方案：

• 使用HAproxy：当其中一台ElasticSearch Master宕掉时，ElasticSearch集群会自动将运行正常的节点提升为Master，但HAproxy不会将失败的请求重新分发到新的Master Node。
• 使用ElasticSearch：单search load balancer（外层负载均衡节点）、双coordinator（调度节点）、若干workhorse（数据节点）。先后在200并发Index、200并发Update测试下（跑在虚拟机下，线程太多就卡爆了），并前后分别测试了Down掉一台主coordinator、Down掉一台workhorse，都没有引起数据异常，集群工作正常。

先贴一下使用HAproxy搭建集群失败的配置吧：

#全局配置global        daemon        nbproc 4        pidfile /tmp/haproxy.pid#默认配置defaults        mode http               #默认的模式mode { tcp|http|health }，tcp是4层，http是7层，health只会返回OK        retries 2               #两次连接失败就认为是服务器不可用，也可以通过后面设置        option redispatch           #当serverId对应的服务器挂掉后，强制定向到其他健康的服务器        option httpclose            #HAProxy会针对客户端的第一条请求的返回添加cookie并返回给客户端，客户端发送后续请求时会发送此cookie到HAProxy        #option abortonclose            #当服务器负载很高的时候，自动结束掉当前队列处理比较久的链接        maxconn 4096                #默认的最大连接数        timeout connect 5000ms          #连接超时        timeout client 30000ms          #客户端超时        timeout server 30000ms          #服务器超时        timeout check 2000          #心跳检测超时        log 127.0.0.1 local0 err #[err warning info debug]#统计页面配置listen admin_stats        bind 0.0.0.0:8888               #监听端口        mode http                       #http的7层模式        option httplog                  #采用http日志格式        #log 127.0.0.1 local0 err        maxconn 10        stats refresh 30s               #统计页面自动刷新时间        stats uri /                     #统计页面url        stats realm XingCloud\ Haproxy  #统计页面密码框上提示文本        stats auth admin:admin          #统计页面用户名和密码设置        #stats hide-version             #隐藏统计页面上HAProxy的版本信息#ElasticSearch Frontendfrontend eshttp    bind 0.0.0.0:9200    mode tcp    use_backend eshttp_server#ElasticSearch Backendbackend eshttp_server    server eshttp1      vm12:9200 cookie 1 check inter 2000 rise 3 fall 3 weight 2    server eshttp2      vm13:9200 cookie 2 check inter 2000 rise 3 fall 3 weight 1    server eshttp3_bk   vm14:9200 cookie 3 check inter 1000 rise 3 fall 3 backup

采用ElasticSearch搭建集群的关键几个配置：

search load balancer（LB负载均衡节点）:

cluster.name: harold                    #集群名称node.name: "harold_lb"                  #节点名称# 3. You want this node to be neither master nor data node, but#    to act as a "search load balancer" (fetching data from nodes,#    aggregating results, etc.)#node.master: falsenode.data: falsediscovery.zen.ping.unicast.hosts: ["vm11", "vm12", "vm13", "vm14", "vm15", "vm16"] #自动发现节点hosts

coordinator（Master调度节点）:

cluster.name: harold                    #集群名称node.name: "harold_coordinator_1"           #节点名称# 2. You want this node to only serve as a master: to not store any data and#    to have free resources. This will be the "coordinator" of your cluster.#node.master: truenode.data: falsediscovery.zen.ping.unicast.hosts: ["vm11", "vm12", "vm13", "vm14", "vm15", "vm16"] #自动发现节点hosts

workhorse（Data数据节点）:

cluster.name: harold                    #集群名称node.name: "harold_data_1"              #节点名称# 1. You want this node to never become a master node, only to hold data.#    This will be the "workhorse" of your cluster.#node.master: falsenode.data: truediscovery.zen.ping.unicast.hosts: ["vm11", "vm12", "vm13", "vm14", "vm15", "vm16"] #自动发现节点hosts

配置完，启动后，/_plugin/head/页面应该是这个样子:

这样配置完的集群应该就是类似这样的：

可以使用curl初始化Index的主分片与复制分片:

curl -XPUT -d'{"settings":{"number_of_shards":6, "number_of_replicas":1}}' http://vm11:9200/app1

Tip:

number_of_shards 主分片在集群中的总数量

number_of_replicas 每个主分片的复制分片数量

#复制分片在今后的分布式集群变化过程中，随时都可以根据业务进行新增或减少：curl -XPUT -d'{"number_of_replicas":2}' http://vm11:9200/app1/_settings

#另外，ElasticSearch在没有任何索引的情况下新增一个文档，便自动创建了索引，为避免发生这种情况，可以在配置文件中添加:action.auto_create_index: false

删除Index:

curl -XDELETE http://vm11:9200/app1

在当前版本中，这样组建集群会有一个小问题:

当单独把Master CoordinatorDown掉后，/_plugin/head/插件页面会是这个样子：

但可喜的是，并不影响集群与集群客户端之间数据的CRUD操作。

数据有所改变而且较长一段时间后（大约10几分钟？），/_plugin/head/插件页面会恢复正常。

贴下PHP操作ElasticSearch的多进程并发测试代码吧，做下记录:

    sum % $this->process !== 0 && die("invalid num. \n");        $this->num_per_proc = $this->sum / $this->process;    }    private function insert()    {        $es = new ClientBuilder();        $es->setHosts($this->hosts);        $client = $es->build();        $words = str_split("abcdefghijklmnopqrstuvwxyz");        $birth_year = [];        for ($i = 1; $i <= 50; $i++) {            $birth_year[] = 1960 + $i;        }        $type = ['1', '2', '3', '4'];        $process = [];        for ($p = 0; $p < $this->process; $p++) {            $process[] = new \swoole_process(function () use ($client, $birth_year, $type, $words, $p) {                for ($i = $this->num_per_proc * $p; $i < $this->num_per_proc * ($p + 1); $i++) {                    $client->index([                        'index' => $this->index,                        'type' => $this->type,                        'id' => $i,                        'body' => [                            'birth_year' => $birth_year[array_rand($birth_year)],                            'type' => $type[array_rand($type)],                            'name' => $words[mt_rand(0, 25)] . $words[mt_rand(0, 25)] . $words[mt_rand(0, 25)] . $words[mt_rand(0, 25)],                            'height' => mt_rand(150, 200),                            'weight' => mt_rand(40, 200),                            'test' => 1,                            'userid' => $i                        ]                    ]);                }            });        }        foreach ($process as $p) {            $pid = $p->start();            echo $pid . "\n";        }    }    private function update()    {        $es = new ClientBuilder();        $es->setHosts($this->hosts);        $client = $es->build();        $process = [];        for ($i = 0; $i < $this->process; $i++) {            $process[] = new \swoole_process(function () use ($client, $i) {                $response = $client->search([                    'index' => $this->index,                    'type' => $this->type,                    'size' => $this->num_per_proc,                    'from' => $this->num_per_proc * $i,                    'sort' => "userid:asc"                ]);                foreach ($response['hits']['hits'] as $v) {                    $id = $v['_id'];                    $test = $v['_source']['test'];                    $test++;                    file_put_contents("/tmp/s", $test . "\n", FILE_APPEND);                    $client->update([                        'index' => $this->index,                        'type' => $this->type,                        'id' => $id,                        'body' => [                            'doc' => [                                'test' => $test                            ]                        ]                    ]);                }            });        }        foreach ($process as $p) {            $pid = $p->start();            echo $pid . "\n";        }    }    private function gets()    {        $es = new ClientBuilder();        $es->setHosts($this->hosts);        $client = $es->build();        $response = $client->search([            'index' => $this->index,            'type' => $this->type,            'size' => 5000,            'from' => 500,            'sort' => "userid:asc"        ]);        foreach ($response['hits']['hits'] as $v) {            $id = $v['_id'];            $test = $v['_source']['test'];            // file_put_contents("/tmp/s", $test . "\n", FILE_APPEND);            var_dump($test);        }    }    /**     * Execute the console command.     *     * @return mixed     */    public function handle()    {        $this->insert();    }}