Startup.cs

using HealthChecks.UI.Client;
using Microsoft.AspNetCore.Diagnostics.HealthChecks;
using Microsoft.Extensions.Diagnostics.HealthChecks;

namespace HealthChecks.Sample;

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        /*
         * If you have different hosted services, please check this open bug on 2.2 HealthChecks
         * https://github.com/aspnet/Extensions/issues/639 and the workaround proposed by @NatMarchand
         * or register all hosted service before call AddHealthChecks.
         */

        services
            .AddApplicationInsightsTelemetry()
            .AddHealthChecks()
            //.AddRabbitMQ(rabbitConnectionString: "amqp://localhost:5672", name: "rabbit1")
            //.AddRabbitMQ(rabbitConnectionString: "amqp://localhost:6672", name: "rabbit2")
            //.AddSqlServer(connectionString: Configuration["Data:ConnectionStrings:Sample"])
            .AddCheck<RandomHealthCheck>("random")
            //.AddOpenIdConnectServer(new Uri("http://localhost:6060"))
            //.AddAzureServiceBusQueue("Endpoint=sb://unaidemo.servicebus.windows.net/;SharedAccessKeyName=policy;SharedAccessKey=5RdimhjY8yfmnjr5L9u5Cf0pCFkbIM7u0HruJuhjlu8=", "que1")
            //.AddAzureServiceBusTopic("Endpoint=sb://unaidemo.servicebus.windows.net/;SharedAccessKeyName=policy;SharedAccessKey=AQhdhXwnkzDO4Os0abQV7f/kB6esTfz2eFERMYKMsKk=", "to1")
            .AddApplicationInsightsPublisher(saveDetailedReport: true);

        services.AddControllers();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    [global::System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE0060:Remove unused parameter", Justification = "Sample")]
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        app
            .UseHealthChecks("/health", new HealthCheckOptions
            {
                Predicate = _ => true
            })
            .UseHealthChecks("/healthz", new HealthCheckOptions
            {
                Predicate = _ => true,
                ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
            })
            .UseHealthChecksPrometheusExporter("/metrics")
            .UseRouting()
            .UseEndpoints(config => config.MapDefaultControllerRoute());
    }

    public class RandomHealthCheck : IHealthCheck
    {
        public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
        {
            if (DateTime.UtcNow.Minute % 2 == 0)
            {
                return Task.FromResult(HealthCheckResult.Healthy());
            }

            return Task.FromResult(HealthCheckResult.Unhealthy(description: "failed", exception: new InvalidCastException("Invalid cast from to to to")));
        }
    }
}