升级CentOS 7内核版本的三种方案
<h1 class="postTitle"> </h1><div class="postBody">
<div id="cnblogs_post_body" class="blogpost-body blogpost-body-html">
<p>在实验环境下，已安装了最新的CentOS 7.4操作系统，现在需要升级内核版本。</p>
<p>实验环境</p>
<p>CentOS-7-x86_64-Minimal-1708.iso<br>CentOS Linux release 7.4.1708 (Core)<br>Kernel 3.10.0-693.el7.x86_64</p>
<h1>方案一：小版本升级</h1>
<p>连接并同步CentOS自带yum源，更新内核版本。此方法适用于更新内核补丁 。<br>具体实验步骤：</p>
<p> </p>
<div class="cnblogs_code">
<pre>sudo yum list kernel
sudo yum update -y kernel</pre>
</div>
<p> </p>
<p><br>此时，已安装成功，但若想将系统运行在新版本的kernel上，则需要重新启动操作系统。<br><br>重启完成，至此，Kernel版本已升级至【3.10.0-693.17.1.el7.x86_64】</p>
<p><br><strong>方案二：大版本升级</strong></p>
<p>载入elrepo源，搜索内核更新资源，并进行更新操作。<br>具体实验步骤：</p>
<div class="cnblogs_Highlighter sh-gutter">
<div>
<div id="highlighter_513318" class="syntaxhighlighterjavascript">
<table border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td class="gutter">
<div class="line number1 index0 alt2">1</div>
<div class="line number2 index1 alt1">2</div>
<div class="line number3 index2 alt2">3</div>
<div class="line number4 index3 alt1">4</div>
<div class="line number5 index4 alt2">5</div>
<div class="line number6 index5 alt1">6</div>
<div class="line number7 index6 alt2">7</div>
<div class="line number8 index7 alt1">8</div>
<div class="line number9 index8 alt2">9</div>
<div class="line number10 index9 alt1">10</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2"><code class="javascript preprocessor"># 载入公钥</code></div>
<div class="line number2 index1 alt1"><code class="javascript plain">rpm --</code><code class="javascript keyword">import</code> <code class="javascript plain">https:</code><code class="javascript comments">//www.elrepo.org/RPM-GPG-KEY-elrepo.org</code></div>
<div class="line number3 index2 alt2"><code class="javascript preprocessor"># 安装ELRepo</code></div>
<div class="line number4 index3 alt1"><code class="javascript plain">rpm -Uvh http:</code><code class="javascript comments">//www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm</code></div>
<div class="line number5 index4 alt2"><code class="javascript preprocessor"># 载入elrepo-kernel元数据</code></div>
<div class="line number6 index5 alt1"><code class="javascript plain">yum --disablerepo=\* --enablerepo=elrepo-kernel repolist</code></div>
<div class="line number7 index6 alt2"><code class="javascript preprocessor"># 查看可用的rpm包</code></div>
<div class="line number8 index7 alt1"><code class="javascript plain">yum --disablerepo=\* --enablerepo=elrepo-kernel list kernel*</code></div>
<div class="line number9 index8 alt2"><code class="javascript preprocessor"># 安装最新版本的kernel</code></div>
<div class="line number10 index9 alt1"><code class="javascript plain">yum --disablerepo=\* --enablerepo=elrepo-kernel install -y kernel-ml.x86_64</code></div>
</div>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<p><br>重启，选择新版本内核进入系统。</p>
<p>此时，操作系统使用的内核已升级为【4.15.0-1.el7.elrepo.x86_64】</p>
<p>最后一步，需要将内核工具包一并升级</p>
<div class="cnblogs_code">
<pre># 删除旧版本工具包
yum remove kernel-tools-libs.x86_64 kernel-tools.x86_64
# 安装新版本工具包
yum --disablerepo=\* --enablerepo=elrepo-kernel install -y kernel-ml-tools.x86_64</pre>
</div>
<p>至此，已完成升级。</p>
<h3>注意：内核安装好后，需要设置为默认启动选项并重启后才会生效</h3>
<h3 id="51-查看系统上的所有可以内核">查看系统上的所有可用内核：</h3>
<div class="cnblogs_code">
<pre>$ sudo awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg
0 : CentOS Linux (4.18.7-1.el7.elrepo.x86_64) 7 (Core)
1 : CentOS Linux (3.10.0-862.11.6.el7.x86_64) 7 (Core)
2 : CentOS Linux (3.10.0-514.el7.x86_64) 7 (Core)
3 : CentOS Linux (0-rescue-063ec330caa04d4baae54c6902c62e54) 7 (Core)</pre>
</div>
<h3>设置新的内核为grub2的默认版本</h3>
<p>服务器上存在4 个内核，我们要使用 4.18 这个版本，可以通过 <code>grub2-set-default 0</code> 命令或编辑 <code>/etc/default/grub</code> 文件来设置</p>
<h4 id="1-通过-grub2-set-default-0-命令设置">方法1、通过 <code>grub2-set-default 0</code> 命令设置</h4>
<p>其中 0 是上面查询出来的可用内核</p>
<div class="cnblogs_code">
<pre>grub2-set-default 0</pre>
</div>
<h4 id="2-编辑-etcdefaultgrub-文件">方法2、编辑 <code>/etc/default/grub</code> 文件</h4>
<p>设置 GRUB_DEFAULT=0，通过上面查询显示的编号为 0 的内核作为默认内核：</p>
<div class="cnblogs_code">
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<pre>$ vim /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=0
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=cl/root rhgb quiet"
GRUB_DISABLE_RECOVERY="true"</pre>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
</div>
<h3 id="53-生成-grub-配置文件并重启">生成 grub 配置文件并重启</h3>
<div class="cnblogs_code">
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<pre>$ grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.18.7-1.el7.elrepo.x86_64
Found initrd image: /boot/initramfs-4.18.7-1.el7.elrepo.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-862.11.6.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-862.11.6.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-514.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-514.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-063ec330caa04d4baae54c6902c62e54
Found initrd image: /boot/initramfs-0-rescue-063ec330caa04d4baae54c6902c62e54.img
done<br><br>$ <code class="hljs bash has-numbering">reboot</code></pre>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
</div>
<h2> 验证</h2>
<div class="cnblogs_code">
<pre>$ uname -r
4.18.7-1.el7.elrepo.x86_64</pre>
</div>
<h2> 删除旧内核（可选）</h2>
<h3>查看系统中全部的内核：</h3>
<div class="cnblogs_code">
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<pre>$ rpm -qa | grep kernel
kernel-3.10.0-514.el7.x86_64
kernel-ml-4.18.7-1.el7.elrepo.x86_64
kernel-tools-libs-3.10.0-862.11.6.el7.x86_64
kernel-tools-3.10.0-862.11.6.el7.x86_64
kernel-3.10.0-862.11.6.el7.x86_64</pre>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><img src="https://common.cnblogs.com/images/copycode.gif" alt="复制代码"></span></div>
</div>
<h3>方法1、yum remove 删除旧内核的 RPM 包</h3>
<div class="cnblogs_code">
<pre>$ yum remove kernel-3.10.0-514.el7.x86_64 \<br>kernel-tools-libs-3.10.0-862.11.6.el7.x86_64 \<br>kernel-tools-3.10.0-862.11.6.el7.x86_64 \<br>kernel-3.10.0-862.11.6.el7.x86_64</pre>
</div>
<h3 id="62-通过-yum-utils-工具"><code>方法2、yum-utils</code> 工具</h3>
<p>如果安装的内核不多于 3 个，<code>yum-utils</code> 工具不会删除任何一个。只有在安装的内核大于 3 个时，才会自动删除旧内核。</p>
<p>安装yum-utils</p>
<div class="cnblogs_code">
<pre>$ yum install yum-utils</pre>
</div>
<p>删除旧版本 </p>
<div class="cnblogs_code">
<pre>package-cleanup --oldkernels</pre>
</div>
<h1>方案三：自编译升级</h1>
<p>Step1: 下载源码<br>Step2: 安装gcc bc cmake<br>Step3: 编译源码，安装新内核<br>自编译升级过程略微复杂，且不便于后期维护，具体操作步骤在此略去不表。</p>
<p>话题扩展</p>
<p>如何将新安装的内核设定为操作系统的默认内核，或者说如何将新版本的内核设置为重启后的默认内核？<br>仅需两步，之后重启即可。</p>
<div class="cnblogs_code">
<pre>grub2-set-default 0
grub2-mkconfig -o /etc/grub2.cfg</pre>
</div>
<p> </p>
<p><br>术语解析</p>
<p>kernel-ml<br>kernel-ml 中的ml是英文【mainline stable】的缩写，elrepo-kernel中罗列出来的是最新的稳定主线版本。</p>
<p>kernel-lt<br>kernel-lt 中的lt是英文【long term support】的缩写，elrepo-kernel中罗列出来的长期支持版本。</p>
</div>
<div id="MySignature">那些年 弹指间逝去的青春</div>
</div>
</div>
<div id="MySignature" role="contentinfo">
时来天地皆同力，运去英雄不自由<br><br>
来源：https://www.cnblogs.com/gaoyuechen/p/16848807.html
頁:
[1]