

We took a different approach to what's out there - we believe for a good reason - please read on to understand more about our design motivations and some of the scenarios which were driving us to create the Banzai Cloud Kafka operator.

Finally, our motivation is to build an open source solution and a community which drives the innovation and features of this operator. We are long term contributors and active community members of both Apache Kafka and Kubernetes, and we hope to recreate a similar community around this operator.

If you are willing to kickstart your managed Apache Kafka experience on 5 cloud providers, on-premise or hybrid environments, check out the free developer beta:

Installation

The operator installs the 2.1.0 version of Apache Kafka, and can run on Minikube v0.33.1+ and Kubernetes 1.12.0+.

As a pre-requisite it needs a Kubernetes cluster (you can create one using Pipeline). Also, Kafka requires Zookeeper so you need to first have a Zookeeper cluster if you don't already have one.

The operator also uses cert-manager for issuing certificates to users and brokers, so you'll need to have it setup in case you haven't already.

We believe in the separation of concerns principle, thus the Kafka operator does not install nor manage Zookeeper or cert-manager. If you would like to have a fully automated and managed experience of Apache Kafka on Kubernetes please try it with Pipeline.

Install cert-manager

# pre-create cert-manager namespace and CRDs per their installation instructions
kubectl create ns cert-manager
kubectl label namespace cert-manager certmanager.k8s.io/disable-validation=true

Install cert-manager and CustomResourceDefinitions

# Install the CustomResourceDefinitions and cert-manager itself
kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v0.10.0/cert-manager.yaml

Or install with helm

# Install only the CustomResourceDefinitions
kubectl apply -f https://raw.githubusercontent.com/jetstack/cert-manager/release-0.10/deploy/manifests/00-crds.yaml

# Add the jetstack helm repo
helm repo add jetstack https://charts.jetstack.io
# Install cert-manager into the cluster
# --set webhook.enabled=false may not be required for you, but avoids issues with
# certificates not being able to be issued due to the webhook not working.
helm install --name cert-manager --namespace cert-manager --version v0.10.0 --set webhook.enabled=false jetstack/cert-manager

Install Zookeeper

To install Zookeeper we recommend using the Pravega's Zookeeper Operator. You can deploy Zookeeper by using the Helm chart.

helm repo add banzaicloud-stable https://kubernetes-charts.banzaicloud.com/
helm install --name zookeeper-operator --namespace=zookeeper banzaicloud-stable/zookeeper-operator
kubectl create --namespace zookeeper -f - <<EOF
apiVersion: zookeeper.pravega.io/v1beta1
kind: ZookeeperCluster
metadata:
  name: example-zookeepercluster
  namespace: zookeeper
spec:
  replicas: 3
EOF

Install Prometheus-operator

Install the Operator and CustomResourceDefinitions to the default namespace

# Install Prometheus-operator and CustomResourceDefinitions
kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/bundle.yaml

Or install with helm

# Install CustomResourceDefinitions
kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/prometheus-operator-crd/alertmanager.crd.yaml
kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/prometheus-operator-crd/prometheus.crd.yaml
kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/prometheus-operator-crd/prometheusrule.crd.yaml
kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/prometheus-operator-crd/servicemonitor.crd.yaml
kubectl apply -f https://raw.githubusercontent.com/coreos/prometheus-operator/master/example/prometheus-operator-crd/podmonitor.crd.yaml

# Install only the Prometheus-operator
helm install --name test  stable/prometheus-operator \
--set prometheusOperator.createCustomResource=false \
--set defaultRules.enabled=false \
--set alertmanager.enabled=false \
--set grafana.enabled=false \
--set kubeApiServer.enabled=false \
--set kubelet.enabled=false \
--set kubeControllerManager.enabled=false \
--set coreDNS.enabled=false \
--set kubeEtcd.enabled=false \
--set kubeScheduler.enabled=false \
--set kubeProxy.enabled=false \
--set kubeStateMetrics.enabled=false \
--set nodeExporter.enabled=false \
--set prometheus.enabled=false

Installation

We recommend to use a custom StorageClass to leverage the volume binding mode WaitForFirstConsumer

apiVersion: storage.k8s.io/v1
kind: StorageClass
  name: exampleStorageclass
parameters:
  type: pd-standard
provisioner: kubernetes.io/gce-pd
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer

Remember to set your Kafka CR properly to use the newly created StorageClass.

1. Set KUBECONFIG pointing towards your cluster
2. Run make deploy (deploys the operator in the kafka namespace into the cluster)
3. Set your Kafka configurations in a Kubernetes custom resource (sample: config/samples/simplekafkacluster.yaml) and run this command to deploy the Kafka components:

# Add your zookeeper svc name to the configuration
kubectl create -n kafka -f config/samples/simplekafkacluster.yaml
# If prometheus operator installed create the ServiceMonitors
kubectl create -n kafka -f config/sample/kafkacluster-prometheus.yaml

In this case you have to install Prometheus with proper configuration if you want the Kafka-Operator to react to alerts. Again, if you need Prometheus and would like to have a fully automated and managed experience of Apache Kafka on Kubernetes please try it with Pipeline.

Easy way: installing with Helm

Alternatively, if you are using Helm, you can deploy the operator using a Helm chart Helm chart:

helm repo add banzaicloud-stable https://kubernetes-charts.banzaicloud.com/
helm install --name=kafka-operator --namespace=kafka banzaicloud-stable/kafka-operator -f config/samples/example-prometheus-alerts.yaml
# Add your zookeeper svc name to the configuration
kubectl create -n kafka -f config/samples/simplekafkacluster.yaml
# If prometheus operator installed create the ServiceMonitors
kubectl create -n kafka -f config/sample/kafkacluster-prometheus.yaml

In this case Prometheus will be installed and configured properly for the Kafka-Operator.

Test Your Deployment

For simple test code please check out the test docs

For a more in-depth view at using SSL and the KafkaUser CRD see the SSL docs

For creating topics via with KafkaTopic CRD there is an example and more information in the topics docs

Development

Check out the developer docs.

Features

Check out the supported features.

Issues, feature requests and roadmap

Please note that the Kafka operator is constantly under development and new releases might introduce breaking changes. We are striving to keep backward compatibility as much as possible while adding new features at a fast pace. Issues, new features or bugs are tracked on the projects GitHub page - please feel free to add yours!

To track some of the significant features and future items from the roadmap please visit the roadmap doc.

Contributing

If you find this project useful here's how you can help:

• Send a pull request with your new features and bug fixes
• Help new users with issues they may encounter
• Support the development of this project and star this repo!

When you are opening a PR to Kafka operator the first time we will require you to sign a standard CLA.

Community

If you have any questions about the Kafka operator, and would like to talk to us and the other members of the Banzai Cloud community, please join our #kafka-operator channel on Slack.

License

Copyright (c) 2019 Banzai Cloud, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.