Tips for a Linux Installation
A number of factors affect the installation of NetFlow Auditor in RedHat Enterprise Linux /CentOS platform. We recommend CentOS Minimal installation as the supported platform for NetFlow installation; the installation of any additional packages is not recommended. However, installation of NetFlow Auditor may still succeed if the following tips have been followed:
MySQL packages are shipped together in CentOS. However, that version is not compatible with NetFlow Auditor, therefore please make sure mysql package is installed before NetFlow Auditor installation.
Type the command to check if mysql packages installed or not:
rpm -qa | grep -i mysql
To uninstall the existing mysql packages, type the command:
rpm -e --nodeps [package]
gcc Java package is shipped together in CentOS. NetFlow Auditor works with Sun Java only and is not compatible with gcc java. Therefore, gcc java package must be not be installed before NetFlow Auditor installation.
To check the gcc java package, type the command:
rpm -qa | grep -i java
To uninstall the gcc java packages, type the command:
rpm -e --nodeps [package]
perl-DBI is required for the current version of MySQL package in NetFlow Auditor. perl-DBI is also shipped with CentOS, and if the perl-DBI version is lower than required by NetFlow Auditor, NetFlow Auditor will uninstall the existing one and install the suitable version. However, this may disrupt those packages which depend on the old perl-DBI. To avoid the disruption please either choose Minimal installation when installing CentOS or allocate a dedicated box for NetFlow Auditor.
Path and Permission
NetFlow Auditor need to run certain Linux system commands during installation process. Linux searches the system commands within the directories set up in $PATH environment variable. If $PATH is not configured properly, Linux shell could not found the commands and error messages like 'command not found' will come up. If the Linux user who launches the installation does not have the permissions to run the commands, error messages like 'Permission denied' will show up. In either case the installation will fail.
To ensure a successful installation please make sure root user is used for installation and $PATH is correctly configured.
NetFlow Auditor employs Cron as part of its health checking mechanism. During installation, NetFlow Auditor sets up a job in the Cron table, "digitoll.cron". The digitoll.cron job runs a script every 5 minutes to check if NetFlow Auditor service is still running. If the NetFlow Auditor service is not running, the script will automatically restart NetFlow Auditor. The periodical running of the job by the Cron ensures minimal data loss.
When upgrading from v3.6.6 or earlier to v3.6.7 and later, the digitoll.cron Cron job should be disabled. This is because the v3.6.7 (and higher versions) Upgrade Package has to upgrade the physical traffic data tables from v3.6.6. Upgrading these table may take a long time depending on the size of traffic volume and the Upgrade Package should have sole and exclusive access to these data tables. NetFlow Auditor service should be prevented from restarting to avoid access of these table.
After completing the update please ensure that you re-enable the job again to reactivate the digitoll.cron collection protection mechanism.
The command to edit the crontab file is:
Find the lines which contains the text '/usr/local/digitoll/bin/digitoll.cron' to locate the job. This line could be
'0,5,10,15,20,25,30,35,40,45,50,55 * * * * /usr/local/digitoll/bin/digitoll.cron'
for v3.6.8 or earlier
'* * * * * /usr/local/digitoll/bin/digitoll.cron'
Press i key to enter Input Mode.
To disable the job, insert a '#' at the beginning of the line;
To enable it again, delete the '#'.
The new cron table will only be activated after it has been saved
Press Esc to exit the Input mode.
Type ':wq' to save and exit.