USHIFT-5402: Use nmcli instead of log parsing

Author: pacevedom

test/kickstart-templates/includes/post-network.cfg

@@ -23,11 +23,17 @@ done
 # will issue a lease for that DUID and MAC address. When the system boots into anaconda to install
 # the OS with kickstart files, the DUID is automatically generated. After the system boots into the
 # OS a new DUID may be generated, causing DHCP to identify the VM as a new system, thus allocating
-# a new IP address. In order to avoid this, the DUID generated during the installarion is saved and
+# a new IP address. In order to avoid this, the DUID generated during the installation is saved and
 # configured in NetworkManager to use it when the system boots into the OS.
-# The DUID is extracted from the journal logs to avoid pinning to a specific NIC name (which would
-# use nmcli commands).
-DUID=$(journalctl -u NetworkManager | grep duid | grep -Eo "([0-9a-f]{2}:){17}[0-9a-f]{2}" | uniq)
+# The DUID is unique per host, and is extracted from the DHCP6 options of the active connections
+# from NetworkManager.
+DUID=$(nmcli con show --active | \
+  awk '{print $1}' | \
+  grep -v NAME | \
+  xargs nmcli --fields DHCP6.OPTION con show | \
+  grep dhcp6_client_id | \
+  awk '{print $4}' | \
+  uniq)
 if [ -n "$DUID" ]; then
     mkdir -p /etc/NetworkManager/conf.d/
     echo -e "[connection]\nipv6.dhcp-duid=$DUID" > /etc/NetworkManager/conf.d/dhcp-client.conf