Rsync Passwords and other Tidbits

I like Rsync allot and I tend to use it allot in daemon mode. I like to run it from Cron so that I know about every 1 to 5 min it back up certain files. Using it like this can be tricky b/c I also want to use some extra security, another thing is I don't want it to eat all up all my network bandwidth when syncing remotely with servers. So today we are going to Show you how to secure your Rsync with passwords, and limit bandwidth connections.

Lets start out with the basic config first.
This example is to rsync my pxe images directory.
#rsyncd.conf
uid = nobody
gid = nobody
use chroot = yes
max connections = 4
syslog facility = local5
pid file = /var/run/rsyncd.pid

[images]
path = /var/www/html/install/images
comment = whole linux image area (approx 6.1 GB)

Nothing special here just basic setup
But lets get fancy

Using Rsync Passwords

Here is the same config with rsync's own authentication configured.

#rsyncd.conf with auth
uid = nobody
gid = nobody
use chroot = yes
max connections = 4
syslog facility = local5
pid file = /var/run/rsyncd.pid

[images]
path = /var/www/html/install/images
comment = whole linux image area (approx 6.1 GB)
auth users = miuser nobody
secrets file = /etc/rsyncd.secrets

#rsyncd.secrets
miuser:passw0rd
nobody:passw0rd

Remember to make sure there is non-world readable on the secrets file
just to make sure and rest easy.

chmod 700 /etc/rsyncd.secrets

Now lets move to the client side we need to setup a password file so we can run this whole thing from a cronjob.

#pass
passw0rd

Just like secrets file you need to make it non-world readable

chmod 700 pass

Then give it a shot

rsync -avz --password-file=./pass miuser@yourserver.yourdomain.org::images/* /tftp

There you can add that to a cron job put it in a wrapper script or something else, now only authenticated clients can access rsync targets.

Bandwidth Limiting
Another handy option is to limit the bandwidth when rsyncing, b/c you don't want to saturate your pipe between Data centers or networks. From the man page it says

--bwlimit=KBPS
This option allows you to specify a maximum trans­
fer rate in kilobytes per second. This option is
most effective when using rsync with large files
(several megabytes and up). Due to the nature of
rsync transfers, blocks of data are sent, then if
rsync determines the transfer was too fast, it will
wait before sending the next data block. The result
is an average transfer rate equaling the specified
limit. A value of zero specifies no limit.

This trick is very useful here is an example of it

rsync -avz --bwlimit=300 --password-file=./pass miuser@yourserver.youdomain.org::images/* /tftp