Health checks, Liveness vs Readiness probes?

builder.Services.AddHealthChecks()
    // liveness: только «я жив»
    .AddCheck("self", () => HealthCheckResult.Healthy(), tags: ["live"])
    // readiness: зависимости (пакеты AspNetCore.HealthChecks.*)
    .AddNpgSql(builder.Configuration.GetConnectionString("Default")!, name: "postgres", tags: ["ready"], timeout: TimeSpan.FromSeconds(3))
    .AddRedis(builder.Configuration["Redis:Connection"]!, name: "redis", tags: ["ready"], failureStatus: HealthStatus.Degraded)
    .AddCheck<CacheWarmupHealthCheck>("warmup", tags: ["ready", "startup"]);

var app = builder.Build();

app.MapHealthChecks("/health/live",  new HealthCheckOptions { Predicate = c => c.Tags.Contains("live") });
app.MapHealthChecks("/health/ready", new HealthCheckOptions
{
    Predicate = c => c.Tags.Contains("ready"),
    ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse     // подробный JSON (пакет HealthChecks.UI.Client)
});
app.MapHealthChecks("/health/startup", new HealthCheckOptions { Predicate = c => c.Tags.Contains("startup") });

public sealed class CacheWarmupHealthCheck(CatalogCache cache) : IHealthCheck
{
    public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken ct = default) =>
        Task.FromResult(cache.IsWarmedUp
            ? HealthCheckResult.Healthy("Кэш каталога загружен")
            : HealthCheckResult.Unhealthy("Кэш каталога ещё загружается"));
}

containers:
  - name: orders-api
    image: registry.example.com/orders-api:1.4.2
    ports: [{ containerPort: 8080 }]
    startupProbe:
      httpGet: { path: /health/startup, port: 8080 }
      periodSeconds: 5
      failureThreshold: 30          # до 150 секунд на старт
    livenessProbe:
      httpGet: { path: /health/live, port: 8080 }
      periodSeconds: 10
      timeoutSeconds: 2
      failureThreshold: 3           # перезапуск после ~30 секунд зависания
    readinessProbe:
      httpGet: { path: /health/ready, port: 8080 }
      periodSeconds: 5
      timeoutSeconds: 3
      failureThreshold: 2