Let’s start:
1. Create a folder for your new project
Open a command prompt an run:
mkdir kuberenetes.scale 2. Create the project
cd kuberenetes.scale dotnet new api 3. Add the references to KubernetesClient
dotnet add package KubernetesClient -v 1.5.18 dotnet restore 4. Create a PodsController.cs with the following code
using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using k8s; using k8s.Models; using Microsoft.AspNetCore.JsonPatch; using Microsoft.AspNetCore.Mvc; using Microsoft.Extensions.Configuration; namespace kubernetes.scale { [Route("api/[controller]")] [ApiController] public class PodsController : ControllerBase { private KubernetesClientConfiguration k8sConfig = null; public PodsController(IConfiguration config) { // Reading configuration to know if running inside a cluster or in local mode. var useKubeConfig = bool.Parse(config["UseKubeConfig"]); if (!useKubeConfig) { // Running inside a k8s cluser k8sConfig = KubernetesClientConfiguration.InClusterConfig(); } else { // Running on dev machine k8sConfig = KubernetesClientConfiguration.BuildConfigFromConfigFile(); } } [HttpPatch("scale")] public IActionResult Scale([FromBody]ReplicaRequest request) { // Use the config object to create a client. using (var client = new Kubernetes(k8sConfig)) { // Create a json patch for the replicas var jsonPatch = new JsonPatchDocument<V1Scale>(); // Set the new number of repplcias jsonPatch.Replace(e => e.Spec.Replicas, request.Replicas); // Creat the patch var patch = new V1Patch(jsonPatch); // Patch the "minions" Deployment in the "default" namespace client.PatchNamespacedDeploymentScale(patch, request.Deployment, request.Namespace); return NoContent(); } } } public class ReplicaRequest { public string Deployment { get; set; } public string Namespace { get; set; } public int Replicas { get; set; } } } 5. Replace the contents of the appsettings.Development.json file
Note the UseKubeConfig property is set to true.
{ "Logging": { "LogLevel": { "Default": "Debug", "System": "Information", "Microsoft": "Information" } }, "UseKubeConfig": true } 6. Replace the contents of the appsettings.json file
Note the UseKubeConfig property is set to false.
{ "Logging": { "LogLevel": { "Default": "Warning" } }, "AllowedHosts": "*", "UseKubeConfig": false } 7. Test the application
Test the app from your dev machine running:
dotnet run curl -k -i -H 'Content-Type: application/json' -d '{"Deployment": "<YOUR DEPLOYMENT NAME>", "Namespace": "<YOUR NAMESPACE>", "Replicas": 3}' -X PATCH https://localhost:5001/api/pods/scale Note : You must have a valid config file to connect to the k8s cluster.
Please find all the code used in this post here.
Hope it helps!
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