CP-Zookeeper Helm Chart

This chart bootstraps an ensemble of Confluent Zookeeper

Prerequisites

• Kubernetes 1.9.2+
• Helm 2.8.2+

Developing Environment

• Pivotal Container Service (PKS)
• Google Kubernetes Engine (GKE)

Docker Image Source

• DockerHub -> ConfluentInc

Installing the Chart

Install along with cp-helm-charts

git clone https://github.com/confluentinc/cp-helm-charts.git
helm install cp-helm-charts

To install with a specific name, you can do:

helm install --name my-zookeeper ./cp-zookeeper

Install with cp-zookeeper alone

helm install cp-helm-charts/charts/cp-zookeeper

Installed Components

You can use helm status <release name> to view all of the installed components.

For example:

$ helm status unsung-salamander

RESOURCES:
==> v1/Service
NAME                                     TYPE       CLUSTER-IP     EXTERNAL-IP  PORT(S)            AGE
unsung-salamander-cp-zookeeper-headless  ClusterIP  None           <none>       2888/TCP,3888/TCP  6m
unsung-salamander-cp-zookeeper           ClusterIP  10.19.241.242  <none>       2181/TCP           6m

==> v1beta1/StatefulSet
NAME                            DESIRED  CURRENT  AGE
unsung-salamander-cp-zookeeper  3        3        6m

==> v1beta1/PodDisruptionBudget
NAME                                MIN AVAILABLE  MAX UNAVAILABLE  ALLOWED DISRUPTIONS  AGE
unsung-salamander-cp-zookeeper-pdb  N/A            1                1                    6m

==> v1/Pod(related)
NAME                              READY  STATUS   RESTARTS  AGE
unsung-salamander-cp-zookeeper-0  1/1    Running  0         6m
unsung-salamander-cp-zookeeper-1  1/1    Running  0         6m
unsung-salamander-cp-zookeeper-2  1/1    Running  0         6m

==> v1/ConfigMap
NAME                                          DATA  AGE
unsung-salamander-cp-zookeeper-jmx-configmap  1     6m

There are

1. A StatefulSet unsung-salamander-cp-zookeeper which contains 3 Zookeeper Pods: unsung-salamander-cp-zookeeper-<0|1|2>. Each Pod has a container running a ZooKeeper server and an optional sidecar JMX Exporter Container.
2. A PodDisruptionBudget unsung-salamander-cp-zookeeper-pdb to ensure service availability during planned maintenance.
3. A Service unsung-salamander-cp-zookeeper for clients to connect to Zookeeper.
4. A Headless Service unsung-salamander-cp-zookeeper-headless to control the network domain for the ZooKeeper processes.
5. A ConfigMap which contains configuration for Prometheus JMX Exporter.

Configuration

You can specify each parameter using the --set key=value[,key=value] argument to helm install.

Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,

helm install --name my-zookeeper -f my-values.yaml ./cp-zookeeper

Tip: A default values.yaml is provided

Zookeeper Ensemble

The configuration parameters in this section control the resources requested and utilized by the cp-zookeeper chart.

Parameter	Description	Default
servers	The number of ZooKeeper servers. This should always be (1,3,5, or 7).	3

PodDisruptionBudget

Parameter	Description	Default
minAvailable	The minimum number of servers that must be available during evictions. This should in the interval [(servers/2) + 1,(servers - 1)]. If not set, maxUnavailable: 1 will be applied.	servers-1

Image

Parameter	Description	Default
image	Docker Image of Confluent Zookeeper.	confluentinc/cp-zookeeper
imageTag	Docker Image Tag of Confluent Zookeeper.	5.0.1
imagePullPolicy	Docker Image Tag of Confluent Zookeeper.	IfNotPresent
imagePullSecrets	Secrets to be used for private registries.	see values.yaml for details

StatefulSet Configurations

Parameter	Description	Default
podManagementPolicy	The Zookeeper StatefulSet Pod Management Policy: Parallel or OrderedReady.	OrderedReady
updateStrategy	The ZooKeeper StatefulSet update strategy: RollingUpdate or OnDelete.	RollingUpdate

Confluent Zookeeper Configuration

Parameter	Description	Default
tickTime	The length of a single tick, which is the basic time unit used by ZooKeeper, as measured in milliseconds. It is used to regulate heartbeats, and timeouts. For example, the minimum session timeout will be two ticks.	2000
syncLimit	Amount of time, in ticks (see tickTime), to allow followers to sync with ZooKeeper. If followers fall too far behind a leader, they will be dropped.	5
initLimit	Amount of time, in ticks (see tickTime), to allow followers to connect and sync to a leader. Increased this value as needed, if the amount of data managed by ZooKeeper is large.	10
maxClientCnxns	Limits the number of concurrent connections (at the socket level) that a single client, identified by IP address, may make to a single member of the ZooKeeper ensemble. This is used to prevent certain classes of DoS attacks, including file descriptor exhaustion.	60
autoPurgeSnapRetainCount	When enabled, ZooKeeper auto purge feature retains the autopurge.snapRetainCount most recent snapshots and the corresponding transaction logs in the dataDir and dataLogDir respectively and deletes the rest.	3
autoPurgePurgeInterval	The time interval in hours for which the purge task has to be triggered. Set to a positive integer (1 and above) to enable the auto purging.	72

Zookeeper JVM Heap Options

Parameter	Description	Default
heapOptions	The JVM Heap Options for Zookeeper	"-Xms512M -Xmx512M"

Port

Parameter	Description	Default
serverPort	The port on which the ZooKeeper servers listen for requests from other servers in the ensemble.	2888
leaderElectionPort	The port on which the ZooKeeper servers perform leader election.	3888
clientPort	The port to listen for client connections; that is, the port that clients attempt to connect to.	2181

Persistence

Parameter	Description	Default
persistence.enabled	Whether to create a PVC. If false, an emptyDir on the host will be used.	true
persistence.dataDirSize	Size for Data dir, where ZooKeeper will store the in-memory database snapshots.	5Gi
persistence.dataDirStorageClass	Valid options: nil, "-", or storage class name.	nil
persistence.dataLogDirSize	Size for data log dir, which is a dedicated log device to be used, and helps avoid competition between logging and snaphots.	5Gi
persistence.dataLogDirStorageClass	Valid options: nil, "-", or storage class name.	nil

Resources

Parameter	Description	Default
resources.requests.cpu	The amount of CPU to request.	see values.yaml for details
resources.requests.memory	The amount of memory to request.	see values.yaml for details
resources.requests.limit	The upper limit CPU usage for a Zookeeper Pod.	see values.yaml for details
resources.requests.limit	The upper limit memory usage for a Zookeeper Pod.	see values.yaml for details

Annotations

Parameter	Description	Default
podAnnotations	Map of custom annotations to attach to the pod spec.	{}

JMX Configuration

Parameter	Description	Default
jmx.port	The jmx port which JMX style metrics are exposed.	5555

Prometheus JMX Exporter Configuration

Parameter	Description	Default
prometheus.jmx.enabled	Whether or not to install Prometheus JMX Exporter as a sidecar container and expose JMX metrics to Prometheus.	true
prometheus.jmx.image	Docker Image for Prometheus JMX Exporter container.	solsson/kafka-prometheus-jmx-exporter@sha256
prometheus.jmx.imageTag	Docker Image Tag for Prometheus JMX Exporter container.	6f82e2b0464f50da8104acd7363fb9b995001ddff77d248379f8788e78946143
prometheus.jmx.port	JMX Exporter Port which exposes metrics in Prometheus format for scraping.	5556

Deployment Topology

Parameter	Description	Default
nodeSelector	Dictionary containing key-value-pairs to match labels on nodes. When defined pods will only be scheduled on nodes, that have each of the indicated key-value pairs as labels. Further information can be found in the Kubernetes documentation	{}
tolerations	Array containing taint references. When defined, pods can run on nodes, which would otherwise deny scheduling. Further information can be found in the Kubernetes documentation	{}