Linux下搭建高可用Keepalived运行环境

傷城~ 2021-09-24 10:40 622阅读 0赞

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### 文章目录 ###

*  1 前言
 *  2 下载keepalived安装包
 *  3 安装keepalived
 *   *  3.1 安装相关依赖
     *  3.2 解压缩下载的安装包文件
     *  3.3 安装配置keepalived
     *  3.4 编译可能出现的问题
 *  4 keepalived的启动与停止
 *   *  4.1 keepalived的启动
     *  4.2 keepalived的停止
 *  5 将keepalived添加到系统服务中
 *   *  5.1 第一种方式（推荐）
     *  5.2 第二种方式
     *  5.3 自启动后keepalived的启动和停止

# 1 前言 #

`keepalived`是一款可以实现高可用的软件（可以用来实现双机热备），通常来说，我们会部署在2台或者3台服务器上，分为一主一备（2备）。Keepalived内部C语言实现的有一套机制，可以对本机上的进程进行检测，一旦Master(主)节点检测出某个进程出现问题，将自己切换成Backup(备用)状态，然后通知另外一个备用节点切换成Master(主)节点状态。

# 2 下载keepalived安装包 #

**下载链接：** [https://www.keepalived.org/download.html][https_www.keepalived.org_download.html]

本文以 [keepalived-2.0.20][] 版本为例，介绍keepalived的安装过程。

# 3 安装keepalived #

在Linux上安装软件可以选择`yum安装`、`rpm包安装`、`.tar.gz`的源码包安装，对于`.tar.gz的源码包`安装，经常会用到了`./configure`脚本，比如说nginx、keepalived等等。

configure脚本有大量的命令行选项，可以通过–help可以查看：`./configure --help`

## 3.1 安装相关依赖 ##

安装keepalived跟安装nginx一样，也需要一些依赖环境。

**添加依赖，执行以下命令：**  
`yum install openssl openssl-devel libnl libnl-devel -y`

## 3.2 解压缩下载的安装包文件 ##

**使用以下命令：**  
`tar -zxvf keepalived-2.0.20.tar.gz`

## 3.3 安装配置keepalived ##

**configure需要的依赖：** `openssl` 、`libnl`

*  **进入keepalived-2.0.20目录**  
    `cd keepalived-2.0.20/`
 *  **执行配置**  
    `./configure --prefix=/usr/local/keepalived`  
    其中`--prefix`是指定要将`keepalived`安装到哪个位置  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtaWxlaGFwcGluZXNz_size_16_color_FFFFFF_t_70]  
    以上configure配置没有错误和警告，说明配置成功。
 *  **执行编译**  
    `make`  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtaWxlaGFwcGluZXNz_size_16_color_FFFFFF_t_70 1]  
    出现如上框起来的内容，说明make编译成功（以上可能会出现warning，不影响使用）。
 *  **执行安装**  
    `make install`  
    这一步执行完之后，才会真正的在`/usr/local/`下生成安装的目录`keepalived`
    
    **也可以将上面的编译和安装，使用一条命令执行：**  
    `make && make install`

## 3.4 编译可能出现的问题 ##

*  **第一种错误**
    
        configure: error: 
          !!! OpenSSL is not properly installed on your system. !!!
          !!! Can not include OpenSSL headers files.
    
    **这个错误说明，没有`openssl`依赖，执行以下命令，安装openssl：**  
    `yum install openssl openssl-devel -y`
 *  **第一种错误**
    
        *** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.
    
    **以上警告问题，说明没有`libnl`依赖，执行以下命令安装libnl依赖：**  
    `yum install libnl libnl-devel -y`
 *  **第一种错误**
    
        configure: error: in `/opt/mysoft/keepalived-2.0.11': configure: error: no acceptable C compiler found in $PATH See `config.log' for more details
    
    **这个error错误说明缺少c语言编译器，没有`c`语言编译依赖，执行以下命令，安装gcc：**  
    `yum install gcc`

至此，keepalived就安装完成了

# 4 keepalived的启动与停止 #

## 4.1 keepalived的启动 ##

*  **启动keepalived使用以下命令：**  
    `/usr/local/keepalived/sbin/keepalived -D`
    
    **注意：**  
    以上启动方式，会出现`Unable to find configuration file /etc/keepalived/keepalived.conf (glob returned 3)`，导致服务启动失败，因为配置文件默认需要放在`/etc/keepalived`目录下，启动的时候找这个配置文件，所以需要把配置文件拷贝到`/etc/keepalived/`目录下。
    
    **使用命令，将keepalived配置文件拷贝到etc下：**  
    `mkdir /etc/keepalived && cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/`
 *  **启动keepalived的另一种方式（推荐使用）：**  
    `/usr/local/keepalived/sbin/keepalived -D -f /usr/local/keepalived/etc/keepalived/keepalived.conf`
    
    **参数说明：**  
    `-D`表示把启动信息打印到日志记录，即`/var/log/messages`可以查看到keepalived的日志信息  
    `-f`指定`keepalived.conf`的配置文件路径
    
    ![在这里插入图片描述][20200614142335353.png]  
    keepalived服务启动成功后会有三个进程，包括`父进程`、`vrrp子进程`，原来老版本还有一个`healthchecker子进程`，现在新版本已经没有了。`父进程主要负责读取配置文件初始化 、监控子进程等，vrrp子进程负责高可用`。

## 4.2 keepalived的停止 ##

**执行命令：**  
`kill 主pid`即可关闭keepalived服务

**如果已经将keepalived添加到系统服务中，可以使用以下命令进行关闭服务：**  
`service keepalived stop` 或者`systemctl stop keepalived`

# 5 将keepalived添加到系统服务中 #

## 5.1 第一种方式（推荐） ##

为了方便启动和停止keepalived服务，将keepalived添加到系统服务中。

**可以直接修改配置文件：**`vim /lib/systemd/system/keepalived.service`

**修改后的内容如下：**

[Unit]
    Description=LVS and VRRP High Availability Monitor
    After=network-online.target syslog.target
    Wants=network-online.target
    
    [Service]
    Type=forking
    PIDFile=/run/keepalived.pid
    KillMode=process
    EnvironmentFile=-/usr/local/keepalived/etc/sysconfig/keepalived
    #ExecStart=/usr/local/keepalived/sbin/keepalived $KEEPALIVED_OPTIONS
    ExecStart=/usr/local/keepalived/sbin/keepalived -D -f /usr/local/keepalived/etc/keepalived/keepalived.conf
    ExecReload=/bin/kill -HUP $MAINPID
    
    [Install]
    WantedBy=multi-user.target

**Run `systemctl daemon-reload` to reload units：**  
使用`systemctl daemon-reload`命令重新加载systemctl配置

此时已加入系统服务，可以使用systemctl或者services方式启动与停止。

## 5.2 第二种方式 ##

为了方便启动和停止keepalived服务，将keepalived添加到系统服务中。

<table> 
 <thead> 
  <tr> 
   <th>路径说明</th> 
   <th>路径</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>解压后源码存放路径</td> 
   <td>/opt/mysoft/keepalived-2.0.10</td> 
  </tr> 
  <tr> 
   <td>安装目录</td> 
   <td>/usr/local/keepalived</td> 
  </tr> 
 </tbody> 
</table>

**配置keepalived自启动：**

# 创建keepalived文件夹
    mkdir /etc/keepalived/
    
    # 将keepalived配置文件拷贝到etc下
    cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
    
    # 拷贝执行文件
    cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
    
    # 将初始化脚本拷贝到系统初始化目录下
    cp /opt/mysoft/keepalived-2.0.20/keepalived/etc/init.d/keepalived /etc/init.d/
    
    # 将keepalived系统配置文件拷贝到etc下
    cp /opt/mysoft/keepalived-2.0.20/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
    
    # 添加可执行权限
    chmod +x /etc/init.d/keepalived
    
    # 添加keepalived到开机启动
    chkconfig --add keepalived
    chkconfig keepalived on
    
    # 查看添加到chkconfig的自启动服务
    chkconfig --list

此时已加入系统服务，可以使用systemctl或者services方式启动与停止。

## 5.3 自启动后keepalived的启动和停止 ##

*  **启动keepalived服务**  
    `systemctl start keepalived`或者`service keepalived start`
 *  **停止keepalived服务**  
    `systemctl stop keepalived`或者`service keepalived stop`
 *  **重启keepalived服务**  
    `systemctl restart keepalived`或者`service keepalived restart`
 *  **查看keepalived服务运行情况**  
    `ps -ef | grep keepalived`或者`systemctl status keepalived`或者`service keepalived status`
 *  **禁止keepalived开机自启动**  
    `systemctl disable keepalived`
 *  **启用keepalived开机自启动**  
    `systemctl enable keepalived`

好啦，至此，基础的keepalived服务运行环境就安装完成了。keepalived的基础使用，可以参考博主另一篇博文：[服务高可用之Keepalived使用详解][Keepalived]

**本文参考资料：** [https://www.jianshu.com/p/fae5e3252fc8][https_www.jianshu.com_p_fae5e3252fc8]

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[https_www.keepalived.org_download.html]: https://www.keepalived.org/download.html
[keepalived-2.0.20]: https://www.keepalived.org/software/keepalived-2.0.20.tar.gz
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtaWxlaGFwcGluZXNz_size_16_color_FFFFFF_t_70]: /images/20210923/c53d901b822246f7bfc1f1cf3befe5bf.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtaWxlaGFwcGluZXNz_size_16_color_FFFFFF_t_70 1]: /images/20210923/2105ec4c8f5d4474b16fa1e38ad833c5.png
[20200614142335353.png]: /images/20210923/7b093ece39a44b7aa48b0dff224abfc2.png
[Keepalived]: https://blog.csdn.net/smilehappiness/article/details/106741956
[https_www.jianshu.com_p_fae5e3252fc8]: https://www.jianshu.com/p/fae5e3252fc8