USHIFT-5402: Handle DUID in ipv6 test harness

Author: pacevedom

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

@@ -17,3 +17,18 @@ find /etc/NetworkManager -name '*.nmconnection' -print0 | while IFS= read -r -d
         sed -i 's/method=.*/method=auto/g' "${file}"
     fi
 done
+
+# IPv6 only feature. An IPv6 VM will use DHCPv6 to get an IP address. To identify itself to a DHCP
+# server it uses something called DHCP Unique Identifier (DUID), and based on that the DHCP server
+# will issue a lease for that DUID and MAC address. When the system boots into anaconda to install
+# the OS with kickstart files, the DUID is automatically generated. After the system boots into the
+# OS a new DUID may be generated, causing DHCP to identify the VM as a new system, thus allocating
+# a new IP address. In order to avoid this, the DUID generated during the installarion is saved and
+# configured in NetworkManager to use it when the system boots into the OS.
+# The DUID is extracted from the journal logs to avoid pinning to a specific NIC name (which would
+# use nmcli commands).
+DUID=$(journalctl -u NetworkManager | grep duid | grep -Eo "([0-9a-f]{2}:){17}[0-9a-f]{2}" | uniq)
+if [ -n "$DUID" ]; then
+    mkdir -p /etc/NetworkManager/conf.d/
+    echo -e "[connection]\nipv6.dhcp-duid=$DUID" > /etc/NetworkManager/conf.d/dhcp-client.conf
+fi