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分布式服務(wù)注冊發(fā)現(xiàn)與統(tǒng)一配置管理之 Consul

猿友 2020-09-01 15:07:24 瀏覽數(shù) (5369)
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文章轉(zhuǎn)載自公眾號(hào)：Java極客技術(shù) 作者：鴨血粉絲

今天這篇文章給大家介紹一個(gè)用于服務(wù)注冊發(fā)現(xiàn)和管理配置的開源組件-- Consul 。接下來讓我們一起來看一下它的功能吧。

背景

目前分布式系統(tǒng)架構(gòu)已經(jīng)基本普及，很多項(xiàng)目都是基于分布式架構(gòu)的，以往的單機(jī)模式基本已經(jīng)不適應(yīng)當(dāng)下互聯(lián)網(wǎng)行業(yè)的發(fā)展。隨著分布式項(xiàng)目的普及，項(xiàng)目服務(wù)實(shí)例數(shù)目的增加，服務(wù)的注冊與發(fā)現(xiàn)功能就成了一項(xiàng)必不可少的架構(gòu)。服務(wù)的注冊與發(fā)現(xiàn)的功能，有很多開源方案。包括早期的zookeeper，百度的disconf，阿里的diamond，基于Go語言的ETCD，Spring集成的Eureka，以及前文提到的 Nacos 還有本文的主角Consul。這里不對上面提到的進(jìn)行比較，本文僅介紹Consul，詳細(xì)的對比，說明網(wǎng)上有很多資料，可以參考，例如：服務(wù)發(fā)現(xiàn)比較:Consul vs Zookeeper vs Etcd vs Eureka說到服務(wù)的注冊與發(fā)現(xiàn)主要是下面兩個(gè)主要功能：

  1. 服務(wù)注冊與發(fā)現(xiàn)
  2. 配置中心即分布式項(xiàng)目統(tǒng)一配置管理

Consul 服務(wù)端配置使用

  1. 下載相應(yīng)版本解壓，并將可執(zhí)行文件復(fù)制到/usr/local/consul目錄下

  1. 創(chuàng)建一個(gè)service的配置文件 
    silence$ sudo mkdir /etc/consul.d
silence$ echo '{"service":{"name": "web", "tags": ["rails"], "port": 80}}' | sudo tee /etc/consul.d/web.json

  1. 啟動(dòng)代理

   silence$ /usr/local/consul/consul agent -dev -node consul_01 -config-dir=/etc/consul.d/ -ui

-dev 參數(shù)代表本地測試環(huán)境啟動(dòng)；-node 參數(shù)表示自定義集群名稱；-config-drir 參數(shù)表示services的注冊配置文件目錄，即上面創(chuàng)建的文件夾-ui 啟動(dòng)自帶的web-ui管理頁面

  1. 集群成員查詢方式

   silence-pro:~ silence$ /usr/local/consul/consul members

  1. HTTP協(xié)議數(shù)據(jù)查詢

silence-pro:~ silence$ curl http://127.0.0.1:8500/v1/catalog/service/web
[
    {
        "ID": "ab1e3577-1b24-d254-f55e-9e8437956009",
        "Node": "consul_01",
        "Address": "127.0.0.1",
        "Datacenter": "dc1",
        "TaggedAddresses": {
            "lan": "127.0.0.1",
            "wan": "127.0.0.1"
        },
        "NodeMeta": {
            "consul-network-segment": ""
        },
        "ServiceID": "web",
        "ServiceName": "web",
        "ServiceTags": [
            "rails"
],
        "ServiceAddress": "",
        "ServicePort": 80,
        "ServiceEnableTagOverride": false,
        "CreateIndex": 6,
        "ModifyIndex": 6
    }
]
silence-pro:~ silence$

  1. web-ui管理 Consul Web UI

Consul Web UI

Consul的web-ui可以用來進(jìn)行服務(wù)狀態(tài)的查看，集群節(jié)點(diǎn)的檢查，訪問列表的控制以及KV存儲(chǔ)系統(tǒng)的設(shè)置，相對于Eureka和ETCD，Consul的web-ui要好用的多。（Eureka和ETCD將在下一篇文章中簡單介紹。）

7.KV存儲(chǔ)的數(shù)據(jù)導(dǎo)入和導(dǎo)出

silence-pro:consul silence$ ./consul kv import @temp.json


silence-pro:consul silence$ ./consul kv export redis/

temp.json文件內(nèi)容格式如下，一般是管理頁面配置后先導(dǎo)出保存文件，以后需要再導(dǎo)入該文件

[
    {
        "key": "redis/config/password",
        "flags": 0,
        "value": "MTIzNDU2"
    },
    {
        "key": "redis/config/username",
        "flags": 0,
        "value": "U2lsZW5jZQ=="
    },
    {
        "key": "redis/zk/",
        "flags": 0,
        "value": ""
    },
    {
        "key": "redis/zk/password",
        "flags": 0,
        "value": "NDU0NjU="
    },
    {
        "key": "redis/zk/username",
        "flags": 0,
        "value": "ZGZhZHNm"
    }
]

Consul的KV存儲(chǔ)系統(tǒng)是一種類似zk的樹形節(jié)點(diǎn)結(jié)構(gòu)，用來存儲(chǔ)相關(guān)key/value鍵值對信息的，我們可以使用KV存儲(chǔ)系統(tǒng)來實(shí)現(xiàn)上面提到的配置中心，將統(tǒng)一的配置信息保存在KV存儲(chǔ)系統(tǒng)里面，方便各個(gè)實(shí)例獲取并使用同一配置。而且更改配置后各個(gè)服務(wù)可以自動(dòng)拉取最新配置，不需要重啟服務(wù)。

Consul Java 客戶端使用

  1. maven pom依賴增加，版本可自由更換

<dependency>
    <groupId>com.orbitz.consul</groupId>
    <artifactId>consul-client</artifactId>
    <version>0.12.3</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

  1. Consul 基本工具類，根據(jù)需要相應(yīng)擴(kuò)展

package com.coocaa.consul.consul.demo;


import com.google.common.base.Optional;
import com.google.common.net.HostAndPort;
import com.orbitz.consul.*;
import com.orbitz.consul.model.agent.ImmutableRegCheck;
import com.orbitz.consul.model.agent.ImmutableRegistration;
import com.orbitz.consul.model.health.ServiceHealth;


import java.net.MalformedURLException;
import java.net.URI;
import java.util.List;


public class ConsulUtil {


    private static Consul consul = Consul.builder().withHostAndPort(HostAndPort.fromString("127.0.0.1:8500")).build();


    /**


     * 服務(wù)注冊


     */
    public static void serviceRegister() {
        AgentClient agent = consul.agentClient();


        try {
            /**


             * 注意該注冊接口：
             * 需要提供一個(gè)健康檢查的服務(wù)URL，以及每隔多長時(shí)間訪問一下該服務(wù)（這里是3s）


             */
            agent.register(8080, URI.create("http://localhost:8080/health").toURL(), 3, "tomcat", "tomcatID", "dev");


        } catch (MalformedURLException e) {
            e.printStackTrace();
        }


    }


    /**


     * 服務(wù)獲取


     *


     * @param serviceName


     */
    public static void findHealthyService(String serviceName) {
        HealthClient healthClient = consul.healthClient();
        List<ServiceHealth> serviceHealthList = healthClient.getHealthyServiceInstances(serviceName).getResponse();
        serviceHealthList.forEach((response) -> {
            System.out.println(response);
        });
    }


    /**


     * 存儲(chǔ)KV


     */
    public static void storeKV(String key, String value) {
        KeyValueClient kvClient = consul.keyValueClient();
        kvClient.putValue(key, value);
    }


    /**


     * 根據(jù)key獲取value


     */
    public static String getKV(String key) {
        KeyValueClient kvClient = consul.keyValueClient();
        Optional<String> value = kvClient.getValueAsString(key);
        if (value.isPresent()) {
            return value.get();
        }
        return "";
    }


    /**


     * 找出一致性的節(jié)點(diǎn)（應(yīng)該是同一個(gè)DC中的所有server節(jié)點(diǎn)）


     */
    public static List<String> findRaftPeers() {
        StatusClient statusClient = consul.statusClient();
        return statusClient.getPeers();
    }


    /**


     * 獲取leader


     */
    public static String findRaftLeader() {
        StatusClient statusClient = consul.statusClient();
        return statusClient.getLeader();
    }


    public static void main(String[] args) {
        AgentClient agentClient = consul.agentClient();
        agentClient.deregister("tomcatID");
    }
}

temp.json 和 ConsulUtil.java 文件以及上傳到 GitHub 資源庫，回復(fù)【源碼倉庫】獲取代碼地址。

3.通過上面的基本工具類可以實(shí)現(xiàn)服務(wù)的注冊和KV數(shù)據(jù)的獲取與存儲(chǔ)功能

Consul集群搭建

  1. 三臺(tái)主機(jī)Consul下載安裝，我這里沒有物理主機(jī)，所以通過三臺(tái)虛擬機(jī)來實(shí)現(xiàn)。虛擬機(jī)IP分192.168.231.145，192.168.231.146，192.168.231.147

  1. 將145和146兩臺(tái)主機(jī)作為Server模式啟動(dòng)，147作為Client模式啟動(dòng)，Server和Client只是針對Consul集群來說的，跟服務(wù)沒有任何關(guān)系！

  1. Server模式啟動(dòng)145，節(jié)點(diǎn)名稱設(shè)為n1，數(shù)據(jù)中心統(tǒng)一用dc1

[root@centos145 consul]# ./consul agent -server -bootstrap-expect 2 -data-dir /tmp/consul -node=n1 -bind=192.168.231.145 -datacenter=dc1
bootstrap_expect = 2: A cluster with 2 servers will provide no failure tolerance. See https://www.consul.io/docs/internals/consensus.html#deployment-table
bootstrap_expect > 0: expecting 2 servers
==> Starting Consul agent...
==> Consul agent running!
           Version: 'v1.0.1'
           Node ID: '6cc74ff7-7026-cbaa-5451-61f02114cd25'
         Node name: 'n1'
        Datacenter: 'dc1' (Segment: '<all>')
            Server: true (Bootstrap: false)
       Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, DNS: 8600)
      Cluster Addr: 192.168.231.145 (LAN: 8301, WAN: 8302)
           Encrypt: Gossip: false, TLS-Outgoing: false, TLS-Incoming: false


==> Log data will now stream in as it occurs:


    2017/12/06 23:26:21 [INFO] raft: Initial configuration (index=0): []
    2017/12/06 23:26:21 [INFO] serf: EventMemberJoin: n1.dc1 192.168.231.145
    2017/12/06 23:26:21 [INFO] serf: EventMemberJoin: n1 192.168.231.145
    2017/12/06 23:26:21 [INFO] agent: Started DNS server 127.0.0.1:8600 (udp)
    2017/12/06 23:26:21 [INFO] raft: Node at 192.168.231.145:8300 [Follower] entering Follower state (Leader: "")
    2017/12/06 23:26:21 [INFO] consul: Adding LAN server n1 (Addr: tcp/192.168.231.145:8300) (DC: dc1)
    2017/12/06 23:26:21 [INFO] consul: Handled member-join event for server "n1.dc1" in area "wan"
    2017/12/06 23:26:21 [INFO] agent: Started DNS server 127.0.0.1:8600 (tcp)
    2017/12/06 23:26:21 [INFO] agent: Started HTTP server on 127.0.0.1:8500 (tcp)
    2017/12/06 23:26:21 [INFO] agent: started state syncer
    2017/12/06 23:26:28 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:26:30 [WARN] raft: no known peers, aborting election
    2017/12/06 23:26:49 [ERR] agent: Coordinate update error: No cluster leader
    2017/12/06 23:26:54 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:27:24 [ERR] agent: Coordinate update error: No cluster leader
    2017/12/06 23:27:27 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:27:56 [ERR] agent: Coordinate update error: No cluster leader
    2017/12/06 23:28:02 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:28:27 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:28:33 [ERR] agent: Coordinate update error: No cluster leader

目前只啟動(dòng)了145，所以還沒有集群

4.Server模式啟動(dòng)146，節(jié)點(diǎn)名稱用n2，并在n2上啟用了web-ui管理頁面功能

[root@centos146 consul]# ./consul agent -server -bootstrap-expect 2 -data-dir /tmp/consul -node=n2 -bind=192.168.231.146 -datacenter=dc1 -ui
bootstrap_expect = 2: A cluster with 2 servers will provide no failure tolerance. See https://www.consul.io/docs/internals/consensus.html#deployment-table
bootstrap_expect > 0: expecting 2 servers
==> Starting Consul agent...
==> Consul agent running!
           Version: 'v1.0.1'
           Node ID: 'eb083280-c403-668f-e193-60805c7c856a'
         Node name: 'n2'
        Datacenter: 'dc1' (Segment: '<all>')
            Server: true (Bootstrap: false)
       Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, DNS: 8600)
      Cluster Addr: 192.168.231.146 (LAN: 8301, WAN: 8302)
           Encrypt: Gossip: false, TLS-Outgoing: false, TLS-Incoming: false


==> Log data will now stream in as it occurs:


    2017/12/06 23:28:30 [INFO] raft: Initial configuration (index=0): []
    2017/12/06 23:28:30 [INFO] serf: EventMemberJoin: n2.dc1 192.168.231.146
    2017/12/06 23:28:31 [INFO] serf: EventMemberJoin: n2 192.168.231.146
    2017/12/06 23:28:31 [INFO] raft: Node at 192.168.231.146:8300 [Follower] entering Follower state (Leader: "")
    2017/12/06 23:28:31 [INFO] consul: Adding LAN server n2 (Addr: tcp/192.168.231.146:8300) (DC: dc1)
    2017/12/06 23:28:31 [INFO] consul: Handled member-join event for server "n2.dc1" in area "wan"
    2017/12/06 23:28:31 [INFO] agent: Started DNS server 127.0.0.1:8600 (tcp)
    2017/12/06 23:28:31 [INFO] agent: Started DNS server 127.0.0.1:8600 (udp)
    2017/12/06 23:28:31 [INFO] agent: Started HTTP server on 127.0.0.1:8500 (tcp)
    2017/12/06 23:28:31 [INFO] agent: started state syncer
    2017/12/06 23:28:38 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:28:39 [WARN] raft: no known peers, aborting election
    2017/12/06 23:28:57 [ERR] agent: Coordinate update error: No cluster leader
    2017/12/06 23:29:11 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:29:30 [ERR] agent: Coordinate update error: No cluster leader
    2017/12/06 23:29:38 [ERR] agent: failed to sync remote state: No cluster leader
    2017/12/06 23:29:57 [ERR] agent: Coordinate update error: No cluster leader

同樣沒有集群發(fā)現(xiàn)，此時(shí)n1和n2都啟動(dòng)起來，但是互相并不知道集群的存在！

5.將n1節(jié)點(diǎn)加入n2

   [silence@centos145 consul]$ ./consul join 192.168.231.146

此時(shí)n1和n2都打印發(fā)現(xiàn)了集群的日志信息

6.這個(gè)時(shí)候n1和n2兩個(gè)節(jié)點(diǎn)已經(jīng)是一個(gè)集群里面的Server模式的節(jié)點(diǎn)了

7.Client模式啟動(dòng)147

[root@centos147 consul]# ./consul agent -data-dir /tmp/consul -node=n3 -bind=192.168.231.147 -datacenter=dc1
==> Starting Consul agent...
==> Consul agent running!
           Version: 'v1.0.1'
           Node ID: 'be7132c3-643e-e5a2-9c34-cad99063a30e'
         Node name: 'n3'
        Datacenter: 'dc1' (Segment: '')
            Server: false (Bootstrap: false)
       Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, DNS: 8600)
      Cluster Addr: 192.168.231.147 (LAN: 8301, WAN: 8302)
           Encrypt: Gossip: false, TLS-Outgoing: false, TLS-Incoming: false


==> Log data will now stream in as it occurs:


    2017/12/06 23:36:46 [INFO] serf: EventMemberJoin: n3 192.168.231.147
    2017/12/06 23:36:46 [INFO] agent: Started DNS server 127.0.0.1:8600 (udp)
    2017/12/06 23:36:46 [INFO] agent: Started DNS server 127.0.0.1:8600 (tcp)
    2017/12/06 23:36:46 [INFO] agent: Started HTTP server on 127.0.0.1:8500 (tcp)
    2017/12/06 23:36:46 [INFO] agent: started state syncer
    2017/12/06 23:36:46 [WARN] manager: No servers available
    2017/12/06 23:36:46 [ERR] agent: failed to sync remote state: No known Consul servers
    2017/12/06 23:37:08 [WARN] manager: No servers available
    2017/12/06 23:37:08 [ERR] agent: failed to sync remote state: No known Consul servers
    2017/12/06 23:37:36 [WARN] manager: No servers available
    2017/12/06 23:37:36 [ERR] agent: failed to sync remote state: No known Consul servers
    2017/12/06 23:38:02 [WARN] manager: No servers available
    2017/12/06 23:38:02 [ERR] agent: failed to sync remote state: No known Consul servers
    2017/12/06 23:38:22 [WARN] manager: No servers available
    2017/12/06 23:38:22 [ERR] agent: failed to sync remote state: No known Consul servers

8.在n3上面將節(jié)點(diǎn)n3加入集群

   [silence@centos147 consul]$ ./consul join 192.168.231.145

9.再次查看集群節(jié)點(diǎn)信息

10.此時(shí)三個(gè)節(jié)點(diǎn)的Consul集群搭建成功了！其實(shí)n1和n2是Server模式啟動(dòng)，n3是Client模式啟動(dòng)。

11.關(guān)于Consul的Server模式和Client模式主要的區(qū)別是這樣的，一個(gè)Consul集群通過啟動(dòng)的參數(shù)-bootstrap-expect來控制這個(gè)集群的Server節(jié)點(diǎn)個(gè)數(shù)，Server模式的節(jié)點(diǎn)會(huì)維護(hù)集群的狀態(tài)，并且如果某個(gè)Server節(jié)點(diǎn)退出了集群，則會(huì)觸發(fā)Leader重新選舉機(jī)制，在會(huì)剩余的Server模式節(jié)點(diǎn)中重新選舉一個(gè)Leader；而Client模式的節(jié)點(diǎn)的加入和退出很自由。

12.在n2中啟動(dòng)web-ui

分布式服務(wù)注冊發(fā)現(xiàn)與統(tǒng)一配置管理之 Consul

以上就是W3Cschool編程獅關(guān)于分布式服務(wù)注冊發(fā)現(xiàn)與統(tǒng)一配置管理之 Consul的相關(guān)介紹了，希望對大家有所幫助。

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