基于Docker的Consul服务发现集群搭建

在去年的.NET Core微服务系列文章中,初步学习了一下Consul服务发现,总结了两篇文章。本次基于Docker部署的方式,以一个Demo示例来搭建一个Consul的示例集群,最后给出一个HA的架构示范,也会更加贴近于实际应用环境。

一、示例整体架构

  此示例会由一个API Gateway, 一个Consul Client以及三个Consul Server组成,有关Consul的Client和Server这两种模式的Agent的背景知识,请移步我之前的文章加以了解:《.NET Core微服务之基于Consul实现服务治理》。其中,Consul的Client和Server节点共同构成一个Data Center,而API Gateway则从Consul中获取到服务的IP和端口号,并返回给服务消费者。这里的API Gateway是基于Ocelot来实现的,它不是这里的重点,也就不过多说明了,不了解的朋友请移步我的另一篇:《.NET Core微服务之基于Ocelot实现API网关服务》。

二、Consul集群搭建

2.1 Consul镜像拉取

docker pull consul:1.4.4

  验证:docker images

  

2.2 Consul Server实例创建

  以下我的实践是在一台机器上(CentOS 7)操作的,因此将三个实例分别使用了不同的端口号(区别于默认端口号8500)。实际环境中,建议多台机器部署。

  (1)Consul实例1

docker run -d -p 8510:8500 --restart=always -v /XiLife/consul/data/server1:/consul/data -v /XiLife/consul/conf/server1:/consul/config -e CONSUL_BIND_INTERFACE='eth0' --privileged=true --name=consul_server_1 consul:1.4.4 agent -server -bootstrap-expect=3 -ui -node=consul_server_1 -client='0.0.0.0' -data-dir /consul/data -config-dir /consul/config -datacenter=xdp_dc;

  (2)Consul实例2

  为了让Consul实例2加入集群,首先获取一下Consul实例1的IP地址:

  JOIN_IP="$(docker inspect -f '{{.NetworkSettings.IPAddress}}' consul_server_1)";

docker run -d -p 8520:8500 --restart=always -v /XiLife/consul/data/server2:/consul/data -v /XiLife/consul/conf/server2:/consul/config -e CONSUL_BIND_INTERFACE='eth0' --privileged=true --name=consul_server_2 consul:1.4.4 agent -server -ui -node=consul_server_2 -client='0.0.0.0' -datacenter=xdp_dc -data-dir /consul/data -config-dir /consul/config -join=$JOIN_IP;  

  (3)Consul实例3

docker run -d -p 8530:8500 --restart=always -v /XiLife/consul/data/server3:/consul/data -v /XiLife/consul/conf/server3:/consul/config -e CONSUL_BIND_INTERFACE='eth0' --privileged=true --name=consul_server_3 consul:1.4.4 agent -server -ui -node=consul_server_3 -client='0.0.0.0' -datacenter=xdp_dc -data-dir /consul/data -config-dir /consul/config -join=$JOIN_IP;

  验证1:docker exec consul_server_1 consul operator raft list-peers

  

  验证2:http://192.168.16.170:8500/

  

2.3 Consul Client实例创建

  (1)准备services.json配置文件,向Consul注册两个同样的Product API服务

    {
      "services": [
        {
          "id": "core.product-/192.168.16.170:8000",
          "name": "core.product",
          "tags": [ "xdp-/core.product" ],
          "address": "192.168.16.170",
          "port": 8000,
          "checks": [
            {
              "name": "core.product.check",
              "http": "http://192.168.16.170:8000/api/health",
              "interval": "10s",
              "timeout": "5s"
            }
          ]
        },
        {
          "id": "core.product-/192.168.16.170:8001",
          "name": "core.product",
          "tags": [ "xdp-/core.product" ],
          "address": "192.168.16.170",
          "port": 8001,
          "checks": [
            {
              "name": "core.product.check",
              "http": "http://192.168.16.170:8001/api/health",
              "interval": "10s",
              "timeout": "5s"
            }
          ]
        }
      ]
    }

  有关配置文件的细节,请移步另一篇文章:《.NET Core微服务之基于Consul实现服务治理(续)

  (2)Consul Client实例

docker run -d -p 8550:8500 --restart=always -v /XiLife/consul/conf/client1:/consul/config -e CONSUL_BIND_INTERFACE='eth0' --name=consul_client_1 consul:1.4.4 agent -node=consul_client_1 -join=$JOIN_IP -client='0.0.0.0' -datacenter=xdp_dc -config-dir /consul/config

  (3)验证

  

  

  

2.4 服务检查监控邮件提箱

  (1)为Client添加watches.json

       {
          "watches": [
            {
              "type": "checks",
              "handler_type": "http",
              "state": "critical",
              "http_handler_config": {
                "path": "http://192.168.16.170:6030/api/Notifications/consul",
                "method": "POST",
                "timeout": "10s",
                "header": { "Authorization": [ "token" ] }
              }
            }
          ]
        }

  *.这里的api接口 http://192.168.16.170:6030/api/Notifications/consul是我的一个通知服务接口,下面是实现的代码

        /// <summary>
        /// 发送Consul服务中心健康检查Email
        /// </summary>
        [HttpPost("consul")]
        public async Task SendConsulHealthCheckEmail()
        {
            using (var stream = new MemoryStream())
            {
                HttpContext.Request.Body.CopyTo(stream);
                var ary = stream.ToArray();
                var str = Encoding.UTF8.GetString(ary);

                dynamic notifications = JsonConvert.DeserializeObject(str);
                if (notifications == null || notifications.Count == 0)
                {
                    return;
                }

                var title = "XDP服务中心健康检查通知";
                var emailBody = new StringBuilder($"<span style='font-weight:bold; color:red;'>{title}</span> : <br/>");
                foreach (var notification in notifications)
                {
                    emailBody.AppendLine($"---------------------------------------------------------<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>节点</span>:{notification.Node}<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>服务ID</span>:{notification.ServiceID}<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>服务名称</span>:{notification.ServiceName}<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>检查ID</span>:{notification.CheckID}<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>检查名称</span>:{notification.Name}<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>检查状态</span>:{notification.Status}<br/>");
                    emailBody.AppendLine($"<span style='font-weight:bold;'>检查输出</span>:{notification.Output}<br/>");
                    emailBody.AppendLine($"---------------------------------------------------------<br/>");
                }

                var email = new Email()
                {
                    Username = _configuration["EmailSettings:Username"],
                    Password = _configuration["EmailSettings:Password"],
                    SmtpServerAddress = _configuration["EmailSettings:SmtpServerAddress"],
                    SmtpPort = Convert.ToInt32(_configuration["EmailSettings:SmtpPort"]),
                    Subject = title,
                    Body = emailBody.ToString(),
                    Recipients = _configuration["EmailSettings:Recipients"]
                };

                email.Send();
            }
        }

            /// <summary>
            /// 使用同步发送邮件
            /// </summary>
            public void Send()
            {
                using (SmtpClient smtpClient = GetSmtpClient)
                {
                    using (MailMessage mailMessage = GetClient)
                    {
                        if (smtpClient == null || mailMessage == null) return;
                        Subject = Subject;
                        Body = Body;
                        //EnableSsl = false;
                        smtpClient.Send(mailMessage); //异步发送邮件,如果回调方法中参数不为"true"则表示发送失败
                    }
                }
            }    
View Code

  (2)验证

  

三、Ocelot网关配置

3.1 为Ocelot增加Consul支持

  (1)增加Nuget包:Ocelot.Provider.Consul

Nuget>> Install-Package Ocelot.Provider.Consul  

  (2)修改StartUp.cs,增加Consul支持

s.AddOcelot()
    .AddConsul();

  更多内容,请移步:Ocelot官方文档-服务发现

3.2 修改Ocelot配置文件增加Consul配置

    "GlobalConfiguration": {
        "BaseUrl": "http://api.xique.com",
        "ServiceDiscoveryProvider": {
             "Host": "192.168.16.170",
             "Port": 8550,
             "Type": "Consul"
        }
    }

  *.这里指向的是Consul Client实例的地址

  此外,Ocelot默认策略是每次请求都去Consul中获取服务地址列表,如果想要提高性能,也可以使用PollConsul的策略,即Ocelot自己维护一份列表,然后定期从Consul中获取刷新,就不再是每次请求都去Consul中拿一趟了。例如下面的配置,它告诉Ocelot每2秒钟去Consul中拿一次。

    "Type": "PollConsul",
    "PollingInterval": 2000

3.3 Service配置

    // -- Service
    {
      "UseServiceDiscovery": true,
      "DownstreamPathTemplate": "/api/{url}",
      "DownstreamScheme": "http",
      "ServiceName": "core.product",
      "LoadBalancerOptions": {
        "Type": "RoundRobin"
      },
      "UpstreamPathTemplate": "/product/{url}",
      "UpstreamHttpMethod": [ "Get", "Post", "Put", "Delete" ]
    }

  这里配置了在Consul中配置的服务名(ServiceName),以及告诉Ocelot我们使用轮询策略(RoundRobin)做负载均衡。

3.4 验证

  第一次访问:

  

  第二次访问:

  

四、HA示例整体架构

  对于实际应用中,我们往往会考虑单点问题,因此会借助一些负载均衡技术来做高可用的架构,这里给出一个建议的HA示例的整体架构:

  对于一个API请求,首先会经历一个Load Balancer才会到达API Gateway,这个Load Balancer可以是基于硬件的F5,也可以是基于软件的Nginx或LVS再搭配Keepalived,一般来说大部分团队都会选择Nginx。然后API Gateway通过部署多个,来解决单点问题,也达到负载均衡的效果。而对于API Gateway和Consul Client之间的连接,我们往往也会增加一个Load Balancer来实现服务发现的高可用,这个Load Balancer也一般会基于Nginx/LVS搭配Keepalived,API Gateway只需要访问一个Virtual IP即可。而在Consul Data Center中,Consul Server会选择3或5个,Consul Client也会部署多个,刚刚提到的Virtual IP则会指向多个Consul Client,从而防止了Consul Client的单点问题。

  最后,祝大家端午安康!

  

  

posted @ 2019-06-07 09:37 Edison Chou 阅读(...) 评论(...) 编辑 收藏