First, we need to make sure the DESTSERVER has the ability to use key authentication enabled. Find your sshd configuration file (usually ‘/etc/ssh/sshd_config’) and enable the following options if they are not already set.

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile .ssh/authorized_keys

If you edit the file be sure to restart sshd afterwards.

# /etc/init.d/sshd restart

Next, on the SOURCESERVER we will create the public / private key pair to be used for authentication with the following command.

# ssh-keygen -t rsa

• Note: Do not enter a passphrase for this, just hit enter when prompted.

This should create 2 files, a public key file and a private key file. The public key file (usually [homedir]/.ssh/id_rsa.pub) we will upload to the DESTSERVER. The private key file (usually [homedir]/.ssh/id_rsa) we will keep on the SOURCESERVER.

• Be sure to keep this private key safe. With it anyone will be able to connect to the DESTSERVER that contains the public key.

Now we will plant the public key we created on to the DESTSERVER. Choose the user account which you will use to connect to on DESTSERVER, we’ll call this user ‘destuser’ for now.

In that account’s home directory, create a ‘.ssh’ subdirectory, and in that directory create a new text file called ‘authorized_keys’. If it already exists, great, use the existing file. Open the ‘authorized_keys’ file and paste in the contents of the public key you created in the previous step (id_rsa.pub). It should look something like the following

ssh-rsa <lots and lots of characters…> sourceuser@SOURCESERVER

Save the file and change the permissions to 600 for the file and 700 for the ‘.ssh’ directory.

Now to test that the keys are working. From the SOURCESERVER try logging in as normal using ssh to the DESTSERVER.

# ssh destuser@DESTSERVER

If all is working you should not be prompted for a password but instead connected directly to a shell on the DESTSERVER.

 

Now for the rsync script.

#!/bin/sh

SOURCEPATH=’/var/svn/workingcopies/beta.app.jp/’
DESTPATH=’/var/www/lamp_root/wwwapps/app.jp’
DESTUSER=’updater’
LOGFILE=’/var/log/rsync_beta.log’

echo $’\n\n’ >> $LOGFILE
for SERVER in web01 web02
do
        rsync -av –rsh=ssh $SOURCEPATH $DESTUSER@$SERVER:$DESTPATH 2>&1 >> $LOGFILE
        echo “Completed at: `/bin/date`” >> $LOGFILE
done

This is optional. I assume web updates will be done manually.

Assuming everything has worked so far all that’s left is to setup a cron job to run the script automatically at a predefined interval.

Use the ‘crontab’ command to create a new cron job.

>sudo crontab -e -u updater

This will open an editor where you can schedule the job.

Enter the following to have the script run once every hour

0 * * * * /var/scripts/rsync_betajp.sh