/etc/logrotate.d/fail2ban

fail2ban

/var/log/fail2ban.log {

   # weekly
     daily
   # rotate 4
     rotate 30
   # compress

   # delaycompress
    missingok
    postrotate
        fail2ban-client flushlogs 1>/dev/null
    endscript

    # If fail2ban runs as non-root it still needs to have write access
    # to logfiles.
    # create 640 fail2ban adm
    create 640 root adm
}