改变运行级别.md

# 改变运行级别<a name="ZH-CN_TOPIC_0182317340"></a>

## Target和运行级别<a name="zh-cn_topic_0151920939_s41a63cf99f74431da4f8226fb8702bbb"></a>

systemd用目标（target）替代了运行级别的概念，提供了更大的灵活性，如您可以继承一个已有的目标，并添加其他服务，来创建自己的目标。[表1](#zh-cn_topic_0151920939_t9af92c282ad240ea9a79fb08d26e8181)列举了systemd下的目标和常见runlevel的对应关系。

**表 1**  运行级别和systemd目标

<a name="zh-cn_topic_0151920939_t9af92c282ad240ea9a79fb08d26e8181"></a>
<table><thead align="left"><tr id="zh-cn_topic_0151920939_r6198e54b95054c25ad4cbf7f6a4d94a8"><th class="cellrowborder" valign="top" width="13.389999999999999%" id="mcps1.2.4.1.1"><p id="zh-cn_topic_0151920939_a8ca063ccd2b5493eaba60d772b3a210e"><a name="zh-cn_topic_0151920939_a8ca063ccd2b5493eaba60d772b3a210e"></a><a name="zh-cn_topic_0151920939_a8ca063ccd2b5493eaba60d772b3a210e"></a>运行级别</p>
</th>
<th class="cellrowborder" valign="top" width="31.53%" id="mcps1.2.4.1.2"><p id="zh-cn_topic_0151920939_ae345f9616c9e4b99b91537e14bf301fc"><a name="zh-cn_topic_0151920939_ae345f9616c9e4b99b91537e14bf301fc"></a><a name="zh-cn_topic_0151920939_ae345f9616c9e4b99b91537e14bf301fc"></a>systemd目标（target）</p>
</th>
<th class="cellrowborder" valign="top" width="55.08%" id="mcps1.2.4.1.3"><p id="zh-cn_topic_0151920939_a51d30f31c3494031a3cb05ad3f0f83b0"><a name="zh-cn_topic_0151920939_a51d30f31c3494031a3cb05ad3f0f83b0"></a><a name="zh-cn_topic_0151920939_a51d30f31c3494031a3cb05ad3f0f83b0"></a>描述</p>
</th>
</tr>
</thead>
<tbody><tr id="zh-cn_topic_0151920939_rf26e9f9e50504c07a370b9dc87a197c9"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="zh-cn_topic_0151920939_a6d80989a801f4bf4bb4546c17a7b3a33"><a name="zh-cn_topic_0151920939_a6d80989a801f4bf4bb4546c17a7b3a33"></a><a name="zh-cn_topic_0151920939_a6d80989a801f4bf4bb4546c17a7b3a33"></a>0</p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="zh-cn_topic_0151920939_a7d9fff8415094170a9f174a1dc243183"><a name="zh-cn_topic_0151920939_a7d9fff8415094170a9f174a1dc243183"></a><a name="zh-cn_topic_0151920939_a7d9fff8415094170a9f174a1dc243183"></a>runlevel0.target，poweroff.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="zh-cn_topic_0151920939_a70514fee2f27437cbae934e8c574f997"><a name="zh-cn_topic_0151920939_a70514fee2f27437cbae934e8c574f997"></a><a name="zh-cn_topic_0151920939_a70514fee2f27437cbae934e8c574f997"></a>关闭系统。</p>
</td>
</tr>
<tr id="zh-cn_topic_0151920939_r1e5afff728cc4151b419680f76671293"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="zh-cn_topic_0151920939_a6bed301641504e7691830451ccd13084"><a name="zh-cn_topic_0151920939_a6bed301641504e7691830451ccd13084"></a><a name="zh-cn_topic_0151920939_a6bed301641504e7691830451ccd13084"></a>1<span id="ph14312164910584"><a name="ph14312164910584"></a><a name="ph14312164910584"></a>, s,</span><span id="ph916181225917"><a name="ph916181225917"></a><a name="ph916181225917"></a> single</span></p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="zh-cn_topic_0151920939_af07325c424aa41fd91422796a8c5530a"><a name="zh-cn_topic_0151920939_af07325c424aa41fd91422796a8c5530a"></a><a name="zh-cn_topic_0151920939_af07325c424aa41fd91422796a8c5530a"></a>runlevel1.target，rescue.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="zh-cn_topic_0151920939_a835efcb9d2ec42219ba2cf84f320006d"><a name="zh-cn_topic_0151920939_a835efcb9d2ec42219ba2cf84f320006d"></a><a name="zh-cn_topic_0151920939_a835efcb9d2ec42219ba2cf84f320006d"></a>单用户模式。</p>
</td>
</tr>
<tr id="zh-cn_topic_0151920939_re1071d4eed334f439f54040112b05c4a"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="zh-cn_topic_0151920939_zh-cn_topic_0072985277_p188013479275"><a name="zh-cn_topic_0151920939_zh-cn_topic_0072985277_p188013479275"></a><a name="zh-cn_topic_0151920939_zh-cn_topic_0072985277_p188013479275"></a>2<span id="ph60616175913"><a name="ph60616175913"></a><a name="ph60616175913"></a>, 4</span></p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="zh-cn_topic_0151920939_a97565d2aa66a42bba4e87bd5a75413e8"><a name="zh-cn_topic_0151920939_a97565d2aa66a42bba4e87bd5a75413e8"></a><a name="zh-cn_topic_0151920939_a97565d2aa66a42bba4e87bd5a75413e8"></a>runlevel2.target，<span id="ph1462165011"><a name="ph1462165011"></a><a name="ph1462165011"></a>runlevel4.target，</span>multi-user.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="zh-cn_topic_0151920939_a99315964c38d404585856756e975fbfd"><a name="zh-cn_topic_0151920939_a99315964c38d404585856756e975fbfd"></a><a name="zh-cn_topic_0151920939_a99315964c38d404585856756e975fbfd"></a>用户定义/域特定运行级别。默认等同于3。</p>
</td>
</tr>
<tr id="zh-cn_topic_0151920939_rb065a846486b406690e8c4224a0a0ac9"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="zh-cn_topic_0151920939_zh-cn_topic_0072985277_p680154702718"><a name="zh-cn_topic_0151920939_zh-cn_topic_0072985277_p680154702718"></a><a name="zh-cn_topic_0151920939_zh-cn_topic_0072985277_p680154702718"></a>3</p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="zh-cn_topic_0151920939_a0180d9e5e866452ebd0ec8be94dc4f05"><a name="zh-cn_topic_0151920939_a0180d9e5e866452ebd0ec8be94dc4f05"></a><a name="zh-cn_topic_0151920939_a0180d9e5e866452ebd0ec8be94dc4f05"></a>runlevel3.target，multi-user.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="zh-cn_topic_0151920939_a9c5a2a48aa5d49bf8e86a1cce1711303"><a name="zh-cn_topic_0151920939_a9c5a2a48aa5d49bf8e86a1cce1711303"></a><a name="zh-cn_topic_0151920939_a9c5a2a48aa5d49bf8e86a1cce1711303"></a>多用户，非图形化。用户可以通过多个控制台或网络登录。</p>
</td>
</tr>
<tr id="zh-cn_topic_0151920939_r0184cfc9111840b6be09d7621237f91b"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="zh-cn_topic_0151920939_aecd758e276a34d828c7f57d56aba812d"><a name="zh-cn_topic_0151920939_aecd758e276a34d828c7f57d56aba812d"></a><a name="zh-cn_topic_0151920939_aecd758e276a34d828c7f57d56aba812d"></a>5</p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="zh-cn_topic_0151920939_a0519be8c47be4ec4a47bd2942ebdee20"><a name="zh-cn_topic_0151920939_a0519be8c47be4ec4a47bd2942ebdee20"></a><a name="zh-cn_topic_0151920939_a0519be8c47be4ec4a47bd2942ebdee20"></a>runlevel5.target，graphical.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="zh-cn_topic_0151920939_ad3463085cd604e0081dfffaa13efdad9"><a name="zh-cn_topic_0151920939_ad3463085cd604e0081dfffaa13efdad9"></a><a name="zh-cn_topic_0151920939_ad3463085cd604e0081dfffaa13efdad9"></a>多用户，图形化。通常为所有运行级别3的服务外加图形化登录。</p>
</td>
</tr>
<tr id="zh-cn_topic_0151920939_rdd9338b99fb2419fa9257a7a21e2774f"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="zh-cn_topic_0151920939_a7564c4a239924b33af88cbb8a34ec8dc"><a name="zh-cn_topic_0151920939_a7564c4a239924b33af88cbb8a34ec8dc"></a><a name="zh-cn_topic_0151920939_a7564c4a239924b33af88cbb8a34ec8dc"></a>6</p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="zh-cn_topic_0151920939_a86730dd7a4054dedbfd4562630d462e5"><a name="zh-cn_topic_0151920939_a86730dd7a4054dedbfd4562630d462e5"></a><a name="zh-cn_topic_0151920939_a86730dd7a4054dedbfd4562630d462e5"></a>runlevel6.target，reboot.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="zh-cn_topic_0151920939_a473a6a5eca6c4b60a880ce8da3222f83"><a name="zh-cn_topic_0151920939_a473a6a5eca6c4b60a880ce8da3222f83"></a><a name="zh-cn_topic_0151920939_a473a6a5eca6c4b60a880ce8da3222f83"></a>重启系统。</p>
</td>
</tr>
<tr id="row13256325195913"><td class="cellrowborder" valign="top" width="13.389999999999999%" headers="mcps1.2.4.1.1 "><p id="p625642510595"><a name="p625642510595"></a><a name="p625642510595"></a><span id="ph122241428185918"><a name="ph122241428185918"></a><a name="ph122241428185918"></a>emergency</span></p>
</td>
<td class="cellrowborder" valign="top" width="31.53%" headers="mcps1.2.4.1.2 "><p id="p1384413745917"><a name="p1384413745917"></a><a name="p1384413745917"></a>emergency.target</p>
</td>
<td class="cellrowborder" valign="top" width="55.08%" headers="mcps1.2.4.1.3 "><p id="p92561925185919"><a name="p92561925185919"></a><a name="p92561925185919"></a><span id="ph810855365915"><a name="ph810855365915"></a><a name="ph810855365915"></a>紧急Shell</span></p>
</td>
</tr>
</tbody>
</table>

## 查看系统默认启动目标<a name="zh-cn_topic_0151920939_s25ca4013a0784414a5edd3e0e160230a"></a>

查看当前系统默认的启动目标，命令如下：

```
systemctl get-default
```

## 查看当前系统所有的启动目标<a name="zh-cn_topic_0151920939_sd0bbd7d086014f039e017d7697f7f05a"></a>

查看当前系统所有的启动目标，命令如下：

```
systemctl list-units --type=target
```

## 改变默认目标<a name="zh-cn_topic_0151920939_s56ee9cb80ca0481ab3c670c7e40ff2e6"></a>

改变系统默认的目标，在root权限下执行如下命令：

```
systemctl set-default name.target
```

## 改变当前目标<a name="zh-cn_topic_0151920939_sead150d42fb2410a8c5feb936d2d9601"></a>

改变当前系统的目标，在root权限下执行如下命令：

```
systemctl isolate name.target
```

## 切换到救援模式<a name="zh-cn_topic_0151920939_s6b5aa28ee0e141f8a75288f6c1d6d936"></a>

改变当前系统为救援模式，在root权限下执行如下命令：

```
systemctl rescue
```

这条命令和“systemctl isolate rescue.target”类似。命令执行后会在串口有如下打印信息：

```
You are in rescue mode. After logging in, type "journalctl -xb" to viewsystem logs, "systemctl reboot" to reboot, "systemctl default" or "exit"to boot into default mode.
Give root password for maintenance
(or press Control-D to continue): 
```

>![](public_sys-resources/icon-note.gif) **说明：**   
>用户需要重启系统，从救援模式进入正常模式。  

## 切换到紧急模式<a name="zh-cn_topic_0151920939_s961f806e4a9e44b1825aa8a2442a093f"></a>

改变当前系统为紧急模式，在root权限下执行如下命令：

```
systemctl emergency
```

这条命令和“systemctl isolate emergency.target”类似。命令执行后会在串口有如下打印信息：

```
You are in emergency mode. After logging in, type "journalctl -xb" to viewsystem logs, "systemctl reboot" to reboot, "systemctl default" or "exit"to boot into default mode.
Give root password for maintenance
(or press Control-D to continue):
```

>![](public_sys-resources/icon-note.gif) **说明：**   
>用户需要重启系统，从紧急模式进入正常模式。