Procedure for DNS Server Local Service Logging using Logrotate & Automate the Logging using Cron & Anacron Utilities.

1. Lets take a example.

   To start the logging in DNS using Local Service,
    We have to create a channel like query channel that sends the logs to
    local0 system service & we have put these logging statements in named.conf file.
  
          logging {
          channel queries_channel {
          syslog local0;
          severity dynamic;
          print-time yes;
          print-severity yes;
          };
          category queries { queries_channel; };
          };

2. Now, we edit rsyslog.conf file where local0 service listen all the query logs
     sends by DNS & save locally on the file.

        /var/log/query.log

    For this, the statements in /etc/rsyslog.conf are as follows:
    
          local0.*                         /var/log/query.log
   
    Then restart the rsyslog service as

        # service rsyslog restart

3. Now, we rotate this log file using logrotate utility.

    Our requirements for log rotation are as follows:

    a. We need to rotate the log on Daily basis.

    b. We need the Max File Size is of 100 MB only & thereafter again create the
          new 100 MB file with next set of logs.

    c. While rotating the logs on daily basis, copy the present date logs to                   another file & start the main log file (/var/log/query.log) with zero data.

    d. Rotate the Logs for 30 days.

    e. Take the Backup of Logs in the Directory like /var/log/rsyslog/

    f.  If the file size exceed more than 100M then the next file is start with
          .1 & therefore .2, .3, .4 in this way.

    g. Save the 30 days log files as compressed files.
    
     So, to achieve this, we use logrotate utility.

    So, move to /etc/logrotate.d/ folder.

       # cd /etc/logrotate.d/

    Create a new file as rsyslog

        # vi rsyslog

    & Put the below code in this file to achieve our log rotation requirements.

       /var/log/queries222.log {
          daily
          maxsize=100M
          copytruncate
          rotate 30
          olddir /var/log/rsyslog
          start 1
          missingok
          compress
          }

    To make the Log Rotation effective at this moment, run the command as:

        # logrotate -f /etc/logrotate.conf

    which start the rotation for this time.

4. The Logrotate is work combination-ally with cron or anacron to make it
     automatically on daily or weekly or monthly basis.

    So, to achieve this we need to modify the /etc/anacrontab file.

    Open the file & do the following changes on it.

        # /etc/anacrontab

   # See anacron(8) and anacrontab(5) for details.

       SHELL=/bin/sh
         PATH=/sbin:/bin:/usr/sbin:/usr/bin
         MAILTO=root

   # The maximal random delay added to the base delay of the jobs

       RANDOM_DELAY=0

   # The jobs will be started during the following hours only

START_HOURS_RANGE=1-23

   # Period in days   delay in minutes   job-identifier   command

    1                 0                       cron.daily     nice run-parts /etc/cron.daily
     7                      25                           cron.weekly     nice run-parts /etc/cron.weekly
     @monthly        45                           cron.monthly   nice run-parts /etc/cron.monthly

  At last restart the crond service as:

       # service crond restart
          # chkconfig crond on

  The Procedure for Log rotation is completed.

  Thanks
  Saurabh Srivastava