正反向代理集群搭建

代理

正向代理

通过正向代理服务地址由正向代理服务器访问外部网络由内部到外部访问

反向代理

将外部网络请求通过反向代理中转给局域网的服务器由外部到内部中转

upstream

server ip:端口或者unix套接字修饰符
修饰符
weight 权重默认为1 权重就越大负载的概率越大
backup 备份非备份机down或者忙的时候请求备份机
down 停止使用
max_fails 最大失败次数默认为1 超过最大次数时返回proxy_next_upstream定义的错误
fail_timeout 最大失败次数后暂停的时间
ip_hash 按照ip一致性hash分配
keepalive 设置每个worker进程与后端服务器(upstream中的server)保持连接的最大数量
一个连接池缓存的最大数目
这些保持的连接会被放入缓存淘汰算法lru 淘汰最老的

upstream backend{
     ip_hash;
     ##连接池缓存连接最大数目 
     keepalive=2000;
    server 127.0.0.1:81 down; 
    server 127.0.0.1:82 weight=2; 
    server 127.0.0.1:83 max_fails=0  fail_timeout=1s; 
    server 127.0.0.1:84 backup; 
}

proxy

proxy_connect_timeout
默认时间为60s 与upstream的server连接超时时间
proxy_buffers
proxy_buffers 4 64k;
缓冲区数目和每个缓冲区的大小
proxy_set_header X-Real-IP $remote_addr;
设置响应的头部
在php里$_SERVER[‘HTTP_X_REAL_IP’]
proxy_next_upstream
什么时候被转接到下一个upstream的server
proxy_next_upstream http_502 http_504 http_404 error timeout invalid_header non_idempotent;
proxy_pass 连接方式 ip:端口域名或者套接字都可以的

###结尾有/ 表示绝对路径 没有相对路径
location /baidu {
		proxy_pass http://www.baidu.com/   #有斜杠
	 }
###访问http://www.baidu.com
location /baidu{
		proxy_pass http://www.baidu.com
	 }
###访问http://www.baidu.com/baidu

proxy_pass 192.168.1.78:80
#unix套接字连接方式
proxy_pass unix:/dev/shm/php-cgi.sock;
#连接upstream方式
proxy_pass http://backend;

location  /{
	proxy_connect_timeout 75s;
	proxy_buffers   4 64k;
	proxy_next_upstream  error timeout invalid_header non_idempotent;
	proxy_set_header X-Real-IP $remote_addr; 
    proxy_pass http://myproject;  
 }

分配策略

一致性hash
上面的ip_hash 就是按照ip进行一致性hash分配
做过优化解决 hash虚拟节点分布不均的问题
平均散列到1到2147483647之间

namespace helper\assign;
defined('IN')||exit;

class hashAssign
{
    //节点(包含虚拟节点)
    protected $_positionToTarget = array();
    //主机节点
    protected $_targetToPositions = array();
    //排序
    protected $_positionToTargetSorted = false;
	protected $targetNum=1;
	protected $replicas=1;	
	protected $HashList=array();
    public  function init($init=array())
    {
		$this->targetNum = isset($init[0])?$init[0]:10;
        $this->replicas = isset($init[1])?$init[1]:100;
		if(($this->replicas%$this->targetNum)!=0){
			throw new \Exception('虚拟节点数必须是物理节点数的整数倍');
		}
		$chu=intval($this->replicas/$this->targetNum);
		$this->HashList=$this->getHashList($this->replicas);
		for ($i = 0; $i < $this->replicas; $i ++) {
			$target=intval($i/$chu);
            $position = $this->HashList[$i];
            $this->_positionToTarget[$position] = $target;
			$this->_targetToPositions[$target][$i] = $position;
        }
		$this->_positionToTargetSorted = false;
    }
	
	public function move($atarget=0,$starget=1,$replicasStart=10,$replicasEnd=100)
    {
		if (!isset($this->_targetToPositions[$starget])) {
            throw new \Exception('物理节点 '.$starget.' 不存在.');
        }
        if (isset($this->_targetToPositions[$atarget])) {
            throw new \Exception('物理节点 '.$atarget.' 已经存在.');
        }
        $this->_targetToPositions[$atarget] = array();
		for($i = $replicasStart; $i <= $replicasEnd; $i++) {
			$position = $this->HashList[$i];
			if(!isset($this->_targetToPositions[$starget][$i])){
				 throw new \Exception('虚拟节点 '.$starget.'-'.$i.' 不存在.');
			}
			unset($this->_targetToPositions[$starget][$i]);
			$this->_positionToTarget[$position] = $atarget;
            $this->_targetToPositions[$atarget][$i] = $position;
        }
		
        $this->_positionToTargetSorted = false;
    }
	
    private function hash($hash)
    {
        return abs(crc32($hash));
    }
	
	private function getHashList($replicas=10)
    {
	$HashList=array();
	$max=2147483647;
	$num=intval($max/$replicas)+1;
	for($i=0;$i<$replicas-1;$i++){
		$HashList[$i]=$num*($i+1);
	}
	$HashList[]=2147483647;
	return $HashList;
    }

    public function lookup($resource)
    {
        $targets = $this->lookupList($resource, 1);

        if (empty($targets)){
			throw new \Exception('No targets exist');
		}
            
        return $targets[0];
    }

    public function lookupList($resource,$requestedCount=1)
    {
        if(empty($this->_positionToTarget)){return array();}   
        $resourcePosition = $this->hash($resource);
        $this->_sortPositionTargets();
        return $this->find($this->_positionToTarget, $resourcePosition, $requestedCount);
    }

    protected function _sortPositionTargets()
    {
        if (!$this->_positionToTargetSorted) {
            ksort($this->_positionToTarget, SORT_REGULAR);
            $this->_positionToTargetSorted = true;
        }
    }
	
	private function find($node,$resourcePosition,$requestedCount)
    {
        $results = array();
        $collect = false;
        foreach ($node as $key => $value) {
            if (! $collect && $key > $resourcePosition) {
                $collect = true;
            }
            if ($collect && ! in_array($value, $results)) {
                $results[] = $value;
            }
            if (count($results) == $requestedCount) {
                return $results;
            }
        }
        foreach ($node as $key => $value) {
            if (! in_array($value, $results)) {
                $results[] = $value;
            }
            if (count($results) == $requestedCount) {
                return $results;
            }
        }
        return $results;
    }
	
}

加权轮询策略

namespace helper\assign;
defined('IN')||exit;
class weightAssign
{
	public $default_sign='default';
    public function setHost($hosts)
    {
       return $this->host=$hosts;
    }
	
	public function getHostIndex($sign='')
    {
        $weight_sum = 0;
        foreach ($this->host as $v) {
            if (! isset($v['sign'])) {
                $v['sign'] = $this->default_sign;
            }
            if ($v['sign'] != $sign) {
                continue;
            }
            if (! isset($v['weight'])) {
                $v['weight'] = 1;
            }
            $weight_sum += $v['weight'];
        }
        $roll = mt_rand(1, $weight_sum);
        $tmp = 0;
        foreach ($this->host as $k => $v) {
            if (! isset($v['sign'])) {
                $v['sign'] = $this->default_sign;
            }
            if ($v['sign'] != $sign) {
                continue;
            }
            if (! isset($v['weight'])) {
                $v['weight'] = 1;
            }
            $tmp += $v['weight'];
            if ($tmp >= $roll) {
                return $k;
            }
        }
    }
	
}

正反向代理 集群搭建

代理

upstream

proxy

分配策略

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