Using a NAS box as 24/7 file server, I'd like to use sshfs to connect to it from an Ubuntu 9.04 desktop. Currently, I have this line in the desktop's fstab:

sshfs#jldugger@storage:/mnt/HD_a2/    /mnt/storage    fuse   comment=sshfs,auto,users,exec,uid=1000,gid=1000,allow_other,reconnect,transform_symlinks,BatchMode=yes,fsname=sshfs#jldugger@storage/mnt/HD_a2/ 0 0

I can confirm it works with mount /mnt/storage. What I need is some method of mounting it at startup, but after the network connection is established.

  • How do you have authentication setup? Are you prompted for a password when you mount that manually?
    – Zoredache
    May 19 '09 at 2:31
  • Keypair auth. Not the most secure, but likely sufficient.
    – jldugger
    May 19 '09 at 3:36

Currently, Upstart in Ubuntu does not generate network events. Instead it calls traditional sysvinit. By default NetworkManager is installed and running; rather than emit network events to upstart, it contains a run-parts dispatcher (/etc/NetworkManager/dispatcher.d/) which itself simply relies on ifupdown's run-parts dispatcher (/etc/network/*.d/). In particular you care about /etc/network/if-up.d/ and /etc/network/if-down.d/

First set up a unencrypted ssh keypair, so you can mount the point without a prompt. Write a script, place it in /etc/network/if-up.d/ and make executable. The following was discovered on UbuntuForums and was sufficient for me:

## http://ubuntuforums.org/showthread.php?t=430312
## The script will attempt to mount any fstab entry with an option
## "...,comment=$SELECTED_STRING,..."
## Use this to select specific sshfs mounts rather than all of them.

# Not for loopback
[ "$IFACE" != "lo" ] || exit 0

## define a number of useful functions

## returns true if input contains nothing but the digits 0-9, false otherwise
## so realy, more like isa_positive_integer 
isa_number () {
    ! echo $1 | egrep -q '[^0-9]'
    return $?

## returns true if the given uid or username is that of the current user
am_i () {
        [ "$1" = "`id -u`" ] || [ "$1" = "`id -un`" ]

## takes a username or uid and finds it in /etc/passwd
## echoes the name and returns true on success
## echoes nothing and returns false on failure 
user_from_uid () {
    if isa_number "$1"
                # look for the corresponding name in /etc/passwd
        local IFS=":"
        while read name x uid the_rest
                if [ "$1" = "$uid" ]
                                echo "$name"
                                return 0
        done </etc/passwd
        # look for the username in /etc/passwd
        if grep -q "^${1}:" /etc/passwd
                echo "$1"
                return 0
    # if nothing was found, return false
        return 1

## Parses a string of comma-separated fstab options and finds out the 
## username/uid assigned within them. 
## echoes the found username/uid and returns true if found
## echoes "root" and returns false if none found
uid_from_fs_opts () {
        local uid=`echo $1 | egrep -o 'uid=[^,]+'`
        if [ -z "$uid" ]; then
                # no uid was specified, so default is root
                echo "root"
                return 1
                # delete the "uid=" at the beginning
                uid_length=`expr length $uid - 3`
                uid=`expr substr $uid 5 $uid_length`
                echo $uid
                return 0

# unmount all shares first
sh "/etc/network/if-down.d/umountsshfs"

while read fs mp type opts dump pass extra
    # check validity of line
    if [ -z "$pass" -o -n "$extra" -o "`expr substr ${fs}x 1 1`" = "#" ]; 
        # line is invalid or a comment, so skip it

    # check if the line is a selected line
    elif echo $opts | grep -q "comment=$SELECTED_STRING"; then

        # get the uid of the mount
        mp_uid=`uid_from_fs_opts $opts`

        if am_i "$mp_uid"; then
                        # current user owns the mount, so mount it normally
                        { sh -c "mount $mp" && 
                                echo "$mp mounted as current user (`id -un`)" || 
                                echo "$mp failed to mount as current user (`id -un`)"; 
                        } &
                elif am_i root; then
                        # running as root, so sudo mount as user
                        if isa_number "$mp_uid"; then
                                # sudo wants a "#" sign icon front of a numeric uid
                        { sudo -u "$mp_uid" sh -c "mount $mp" && 
                                echo "$mp mounted as $mp_uid" || 
                                echo "$mp failed to mount as $mp_uid"; 
                        } &
                        # otherwise, don't try to mount another user's mount point
                        echo "Not attempting to mount $mp as other user $mp_uid"
                        echo "Not attempting to mount $mp as other user $mp_uid"
    # if not an sshfs line, do nothing
done </etc/fstab


If you have a wifi or otherwise unreliable connection, place the following in /etc/network/if-down.d/:

# Not for loopback!
[ "$IFACE" != "lo" ] || exit 0

# comment this for testing
exec 1>/dev/null # squelch output for non-interactive

# umount all sshfs mounts
mounted=`grep 'fuse.sshfs\|sshfs#' /etc/mtab | awk '{ print $2 }'`
[ -n "$mounted" ] && { for mount in $mounted; do umount -l $mount; done; }
  • 2
    This worked great for me. I will note that I changed the echo commands that were outputing to stdout to logger -t mountsshfs commands instead so the output would go to syslog.
    – Matthew
    Apr 10 '12 at 14:35

Upstart is the preferred method of issuing startup scripts or services in Ubuntu now, although editing /etc/rc.local still works. Upstart allows you to control when the service is run, making sure it happens after initiating your network connection.

It's also possible to edit the symlinks in /etc/rc.X.d directly, (substitute X for the run-level you are using) and add a name such as S99mount to ensure that it's run after the network setup. This will need to point to a script file that mounts the sshfs you are requesting.


_netdev as a mount option should solve this, I believe

  • i know, ubuntu and centos are not the same... but in centos anyways, this is the correct way to have /etc/init.d/netfs handle sshfs mounts. which will be called after the network has been brought up. Sep 14 '12 at 16:32

Just a thought, but if you're using this as a file server, maybe NFS or Samba would be a better solution than ssh.


Here is another solution in case you don't have a certificate from your remote host and have to use a login/password instead. I'm using in this example the same username and directories used by jldugger to avoid adding confusion.

  1. Create a file containing your password in your home directory, and secure it:

    echo 'YourRemoteUserPassword' > ~jldugger/.credentials
    chmod 600 ~jldugger/.credentials
  2. Edit your /etc/rc.local file and insert the following command at the bottom, but before the "exit 0":

    sshfs -o password_stdin -o nonempty jldugger@storage:/mnt/HD_a2/ /mnt/storage < ~jldugger/.credentials

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.