charts/bitnami/cassandra

cassandra

Apache Cassandra is a free and open-source distributed database management system designed to handle large amounts of data across many commodity servers or datacenters.

TL;DR;

$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm install bitnami/cassandra

Introduction

This chart bootstraps a Cassandra deployment on a Kubernetes cluster using the Helm package manager.

Bitnami charts can be used with Kubeapps for deployment and management of Helm Charts in clusters. This Helm chart has been tested on top of Bitnami Kubernetes Production Runtime (BKPR). Deploy BKPR to get automated TLS certificates, logging and monitoring for your applications.

Prerequisites

• Kubernetes 1.8+
• PV provisioner support in the underlying infrastructure

Installing the Chart

To install the chart with the release name my-release:

$ helm install --name my-release bitnami/cassandra

The command deploys one node with Cassandra on the Kubernetes cluster in the default configuration. The configuration section lists the parameters that can be configured during installation.

Tip

: List all releases using helm list

Uninstalling the Chart

To uninstall/delete the my-release release:

$ helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Configuration

The following tables lists the configurable parameters of the cassandra chart and their default values.

Parameter	Description	Default
global.imageRegistry	Global Docker Image registry	nil
global.imagePullSecrets	Global Docker registry secret names as an array	[] (does not add image pull secrets to deployed pods)
image.registry	Cassandra Image registry	docker.io
image.repository	Cassandra Image name	bitnami/cassandra
image.tag	Cassandra Image tag	{TAG_NAME}
image.pullPolicy	Image pull policy	IfNotPresent
image.pullSecrets	Specify docker-registry secret names as an array	[] (does not add image pull secrets to deployed pods)
nameOverride	String to partially override cassandra.fullname template with a string (will prepend the release name)	nil
fullnameOverride	String to fully override cassandra.fullname template with a string	nil
volumePermissions.enabled	Enable init container that changes volume permissions in the data directory (for cases where the default k8s runAsUser and fsUser values do not work)	false
volumePermissions.image.registry	Init container volume-permissions image registry	docker.io
volumePermissions.image.repository	Init container volume-permissions image name	bitnami/minideb
volumePermissions.image.tag	Init container volume-permissions image tag	latest
volumePermissions.image.pullPolicy	Init container volume-permissions image pull policy	Always
volumePermissions.resources	Init container resource requests/limit	nil
service.type	Kubernetes Service type	ClusterIP
service.nodePort	Kubernetes Service nodePort	nil
service.loadBalancerIP	LoadBalancerIP if service type is LoadBalancer	nil
service.annotations	Annotations for the service	{}
persistence.enabled	Use PVCs to persist data	true
persistence.storageClass	Persistent Volume Storage Class	generic
persistence.annotations	Persistent Volume Claim annotations Annotations	{}
persistence.accessModes	Persistent Volume Access Modes	[ReadWriteOnce]
persistence.size	Persistent Volume Size	8Gi
tlsEncryptionSecretName	Secret with keystore, keystore password, truststore and truststore password	{}
resources	CPU/Memory resource requests/limits	{}
existingConfiguration	Pointer to a configMap that contains custom Cassandra configuration files. This will override any Cassandra configuration variable set in the chart	{}
cluster.name	Cassandra cluster name	cassandra
cluster.replicaCount	Number of Cassandra nodes	1
cluster.seedCount	Number of seed nodes (note: must be greater or equal than 1 and less or equal to cluster.replicaCount)	1
cluster.numTokens	Number of tokens for each node	256
cluster.datacenter	Datacenter name	dc1
cluster.rack	Rack name	rack1
cluster.enableRPC	Enable Thrift RPC endpoint	true
cluster.minimumAvailable	Minimum nuber of instances that must be available in the cluster (used of PodDisruptionBudget)	1
cluster.internodeEncryption	Set internode encryption. NOTE: A value different from 'none' requires setting tlsEncryptionSecretName	none
cluster.clientEncryption	Set client-server encryption. NOTE: A value different from 'false' requires setting tlsEncryptionSecretName	false
cluster.jvm.extraOpts	Set the value for Java Virtual Machine extra optinos (JVM_EXTRA_OPTS)	nil
cluster.jvm.maxHeapSize	Set Java Virtual Machine maximum heap size (MAX_HEAP_SIZE). Calculated automatically if nil	nil
cluster.jvm.newHeapSize	Set Java Virtual Machine new heap size (HEAP_NEWSIZE). Calculated automatically if nil	nil
cluster.domain	Set the kubernetes cluster domain	cluster.local
service.port	CQL Port for the Kubernetes service	9042
service.thriftPort	Thrift Port for the Kubernetes service	9160
dbUser.user	Cassandra admin user	cassandra
dbUser.forcePassword	Force the user to provide a non-empty password for dbUser.user	false
dbUser.password	Password for dbUser.user. Randomly generated if empty	(Random generated)
dbUser.existingSecret	Use an existing secret object for dbUser.user password (will ignore dbUser.password)	nil
initDBConfigMap	Configmap for initialization CQL commands (done in the first node). Useful for creating keyspaces at startup, for instance	nil
livenessProbe.enabled	Turn on and off liveness probe	true
livenessProbe.initialDelaySeconds	Delay before liveness probe is initiated	30
livenessProbe.periodSeconds	How often to perform the probe	30
livenessProbe.timeoutSeconds	When the probe times out	5
livenessProbe.successThreshold	Minimum consecutive successes for the probe to be considered successful after having failed	1
livenessProbe.failureThreshold	Minimum consecutive failures for the probe to be considered failed after having succeeded.	5
readinessProbe.enabled	Turn on and off readiness probe	true
readinessProbe.initialDelaySeconds	Delay before readiness probe is initiated	5
readinessProbe.periodSeconds	How often to perform the probe	10
readinessProbe.timeoutSeconds	When the probe times out	5
readinessProbe.successThreshold	Minimum consecutive successes for the probe to be considered successful after having failed	1
readinessProbe.failureThreshold	Minimum consecutive failures for the probe to be considered failed after having succeeded.	5
podAnnotations	Additional pod annotations	{}
podLabels	Additional pod labels	{}
statefulset.updateStrategy	Update strategy for StatefulSet	onDelete
statefulset.rollingUpdatePartition	Partition update strategy	nil
securityContext.enabled	Enable security context	true
securityContext.fsGroup	Group ID for the container	1001
securityContext.runAsUser	User ID for the container	1001
affinity	Enable node/pod affinity	{}
tolerations	Toleration labels for pod assignment	[]
networkPolicy.enabled	Enable NetworkPolicy	false
networkPolicy.allowExternal	Don't require client label for connections	true
metrics.enabled	Start a side-car prometheus exporter	false
metrics.image.registry	Cassandra exporter Image registry	docker.io
metrics.image.repository	Cassandra exporter Image name	bitnami/cassandra-exporter
metrics.image.tag	Cassandra exporter Image tag	{TAG_NAME}
metrics.image.pullPolicy	Image pull policy	IfNotPresent
metrics.image.pullSecrets	Specify docker-registry secret names as an array	[] (does not add image pull secrets to deployed pods)
metrics.podAnnotations	Additional annotations for Metrics exporter	{prometheus.io/scrape: "true", prometheus.io/port: "8080"}
metrics.resources	Exporter resource requests/limit	{}

The above parameters map to the env variables defined in bitnami/cassandra. For more information please refer to the bitnami/cassandra image documentation.

Specify each parameter using the --set key=value[,key=value] argument to helm install. For example,

$ helm install --name my-release \
  --set dbUser.user=admin,dbUser.password=password\
    bitnami/cassandra

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

$ helm install --name my-release -f values.yaml bitnami/cassandra

Tip

: You can use the default values.yaml

Production configuration

This chart includes a values-production.yaml file where you can find some parameters oriented to production configuration in comparison to the regular values.yaml.

$ helm install --name my-release -f ./values-production.yaml bitnami/cassandra

• Number of Cassandra and seed nodes:

- master.replicaCount: 1
- master.seedCount: 1
+ master.replicaCount: 3
+ master.seedCount: 2

• Minimum nuber of instances that must be available in the cluster:

- cluster.minimumAvailable: 1
+ cluster.minimumAvailable: 2

• Force the user to provide a non-empty password for dbUser.user:

- dbUser.forcePassword: false
+ dbUser.forcePassword: true

• Enable NetworkPolicy:

- networkPolicy.enabled: false
+ networkPolicy.enabled: true

• Start a side-car prometheus exporter:

- metrics.enabled: false
+ metrics.enabled: true

Rolling VS Immutable tags

It is strongly recommended to use immutable tags in a production environment. This ensures your deployment does not change automatically if the same tag is updated with a different image.

Bitnami will release a new chart updating its containers if a new version of the main container, significant changes, or critical vulnerabilities exist.

Persistence

The Bitnami cassandra image stores the cassandra data at the /bitnami/cassandra path of the container.

Persistent Volume Claims are used to keep the data across deployments. This is known to work in GCE, AWS, and minikube. See the Configuration section to configure the PVC or to disable persistence.

Adjust permissions of persistent volume mountpoint

As the image run as non-root by default, it is necessary to adjust the ownership of the persistent volume so that the container can write data into it.

By default, the chart is configured to use Kubernetes Security Context to automatically change the ownership of the volume. However, this feature does not work in all Kubernetes distributions. As an alternative, this chart supports using an initContainer to change the ownership of the volume before mounting it in the final destination.

You can enable this initContainer by setting volumePermissions.enabled to true.

Enable TLS for Cassandra

You can enable TLS between client and server and between nodes. In order to do so, you need to set the following values:

• For internode cluster encryption, set cluster.internodeEncryption to a value different from none. Available values are all, dc or rack.
• For client-server encryption, set cluster.clientEncryption to true.

In addition to this, you must create a secret containing the keystore and truststore certificates and their corresponding protection passwords. Then, set the tlsEncryptionSecretName when deploying the chart.

You can create the secret with this command assuming you have your certificates in your working directory (replace the PUT_YOUR_KEYSTORE_PASSWORD and PUT_YOUR_TRUSTSTORE_PASSWORD placeholders):

kubectl create secret generic casssandra-tls --from-file=./keystore --from-file=./truststore --from-literal=keystore-password=PUT_YOUR_KEYSTORE_PASSWORD --from-literal=truststore-password=PUT_YOUR_TRUSTSTORE_PASSWORD

As an example of Cassandra installed with TLS you can use this command:

helm install --name my-release bitnami/cassandra --set cluster.internodeEncryption=all \
             --set cluster.clientEncryption=true --set tlsEncryptionSecretName=cassandra-tls \

Initializing the database

The Bitnami cassandra image allows having initialization scripts mounted in /docker-entrypoint.initdb. This is done in the chart by adding files in the files/docker-entrypoint-initdb.d folder (in order to do so, clone this chart) or by setting the initDBConfigMap value with a ConfigMap that includes the necessary sh or cql scripts:

kubectl create configmap init-db --from-file=path/to/scripts
helm install bitnami/cassandra --set initDBConfigMap=init-db

Upgrade

2.0.0

This releases make it possible to specify custom initialization scripts in both cql and sh files.

Breaking changes

• startupCQL has been removed. Instead, for initializing the database, see this section.