diff --git a/google-guest-agent.service b/google-guest-agent.service
index 05fbf12b..2a18698e 100644
--- a/google-guest-agent.service
+++ b/google-guest-agent.service
@@ -1,10 +1,16 @@
 [Unit]
 Description=Google Compute Engine Guest Agent
+# Start before sshd in order to regenerate SSH host keys.
 Before=sshd.service
-After=network-online.target rsyslog.service network.service networking.service
-After=NetworkManager.service
+# Start after network is online and restart when network service is restarted.
+#   Debian/Ubuntu 16.04: networking.service
+#   SLES/EL7: network.service (SLES via wicked.service)
+#   EL8: NetworkManager.service
+#   COS/Ubuntu 18.04+: systemd-networkd.service
+After=network-online.target syslog.service
+After=network.service networking.service NetworkManager.service systemd-networkd.service
 Wants=network-online.target
-PartOf=network.service networking.service NetworkManager.service
+PartOf=network.service networking.service NetworkManager.service systemd-networkd.service
 
 [Service]
 Type=simple