【微服务部署】03-健康检查

1. 探针集成实现高可用

• Liveness
• Readiness
• Startup

1.1 LivenessProbe

• 判断服务是否存活
• 结束“非存活”状态服务
• 根据重启策略决定是否重启服务

1.2 ReadinessProbe

• 判断服务是否“就绪”
• “就绪”状态的服务可以接收请求
• 非“就绪”状态的服务将会被从流量负载中摘除

1.3 StartupProbe

• 检测应用程序是否启动成功
• 启动探针执行成功后，将不再执行，除非应用重启
• 当启动探针检测成功后，其它探针才开始工作
• 适合启动较慢的应用配置
• Kuberbetes 1.16以后的支持

// startup
internal static bool Ready { get; set; } = true;
internal static bool Live { get; set; } = true;public void ConfigureServices(IServiceCollection services)
{...// 注册健康检查services.AddHealthChecks().AddMySql(Configuration.GetValue<string>("Mysql"), "mysql", tags: new string[] { "mysql", "live", "all" })// tags标签分组.AddRabbitMQ(s =>{var connectionFactory = new RabbitMQ.Client.ConnectionFactory();Configuration.GetSection("RabbitMQ").Bind(connectionFactory);return connectionFactory;}, "rabbitmq", tags: new string[] { "rabbitmq", "live", "all" }).AddCheck("liveChecker", () =>{return Live ? HealthCheckResult.Healthy() : HealthCheckResult.Unhealthy();}, new string[] { "live", "all" }).AddCheck("readyChecker", () =>{return Ready ? HealthCheckResult.Healthy() : HealthCheckResult.Unhealthy();}, new string[] { "ready", "all" });
}// public void Configure(IApplicationBuilder app, IWebHostEnvironment env){...app.UseEndpoints(endpoints =>{endpoints.MapMetrics();endpoints.MapHealthChecks("/live", new HealthCheckOptions { Predicate = registration => registration.Tags.Contains("live") });// 检查标记了live的检查项endpoints.MapHealthChecks("/ready", new HealthCheckOptions { Predicate = registration => registration.Tags.Contains("ready") });endpoints.MapHealthChecks("/hc", new Microsoft.AspNetCore.Diagnostics.HealthChecks.HealthCheckOptions{ResponseWriter = HealthChecks.UI.Client.UIResponseWriter.WriteHealthCheckUIResponse});// 没有传检查项，检查所有endpoints.MapControllers();endpoints.MapGrpcService<GeekTime.Ordering.API.Grpc.OrderServiceImpl>();});}// Controller调用// 设置Ready的值[HttpGet]public IActionResult SetReady([FromQuery]bool ready){Startup.Ready = ready;if (!ready){Task.Run(async () =>{await Task.Delay(60000);Startup.Ready = true;});}return Content($"{Environment.MachineName} : Ready={Startup.Ready}");}// 设置live
[HttpGet]
public IActionResult SetLive([FromQuery]bool live){Startup.Live = live;return Content($"{Environment.MachineName} : Live={Startup.Live}");}// 程序退出
[HttpGet]
public IActionResult Exit([FromServices]IHostApplicationLifetime application){Task.Run(async () =>{await Task.Delay(3000);application.StopApplication();});return Content($"{Environment.MachineName} : Stopping");}

2. 健康检查看板

AspNetCore.Diagnostics.HealthCheck项目，开源社区项目插件

2.1 组件包

• 探针检测端：AspNetCore.HealthChecks.UI
• 应用端输出：AspNetCore.HealthChecks.UI.Client
• 应用端检查项：AspNetCore.HealthChecks.Xxx

// startup
public void ConfigureServices(IServiceCollection services)
{services.AddMvc();services.AddHealthChecks();services.AddHealthChecksUI();}public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{if (env.IsDevelopment()){app.UseDeveloperExceptionPage();}app.UseRouting();app.UseEndpoints(endpoints =>{endpoints.MapHealthChecks("/live");endpoints.MapHealthChecks("/ready");endpoints.MapHealthChecks("/hc");endpoints.MapMetrics();endpoints.MapHealthChecksUI();// 使得dashboard生效endpoints.MapControllers();});}// 配置文件配置需要检查的项目
"HealthChecksUI": {"HealthChecks": [{"Name": "geektime-ordering-api","Uri": "http://geektime-ordering-api/hc"},{"Name": "geektime-mobile-apiaggregator","Uri": "http://geektime-mobile-apiaggregator/hc"},{"Name": "geektime-mobile-gateway","Uri": "http://geektime-mobile-gateway/hc"}],