CentOS7下无法启动mysql的解决办法

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MariaDB数据库管理系统是MySQL的一个分支，主要由开源社区在维护，采用GPL授权许可。开发这个分支的原因之一是：甲骨文公司收购了MySQL后，有将MySQL闭源的潜在风险，因此社区采用分支的方式来避开这个风险。[3]

MariaDB的目的是完全兼容MySQL，包括API和命令行，使之能轻松成为MySQL的代替品。在存储引擎方面，10.0.9版起使用XtraDB（名称代号为Aria）来代替MySQL的InnoDB

<code class="hljs vala has-numbering" style="padding: 0px; margin: 0px; display: block; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="padding: 0px; margin: 0px; color: rgb(68, 68, 68); box-sizing: border-box;"># yum install mysql -y</span>
<span class="hljs-preprocessor" style="padding: 0px; margin: 0px; color: rgb(68, 68, 68); box-sizing: border-box;"># mysql</span>
ERROR <span class="hljs-number" style="padding: 0px; margin: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">2002</span> (HY000): Can<span class="hljs-string" style="padding: 0px; margin: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">'t connect to local MySQL server through socket '</span>/<span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">var</span>/lib/mysql/mysql.sock<span class="hljs-string" style="padding: 0px; margin: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">' (111)</span></code>

试着去启动mysql服务，仍然不行

<code class="hljs oxygene has-numbering" style="padding: 0px; margin: 0px; display: block; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"># systemctl start mysql
Failed <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">to</span> issue <span class="hljs-function" style="padding: 0px; margin: 0px; box-sizing: border-box;"><span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">method</span> <span class="hljs-title" style="padding: 0px; margin: 0px; box-sizing: border-box;">call</span>:</span> <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">Unit</span> mysql.service failed <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">to</span> load: No such file <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">or</span> directory.

# systemctl start  mysql.service
Failed <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">to</span> issue <span class="hljs-function" style="padding: 0px; margin: 0px; box-sizing: border-box;"><span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">method</span> <span class="hljs-title" style="padding: 0px; margin: 0px; box-sizing: border-box;">call</span>:</span> <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">Unit</span> mysql.service failed <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">to</span> load: No such file <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">or</span> directory

# systemctl enable mysql.service
Failed <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">to</span> issue <span class="hljs-function" style="padding: 0px; margin: 0px; box-sizing: border-box;"><span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">method</span> <span class="hljs-title" style="padding: 0px; margin: 0px; box-sizing: border-box;">call</span>:</span> Access denied</code>

下面讲正确的步骤

<code class="hljs livecodeserver has-numbering" style="padding: 0px; margin: 0px; display: block; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="padding: 0px; margin: 0px; color: rgb(136, 0, 0); box-sizing: border-box;"># yum install mariadb-server -y</span>
<span class="hljs-comment" style="padding: 0px; margin: 0px; color: rgb(136, 0, 0); box-sizing: border-box;"># systemctl start mariadb.service</span>
<span class="hljs-comment" style="padding: 0px; margin: 0px; color: rgb(136, 0, 0); box-sizing: border-box;"># systemctl enable mariadb.service</span>
<span class="hljs-comment" style="padding: 0px; margin: 0px; color: rgb(136, 0, 0); box-sizing: border-box;"># mysql</span>
Welcome <span class="hljs-built_in" style="padding: 0px; margin: 0px; color: rgb(102, 0, 102); box-sizing: border-box;">to</span> <span class="hljs-operator" style="padding: 0px; margin: 0px; box-sizing: border-box;">the</span> MariaDB monitor.  Commands <span class="hljs-function" style="padding: 0px; margin: 0px; box-sizing: border-box;"><span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">end</span> <span class="hljs-title" style="padding: 0px; margin: 0px; box-sizing: border-box;">with</span> ; <span class="hljs-title" style="padding: 0px; margin: 0px; box-sizing: border-box;">or</span> \<span class="hljs-title" style="padding: 0px; margin: 0px; box-sizing: border-box;">g</span>.</span>
Your MariaDB connection id is <span class="hljs-number" style="padding: 0px; margin: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">10</span>
Server <span class="hljs-built_in" style="padding: 0px; margin: 0px; color: rgb(102, 0, 102); box-sizing: border-box;">version</span>: <span class="hljs-number" style="padding: 0px; margin: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">5.5</span><span class="hljs-number" style="padding: 0px; margin: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">.44</span>-MariaDB MariaDB Server

Copyright (c) <span class="hljs-number" style="padding: 0px; margin: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">2000</span>, <span class="hljs-number" style="padding: 0px; margin: 0px; color: rgb(0, 102, 102); box-sizing: border-box;">2015</span>, Oracle, MariaDB Corporation Ab <span class="hljs-operator" style="padding: 0px; margin: 0px; box-sizing: border-box;">and</span> others.

Type <span class="hljs-string" style="padding: 0px; margin: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">'help;'</span> <span class="hljs-operator" style="padding: 0px; margin: 0px; box-sizing: border-box;">or</span> <span class="hljs-string" style="padding: 0px; margin: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">'\h'</span> <span class="hljs-keyword" style="padding: 0px; margin: 0px; color: rgb(0, 0, 136); box-sizing: border-box;">for</span> help. Type <span class="hljs-string" style="padding: 0px; margin: 0px; color: rgb(0, 136, 0); box-sizing: border-box;">'\c'</span> <span class="hljs-built_in" style="padding: 0px; margin: 0px; color: rgb(102, 0, 102); box-sizing: border-box;">to</span> <span class="hljs-built_in" style="padding: 0px; margin: 0px; color: rgb(102, 0, 102); box-sizing: border-box;">clear</span> <span class="hljs-operator" style="padding: 0px; margin: 0px; box-sizing: border-box;">the</span> current input statement.

MariaDB [(<span class="hljs-constant" style="padding: 0px; margin: 0px; box-sizing: border-box;">none</span>)]> 
</code>

搞定!

如何设置mysql root密码

<code class="hljs vala has-numbering" style="padding: 0px; margin: 0px; display: block; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-preprocessor" style="padding: 0px; margin: 0px; color: rgb(68, 68, 68); box-sizing: border-box;"># mysql_secure_installation</span></code>