4.2. Cobbler

Procedure 4.1. Configuring SELinux for use with Cobbler

1. To enable SELinux for Cobbler support, set the SELinux Boolean to allow HTTPD web service components, using the following command:

   setsebool -P httpd_can_network_connect true
   

   The -P switch is essential, as it enables HTTPD connection persistently across all system reboots.
2. Set SELinux file context rules for TFTP to serve the boot image file, using the following command on the Cobbler server:

   semanage fcontext -a -t public_content_t "var/lib/tftpboot/.*"
   

3. IPTables must be configured to allow incoming and outgoing network traffic on the Cobbler server.
   If you have an existing firewall ruleset using iptables, add the following rules to open the Cobbler-related ports, as follows:
   For TFTP:

   /sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 69 -j ACCEPT
   /sbin/iptables -A INPUT -m state --state NEW -m udp -p udp --dport 69 -j ACCEPT
   

   For HTTPD:

   /sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
   /sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT
   

   For Cobbler:

   /sbin/iptables -A INPUT -m state --state NEW -m udp -p udp --dport 25150 -j ACCEPT
   /sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 25150 -j ACCEPT
   

   For Koan:

   /sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 25151 -j ACCEPT
   

4. Save the firewall configuration:

   /sbin/iptables-save
   

5. Ensure that the configuration files are all synchronized by running the following command:

   cobbler sync
   

6. Start the Satellite server:

   /usr/sbin/rhn-satellite start
   

   Warning

   Do not start or stop the cobblerd service independent of the Satellite service, as doing so may cause errors and other issues.

   Always use /usr/sbin/rhn-satellite to start or stop RHN Satellite.

Procedure 4.2. Configuring Cobbler System Records

1. Go to System Details Provisioning for each system and select the kickstart profile to be associated.
2. Click Create Cobbler System Record to make the association.
3. This association will remain in place indefinitely unless you set the pxe_just_once option to true for any given machine. In that case the association will be broken after a successful kickstart. See Procedure 4.3, “Configuring Cobbler to use PXE” for more information about this setting.

Procedure 4.3. Configuring Cobbler to use PXE

1. Often, the BIOS order will be set to have the PXE boot occur first. This means that the system will not boot off the local disk unless the PXE server instructs it to do so remotely. This setup can create a boot loop, where the system continually reinstalls.
   In order to prevent boot loops, open the /etc/cobbler/settings file and add the following line:

   pxe_just_once: 1
   

   This setting adds a $kickstart_done macro in the kickstart template, which tells the system to boot locally after it has completed the installation, instead of booting from the network.
2. If you include the pxe_just_once: 1 setting, and you want to reinstall the system later on, you will need to toggle the netboot-enabled flag on the system. This can be done using either the RHN Satellite web interface, or in Cobbler directly. When the system next reboots, it will perform a PXE install, and then return to booting from the local disk until the flag is reset.
   If the BIOS is set to boot from local hard drives first, there is no need to have the pxe_just_once enabled. However, to reprovision the system using PXE, it will be necessary to zero out the MBR (master boot record).