I dont feel so well. Integrating health checks in your .NET Core solutions - Techorama NL Ede 2019
Download as PPTX, PDF3 likes2,630 views
Conference: Techorama NL 2019 Location: Ede, The Netherlands Abstract: Do you have any idea how your ASP.NET Web Apps and APIs are functioning? Are they behaving healthily or in a degraded state? You might be able to tell from log information and telemetry data, but why not have them tell you how healthy they are themselves? ASP.NET Core 2.2 introduces health endpoints that let your apps and APIs do just that. In this session you will learn how to make health checks an integral part of your solution. We will cover various types of health checks ranging from internal status, such as memory thresholds, to health based on external dependencies, such as databases and HTTP endpoints. Finally, you are going to see how this all can be used in a container cluster to allow the orchestrator to check for liveliness and readiness based on your health endpoints.
![1. Add health checks with tags
2. Register multiple endpoints
with filter using
Options predicate
/api/v1/…
/health
/health/ready
/health/lively
app.UseHealthChecks("/health/ready",
new HealthCheckOptions() {
Predicate = reg => reg.Tags.Contains("ready")
});
services.AddHealthChecks()
.AddCheck<CircuitBreakerHealthCheck>(
"circuitbreakers",
tags: new string[] { "ready" });
app.UseHealthChecks("/health/lively",
new HealthCheckOptions() {
Predicate = _ => true
});](https://image.slidesharecdn.com/idontfeelsowell-integratinghealthchecksinyour-191003073053/85/I-dont-feel-so-well-Integrating-health-checks-in-your-NET-Core-solutions-Techorama-NL-Ede-2019-23-320.jpg)
Ad
More Related Content
What's hot (20)
Similar to I dont feel so well. Integrating health checks in your .NET Core solutions - Techorama NL Ede 2019 (20)
![The Selfish Stack [FutureStack16 NYC]](https://cdn.slidesharecdn.com/ss_thumbnails/selfishstackpresentationfinal1-160815212335-thumbnail.jpg?width=560&fit=bounds)
Ad
More from Alex Thissen (18)
Ad
Recently uploaded (20)
I dont feel so well. Integrating health checks in your .NET Core solutions - Techorama NL Ede 2019
- 2. Keeping entire system running Determine state of entire system and intervene How to know health status of individual services? Collecting/correlating performance and health data Sentry.ioRaygun.io RunscopeNewRelic AlertSite DataDogAppMetrics Azure Monitor
- 3. Centralized Challenging Doctor, am I sick? 12:34 Let's look at your vitals we measured earlier: - Pulse 60 per minute - Blood pressure 130/80 12:34 Looks fine to me. It seems you are healthy. 12:35 Thanks, doctor! 12:36 Let's look at your vitals we measured: - Pulse 180 per minute - Blood pressure 150/110 12:34 Does not look good. It seems you are unhealthy. 12:35
- 4. Modern medicine and health Self-assessment Context matters You know best Let's see. My vitals say: - Pulse 180 per minute - Blood pressure 150/110 12:34 How are you doing today? 12:36 Does not look good. It seems I am unhealthy. 12:34 Oops, we need to do something about that! 3:24 Good to know. Stay healthy! 12:36 It's okay, as I am working out now My back does not hurt. So, I'm healthy! 12:34
- 5. Difference between metrics and health info Metrics Many individual measured values and counts of events Watch performance and trends Useful for diagnostics and troubleshooting Logic external to origin Health Intrinsic knowledge of implementation required DevOps mindset: Logic to determine health is part of origin Deployed together, good for autonomy
- 6. Availability Latency Internals Simple Advanced External dependencies Readiness & liveliness Preventive Predicting Examples
- 7. Healthy • 200 OK • "Everything is fine" Degraded • 200 OK • "Could be doing better or about to become unhealthy" Unhealthy • 503 Service Unavailable • "Not able to perform"
- 8. ASP.NET Core application /api/v1/… Middle ware New in .NET Core 2.2 Bootstrap health checks in ASP.NET Core app services.AddHealthChecks(); endpoints.MapHealthChecks("/health); /health DefaultHealthCheckService Microsoft.Extensions.Diagnostics.HealthChecks .Abstractions .EntityFramework Microsoft.AspNetCore.Diagnostics.HealthChecks
- 9. What? When? How? When a service is unhealthy, how can you trust its health status?public interface IHealthCheck { Task<HealthCheckResult> CheckHealthAsync( HealthCheckContext context, CancellationToken cancellationToken = default); } From: https://github.com/aspnet/Diagnostics/blob/master/src/ Microsoft.Extensions.Diagnostics.HealthChecks.Abstractions/HealthReport.cs
- 10. services .AddHealthChecks() .AddCheck("sync", () => … ) .AddAsyncCheck("async", async () => … ) .AddCheck<SqlConnectionHealthCheck>("SQL") .AddCheck<UrlHealthCheck>("URL"); ASP.NET Core application /health DefaultHealthCheckService
- 11. Demo ASP.NET Core 2.2 Health object model Health checks Endpoints
- 12. Only 1 out-of-box check DbContext Build your own IHealthCheck Community packages Xabaril/BeatPulse Yours?AspNetCore.Diagnostics.HealthChecks.* Microsoft.Extensions.Diagnostics. HealthChecks.EntityFrameworkCore services.AddHealthChecks() .AddDbContextCheck<GamingDbContext>("EF")
- 13. Register multiple health endpoints Middleware options Register custom health check as singleton /api/v1/… /health /ping services.AddSingleton<KafkaHealthCheck>()); services.AddSingleton(new SqlConnectionHealthCheck( new SqlConnection(Configuration.GetConnectionString("TestDB"))));
- 14. 1. Customize health endpoint output for more details 2. Query endpoint(s) 3. Build user interface
- 15. Demo A bit more advanced
- 16. Endpoints Frequency Locations Alerts
- 17. Pushes out health info periodically Options ASP.NET Core application DefaultHealthCheckService HealthCheckPublisher HostedService IEnumerable<IHealthCheckPublisher> services.AddHealthChecks() .AddApplicationInsightsPublisher() .AddPrometheusGatewayPublisher( "http://pushgateway:9091/metrics", "pushgateway") IHealthCheckPublisher
- 18. Registering a HealthCheckPublisher pre-.NET Core 3.0 // The following workaround permits adding an IHealthCheckPublisher // instance to the service container when one or more other hosted // services have already been added to the app. This workaround // won't be required with the release of ASP.NET Core 3.0. For more // information, see: https://github.com/aspnet/Extensions/issues/639. services.TryAddEnumerable( ServiceDescriptor.Singleton(typeof(IHostedService), typeof(HealthCheckPublisherOptions).Assembly .GetType(HealthCheckServiceAssembly)));
- 19. PrometheusGrafana .NET Core app Push gateway HealthCheckPublisher HostedServiceNotification channel Slack Telegram VictorOps PagerDuty …
- 22. Probing containers to check for availability and health Kubernetes node Kubernetes node Kubernetes nodes Containers Readiness Liveliness
- 23. 1. Add health checks with tags 2. Register multiple endpoints with filter using Options predicate /api/v1/… /health /health/ready /health/lively app.UseHealthChecks("/health/ready", new HealthCheckOptions() { Predicate = reg => reg.Tags.Contains("ready") }); services.AddHealthChecks() .AddCheck<CircuitBreakerHealthCheck>( "circuitbreakers", tags: new string[] { "ready" }); app.UseHealthChecks("/health/lively", new HealthCheckOptions() { Predicate = _ => true });
- 24. Original pods only taken offline after new healthy one is up Allows roll forward upgrades: Never roll back to previous version
- 25. Demo Readiness and liveness probes Docker containers Kubernetes
- 26. Expose as little detail as possible Use different internal port Add authentication using middleware Publish instead of endpoint app.UseWhen( ctx => ctx.User.Identity.IsAuthenticated, a => a.UseHealthChecks("/securehealth") );
- 27. 1. Assume degraded state 2. Set short timeouts on checks 3. Avoid complicated health checks 4. Register health check as singletons in DI
Editor's Notes
- #17: Alert conditions (failures and latency)
- #18: https://github.com/PeterOrneholm/Orneholm.ApplicationInsights
- #22: Resilient applications: tricky to choose when to intervene and when not (when degraded, should you consider it not lively, e.g.)
- #23: How can restarting a container instance solve health?
- #28: Evaluate log values