samba、nfs服务、或者其他的硬盘、光盘挂载内容均可以把挂载信息写入到自动挂载的配置文件，/etc/fstab中，以实现开机自动挂载。
自动挂载简化了挂载工作，但是长时间不使用的资源挂载在服务器上，会占用带框、增加硬件负载。
autofs服务解决的问题就是：在需要使用硬盘等的资源时，才去自动进行挂载，避免不使用时挂载对资源的浪费。
下面实验在一台主机中完成，PC1主机。
1、在PC1主机中安装autofs
[root@PC1 ~]# yum install autofs.x86_64 -y
Loaded plugins: langpacks, product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
rhel7 | 4.1 kB 00:00
Resolving Dependencies
--> Running transaction check
---> Package autofs.x86_64 1:5.0.7-40.el7 will be installed
--> Processing Dependency: libhesiod.so.0()(64bit) for package: 1:autofs-5.0.7-40.el7.x86_64
--> Running transaction check
---> Package hesiod.x86_64 0:3.2.1-3.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
autofs x86_64 1:5.0.7-40.el7 rhel7 550 k
Installing for dependencies:
hesiod x86_64 3.2.1-3.el7 rhel7 30 k
Transaction Summary
================================================================================
Install 1 Package (+1 Dependent package)
Total download size: 579 k
Installed size: 3.6 M
Downloading packages:
--------------------------------------------------------------------------------
Total 78 MB/s | 579 kB 00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : hesiod-3.2.1-3.el7.x86_64 1/2
Installing : 1:autofs-5.0.7-40.el7.x86_64 2/2
rhel7/productid | 1.6 kB 00:00
Verifying : hesiod-3.2.1-3.el7.x86_64 1/2
Verifying : 1:autofs-5.0.7-40.el7.x86_64 2/2
Installed:
autofs.x86_64 1:5.0.7-40.el7
Dependency Installed:
hesiod.x86_64 0:3.2.1-3.el7
Complete!
2、在PC1主机中修改主配置文件
[root@PC1 ~]# vim /etc/auto.master
1 #
2 # Sample auto.master file
3 # This is an automounter map and it has the following format
4 # key [ -mount-options-separated-by-comma ] location
5 # For details of the format look at autofs(5).
6 #
7 /media /etc/iso.misc ## /media为指定的挂载点， /etc/iso.misc为子配置文件
8 /misc /etc/auto.misc
9 #
10 # NOTE: mounts done from a hosts map will be mounted with the
11 # "nosuid" and "nodev" options unless the "suid" and "dev"
12 # options are explicitly given.
13 #
14 /net -hosts
15 #
16 # Include /etc/auto.master.d/*.autofs
17 #
18 +dir:/etc/auto.master.d
19 #
20 # Include central master map if it can be found using
21 # nsswitch sources.
22 #
23 # Note that if there are entries for /net or /misc (as
…………
3、在PC1主机中编辑自配置文件
[root@PC1 ~]# vim /etc/iso.misc
iso -fstype=iso9660,ro,nosuid,nodev :/dev/cdrom
## iso 为指定挂载点目录，文件系统类型光盘，光盘权限 ，将要挂载的目录
4、在PC1主机中查看挂载情况
[root@PC1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 3.0G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /media/cdrom
[root@PC1 ~]# ll -d /dev/cdrom
lrwxrwxrwx. 1 root root 3 Dec 3 00:39 /dev/cdrom -> sr0 ## 说明光盘当前挂载状态
5、在PC1主机中启动autofs服务
[root@PC1 ~]# systemctl restart autofs
[root@PC1 ~]# systemctl enable autofs.service
ln -s '/usr/lib/systemd/system/autofs.service' '/etc/systemd/system/multi-user.target.wants/autofs.service'
[root@PC1 ~]# df -h
df: ‘/media/cdrom’: No such file or directory
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 3.0G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86
6、 在PC1主机中进入/media目录查看
[root@PC1 ~]# cd /media/
[root@PC1 media]# df -h
df: ‘/media/cdrom’: No such file or directory
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 3.0G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /run/media/root/RHEL-7.0 Server.x86_64
[root@PC1 media]# ls
[root@PC1 media]# cd iso
[root@PC1 iso]# ls
addons images Packages RPM-GPG-KEY-redhat-release
EFI isolinux release-notes TRANS.TBL
EULA LiveOS repodata
GPL media.repo RPM-GPG-KEY-redhat-beta
[root@PC1 iso]# df -h
df: ‘/media/cdrom’: No such file or directory
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel-root 18G 3.0G 15G 17% /
devtmpfs 985M 0 985M 0% /dev
tmpfs 994M 140K 994M 1% /dev/shm
tmpfs 994M 8.8M 986M 1% /run
tmpfs 994M 0 994M 0% /sys/fs/cgroup
/dev/sda1 497M 119M 379M 24% /boot
/dev/sr0 3.5G 3.5G 0 100% /media/iso ## 当访问挂载点目录时，实现了自动挂载
以上实验实现了只有在使用硬盘资源时，能够实现自动挂载。