[baremetal] Add dispatcher script to statically configure DHCP address

We have a feature request for nodes to be able to initially get
assigned their IP addresses via infinite DHCP leases, but then to
have those addresses statically configured on the node so that if
the DHCP server is unavailable for any reason they don't lose their
network configuration.

This adds a dispatcher script for NetworkManager that does so. It
looks at the DHCP assigned network settings and adds static
configuration with the same values.

Author: cybertron

templates/common/baremetal/files/NetworkManager-static-dhcp.yaml

@@ -0,0 +1,63 @@
+mode: 0755
+path: "/etc/NetworkManager/dispatcher.d/30-static-dhcp"
+contents:
+  inline: |
+    #!/bin/bash
+    set -ex -o pipefail
+
+    if [[ "{{ .NetworkType }}" == "OVNKubernetes" && "$CONNECTION_ID" == "Wired Connection" ]]
+    then
+        >&2 echo "Refusing to modify default connection."
+        exit 0
+    fi
+
+    if [ -z ${DHCP4_IP_ADDRESS:-} ]
+    then
+        >&2 echo "Not a DHCP4 address. Ignoring."
+        exit 0
+    fi
+
+    if [ ${DHCP4_DHCP_LEASE_TIME:-0} -lt 4294967295 ]
+    then
+        >&2 echo "Not an infinite DHCP4 lease. Ignoring."
+        exit 0
+    fi
+
+    IPS=($IP4_ADDRESS_0)
+    CIDR=${IPS[0]}
+    GATEWAY=${IPS[1]}
+
+    TYPE=$(nmcli --get-values connection.type connection show "$CONNECTION_ID")
+
+    if ! nmcli con show inf-lease-to-static
+    then
+        nmcli con add type "$TYPE" con-name inf-lease-to-static
+    fi
+    nmcli con mod inf-lease-to-static \
+      conn.interface "$1" \
+      connection.autoconnect yes \
+      ipv4.addresses "$CIDR" \
+      ipv4.method manual \
+      ipv4.gateway "$GATEWAY" \
+      ipv4.dns "$IP4_NAMESERVERS"
+
+    if [ -n "$IP4_DOMAINS" ]; then
+        nmcli con mod inf-lease-to-static ipv4.dns-search "$IP4_DOMAINS"
+    fi
+    plus=''
+    for i in $(seq 0 $(($IP4_NUM_ROUTES-1)) )
+    do
+        varname="IP4_ROUTE_$i"
+        nmcli con mod inf-lease-to-static ${plus}ipv4.routes "${!varname}"
+        plus='+'
+    done
+
+    nmcli con up inf-lease-to-static
+
+    # Copy it from the OverlayFS mount to the persistent lowerdir
+    cp "/etc/NetworkManager/system-connections-merged/inf-lease-to-static.nmconnection" /etc/NetworkManager/system-connections
+
+    if [ -n "${DHCP4_HOST_NAME:-}" ]
+    then
+        hostnamectl set-hostname --static --transient "$DHCP4_HOST_NAME"
+    fi