Add KubernetesProbesOptionsValidator to ensure different ports for probes

src/Libraries/Microsoft.Extensions.Diagnostics.Probes/KubernetesProbesExtensions.cs

@@ -47,6 +47,10 @@ public static IServiceCollection AddKubernetesProbes(this IServiceCollection ser
         _ = Throw.IfNull(services);
         _ = Throw.IfNull(configure);
 
+        _ = services
+            .AddOptionsWithValidateOnStart<KubernetesProbesOptions, KubernetesProbesOptionsValidator>()
+            .Configure(configure);
+
         var wrapperOptions = new KubernetesProbesOptions();
 
         return services

src/Libraries/Microsoft.Extensions.Diagnostics.Probes/KubernetesProbesOptionsValidator.cs

@@ -0,0 +1,23 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.Extensions.Diagnostics.Probes;
+
+internal sealed class KubernetesProbesOptionsValidator : IValidateOptions<KubernetesProbesOptions>
+{
+    public ValidateOptionsResult Validate(string? name, KubernetesProbesOptions options)
+    {
+        var builder = new ValidateOptionsResultBuilder();
+
+        if (options.LivenessProbe.TcpPort == options.StartupProbe.TcpPort
+            || options.LivenessProbe.TcpPort == options.ReadinessProbe.TcpPort
+            || options.StartupProbe.TcpPort == options.ReadinessProbe.TcpPort)
+        {
+            builder.AddError("Liveness, startup and readiness probes must use different ports.");
+        }
+
+        return builder.Build();
+    }
+}

test/Libraries/Microsoft.Extensions.Diagnostics.Probes.Tests/KubernetesProbesOptionsValidatorTests.cs

@@ -0,0 +1,62 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Xunit;
+
+namespace Microsoft.Extensions.Diagnostics.Probes.Test;
+
+public class KubernetesProbesOptionsValidatorTests
+{
+    [Fact]
+    public void Validator_DefaultValues_Succeeds()
+    {
+        var options = new KubernetesProbesOptions();
+        var result = new KubernetesProbesOptionsValidator().Validate(nameof(options), options);
+
+        Assert.True(result.Succeeded);
+    }
+
+    [Fact]
+    public void Validator_GivenValidOptions_Succeeds()
+    {
+        var options = new KubernetesProbesOptions();
+        options.LivenessProbe.TcpPort = 2305;
+        options.StartupProbe.TcpPort = 2306;
+        options.ReadinessProbe.TcpPort = 2307;
+
+        var result = new KubernetesProbesOptionsValidator().Validate(nameof(options), options);
+
+        Assert.True(result.Succeeded);
+    }
+
+    [Fact]
+    public void Validator_GivenInvalidOptions_Fails()
+    {
+        var options = new KubernetesProbesOptions();
+        options.LivenessProbe.TcpPort = 2305;
+        options.StartupProbe.TcpPort = 2305;
+        options.ReadinessProbe.TcpPort = 2307;
+
+        var validator = new KubernetesProbesOptionsValidator();
+        var result = validator.Validate(nameof(options), options);
+        Assert.True(result.Failed);
+
+        options.LivenessProbe.TcpPort = 2305;
+        options.StartupProbe.TcpPort = 2306;
+        options.ReadinessProbe.TcpPort = 2305;
+        result = validator.Validate(nameof(options), options);
+        Assert.True(result.Failed);
+
+        options.LivenessProbe.TcpPort = 2305;
+        options.StartupProbe.TcpPort = 2306;
+        options.ReadinessProbe.TcpPort = 2306;
+        result = validator.Validate(nameof(options), options);
+        Assert.True(result.Failed);
+
+        options.LivenessProbe.TcpPort = 2305;
+        options.StartupProbe.TcpPort = 2305;
+        options.ReadinessProbe.TcpPort = 2305;
+        result = validator.Validate(nameof(options), options);
+        Assert.True(result.Failed);
+    }
+}