https://github.com/arkatufus/akka.cluster.sharding-kubernetes-scaling
Kubernetes horizontal pod auto scaling with Akka.NET cluster sharding
https://github.com/arkatufus/akka.cluster.sharding-kubernetes-scaling
akka-cluster autoscaler k8s kubernetes sharding
Last synced: about 2 months ago
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Kubernetes horizontal pod auto scaling with Akka.NET cluster sharding
- Host: GitHub
- URL: https://github.com/arkatufus/akka.cluster.sharding-kubernetes-scaling
- Owner: Arkatufus
- Created: 2023-07-06T13:51:49.000Z (about 2 years ago)
- Default Branch: master
- Last Pushed: 2023-07-13T16:46:00.000Z (about 2 years ago)
- Last Synced: 2025-04-02T05:11:20.416Z (6 months ago)
- Topics: akka-cluster, autoscaler, k8s, kubernetes, sharding
- Language: C#
- Homepage:
- Size: 319 KB
- Stars: 6
- Watchers: 1
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Horizontal Pod Auto Scaling With Akka.NET Cluster Sharding
This repository is a clone of [Akka.NET](https://github.com/akkadotnet/akka.net) [shopping cart example](https://github.com/akkadotnet/akka.net/tree/dev/src/examples/Cluster/ClusterSharding/ShoppingCart), modifying it to use [Akka.Hosting](https://github.com/akkadotnet/Akka.Hosting/) and [Akka.Discovery.KubernetesApi](https://github.com/akkadotnet/Akka.Management/tree/dev/src/discovery/kubernetes/Akka.Discovery.KubernetesApi) and designed as a showcase of how Akka.NET cluster pods can be auto scaled.
- The sharding entity actor in this example has been modified to generate synthetic CPU load when it is initialized.
- The Kubernetes YAML configuration file was designed to auto scale the cluster from 3 replicas to a maximum of 10 replicas when the metric server detects a spike of average pod CPU consumption over 80% (800m)
# How To Use The Example
## Setup
1. Make sure that you have Docker Desktop installed on your computer
2. Make sure that Docker Desktop is running using WSL Linux containers
3. Make sure that Docker Desktop Kubernetes feature is enabled
4. In a Windows PowerShell terminal, navigate to the project directory and execute
```powershell
.\install-metrics.cmd
```
You should see an output similar to this:
```
PS C:\> .\install-metrics.cmd
serviceaccount/metrics-server created
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
clusterrole.rbac.authorization.k8s.io/system:metrics-server created
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created
service/metrics-server created
deployment.apps/metrics-server created
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created
```
5. Wait a minute or so for Kubernetes `metrics-server` to spin up.
6. Confirm that Kubernetes `metrics-server` is up by executing:
```powershell
kubectl top node
```
If `metrics-server` has been installed successfully, you should see an output similar to this:
```
PS C:\> kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
docker-desktop 172m 2% 3041Mi 52%
```
## Running The Example
In a Windows PowerShell terminal, navigate to the project directory and execute
```powershell
.\start-k8s.cmd
```
This will:
- Compile the project,
- Build the docker image
- Create an Akka.NET sharded cluster inside the `shopping-cart` namespace
Execute `kubectl top pod -n shopping-cart` a few times until you see that `metrics-server` has successfully collected metrics from the pods:
```
PS C:\> kubectl top pod -n shopping-cart
error: metrics not available yet
PS C:\> kubectl top pod -n shopping-cart
error: metrics not available yet
PS C:\> kubectl top pod -n shopping-cart
error: metrics not available yet
PS C:\> kubectl top pod -n shopping-cart
NAME CPU(cores) MEMORY(bytes)
backend-0 39m 69Mi
backend-1 58m 75Mi
frontend-0 90m 89Mi
```
## Confirming Auto-scaling
1. The `frontend-0` pod will spawn 30 actors inside the `backend` stateful set cluster, creating a CPU spike on all 3 `backend` pods.
2. Execute
```powershell
kubectl top pod -n shopping-cart
```
and check that backend pod CPU metrics spikes to above 800m
```
PS C:\> kubectl top pod -n shopping-cart
NAME CPU(cores) MEMORY(bytes)
backend-0 1001m 86Mi
backend-1 975m 84Mi
backend-2 962m 83Mi
frontend-0 63m 99Mi
```
3. The pod auto scaler will scale the `backend` cluster after a few seconds
```powershell
PS C:\> kubectl top pod -n shopping-cart
NAME CPU(cores) MEMORY(bytes)
backend-0 21m 86Mi
backend-1 17m 87Mi
backend-2 18m 86Mi
backend-3 18m 87Mi
backend-4 17m 83Mi
backend-5 16m 88Mi
backend-6 17m 82Mi
backend-7 16m 91Mi
frontend-0 35m 99Mi
```
4. Shut down the `frontend-0` pod by scaling the `frontend` stateful set to 0. Execute:
```powershell
kubectl scale --replicas=0 statefulset/frontend -n shopping-cart
```
5. Confirm that the `frontend-0` pod has been shut down by executing `kubectl top pod -n shopping-cart`
```powershell
PS C:\> kubectl top pod -n shopping-cart
NAME CPU(cores) MEMORY(bytes)
backend-0 21m 87Mi
backend-1 21m 88Mi
backend-2 17m 84Mi
backend-3 20m 88Mi
backend-4 20m 84Mi
backend-5 26m 89Mi
backend-6 19m 83Mi
backend-7 17m 92Mi
```
Note that `frontend-0` pod is now missing from the list
6. Wait 5-10 minutes and check the cluster status again by executing `kubectl top pod -n shopping-cart`
```powershell
PS C:\> kubectl top pod -n shopping-cart
NAME CPU(cores) MEMORY(bytes)
backend-0 21m 87Mi
backend-1 21m 88Mi
backend-2 17m 84Mi
```
Note that the cluster has been automatically scaled down
## Stopping The Example
To stop the Kubernetes cluster, execute:
```powershell
.\destroy-k8s.cmd
```