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# Apache Pulsar Helm Chart

This project provides Helm Charts for installing Apache Pulsar on Kubernetes.

Read [Deploying Pulsar on Kubernetes](http://pulsar.apache.org/docs/deploy-kubernetes/) for more details.

> :warning: This helm chart is updated outside of the regular Pulsar release cycle and might lag behind a bit. It only supports basic Kubernetes features now. Currently, it can be used as no more than a template and starting point for a Kubernetes deployment. In many cases, it would require some customizations.

## Features

This Helm Chart includes all the components of Apache Pulsar for a complete experience.

- [x] Pulsar core components:
    - [x] ZooKeeper
    - [x] Bookies
    - [x] Brokers
    - [x] Functions
    - [x] Proxies
- [x] Management & monitoring components:
    - [x] Pulsar Manager
    - [x] Optional PodMonitors for each component (enabled by default)
    - [x] [Kube-Prometheus-Stack](https://github.com/prometheus-community/helm-charts/tree/main/charts/kube-prometheus-stack) (as of 3.0.0)

It includes support for:

- [x] Security
    - [x] Automatically provisioned TLS certs, using [Jetstack](https://www.jetstack.io/)'s [cert-manager](https://cert-manager.io/docs/)
        - [x] self-signed
        - [x] [Let's Encrypt](https://letsencrypt.org/)
    - [x] TLS Encryption
        - [x] Proxy
        - [x] Broker
        - [x] Toolset
        - [x] Bookie
        - [x] ZooKeeper
    - [x] Authentication
        - [x] JWT
        - [ ] Mutal TLS
        - [ ] Kerberos
    - [x] Authorization
    - [x] Non-root broker, bookkeeper, proxy, and zookeeper containers (version 2.10.0 and above)
- [x] Storage
    - [x] Non-persistence storage
    - [x] Persistence Volume
    - [x] Local Persistent Volumes
    - [x] Tiered Storage
- [x] Functions
    - [x] Kubernetes Runtime
    - [x] Process Runtime
    - [x] Thread Runtime
- [x] Operations
    - [x] Independent Image Versions for all components, enabling controlled upgrades

## Requirements

In order to use this chart to deploy Apache Pulsar on Kubernetes, the followings are required.

1. kubectl 1.21 or higher, compatible with your cluster ([+/- 1 minor release from your cluster](https://kubernetes.io/docs/tasks/tools/install-kubectl/#before-you-begin))
2. Helm v3 (3.0.2 or higher)
3. A Kubernetes cluster, version 1.21 or higher.

## Environment setup

Before proceeding to deploying Pulsar, you need to prepare your environment.

### Tools

`helm` and `kubectl` need to be [installed on your computer](https://pulsar.apache.org/docs/helm-tools/).

## Add to local Helm repository

To add this chart to your local Helm repository:

```bash
helm repo add apache https://pulsar.apache.org/charts
```

## Kubernetes cluster preparation

You need a Kubernetes cluster whose version is 1.21 or higher in order to use this chart, due to the usage of certain Kubernetes features.

We provide some instructions to guide you through the preparation: http://pulsar.apache.org/docs/helm-prepare/

## Deploy Pulsar to Kubernetes

1. Configure your values file. The best way to know which values are available is to read the [values.yaml](./charts/pulsar/values.yaml).

2. Install the chart:

    ```bash
    helm install <release-name> -n <namespace> -f your-values.yaml apache/pulsar
    ```

3. Access the Pulsar cluster

    The default values will create a `ClusterIP` for the proxy you can use to interact with the cluster. To find the IP address of proxy use:

    ```bash
    kubectl get service -n <k8s-namespace>
    ```

For more information, please follow our detailed
[quick start guide](https://pulsar.apache.org/docs/getting-started-helm/).

## Customize the deployment 

We provide a [detailed guideline](https://pulsar.apache.org/docs/helm-deploy/) for you to customize
the Helm Chart for a production-ready deployment.

You can also checkout out the example values file for different deployments.

- [Deploy ZooKeeper only](examples/values-cs.yaml)
- [Deploy a Pulsar cluster with an external configuration store](examples/values-cs.yaml)
- [Deploy a Pulsar cluster with local persistent volume](examples/values-local-pv.yaml)
- [Deploy a Pulsar cluster to Minikube](examples/values-minikube.yaml)
- [Deploy a Pulsar cluster with no persistence](examples/values-no-persistence.yaml)
- [Deploy a Pulsar cluster with TLS encryption](examples/values-tls.yaml)
- [Deploy a Pulsar cluster with JWT authentication using symmetric key](examples/values-jwt-symmetric.yaml)
- [Deploy a Pulsar cluster with JWT authentication using asymmetric key](examples/values-jwt-asymmetric.yaml)

## Disabling Kube-Prometheus-Stack CRDs

In order to disable the kube-prometheus-stack fully, it is necessary to add the following to your `values.yaml`:

```yaml
kube-prometheus-stack:
  enabled: false
  prometheusOperator:
    enabled: false
  grafana:
    enabled: false
  alertmanager:
    enabled: false
  prometheus:
    enabled: false
```

Otherwise, the helm chart installation will attempt to install the CRDs for the kube-prometheus-stack. Additionally,
you'll need to disable each of the component's `PodMonitors`. This is shown in some [examples](./examples) and is
verified in some [tests](./.ci/clusters).

## Grafana Dashboards

The Apache Pulsar Helm Chart uses the `kube-prometheus-stack` Helm Chart to deploy Grafana. Dashboards are loaded via a Kubernetes `ConfigMap`. Please see their documentation for loading those dashboards.

The `apache/pulsar` GitHub repo contains some dashboards [here](https://github.com/apache/pulsar/tree/master/grafana).

### Third Party Dashboards

* StreamNative provides Grafana Dashboards for Apache Pulsar in this [GitHub repository](https://github.com/streamnative/apache-pulsar-grafana-dashboard).
* DataStax provides Grafana Dashboards for Apache Pulsar in this [GitHub repository](https://github.com/datastax/pulsar-helm-chart/tree/master/helm-chart-sources/pulsar/grafana-dashboards).

Note: if you have third party dashboards that you would like included in this list, please open a pull request.

## Upgrading

Once your Pulsar Chart is installed, configuration changes and chart
updates should be done using `helm upgrade`.

```bash
helm repo add apache https://pulsar.apache.org/charts
helm repo update
helm get values <pulsar-release-name> > pulsar.yaml
helm upgrade -f pulsar.yaml \
    <pulsar-release-name> apache/pulsar
```

For more detailed information, see our [Upgrading](http://pulsar.apache.org/docs/helm-upgrade/) guide.

## Upgrading to Apache Pulsar 2.10.0 and above (or Helm Chart version 3.0.0 and above)

The 2.10.0+ Apache Pulsar docker image is a non-root container, by default. That complicates an upgrade to 2.10.0
because the existing files are owned by the root user but are not writable by the root group. In order to leverage this
new security feature, the Bookkeeper and Zookeeper StatefulSet [securityContexts](https://kubernetes.io/docs/tasks/configure-pod-container/security-context)
are configurable in the `values.yaml`. They default to:

```yaml
  securityContext:
    fsGroup: 0
    fsGroupChangePolicy: "OnRootMismatch"
```

This configuration is ideal for regular Kubernetes clusters where the UID is stable across restarts. If the process
UID is subject to change (like it is in OpenShift), you'll need to set `fsGroupChangePolicy: "Always"`.

The official docker image assumes that it is run as a member of the root group.

If you upgrade to the latest version of the helm chart before upgrading to Pulsar 2.10.0, then when you perform your
first upgrade to version >= 2.10.0, you will need to set `fsGroupChangePolicy: "Always"` on the first upgrade and then
set it back to `fsGroupChangePolicy: "OnRootMismatch"` on subsequent upgrades. This is because the root file won't
mismatch permissions, but the RocksDB lock file will. If you have direct access to the persistent volumes, you can
alternatively run `chgrp -R g+w /pulsar/data` before upgrading.

Here is a sample error you can expect if the RocksDB lock file is not correctly owned by the root group:

```text
2022-05-14T03:45:06,903+0000  ERROR org.apache.bookkeeper.server.Main - Failed to build bookie server
java.io.IOException: Error open RocksDB database
    at org.apache.bookkeeper.bookie.storage.ldb.KeyValueStorageRocksDB.<init>(KeyValueStorageRocksDB.java:199) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.storage.ldb.KeyValueStorageRocksDB.<init>(KeyValueStorageRocksDB.java:88) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.storage.ldb.KeyValueStorageRocksDB.lambda$static$0(KeyValueStorageRocksDB.java:62) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.storage.ldb.LedgerMetadataIndex.<init>(LedgerMetadataIndex.java:68) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.storage.ldb.SingleDirectoryDbLedgerStorage.<init>(SingleDirectoryDbLedgerStorage.java:169) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.storage.ldb.DbLedgerStorage.newSingleDirectoryDbLedgerStorage(DbLedgerStorage.java:150) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.storage.ldb.DbLedgerStorage.initialize(DbLedgerStorage.java:129) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.bookie.Bookie.<init>(Bookie.java:818) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.proto.BookieServer.newBookie(BookieServer.java:152) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.proto.BookieServer.<init>(BookieServer.java:120) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.server.service.BookieService.<init>(BookieService.java:52) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.server.Main.buildBookieServer(Main.java:304) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.server.Main.doMain(Main.java:226) [org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    at org.apache.bookkeeper.server.Main.main(Main.java:208) [org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
Caused by: org.rocksdb.RocksDBException: while open a file for lock: /pulsar/data/bookkeeper/ledgers/current/ledgers/LOCK: Permission denied
    at org.rocksdb.RocksDB.open(Native Method) ~[org.rocksdb-rocksdbjni-6.10.2.jar:?]
    at org.rocksdb.RocksDB.open(RocksDB.java:239) ~[org.rocksdb-rocksdbjni-6.10.2.jar:?]
    at org.apache.bookkeeper.bookie.storage.ldb.KeyValueStorageRocksDB.<init>(KeyValueStorageRocksDB.java:196) ~[org.apache.bookkeeper-bookkeeper-server-4.14.4.jar:4.14.4]
    ... 13 more
```

### Recovering from `helm upgrade` error "unable to build kubernetes objects from current release manifest"

Example of the error message:
```bash
Error: UPGRADE FAILED: unable to build kubernetes objects from current release manifest:
[resource mapping not found for name: "pulsar-bookie" namespace: "pulsar" from "":
no matches for kind "PodDisruptionBudget" in version "policy/v1beta1" ensure CRDs are installed first,
resource mapping not found for name: "pulsar-broker" namespace: "pulsar" from "":
no matches for kind "PodDisruptionBudget" in version "policy/v1beta1" ensure CRDs are installed first,
resource mapping not found for name: "pulsar-zookeeper" namespace: "pulsar" from "":
no matches for kind "PodDisruptionBudget" in version "policy/v1beta1" ensure CRDs are installed first]
```

Helm documentation [explains issues with managing releases deployed using outdated APIs](https://helm.sh/docs/topics/kubernetes_apis/#helm-users) when the Kubernetes cluster has been upgraded
to a version where these APIs are removed. This happens regardless of whether the chart in the upgrade includes supported API versions.
In this case, you can use the following workaround:

1. Install the [Helm mapkubeapis plugin](https://github.com/helm/helm-mapkubeapis):

    ```bash
    helm plugin install https://github.com/helm/helm-mapkubeapis
    ```

2. Run the `helm mapkubeapis` command with the appropriate namespace and release name. In this example, we use the namespace "pulsar" and release name "pulsar":

    ```bash
    helm mapkubeapis --namespace pulsar pulsar
    ```

This workaround addresses the issue by updating in-place Helm release metadata that contains deprecated or removed Kubernetes APIs to a new instance with supported Kubernetes APIs and should allow for a successful Helm upgrade.

## Uninstall

To uninstall the Pulsar Chart, run the following command:

```bash
helm uninstall <pulsar-release-name>
```

For the purposes of continuity, these charts have some Kubernetes objects that are not removed when performing `helm uninstall`.
These items we require you to *conciously* remove them, as they affect re-deployment should you choose to.

* PVCs for stateful data, which you must *consciously* remove
    - ZooKeeper: This is your metadata.
    - BookKeeper: This is your data.
    - Prometheus: This is your metrics data, which can be safely removed.
* Secrets, if generated by our [prepare release script](https://github.com/apache/pulsar-helm-chart/blob/master/scripts/pulsar/prepare_helm_release.sh). They contain secret keys, tokens, etc. You can use [cleanup release script](https://github.com/apache/pulsar-helm-chart/blob/master/scripts/pulsar/cleanup_helm_release.sh) to remove these secrets and tokens as needed.

## Troubleshooting

We've done our best to make these charts as seamless as possible,
occasionally troubles do surface outside of our control. We've collected
tips and tricks for troubleshooting common issues. Please examine these first before raising an [issue](https://github.com/apache/pulsar-helm-chart/issues/new/choose), and feel free to add to them by raising a [Pull Request](https://github.com/apache/pulsar-helm-chart/compare)!

## Release Process

See [RELEASE.md](RELEASE.md)