前言
目录按需挂载，空闲时自动卸载，可以采用automount技术。尤其是在大型HPC环境，成千上万的用户家目录，使用automount降低seek time，提高dentry缓存命中率，可大大节省内存资源。
环境
RHEL 8
实践
安装nfs-utils，它提供nfs server，
[root@112c000520eb ~]# dnf install -y nfs-utils Rocky Linux 8 - AppStream 14 kB/s | 4.8 kB 00:00 Rocky Linux 8 - AppStream 20 MB/s | 8.8 MB 00:00 Rocky Linux 8 - BaseOS 17 kB/s | 4.3 kB 00:00 Rocky Linux 8 - BaseOS 8.7 MB/s | 3.6 MB 00:00 Rocky Linux 8 - Extras 14 kB/s | 3.5 kB 00:00 Rocky Linux 8 - Extras 39 kB/s | 11 kB 00:00 Dependencies resolved. ==================================================================================================================== Package Architecture Version Repository Size ==================================================================================================================== Installing: nfs-utils x86_64 1:2.3.3-51.el8 baseos 503 k Installing dependencies: gssproxy x86_64 0.8.0-20.el8 baseos 118 k keyutils x86_64 1.5.10-9.el8 baseos 65 k libverto-libevent x86_64 0.3.0-5.el8 baseos 15 k python3-pyyaml x86_64 3.12-12.el8 baseos 192 k quota x86_64 1:4.04-14.el8 baseos 213 k quota-nls noarch 1:4.04-14.el8 baseos 94 k rpcbind x86_64 1.2.5-8.el8 baseos 69 k Transaction Summary ==================================================================================================================== Install 8 Packages Total download size: 1.2 M Installed size: 3.8 M Downloading Packages: (1/8): libverto-libevent-0.3.0-5.el8.x86_64.rpm 333 kB/s | 15 kB 00:00 (2/8): gssproxy-0.8.0-20.el8.x86_64.rpm 2.3 MB/s | 118 kB 00:00 (3/8): keyutils-1.5.10-9.el8.x86_64.rpm 1.2 MB/s | 65 kB 00:00 (4/8): python3-pyyaml-3.12-12.el8.x86_64.rpm 16 MB/s | 192 kB 00:00 (5/8): nfs-utils-2.3.3-51.el8.x86_64.rpm 23 MB/s | 503 kB 00:00 (6/8): quota-nls-4.04-14.el8.noarch.rpm 10 MB/s | 94 kB 00:00 (7/8): rpcbind-1.2.5-8.el8.x86_64.rpm 11 MB/s | 69 kB 00:00 (8/8): quota-4.04-14.el8.x86_64.rpm 10 MB/s | 213 kB 00:00 -------------------------------------------------------------------------------------------------------------------- Total 4.5 MB/s | 1.2 MB 00:00 Running transaction check Transaction check succeeded. Running transaction test Transaction test succeeded. Running transaction Preparing : 1/1 Running scriptlet: rpcbind-1.2.5-8.el8.x86_64 1/8 Installing : rpcbind-1.2.5-8.el8.x86_64 1/8 Running scriptlet: rpcbind-1.2.5-8.el8.x86_64 1/8 Installing : quota-nls-1:4.04-14.el8.noarch 2/8 Installing : quota-1:4.04-14.el8.x86_64 3/8 Installing : python3-pyyaml-3.12-12.el8.x86_64 4/8 Installing : libverto-libevent-0.3.0-5.el8.x86_64 5/8 Installing : gssproxy-0.8.0-20.el8.x86_64 6/8 Running scriptlet: gssproxy-0.8.0-20.el8.x86_64 6/8 Installing : keyutils-1.5.10-9.el8.x86_64 7/8 Running scriptlet: nfs-utils-1:2.3.3-51.el8.x86_64 8/8 Installing : nfs-utils-1:2.3.3-51.el8.x86_64 8/8 Running scriptlet: nfs-utils-1:2.3.3-51.el8.x86_64 8/8 Verifying : gssproxy-0.8.0-20.el8.x86_64 1/8 Verifying : keyutils-1.5.10-9.el8.x86_64 2/8 Verifying : libverto-libevent-0.3.0-5.el8.x86_64 3/8 Verifying : nfs-utils-1:2.3.3-51.el8.x86_64 4/8 Verifying : python3-pyyaml-3.12-12.el8.x86_64 5/8 Verifying : quota-1:4.04-14.el8.x86_64 6/8 Verifying : quota-nls-1:4.04-14.el8.noarch 7/8 Verifying : rpcbind-1.2.5-8.el8.x86_64 8/8 Installed: gssproxy-0.8.0-20.el8.x86_64 keyutils-1.5.10-9.el8.x86_64 libverto-libevent-0.3.0-5.el8.x86_64 nfs-utils-1:2.3.3-51.el8.x86_64 python3-pyyaml-3.12-12.el8.x86_64 quota-1:4.04-14.el8.x86_64 quota-nls-1:4.04-14.el8.noarch rpcbind-1.2.5-8.el8.x86_64 Complete!
创建目录并导出，启动nfs server，
[root@112c000520eb ~]# mkdir -p /users/nfs/{lisa,linda,anna}
[root@112c000520eb ~]# echo "/users *(rw,no_root_squash)" > /etc/exports
[root@112c000520eb ~]# systemctl enable --now nfs-server
Created symlink /etc/systemd/system/multi-user.target.wants/nfs-server.service → /usr/lib/systemd/system/nfs-server.service.
[root@112c000520eb ~]# showmount -e localhost
Export list for localhost:
/users *
在客户端，安装autofs，
[root@112c000520eb ~]# dnf install -y autofs Last metadata expiration check: 0:00:19 ago on Sat 02 Jul 2022 07:14:43 AM CEST. Dependencies resolved. ==================================================================================================================== Package Architecture Version Repository Size ==================================================================================================================== Installing: autofs x86_64 1:5.1.4-82.el8 baseos 706 k Transaction Summary ==================================================================================================================== Install 1 Package Total download size: 706 k Installed size: 2.8 M Downloading Packages: autofs-5.1.4-82.el8.x86_64.rpm 9.6 MB/s | 706 kB 00:00 -------------------------------------------------------------------------------------------------------------------- Total 2.6 MB/s | 706 kB 00:00 Running transaction check Transaction check succeeded. Running transaction test Transaction test succeeded. Running transaction Preparing : 1/1 Installing : autofs-1:5.1.4-82.el8.x86_64 1/1 Running scriptlet: autofs-1:5.1.4-82.el8.x86_64 1/1 Verifying : autofs-1:5.1.4-82.el8.x86_64 1/1 Installed: autofs-1:5.1.4-82.el8.x86_64 Complete!
参考/misc配置项，对家目录进行配置，并启动autofs服务，
[root@112c000520eb ~]# grep '^/misc' /etc/auto.master /misc /etc/auto.misc [root@112c000520eb ~]# echo "/home/nfs /etc/auto.nfs" >> /etc/auto.master [root@112c000520eb ~]# grep -i linux /etc/auto.misc #linux -ro,soft ftp.example.org:/pub/linux [root@112c000520eb ~]# echo "* -rw localhost:/users/nfs/&" > /etc/auto.nfs [root@112c000520eb ~]# systemctl enable --now autofs Created symlink /etc/systemd/system/multi-user.target.wants/autofs.service → /usr/lib/systemd/system/autofs.service.
检查/home/nfs目录，没有任何文件（夹），
[root@112c000520eb ~]# ls -al /home/nfs total 0 drwxr-xr-x. 2 root root 0 Jul 2 07:15 . drwxr-xr-x. 4 root root 31 Jul 2 07:15 ..
触发一下其中一个子目录，可以看到挂载上了，
[root@112c000520eb ~]# cd /home/nfs/linda [root@112c000520eb linda]# pwd /home/nfs/linda [root@112c000520eb linda]# mount | tail -5 nfsd on /proc/fs/nfsd type nfsd (rw,relatime) /etc/auto.misc on /misc type autofs (rw,relatime,fd=5,pgrp=10818,timeout=300,minproto=5,maxproto=5,indirect,pipe_ino=41624) -hosts on /net type autofs (rw,relatime,fd=11,pgrp=10818,timeout=300,minproto=5,maxproto=5,indirect,pipe_ino=41636) /etc/auto.nfs on /home/nfs type autofs (rw,relatime,fd=17,pgrp=10818,timeout=300,minproto=5,maxproto=5,indirect,pipe_ino=41640) /dev/mapper/rl-root on /home/nfs/linda type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota)
后记
在大型HPC环境，一般在LDAP里配置好不同location的AUTOMOUNT，实现统一配置。
