Configuration Files

The configuration files of a Linux or Solaris machine determine everything about the environment: the kernel version, the bootloader, the file system, the printers, and so on. All of these files are writable, to a system administrator with permissions and knowledge. Change management in a Linux or Solaris environment usually includes managing files as well as applications.

A local configuration file is any file that you want to store on the knowledge base and distribute to multiple hosts for simultaneous and consistent configurations. Macros (see Macros) are used to localize these files for values relevant to each managed host.

Example 5–6 Updating Configuration Files

Your enterprise with 200 Linux servers is reorganizing; personnel are changing offices and floors. Everyone wants their machine to print to the closest printer. Instead of reconfiguring every printcap file for every host (probably more than once, as the printers and the staff are moved around the complex), you make different versions of this file.

You change printcap slightly for each version:

# /etc/printcap
# Version for RH 9 on 12th floor West
lp:\
    :sd=/var/spool/lpd/lp:\
    :mx#0:\
    :sh:\
    :rm=printer12
    :rp=pr1:

A second version:

# /etc/printcap
# Version for RH WS3 on 10th floor Main
lp:\
    :sd=/var/spool/lpd/lp:\
    :mx#0:\
    :sh:\
    :rm=printer10
    :rp=pr1:

And so on. You create a file declaration for /etc/printcap. Then you upload the versions of the file to the file declaration.

Now you can change the printer configuration of any host within seconds, by selecting the appropriate version and sending it to the hosts that need it. The contents of their old printcap is overwritten with the contents of the version that you selected.