cloud: starting kickstart for GCP cloud image

This is a starting point for a GCP cloud image. The image boots fine
in GCP today. In the future we may want to consider adding the GCP
cloud agents if they get packaged in Fedora.

fedora-cloud-base-gcp.ks

@@ -0,0 +1,25 @@
+# This is a basic Fedora cloud spin designed to work with GCP.
+# Note that GCP prefers UEFI so we'll need to make sure this image
+# is created from a machine that is started in UEFI mode.
+
+# Inherit from cloud base
+%include fedora-cloud-base.ks
+
+# Change serial port configuration to recommended default for GCP (ttyS0,38400n8d)
+# Don't show bootloader as it's impossible for the user to get to it in time
+# So we might as well not waste the 1 second on each boot.
+# https://cloud.google.com/compute/docs/import/import-existing-image
+bootloader --timeout=0 --append="no_timer_check net.ifnames=0 console=ttyS0,38400n8d"
+
+#%packages
+#%end
+
+%post --erroronfail
+cat <<EOF > /etc/NetworkManager/conf.d/gcp-mtu.conf
+# In GCP it is recommended to use 1460 as the MTU.
+# Set it to 1460 for all connections.
+# https://cloud.google.com/network-connectivity/docs/vpn/concepts/mtu-considerations
+[connection]
+ethernet.mtu = 1460
+EOF
+%end