# NATS

[NATS](https://nats.io/) is an open-source, cloud-native messaging system. It provides a lightweight server that is written in the Go programming language.

## TL;DR

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

## Introduction

This chart bootstraps a [NATS](https://github.com/bitnami/bitnami-docker-nats) deployment on a [Kubernetes](http://kubernetes.io) cluster using the [Helm](https://helm.sh) package manager.

Bitnami charts can be used with [Kubeapps](https://kubeapps.com/) 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](https://kubeprod.io/).

## Prerequisites

- Kubernetes 1.12+
- Helm 3.1.0

## Installing the Chart

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

```bash
$ helm install my-release bitnami/nats
```

The command deploys NATS on the Kubernetes cluster in the default configuration. The [Parameters](#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:

```bash
$ 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`                                                   |
| `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,

```bash
$ 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.

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

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

> **Tip**: You can use the default [values.yaml](values.yaml)

## Configuration and installation details

### [Rolling VS Immutable tags](https://docs.bitnami.com/containers/how-to/understand-rolling-tags-containers/)

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.

```yaml
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.

```yaml
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.

```yaml
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](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity).

As an alternative, you can use of the preset configurations for pod affinity, pod anti-affinity, and node affinity available at the [bitnami/common](https://github.com/bitnami/charts/tree/master/bitnami/common#affinities) 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](https://docs.bitnami.com/general/how-to/troubleshoot-helm-chart-issues).

## 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.

```bash
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](https://helm.sh/docs/chart_best_practices/labels/#standard-labels).
- This version also introduces `bitnami/common`, a [library chart](https://helm.sh/docs/topics/library_charts/#helm) as a dependency. More documentation about this new utility could be found [here](https://github.com/bitnami/charts/tree/master/bitnami/common#bitnami-common-library-chart). 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](https://github.com/helm/charts#status-of-the-project), 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](https://helm.sh/docs/topics/charts/#the-apiversion-field) 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](https://helm.sh/docs/topics/v2_v3_migration/#migration-use-cases) 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:

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