Scaling-operator

This is a simple scaling operator based on operator-sdk, it can scale up or down to the number of replicas you want.

Description

The detail of this scaling operator is described in both scaler_types.go and also scaler_controller.go, which contains the spec and also the scaling logic of the scaling operator.

Getting Started

1. Make sure you have Docker installed, and also Kubernetes enabled.
2. You’ll need a Kubernetes cluster to run, You can use KIND to get a local cluster for testing, or run against a remote cluster. You might need to install kind if it's not installed yet in your environment. 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. Clone this project, direct to the folder.

2. Create a local cluster, here I use kind as an example. Make sure Docker is running in the background.

kind create cluster

3. Install Instances of Custom Resources:

kubectl apply -f config/crd/bases/api.nextfaas.com_scalers.yaml

You can check the CRD if it's correctly installed with this command:

kubectl get crd

4. Now you can deploy one function to test the scaling operator. Build and push your image to the location specified by IMG:

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

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

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

6. Run the Operator:

make run

7. Apply the scaling requirements:

kubectl apply -f config/samples/api_v1alpha1_scaler.yaml

8. See the result of the replicas:

kubectl get pods

Uninstall CRDs

To delete the CRDs from the cluster:

make uninstall

Undeploy controller

UnDeploy the controller from the cluster:

make undeploy

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

More information can be found via the Kubebuilder Documentation

License

Copyright 2024.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.