HStream Operator

Introduction

HStream Operator is a Kubernetes operator designed to manage and maintain the HStreamDB cluster within a Kubernetes environment. The HStreamDB cluster comprises of several components including:

• HMeta
• AdminServer
• HServer
• HStore

It simplifies the deployment, scaling, and operations of HStreamDB clusters on Kubernetes, making it easier for users to manage their HStream components effectively. We use and get benefits from kubebuilder to simplify the development of the operator.

Installation

We recommend using the Helm package manager to install the HStreamDB operator on your Kubernetes cluster.

Currently, we haven't released the chart because of this operator is still at an early stage. So you need to clone this repo and install the chart from the local directory.

git clone https://github.com/hstreamdb/hstream-operator.git && cd hstream-operator
helm install hstream-operator deploy/charts/hstream-operator -n hstream-operator-system --create-namespace

Every releases will be published to GitHub Releases, you can also install the operator with the following command:

kubectl create -f https://github.com/hstreamdb/hstream-operator/releases/download/0.0.9/hstream-operator.yaml

You can also use server-side apply to install the operator by running kubectl apply --server-side, please refer to comparison-with-client-side-apply for more details.

Replace 0.0.9 with the version you want to install.

Check the status

You can check the status of the operator by running:

kubectl get pods -l "control-plane=hstream-operator-manager" -n hstream-operator-system

Expected output:

NAME                                                  READY   STATUS    RESTARTS      AGE
hstream-operator-controller-manager-f989476d4-qllfs   1/1     Running   1 (16h ago)   16h

Bootstrap a HStreamDB cluster

After installing the operator, you can bootstrap a HStreamDB cluster by applying config/samples/hstreamdb.yaml:

kubectl apply -f config/samples/hstreamdb.yaml

Note: you need to provide volumeClaimTemplate which comments out in the sample file.

You can check the status of the HStreamDB cluster by running:

kubectl get po -n hstreamdb

Expected output:

NAME                                             READY   STATUS    RESTARTS   AGE
hstreamdb-sample-hmeta-2                         1/1     Running   0          7m45s
hstreamdb-sample-hmeta-0                         1/1     Running   0          7m45s
hstreamdb-sample-hmeta-1                         1/1     Running   0          7m45s
hstreamdb-sample-admin-server-6c547b85c7-7h9gw   1/1     Running   0          7m34s
hstreamdb-sample-hstore-0                        1/1     Running   0          7m34s
hstreamdb-sample-hstore-1                        1/1     Running   0          7m34s
hstreamdb-sample-hstore-2                        1/1     Running   0          7m34s
hstreamdb-sample-hserver-0                       1/1     Running   0          7m18s
hstreamdb-sample-hserver-2                       1/1     Running   0          7m18s
hstreamdb-sample-hserver-1                       1/1     Running   0          7m18s

As a result, we have a HStreamDB cluster with 3 HMeta nodes, 3 HStore nodes, 3 HServer nodes, and 1 AdminServer node.

Testing in a local environment

You’ll need a Kubernetes cluster to run against. You can use KIND to get a local cluster for testing, or run against a remote cluster.

Note: Your controller will automatically use the current context in your kubeconfig file (i.e. whatever cluster kubectl cluster-info shows).

Running on the cluster

1. Build and push your image to the location specified by IMG:

   make docker-build docker-push IMG=<some-registry>/hstream-operator:tag

2. Deploy the controller to the cluster with the image specified by IMG:

   make deploy IMG=<some-registry>/hstream-operator:tag

Uninstall CRDs

To delete the CRDs from the cluster:

make uninstall

Undeploy controller

UnDeploy the controller from the cluster:

make undeploy

Contributing

// TODO(user): Add detailed information on how you would like others to contribute to this project

How it works

This project aims to follow the Kubernetes Operator pattern.

It uses Controllers, which provide a reconcile function responsible for synchronizing resources until the desired state is reached on the cluster.

Test it out

1. Install the CRDs into the cluster:

   make install

2. Run your controller (this will run in the foreground, so switch to a new terminal if you want to leave it running):

   make run

NOTE: You can also run this in one step by running: make install run

Modifying the API definitions

If you are editing the API definitions, generate the manifests such as CRs or CRDs using:

make manifests

NOTE: Run make --help for more information on all potential make targets

More information can be found via the Kubebuilder Documentation

License

Licensed under the Apache License, Version 2.0. See LICENSE for full content.