Autofs
AutoFS provides automounting of removable media or network shares when they are inserted or accessed.
Installation
Install the autofsAUR package.
autofs4
module.Configuration
AutoFS uses template files for configuration which are located in /etc/autofs
The main template is called auto.master
, which can point to one or more other templates for specific media types.
Open the file /etc/autofs/auto.master
with your favorite editor, you will see something similar to this:
/etc/autofs/auto.master
#/media /etc/autofs/auto.media
The first value on each line determines the base directory under which all the media in a template are mounted, the second value is which template to use. The default base path is /media
, but you can change this to any other location you prefer. For instance:
/etc/autofs/auto.master
/media/misc /etc/autofs/auto.misc --timeout=5 /media/net /etc/autofs/auto.net --timeout=60
ENTER
after last word). If there is no correct EOF (end of file) line, the AutoFS daemon will not properly load.timeout
sets the amount of seconds after which to unmount directories. Setting this value to 0
will disable the timeout.The base directory will be created if it does not exist on your system. The base directory will be mounted on to load the dynamically loaded media, which means any content in the base directory will not be accessible while autofs is on. This procedure is however non-destructive, so if you accidentally automount into a live directory you can just change the location in auto.master
and restart AutoFS to regain the original contents.
If you still want to automount to a target non-empty directory and want to have the original files available even after the dynamically loaded directories are mounted, you can use autofs to mount them to another directory (e.g. /var/autofs/net
) and create soft links.
# ln -s /var/autofs/net/share_name /media/share_name
Alternatively, you can have autofs mount your media to a specific folder, rather than inside a common folder.
/etc/autofs/auto.master
/- /etc/autofs/auto.template
/etc/autofs/auto.template
/path/to/folder -options :/device/path /home/user/usbstick -fstype=auto,async,nodev,nosuid,umask=000 :/dev/sdb1
Open the file /etc/nsswitch.conf
and add an entry for automount:
automount: files
When you are done configuring your templates (see below), launch the AutoFS daemon as root by enabling and starting the autofs.service
.
Devices are now automatically mounted when they are accessed, they will remain mounted as long as you access them.
Removable media
Removable devices are assigned block device locations according to the next available spot, e.g. if /dev/sd{a,b,c}
are already occupied, the next removable media will be given block /dev/sdd
. Instead of assigning a mount point based on an unreliable block device path, a more robust approach is to use the UUID or PARTUUID of the removable media as the location in the map file.
For example, to mount a specific USB drive to the path /mnt/black
, configure the template file and map file:
/etc/autofs/auto.master
# master template file /mnt /etc/autofs/auto.mnt # [options here]
Use blkid
to find the UUID of the partition to mount, then generate the map file:
# _ID=$( blkid --output value --match-tag PARTUUID /dev/sdXY ) # printf "%s %s\n" "black -fstype=auto :PARTUUID=" "${_ID}" >/etc/autofs/auto.mnt
NFS network mounts
AutoFS provides automatically discovering and mounting NFS-shares on remote servers (the AutoFS network template in /etc/autofs/auto.net
has been removed in autofs5). To enable automatic discovery and mounting of network shares from all accessible servers without any further configuration, you will need to add the following to the /etc/autofs/auto.master
file:
/net -hosts --timeout=60
/etc/hosts
or via DNS and make sure you have nfs-utils installed and configured. You also have to enable rpcbind
to browse shared directories.For instance, if you have a remote server fileserver (the name of the directory is the hostname of the server) with an NFS share named /home/share
, you can just access the share by typing:
# cd /net/fileserver/home/share
/etc/conf.d/autofs
in order to start the AutoFS daemon.The -hosts
option uses a similar mechanism as the showmount
command to detect remote shares. You can see the exported shares by typing:
# showmount servername -e
Manual NFS configuration
To mount a NFS share for file_server on /srv/shared_dir
at location /mnt/foo
, add a new configuration, e.g. file_server.autofs
:
/etc/autofs/auto.master.d/file_server.autofs
/mnt /etc/autofs/auto.file_server --timeout 60
/etc/autofs/auto.file_server
foo -rw,soft,rsize=8192,wsize=8192 file_server:/srv/shared_dir
Samba
Add the following to /etc/autofs/auto.master
:
/media/[my_server] /etc/autofs/auto.[my_server] --timeout 60 --browse
where --timeout
defines how many seconds to wait before the file system is unmounted. The --browse
option creates empty folders for each mount-point in the file in order to prevent timeouts, if a network share cannot be contacted.
Next create a file /etc/autofs/auto.[my_server]
[any_name] -fstype=cifs,[other_options] ://[remote_server]/[remote_share_name]
You can specify a user name and password to use with the share in the other_options
section:
[any_name] -fstype=cifs,username=[username],password=[password],[other_options] ://[remote_server]/[remote_share_name]
$
, and other characters, with a backslash when necessary.You may be specify multiple shares in the /etc/autofs/auto.[my_server]
, for instance:
[any_name] -fstype=cifs,[other_options] /photos ://[remote_server]/photos /music ://[remote_server]/music /video ://[remote_server]/video
Auto discovery
See the comments in /etc/autofs/auto.smb
.
FTP and SSH (with FUSE)
Remote FTP and SSH servers can be accessed seamlessly with AutoFS using FUSE, a virtual file system layer.
Remote FTP
First, install the curlftpfs package.
Load the fuse module:
# modprobe fuse
Create a /etc/modules-load.d/fuse.conf
file containg fuse
to load it on each system boot.
Next, add a new entry for FTP servers in /etc/autofs/auto.master
:
/media/ftp /etc/autofs/auto.ftp --timeout=60
Create the file /etc/autofs/auto.ftp
and add a server using the ftp://myuser:mypassword@host:port/path
format:
servername -fstype=curl,rw,allow_other,nodev,nonempty,noatime :ftp\://myuser\:mypassword\@remoteserver
df
(only for mounted servers) or view the file /etc/autofs/auto.ftp
.If you want slightly more security you can create the file ~root/.netrc
and add the passwords there.
Passwords are still plain text, but you can have mode 600, and df
command will not show them (mounted or not).
This method is also less sensitive to special characters (that else must be escaped) in the passwords. The format is:
machine remoteserver login myuser password mypassword
The line in /etc/autofs/auto.ftp
looks like this without user and password:
servername -fstype=curl,allow_other :ftp\://remoteserver
Create the file /sbin/mount.curl
with this code:
/sbin/mount.curl
#!/bin/sh curlftpfs $1 $2 -o $4,disable_eprt
Create the file /sbin/umount.curl
with this code:
/sbin/umount.curl
#!/bin/sh fusermount -u $1
Set the permissions for both files:
# chmod 755 /sbin/mount.curl # chmod 755 /sbin/umount.curl
After a restart your new FTP server should be accessible through /media/ftp/servername
.
Remote SSH
These are basic instructions to access a remote filesystem over SSH with AutoFS.
Install the sshfs package.
Load the fuse
module:
# modprobe fuse
Create a /etc/modules-load.d/fuse.conf
file containing fuse
to load it on each system boot if you have not one yet.
Install openssh.
Generate an SSH keypair:
$ ssh-keygen
When the generator ask for a passphrase, just press ENTER
. Using SSH keys without a passphrase is less secure, yet running AutoFS together with passphrases poses some additional difficulties which are not (yet) covered in this article.
Next, copy the public key to the remote SSH server:
$ ssh-copy-id username@remotehost
As root, see that you can login to the remote server:
# ssh username@remotehost
known_hosts
. Hosts can be also be manually added to /etc/ssh/ssh_known_hosts
.Create a new entry for SSH servers in /etc/autofs/auto.master
:
/media/ssh /etc/autofs/auto.ssh --timeout=60
Create the file /etc/autofs/auto.ssh
and add an SSH server:
/etc/autofs/auto.ssh
servername -fstype=fuse,rw,allow_other,IdentityFile=/home/username/.ssh/id_rsa :sshfs\#username@host\:/
After a restart your SSH server should be accessible through /media/ssh/servername
.
MTP
Media Transfer Protocol (MTP) is used in some Android devices.
Install the mtpfs package.
Create a new entry for MTP Device in /etc/autofs/auto.misc
:
android -fstype=fuse,allow_other,umask=000 :mtpfs
Troubleshooting and tweaks
This section contains a few solutions for common issues with AutoFS.
Using NIS
Version 5.0.5 of AutoFS has more advanced support for NIS. To use AutoFS together with NIS, add yp:
in front of the template names in /etc/autofs/auto.master
:
/home yp:auto_home --timeout=60 /sbtn yp:auto_sbtn --timeout=60 +auto.master
On earlier versions of NIS (before 5.0.4), you should add nis
to /etc/nsswitch.conf
:
automount: files nis
Optional parameters
You can set parameters like timeout
systemwide for all AutoFS media in /etc/default/autofs
:
- Open the
/etc/default/autofs
file and edit theOPTIONS
line:OPTIONS='--timeout=5'
- To enable logging (default is no logging at all), uncomment and add
--verbose
to theOPTIONS
line in/etc/default/autofs
e.g.:OPTIONS='--verbose --timeout=5'
After restarting the autofs
daemon, verbose output is visible in the unit status or in the journal.
Identify multiple devices
If you use multiple USB drives/sticks and want to easily tell them apart, you can use AutoFS to set up the mount points and Udev to create distinct names for your USB drives. See udev#Setting static device names for instructions on setting up Udev rules.
AutoFS permissions
If AutoFS is not working for you, make sure that the permissions of the templates files are correct, otherwise AutoFS will not start. This may happen if you backed up your configuration files in a manner which did not preserve file modes. Here are what the modes should be on the configuration files:
0644
—/etc/autofs/auto.master
0644
—/etc/autofs/auto.media
0644
—/etc/autofs/auto.misc
0644
—/etc/conf.d/autofs
In general, scripts (like previous auto.net
) should have executable bits set and lists of mounts should not.
If you are getting errors in /var/log/daemon.log
similar to this, you have a permissions problem:
May 7 19:44:16 peterix automount[15218]: lookup(program): lookup for petr failed May 7 19:44:16 peterix automount[15218]: failed to mount /media/cifs/petr
fusermount problems
With certain versions of util-linux, you may not be able to unmount a fuse file system drive mounted by autofs, even if you use the user=
option. See the discussion on the mailing list.
Debugging auto mount issues
For better debugging, try running automount in the foreground.
Stop autofs.service
, then run:
# automount -f -v
Or if you want more debug info then try:
# automount -f --debug
Alternatives to AutoFS
- Systemd can automount filesystems upon demand; see here for the description and the article on sshfs for an example.
- Thunar Volume Manager is an automount system for users of the Thunar file manager.
- PCManFM is a lightweight file manager with built-in support for accessing remote shares
- Udisks is a minimalistic automatic disk mounting service
See also
- FTP and SFTP usage with AutoFS is based on this Gentoo Wiki article: https://web.archive.org/web/20130414074212/http://en.gentoo-wiki.com/wiki/Mounting_SFTP_and_FTP_shares
- More information on SSH can be found on the SSH and Using SSH Keys pages of this wiki.
- Ubuntu's Autofs help wiki is at https://help.ubuntu.com/community/Autofs
- For filesystem specific mount options see mount(8) § FILESYSTEM-SPECIFIC MOUNT OPTIONS
- For fuse specific mount options see mount.fuse(8)