Apache是一个基金会的名字，httpd才是我们要安装的软件包，早期它的名字就叫apache
Apache官网www.apache.org
cd /usr/local/src/
wget http://mirrors.cnnic.cn/apache/httpd/httpd-2.4.29.tar.gz
wget http://mirrors.cnnic.cn/apache/apr/apr-1.6.3.tar.gz
wget https://mirrors.cnnic.cn/apache/apr/apr-util-1.6.1.tar.gz
apr和apr-util是一个通用的函数库，它让httpd可以不关心底层的操作系统平台，可以很方便地移植（从linux移植到windows）
2.2的apr和2.4所依赖的apr版本是不一样的。Centos的yum安装的apr和2.4是不匹配的。所以需要自己编译
tar zxvf httpd-2.4.27.tar.gz
tar zxvf apr-util-1.5.4.tar.gz
tar zxvf apr-1.5.2.tar.gz
cd apr-1.6.3
./configure --prefix=/usr/local/apr
make && make install

cd /usr/local/src/apr-util-1.5.4
./configure --prefix=/usr/local/apr-util --with-apr=/usr/local/apr
make && make install
cd /usr/local/src/httpd-2.4.27
./configure \ //这里的反斜杠是脱义字符，加上它我们可以把一行命令写成多行
--prefix=/usr/local/apache2.4 \
--with-apr=/usr/local/apr \
--with-apr-util=/usr/local/apr-util \
--enable-so \ //支持动态扩展模块
--enable-mods-shared=most //绝大多数用到的模块都加载
make && make install
/usr/local/apache2.4/bin/apachectl start //启动

cd /usr/local/apache2.4/
ls bin/httpd //二进制脚本
bin/httpd

ls conf/httpd.conf //配置文件
conf/httpd.conf

ls htdocs/ //访问页。默认网站
index.html

ls /usr/local/apache2.4/modules
/usr/local/apache2.4/bin/apachectl -M //apachectl脚本调用了二进制httpd文件
/usr/local/apache2.4/bin/httpd -M //查看加载的模块
so_module (static) //说明是在httpd里面的
http_module (static)
mpm_event_module (static)
authn_file_module (shared) //说明是扩展模块。是一个可以看到的.so文件在/usr/local/apache2.4/modules/下

问题！！make报错
collect2: error: ld returned 1 exit status
make[2]: [htpasswd] 错误 1
make[2]: 离开目录“/usr/local/src/httpd-2.4.27/support”
make[1]: [all-recursive] 错误 1
make[1]: 离开目录“/usr/local/src/httpd-2.4.27/support”
make: *** [all-recursive] 错误 1
解决办法：
cd /usr/local/src/
cp -r apr-1.6.2  /usr/local/src/httpd-2.4.27/srclib/apr
cd apr-1.6.3
./configure --prefix=/usr/local/apr
make && make install
cp -r apr-util-1.6.0  /usr/local/src/httpd-2.4.27/srclib/apr-util
cd /usr/local/src/apr-util-1.5.4
./configure --prefix=/usr/local/apr-util --with-apr=/usr/local/apr
make && make install

cd /usr/local/src/httpd-2.4.27
#./configure --with-included-apr --prefix=/usr/local/apache2.4 --with-apr=/usr/local/apr --with-apr-util=/usr/local/apr-util --enable-so --enable-mods-shared=most
#make &&make install

错误！！
1.xml/apr_xml.c:35:19: 致命错误：expat.h：没有那个文件或目录
#include
解决办法：
[root@lsx-02 apr-util-1.6.0]# yum list |grep 'expat.'

2.configure: error: no acceptable C compiler found in $PATH
yum install -y gcc

3.configure: error: pcre-config for libpcre not found. PCRE is required and available from http://pcre.org/
yum list |grep -i PCRE
yum install -y pcre-devel.x86_64