Temporary SSH Tunnel for backup purposes

Solution 1:

You don't need to bother with all that tunneling :-).

Just let mysqldump stream its data using the SSH connection:

ssh usr@host mysqldump -u dbuser -ppasswd my-database-name >dumpfile

Solution 2:

Add the -N option, the -f option and the sleep 600, this will open the tunnel without running it in the background. Then you can run the command with &, get the PID, then kill the ssh process once the jobs have completed.

/usr/bin/ssh -T -L 4444: -l remoteuser &
kill $PID

(I've tested this with bash - you may need to change things for a different shell)

Solution 3:

A slight variation on sleske's suggestion, you can pipe the mysqldump output through gzip to compress before transfer:

ssh SSH-USER@SERVER mysqldump -u DB-USER -pDB-PASSWORD DB-NAME | gzip -c > DB-NAME.sql.gz

Solution 4:

As sleske said, why bother in this particular case ? However there is a solution to control an ssh tunnel in the general case : use a named pipe. First create the pipe like this :

ssh -l remoteuser mkfifo /tmp/PIPO

Then you write (blocking to the pipe) in your ssh to create the tunnel :

/usr/bin/ssh -T -f -L 4444: -l remoteuser "echo T > /tmp/PIPO"

When you want to close the tunnel, just read the pipe :

ssh -l remoteuser cat /tmp/PIPO

Et voilà!

Solution 5:

This is how I would write it,

scp backup-db.sh [email protected]:/root/backups/
ssh [email protected] exec /root/backups/backup-db.sh

Where the script is,

# backup-db.sh
DUMPARGS=--compress -h -P 4444 -u user -ppassword

/usr/bin/mysqldump $DUMPARGS db1 | bzip2 > $BACKUP_PATH/db1.sql.bz2
/usr/bin/mysqldump $DUMPARGS db2 | bzip2 > $BACKUP_PATH/db2.sql.bz2
/usr/bin/mysqldump $DUMPARGS db3 | bzip2 > $BACKUP_PATH/db3.sql.bz2

Finally, the archive can be scped back with another command.
Yes, I did not pipe or tunnel.