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itemprop="mainEntityOfPage" href="https://ehlxr.me/2022/07/10/docker-keepalived-nginx-ha/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="name" content="!!@_@ ᵛᵉ"><meta itemprop="description" content="瞻前顾后，惶惶不可终日"><meta itemprop="image" content="https://cdn.jsdelivr.net/gh/0vo/oss/images/logo_2.png"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Ehlxr's Blog"></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2022/07/10/docker-keepalived-nginx-ha/" class="post-title-link" itemprop="url">Docker 搭建 Keepalived 实现 Nginx 双机热备</a></h2><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-calendar-o"></i></span> <span class="post-meta-item-text">发表于</span> <time title="创建时间：2022-07-10 13:12:14" itemprop="dateCreated datePublished" datetime="2022-07-10T13:12:14+00:00">2022-07-10</time></span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-folder-o"></i></span> <span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/%E6%9E%B6%E6%9E%84/" itemprop="url" rel="index"><span itemprop="name">架构</span></a></span></span><span id="/2022/07/10/docker-keepalived-nginx-ha/" class="post-meta-item leancloud_visitors" data-flag-title="Docker 搭建 Keepalived 实现 Nginx 双机热备" title="阅读次数"><span class="post-meta-item-icon"><i class="fa fa-eye"></i></span> <span class="post-meta-item-text">阅读次数：</span><span class="leancloud-visitors-count"></span></span><span class="post-meta-item"><a title="show comments" href="/2022/07/10/docker-keepalived-nginx-ha/#show_comments"><span class="post-meta-item-icon"><i class="fa fa-comment-o"></i></span></a></span><span class="post-meta-item" title="本文字数"><span class="post-meta-item-icon"><i class="fa fa-file-word-o"></i></span> <span>3.8k</span></span><span class="post-meta-item" title="阅读时长"><span class="post-meta-item-icon"><i class="fa fa-clock-o"></i></span> <span>3 分钟</span></span></div></header><div class="post-body" itemprop="articleBody"><p><img src="https://cdn.jsdelivr.net/gh/0vo/oss/images/keepalived-nginx-ha.jpg" alt="keepalived Nginx HA"></p><p>docker 搭建 keepalived 实现 nginx 双机热备</p><figure class="highlight shell"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">❯ docker run --privileged -d --name node1 debian:11 top -b</span><br><span class="line">❯ docker run --privileged -d --name node2 debian:11 top -b</span><br></pre></td></tr></table></figure><p><code>–-privileged</code> 是指以特权模式启动容器，否则 keepalived 无法成功生成虚拟 IP</p><p>分别进入 node1、node2 容器节点（<code>docker exec -it node1 /bin/bash</code> 和 <code>docker exec -it node2 /bin/bash</code> ）</p><p>安装以下软件 <code>apt update && apt install curl vim iproute2 inetutils-ping psmisc net-tools systemctl nginx keepalived -y</code></p><div class="post-button"><a class="btn" href="/2022/07/10/docker-keepalived-nginx-ha/#more" rel="contents">阅读全文 »</a></div></div><footer class="post-footer"><div class="post-eof"></div></footer></article><article itemscope itemtype="http://schema.org/Article" class="post-block home" lang="zh-CN"><link itemprop="mainEntityOfPage" href="https://ehlxr.me/2022/03/19/quick-sort/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="name" content="!!@_@ ᵛᵉ"><meta itemprop="description" content="瞻前顾后，惶惶不可终日"><meta itemprop="image" content="https://cdn.jsdelivr.net/gh/0vo/oss/images/logo_2.png"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Ehlxr's Blog"></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2022/03/19/quick-sort/" class="post-title-link" itemprop="url">快速排序理解</a></h2><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-calendar-o"></i></span> <span class="post-meta-item-text">发表于</span> <time title="创建时间：2022-03-19 17:20:32" itemprop="dateCreated datePublished" datetime="2022-03-19T17:20:32+00:00">2022-03-19</time></span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-folder-o"></i></span> <span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/%E6%8E%92%E5%BA%8F%E7%AE%97%E6%B3%95/" itemprop="url" rel="index"><span itemprop="name">排序算法</span></a></span></span><span id="/2022/03/19/quick-sort/" class="post-meta-item leancloud_visitors" data-flag-title="快速排序理解" title="阅读次数"><span class="post-meta-item-icon"><i class="fa fa-eye"></i></span> <span class="post-meta-item-text">阅读次数：</span><span class="leancloud-visitors-count"></span></span><span class="post-meta-item"><a title="show comments" href="/2022/03/19/quick-sort/#show_comments"><span class="post-meta-item-icon"><i class="fa fa-comment-o"></i></span></a></span><span class="post-meta-item" title="本文字数"><span class="post-meta-item-icon"><i class="fa fa-file-word-o"></i></span> <span>1k</span></span><span class="post-meta-item" title="阅读时长"><span class="post-meta-item-icon"><i class="fa fa-clock-o"></i></span> <span>1 分钟</span></span></div></header><div class="post-body" itemprop="articleBody"><p>快速排序算法核心思想，取待排序序列中的某个元素作为分区点，大于分区点的元素挪到分区点右边（从小到大排序），小于分区点的元素挪到分区点左边。然后分区点左右两边的子序列循环以上操作，直至子序列长度为 <code>1</code>。</p><p><strong>左右指针法实现思路</strong></p><p>1、首先定义分区点（pivot）<code>p</code>，<code>p</code> 一般为数组 <code>a</code> 的第一个元素或最后一个元素<br>2、然后定义左（<code>l</code>）、右（<code>r</code>）两个指针分别指向数组的第一个元素（<code>a[0]</code>）和最后一个元素 (<code>a[a.length - 1]</code>)<br>3、如果 <code>a[l] > a[p]</code>，<code>l、p</code> 下标元素互换，<code>l</code> 前进 <code>1</code> 位<br>4、如果 <code>a[r] < a[p]</code>，<code>r、p</code> 下标元素互换，<code>r</code> 后退 <code>1</code> 位<br>5、如果 <code>l >= r</code>，排序结束</p><div class="post-button"><a class="btn" href="/2022/03/19/quick-sort/#more" rel="contents">阅读全文 »</a></div></div><footer class="post-footer"><div class="post-eof"></div></footer></article><article itemscope itemtype="http://schema.org/Article" class="post-block home" lang="zh-CN"><link itemprop="mainEntityOfPage" href="https://ehlxr.me/2022/03/19/heap-sort/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="name" content="!!@_@ ᵛᵉ"><meta itemprop="description" content="瞻前顾后，惶惶不可终日"><meta itemprop="image" content="https://cdn.jsdelivr.net/gh/0vo/oss/images/logo_2.png"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Ehlxr's Blog"></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2022/03/19/heap-sort/" class="post-title-link" itemprop="url">堆排序理解</a></h2><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-calendar-o"></i></span> <span class="post-meta-item-text">发表于</span> <time title="创建时间：2022-03-19 15:09:01" itemprop="dateCreated datePublished" datetime="2022-03-19T15:09:01+00:00">2022-03-19</time></span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-folder-o"></i></span> <span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/%E6%8E%92%E5%BA%8F%E7%AE%97%E6%B3%95/" itemprop="url" rel="index"><span itemprop="name">排序算法</span></a></span></span><span id="/2022/03/19/heap-sort/" class="post-meta-item leancloud_visitors" data-flag-title="堆排序理解" title="阅读次数"><span class="post-meta-item-icon"><i class="fa fa-eye"></i></span> <span class="post-meta-item-text">阅读次数：</span><span class="leancloud-visitors-count"></span></span><span class="post-meta-item"><a title="show comments" href="/2022/03/19/heap-sort/#show_comments"><span class="post-meta-item-icon"><i class="fa fa-comment-o"></i></span></a></span><span class="post-meta-item" title="本文字数"><span class="post-meta-item-icon"><i class="fa fa-file-word-o"></i></span> <span>1.1k</span></span><span class="post-meta-item" title="阅读时长"><span class="post-meta-item-icon"><i class="fa fa-clock-o"></i></span> <span>1 分钟</span></span></div></header><div class="post-body" itemprop="articleBody"><p>堆排序的关键是构建大（小）顶堆，堆顶元素就是最大（小）的元素，然后堆顶元素和末尾元素交换位置，再次堆化除最后一个元素外的其它元素，循环次过程即可完成排序。</p><p>翻译成代码如下：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="keyword">void</span> <span class="title">sort</span><span class="params">(<span class="keyword">int</span> a)</span> </span>{</span><br><span class="line"> <span class="keyword">for</span>(<span class="keyword">int</span> i = a.length - <span class="number">1</span>; i > <span class="number">0</span>; i--) {</span><br><span class="line"> buildHeap(a, i);</span><br><span class="line"> <span class="comment">// 堆顶元素和最后一个元素交换，除过最后一个元素外其它元素再次构建大顶堆</span></span><br><span class="line"> swap(a, <span class="number">0</span>, i);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure><div class="post-button"><a class="btn" href="/2022/03/19/heap-sort/#more" rel="contents">阅读全文 »</a></div></div><footer class="post-footer"><div class="post-eof"></div></footer></article><article itemscope itemtype="http://schema.org/Article" class="post-block home" lang="zh-CN"><link itemprop="mainEntityOfPage" href="https://ehlxr.me/2022/03/12/the-kmp/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="name" content="!!@_@ ᵛᵉ"><meta itemprop="description" content="瞻前顾后，惶惶不可终日"><meta itemprop="image" content="https://cdn.jsdelivr.net/gh/0vo/oss/images/logo_2.png"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Ehlxr's Blog"></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2022/03/12/the-kmp/" class="post-title-link" itemprop="url">KMP 算法理解</a></h2><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-calendar-o"></i></span> <span class="post-meta-item-text">发表于</span> <time title="创建时间：2022-03-12 22:44:00" itemprop="dateCreated datePublished" datetime="2022-03-12T22:44:00+00:00">2022-03-12</time></span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-folder-o"></i></span> <span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/%E7%AE%97%E6%B3%95/" itemprop="url" rel="index"><span itemprop="name">算法</span></a></span></span><span id="/2022/03/12/the-kmp/" class="post-meta-item leancloud_visitors" data-flag-title="KMP 算法理解" title="阅读次数"><span class="post-meta-item-icon"><i class="fa fa-eye"></i></span> <span class="post-meta-item-text">阅读次数：</span><span class="leancloud-visitors-count"></span></span><span class="post-meta-item"><a title="show comments" href="/2022/03/12/the-kmp/#show_comments"><span class="post-meta-item-icon"><i class="fa fa-comment-o"></i></span></a></span><span class="post-meta-item" title="本文字数"><span class="post-meta-item-icon"><i class="fa fa-file-word-o"></i></span> <span>4.4k</span></span><span class="post-meta-item" title="阅读时长"><span class="post-meta-item-icon"><i class="fa fa-clock-o"></i></span> <span>4 分钟</span></span></div></header><div class="post-body" itemprop="articleBody"><h2 id="字符串前缀-与字符串后缀"><a href="#字符串前缀-与字符串后缀" class="headerlink" title="字符串前缀 与字符串后缀"></a><strong>字符串前缀</strong> 与<strong>字符串后缀</strong></h2><ul><li><p>字符串前缀(<code>Proper prefix</code>) ：包含第一个字符，不包含最后一个字符的所有子串<br>例如：<code>abababca</code> 的前缀：<code>a、ab、aba、abab、ababa、ababab、abababc</code></p></li><li><p>字符串后缀(<code>Proper suffix</code>)：不包含第一个字符，包含最后一个字符的所有子串<br>例如：<code>abababca</code> 的后缀：<code>a、ca、bca、abca、babca、ababca、bababca</code></p></li></ul><h2 id="字符串部分匹配表"><a href="#字符串部分匹配表" class="headerlink" title="字符串部分匹配表"></a><strong>字符串部分匹配表</strong></h2><p>字符串部分匹配表 (<code>Partial Match Table</code>) 也称为 <code>next</code> 数组，例如：<code>abababca</code> 的部分匹配表为：</p><table><thead><tr><th>char</th><th>a</th><th>b</th><th>a</th><th>b</th><th>a</th><th>b</th><th>c</th><th>a</th></tr></thead><tbody><tr><td>index</td><td>0</td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td></tr><tr><td>value</td><td>0</td><td>0</td><td>1</td><td>2</td><td>3</td><td>4</td><td>0</td><td>1</td></tr></tbody></table><div class="post-button"><a class="btn" href="/2022/03/12/the-kmp/#more" rel="contents">阅读全文 »</a></div></div><footer class="post-footer"><div class="post-eof"></div></footer></article><article itemscope itemtype="http://schema.org/Article" class="post-block home" lang="zh-CN"><link itemprop="mainEntityOfPage" href="https://ehlxr.me/2021/07/27/jvm-tlab/"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="name" content="!!@_@ ᵛᵉ"><meta itemprop="description" content="瞻前顾后，惶惶不可终日"><meta itemprop="image" content="https://cdn.jsdelivr.net/gh/0vo/oss/images/logo_2.png"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Ehlxr's Blog"></span><header class="post-header"><h2 class="post-title" itemprop="name headline"><a href="/2021/07/27/jvm-tlab/" class="post-title-link" itemprop="url">JVM TLAB</a></h2><div class="post-meta"><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-calendar-o"></i></span> <span class="post-meta-item-text">发表于</span> <time title="创建时间：2021-07-27 09:35:05" itemprop="dateCreated datePublished" datetime="2021-07-27T09:35:05+00:00">2021-07-27</time></span><span class="post-meta-item"><span class="post-meta-item-icon"><i class="fa fa-folder-o"></i></span> <span class="post-meta-item-text">分类于</span> <span itemprop="about" itemscope itemtype="http://schema.org/Thing"><a href="/categories/JVM/" itemprop="url" rel="index"><span itemprop="name">JVM</span></a></span></span><span id="/2021/07/27/jvm-tlab/" class="post-meta-item leancloud_visitors" data-flag-title="JVM TLAB" title="阅读次数"><span class="post-meta-item-icon"><i class="fa fa-eye"></i></span> <span class="post-meta-item-text">阅读次数：</span><span class="leancloud-visitors-count"></span></span><span class="post-meta-item"><a title="show comments" href="/2021/07/27/jvm-tlab/#show_comments"><span class="post-meta-item-icon"><i class="fa fa-comment-o"></i></span></a></span><span class="post-meta-item" title="本文字数"><span class="post-meta-item-icon"><i class="fa fa-file-word-o"></i></span> <span>767</span></span><span class="post-meta-item" title="阅读时长"><span class="post-meta-item-icon"><i class="fa fa-clock-o"></i></span> <span>1 分钟</span></span></div></header><div class="post-body" itemprop="articleBody"><p><strong>TLAB（Thread Local Allocation Buffer）</strong> 线程本地分配缓存区</p><ol><li>由于对象一般分配在堆上，而堆是线程共用的，因此可能会有多个线程在堆上申请空间，而每一次的<strong>对象分配都必须加锁保证线程同步</strong>，会使分配的效率下降。考虑到对象分配几乎是 <code>Java</code> 中最常用的操作，因此 <code>JVM</code> 使用了 <code>TLAB</code> 这样的线程专有区域来避免多线程冲突，提高对象分配的效率。</li><li>我们说 <code>TLAB</code> 是线程独享的，但是只是在 <strong>“分配”</strong> 这个动作上是线程独享的，至于在读取、垃圾回收等动作上都是线程共享的。而且在使用上也没有什么区别</li><li><code>JVM</code> 为了提升对象内存分配的效率，对于所创建的线程都会分配一块独立的空间 <code>TLAB</code>，其大小由 <code>JVM</code> 根据运行的情况计算而得，在 <code>TLAB</code> 上分配对象时不需要加锁，因此 <strong>JVM 在给线程的对象分配内存时会尽量的在 TLAB 上分配</strong>，在这种情况下 JVM 中分配对象内存的性能和 <code>C</code> 基本是一样高效的，但如果对象过大的话则仍然是直接使用堆空间分配</li><li>在 <code>TLAB</code> 分配之后，并不影响对象的移动和回收，也就是说，虽然对象刚开始可能通过 <code>TLAB</code> 分配内存，存放在 <code>Eden</code> 区，但是还是会被垃圾回收或者被移到 <code>Survivor Space、Old Gen</code> 等。</li><li><strong>“堆是线程共享的内存区域” 这句话并不完全正确</strong>，因为 <code>TLAB</code> 是堆内存的一部分，它在读取上确实是线程共享的，但是在内存分配上，是线程独享的。</li><li><code>TLAB</code> 的空间其实并不大（默认是 <code>eden</code> 区空间的 <code>1%</code>），所以大对象还是可能需要在堆内存中直接分配。那么，对象的内存分配步骤就是先尝试 <code>TLAB</code> 分配，空间不足之后，再判断是否应该直接进入老年代，然后再确定是再 <code>eden</code> 分配还是在老年代分配。<div class="post-button"><a class="btn" href="/2021/07/27/jvm-tlab/#more" rel="contents">阅读全文 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