charts/bitnami/nats

NATS

NATS is an open-source, cloud-native messaging system. It provides a lightweight server that is written in the Go programming language.

TL;DR

$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm install my-release bitnami/nats

Introduction

This chart bootstraps a NATS 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 chart has been tested to work with NGINX Ingress, cert-manager, fluentd and Prometheus on top of the BKPR.

Prerequisites

• Kubernetes 1.12+
• Helm 3.1.0

Installing the Chart

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

$ helm install my-release bitnami/nats

The command deploys NATS on the Kubernetes cluster in the default configuration. The Parameters 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 deployment:

$ helm delete my-release

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

Parameters

The following tables lists the configurable parameters of the NATS chart and their default values per section/component:

Global parameters

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)

Common parameters

Parameter	Description	Default
nameOverride	String to partially override common.names.fullname	nil
fullnameOverride	String to fully override common.names.fullname	nil
commonLabels	Labels to add to all deployed objects	{}
commonAnnotations	Annotations to add to all deployed objects	{}
clusterDomain	Default Kubernetes cluster domain	cluster.local
extraDeploy	Array of extra objects to deploy with the release	[] (evaluated as a template)
kubeVersion	Force target Kubernetes version (using Helm capabilities if not set)	nil

NATS parameters

Parameter	Description	Default
image.registry	NATS image registry	docker.io
image.repository	NATS image name	bitnami/nats
image.tag	NATS 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)
hostAliases	Add deployment host aliases	[]
auth.enabled	Switch to enable/disable client authentication	true
auth.user	Client authentication user	nats_client
auth.password	Client authentication password	random alhpanumeric string (10)
auth.token	Client authentication token	nil
auth.timeout	Client authentication timeout (seconds)	1
clusterAuth.enabled	Switch to enable/disable cluster authentication	true
clusterAuth.user	Cluster authentication user	nats_cluster
clusterAuth.password	Cluster authentication password	random alhpanumeric string (10)
clusterAuth.token	Cluster authentication token	nil
debug.enabled	Switch to enable/disable debug on logging	false
debug.trace	Switch to enable/disable trace debug level on logging	false
debug.logtime	Switch to enable/disable logtime on logging	false
maxConnections	Max. number of client connections	nil
maxControlLine	Max. protocol control line	nil
maxPayload	Max. payload	nil
writeDeadline	Duration the server can block on a socket write to a client	nil
natsFilename	Filename used by several NATS files (binary, configurarion file, and pid file)	nats-server
command	Override default container command (useful when using custom images)	nil
args	Override default container args (useful when using custom images)	nil
metrics.kafka.extraFlags	Extra flags to be passed to NATS	{}
extraEnvVars	Extra environment variables to be set on NATS container	{}
extraEnvVarsCM	Name of existing ConfigMap containing extra env vars	nil
extraEnvVarsSecret	Name of existing Secret containing extra env vars	nil

NATS deployment/statefulset parameters

Parameter	Description	Default
resourceType	NATS cluster resource type under Kubernetes (Supported: StatefulSets, or Deployment)	statefulset
replicaCount	Number of NATS nodes	1
schedulerName	Name of an alternate	nil
priorityClassName	Name of pod priority class	nil
podSecurityContext	NATS pods' Security Context	Check values.yaml file
updateStrategy	Strategy to use to update Pods	Check values.yaml file
containerSecurityContext	NATS containers' Security Context	Check values.yaml file
resources.limits	The resources limits for the NATS container	{}
resources.requests	The requested resources for the NATS container	{}
livenessProbe	Liveness probe configuration for NATS	Check values.yaml file
readinessProbe	Readiness probe configuration for NATS	Check values.yaml file
customLivenessProbe	Override default liveness probe	nil
customReadinessProbe	Override default readiness probe	nil
podAffinityPreset	Pod affinity preset. Ignored if affinity is set. Allowed values: soft or hard	""
podAntiAffinityPreset	Pod anti-affinity preset. Ignored if affinity is set. Allowed values: soft or hard	soft
nodeAffinityPreset.type	Node affinity preset type. Ignored if affinity is set. Allowed values: soft or hard	""
nodeAffinityPreset.key	Node label key to match. Ignored if affinity is set.	""
nodeAffinityPreset.values	Node label values to match. Ignored if affinity is set.	[]
affinity	Affinity for pod assignment	{} (evaluated as a template)
nodeSelector	Node labels for pod assignment	{} (evaluated as a template)
tolerations	Tolerations for pod assignment	[] (evaluated as a template)
podLabels	Extra labels for NATS pods	{} (evaluated as a template)
podAnnotations	Annotations for NATS pods	{} (evaluated as a template)
extraVolumeMounts	Optionally specify extra list of additional volumeMounts for NATS container(s)	[]
extraVolumes	Optionally specify extra list of additional volumes for NATS pods	[]
initContainers	Add additional init containers to the NATS pods	{} (evaluated as a template)
sidecars	Add additional sidecar containers to the NATS pods	{} (evaluated as a template)

Exposure parameters

Parameter	Description	Default
client.service.type	Kubernetes Service type (NATS client)	ClusterIP
client.service.port	NATS client port	4222
client.service.nodePort	Port to bind to for NodePort service type (NATS client)	nil
client.service.annotations	Annotations for NATS client service	{}
client.service.loadBalancerIP	loadBalancerIP if NATS client service type is LoadBalancer	nil
cluster.service.type	Kubernetes Service type (NATS cluster)	ClusterIP
cluster.service.port	NATS cluster port	6222
cluster.service.nodePort	Port to bind to for NodePort service type (NATS cluster)	nil
cluster.service.annotations	Annotations for NATS cluster service	{}
cluster.service.loadBalancerIP	loadBalancerIP if NATS cluster service type is LoadBalancer	nil
cluster.connectRetries	Configure number of connect retries for implicit routes	nil
monitoring.service.type	Kubernetes Service type (NATS monitoring)	ClusterIP
monitoring.service.port	NATS monitoring port	8222
monitoring.service.nodePort	Port to bind to for NodePort service type (NATS monitoring)	nil
monitoring.service.annotations	Annotations for NATS monitoring service	{}
monitoring.service.loadBalancerIP	loadBalancerIP if NATS monitoring service type is LoadBalancer	nil
ingress.enabled	Enable ingress controller resource	false
ingress.certManager	Add annotations for cert-manager	false
ingress.enabled	Enable ingress controller resource	false
ingress.certManager	Add annotations for cert-manager	false
ingress.hostname	Default host for the ingress resource	nats.local
ingress.path	Default path for the ingress resource	/
ingress.tls	Create TLS Secret	false
ingress.annotations	Ingress annotations	[] (evaluated as a template)
ingress.extraHosts[0].name	Additional hostnames to be covered	nil
ingress.extraHosts[0].path	Additional hostnames to be covered	nil
ingress.extraPaths	Additional arbitrary path/backend objects	nil
ingress.extraTls[0].hosts[0]	TLS configuration for additional hostnames to be covered	nil
ingress.extraTls[0].secretName	TLS configuration for additional hostnames to be covered	nil
ingress.secrets[0].name	TLS Secret Name	nil
ingress.secrets[0].certificate	TLS Secret Certificate	nil
ingress.secrets[0].key	TLS Secret Key	nil
networkPolicy.enabled	Enable the default NetworkPolicy policy	false
networkPolicy.allowExternal	Don't require client label for connections	true
networkPolicy.additionalRules	Additional NetworkPolicy rules	{} (evaluated as a template)

Metrics parameters

Parameter	Description	Default
metrics.enabled	Enable Prometheus metrics via exporter side-car	false
metrics.image.registry	Prometheus metrics exporter image registry	docker.io
metrics.image.repository	Prometheus metrics exporter image name	bitnami/nats-exporter
metrics.image.tag	Prometheus metrics exporter image tag	{TAG_NAME}
metrics.image.pullPolicy	Prometheus metrics image pull policy	IfNotPresent
metrics.image.pullSecrets	Prometheus metrics image pull secrets	[] (does not add image pull secrets to deployed pods)
metrics.flags	Flags to be passed to Prometheus metrics	Check values.yaml file
metrics.containerPort	Prometheus metrics exporter port	7777
metrics.resources	Prometheus metrics exporter resource requests/limit	{}
metrics.service.type	Kubernetes service type (ClusterIP, NodePort or LoadBalancer)	ClusterIP
metrics.service.port	Prometheus metrics svc port	7777
metrics.service.annotations	Prometheus metrics exporter annotations	prometheus.io/scrape: "true", prometheus.io/port: "7777"
metrics.service.nodePort	Kubernetes HTTP node port	""
metrics.service.annotations	Annotations for Prometheus metrics service	Check values.yaml file
metrics.service.loadBalancerIP	loadBalancerIP if service type is LoadBalancer	nil
metrics.service.loadBalancerSourceRanges	Address that are allowed when service is LoadBalancer	[]
metrics.service.clusterIP	Static clusterIP or None for headless services	nil
metrics.serviceMonitor.enabled	if true, creates a Prometheus Operator ServiceMonitor (also requires metrics.enabled to be true)	false
metrics.serviceMonitor.namespace	Namespace in which Prometheus is running	nil
metrics.serviceMonitor.interval	Interval at which metrics should be scraped.	nil (Prometheus Operator default value)
metrics.serviceMonitor.scrapeTimeout	Timeout after which the scrape is ended	nil (Prometheus Operator default value)
metrics.serviceMonitor.selector	Prometheus instance selector labels	nil

Other parameters

Parameter	Description	Default
pdb.create	Enable/disable a Pod Disruption Budget creation	false
pdb.minAvailable	Minimum number/percentage of pods that should remain scheduled	1
pdb.maxUnavailable	Maximum number/percentage of pods that may be made unavailable	nil

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

$ helm install my-release \
  --set auth.enabled=true,auth.user=my-user,auth.password=T0pS3cr3t \
    bitnami/nats

The above command enables NATS client authentication with my-user as user and T0pS3cr3t as password credentials.

NOTE: Once this chart is deployed, it is not possible to change the application's access credentials, such as usernames or passwords, using Helm. To change these application credentials after deployment, delete any persistent volumes (PVs) used by the chart and re-deploy it, or use the application's built-in administrative tools if available.

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

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

Tip

: You can use the default values.yaml

Configuration and installation details

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.

Adding extra environment variables

In case you want to add extra environment variables (useful for advanced operations like custom init scripts), you can use the extraEnvVars property.

extraEnvVars:
  - name: LOG_LEVEL
    value: DEBUG

Alternatively, you can use a ConfigMap or a Secret with the environment variables. To do so, use the extraEnvVarsCM or the extraEnvVarsSecret values.

Sidecars and Init Containers

If you have a need for additional containers to run within the same pod as the NATS app (e.g. an additional metrics or logging exporter), you can do so via the sidecars config parameter. Simply define your container according to the Kubernetes container spec.

sidecars:
  - name: your-image-name
    image: your-image
    imagePullPolicy: Always
    ports:
      - name: portname
       containerPort: 1234

Similarly, you can add extra init containers using the initContainers parameter.

initContainers:
  - name: your-image-name
    image: your-image
    imagePullPolicy: Always
    ports:
      - name: portname
        containerPort: 1234

Deploying extra resources

There are cases where you may want to deploy extra objects, such a ConfigMap containing your app's configuration or some extra deployment with a micro service used by your app. For covering this case, the chart allows adding the full specification of other objects using the extraDeploy parameter.

Setting Pod's affinity

This chart allows you to set your custom affinity using the affinity parameter. Find more information about Pod's affinity in the kubernetes documentation.

As an alternative, you can use of the preset configurations for pod affinity, pod anti-affinity, and node affinity available at the bitnami/common chart. To do so, set the podAffinityPreset, podAntiAffinityPreset, or nodeAffinityPreset parameters.

Troubleshooting

Find more information about how to deal with common errors related to Bitnami’s Helm charts in this troubleshooting guide.

Upgrading

Deploy chart with NATS version 1.x.x

NATS version 2.0.0 has renamed the server binary filename from gnatsd to nats-server. Therefore, the default values has been changed in the chart, however, it is still possible to use the chart to deploy NATS version 1.x.x using the natsFilename property.

helm install nats-v1 --set natsFilename=gnatsd --set image.tag=1.4.1 bitnami/nats

To 6.0.0

• Some parameters were renamed or disappeared in favor of new ones on this major version. For instance:
  • securityContext.* is deprecated in favor of podSecurityContext and containerSecurityContext.
• Ingress configuration was adapted to follow the Helm charts best practices.
• Chart labels were also adapted to follow the Helm charts standard labels.
• This version also introduces bitnami/common, a library chart as a dependency. More documentation about this new utility could be found here. Please, make sure that you have updated the chart dependencies before executing any upgrade.

Consequences:

• Backwards compatibility is not guaranteed.

To 5.0.0

On November 13, 2020, Helm v2 support was formally finished, this major version is the result of the required changes applied to the Helm Chart to be able to incorporate the different features added in Helm v3 and to be consistent with the Helm project itself regarding the Helm v2 EOL.

What changes were introduced in this major version?

• Previous versions of this Helm Chart use apiVersion: v1 (installable by both Helm 2 and 3), this Helm Chart was updated to apiVersion: v2 (installable by Helm 3 only). Here you can find more information about the apiVersion field.
• The different fields present in the Chart.yaml file has been ordered alphabetically in a homogeneous way for all the Bitnami Helm Charts

Considerations when upgrading to this version

• If you want to upgrade to this version from a previous one installed with Helm v3, you shouldn't face any issues
• If you want to upgrade to this version using Helm v2, this scenario is not supported as this version doesn't support Helm v2 anymore
• If you installed the previous version with Helm v2 and wants to upgrade to this version with Helm v3, please refer to the official Helm documentation about migrating from Helm v2 to v3

Useful links

• https://docs.bitnami.com/tutorials/resolve-helm2-helm3-post-migration-issues/
• https://helm.sh/docs/topics/v2_v3_migration/
• https://helm.sh/blog/migrate-from-helm-v2-to-helm-v3/

To 1.0.0

Backwards compatibility is not guaranteed unless you modify the labels used on the chart's deployments. Use the workaround below to upgrade from versions previous to 1.0.0. The following example assumes that the release name is nats:

$ kubectl delete statefulset nats-nats --cascade=false