Chapter 12. Create client images and templates

Procedure

1. Integrate the image with the Red Hat Update Infrastructure (RHUI) by transferring the RHUI entitlement RPM and GPG key to the target RHEL client system.

2. Install the appropriate client configuration RPM:

   # yum install <rhui-client-rhel7>

3. Import the Red Hat release GPG key (/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release) into the entitlement RPM, along with any custom repository keys.

4. Import the entitlement RPM GPG key:

   #rpm --import <rhui-client-rhui>

5. Updates will come from RHUI instead of the Red Hat Subscription Manager (rhsm); turn off rhsm by editing ./rhsm.conf to reflect enabled=0.
6. Optionally (but strongly recommended), run the yum update command to apply all available updates.

Procedure

1. Run the following script:

   #!/bin/bash
   
   # RHEL 7
   if ! [[ `runlevel | cut -d " " -f 2` =~ ^[1S]$ ]]; then
   echo "Please *boot* to runlevel 1"
   exit 3
   fi
   
   # Kill udev
   killall -9 udevd
   
   # Clean out /root
   rm -rf /root/*
   rm -f /root/.bash_history
   rm -rf /root/.ssh
   
   # SSH host keys
   rm -f /etc/ssh/ssh_host_*
   # Remove all files in /var that are not owned by an RPM
   
   for FILE in `find /var -type f`; do
   rpm -qf --quiet "$FILE" || rm -f "$FILE"
   
   done
   
   # Remove empty directories in /var that are not owned by an RPM
   
   until [ "$REMOVED_DIR" = false ]; do
        REMOVED_DIR=false
        for DIR in `find /var -type d -empty`; do
       if ! rpm -qf --quiet "$DIR"; then
            REMOVED_DIR=true
            rmdir "$DIR"
       fi
    done
   
   done
   
   # Truncate any remaining files in /var/log
   for FILE in `find /var/log -type f`; do
      echo -n > "$FILE"
   
   done
   
   # Make sure the RPM GPG key has been imported
   rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release 2> /dev/null
   
   # Remove MAC addresses from /etc/sysconfig/network-scripts/ifcfg-*
   for FILE in /etc/sysconfig/network-scripts/ifcfg-*; do
   
      sed -i /^HWADDR/d "$FILE"
   
   done
   
   # Remove auto-generated udev rules for CD-ROM and network devices
   rm -f /etc/udev/rules.d/70-persistent-{cd,net}.rules
   
   # Clean out /tmp
   find /tmp -mindepth 1 -delete

2. Copy the script to /mktemplate.sh and reboot the system to runlevel 1.

   Note

   Do not change to runlevel 1 instead of rebooting (with init 1, for example). Changing to runlevel 1 leaves certain daemons running that are not running when the system is booted to single-user mode (notably rsyslog).

3. When the system has rebooted into single-user mode, run the following commands:

   # unset HISTFILE
   # chmod 0755  /mktemplate.sh
   # /mktemplate.sh
   # rm -f /mktemplate.sh
   # poweroff