If IP4_NAMESERVERS are unset then pull the value from /etc/resolv.conf

This will happen whenever someone has directly modified /etc/resolv.conf

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1480438

roles/openshift_node_dnsmasq/files/networkmanager/99-origin-dns.sh

@@ -46,9 +46,7 @@ if [[ $2 =~ ^(up|dhcp4-change|dhcp6-change)$ ]]; then
   def_route=$(/sbin/ip route list match 0.0.0.0/0 | awk '{print $3 }')
   def_route_int=$(/sbin/ip route get to ${def_route} | awk '{print $3}')
   def_route_ip=$(/sbin/ip route get to ${def_route} | awk '{print $5}')
-  if [[ ${DEVICE_IFACE} == ${def_route_int} && \
-       -n "${IP4_NAMESERVERS}" && \
-       "${IP4_NAMESERVERS}" != "${def_route_ip}" ]]; then
+  if [[ ${DEVICE_IFACE} == ${def_route_int} ]]; then
     if [ ! -f /etc/dnsmasq.d/origin-dns.conf ]; then
       cat << EOF > /etc/dnsmasq.d/origin-dns.conf
 no-resolv
@@ -61,35 +59,40 @@ EOF
       NEEDS_RESTART=1
     fi
 
-    ######################################################################
-    # Write out default nameservers for /etc/dnsmasq.d/origin-upstream-dns.conf
-    # and /etc/origin/node/resolv.conf in their respective formats
-    for ns in ${IP4_NAMESERVERS}; do
-      if [[ ! -z $ns ]]; then
-        echo "server=${ns}" >> $UPSTREAM_DNS_TMP
-        echo "nameserver ${ns}" >> $NEW_NODE_RESOLV_CONF
+    # If network manager doesn't know about the nameservers then the best
+    # we can do is grab them from /etc/resolv.conf but only if we've got no
+    # watermark
+    if ! grep -q '99-origin-dns.sh' /etc/resolv.conf; then
+      if [[ -z "${IP4_NAMESERVERS}" || "${IP4_NAMESERVERS}" == "${def_route_ip}" ]]; then
+            IP4_NAMESERVERS=`grep '^nameserver ' /etc/resolv.conf | awk '{ print $2 }'`
+      fi
+      ######################################################################
+      # Write out default nameservers for /etc/dnsmasq.d/origin-upstream-dns.conf
+      # and /etc/origin/node/resolv.conf in their respective formats
+      for ns in ${IP4_NAMESERVERS}; do
+        if [[ ! -z $ns ]]; then
+          echo "server=${ns}" >> $UPSTREAM_DNS_TMP
+          echo "nameserver ${ns}" >> $NEW_NODE_RESOLV_CONF
+        fi
+      done
+      # Sort it in case DNS servers arrived in a different order
+      sort $UPSTREAM_DNS_TMP > $UPSTREAM_DNS_TMP_SORTED
+      sort $UPSTREAM_DNS > $CURRENT_UPSTREAM_DNS_SORTED
+      # Compare to the current config file (sorted)
+      NEW_DNS_SUM=`md5sum ${UPSTREAM_DNS_TMP_SORTED} | awk '{print $1}'`
+      CURRENT_DNS_SUM=`md5sum ${CURRENT_UPSTREAM_DNS_SORTED} | awk '{print $1}'`
+      if [ "${NEW_DNS_SUM}" != "${CURRENT_DNS_SUM}" ]; then
+        # DNS has changed, copy the temp file to the proper location (-Z
+        # sets default selinux context) and set the restart flag
+        cp -Z $UPSTREAM_DNS_TMP $UPSTREAM_DNS
+        NEEDS_RESTART=1
+      fi
+      # compare /etc/origin/node/resolv.conf checksum and replace it if different
+      NEW_NODE_RESOLV_CONF_MD5=`md5sum ${NEW_NODE_RESOLV_CONF}`
+      OLD_NODE_RESOLV_CONF_MD5=`md5sum /etc/origin/node/resolv.conf`
+      if [ "${NEW_NODE_RESOLV_CONF_MD5}" != "${OLD_NODE_RESOLV_CONF_MD5}" ]; then
+        cp -Z $NEW_NODE_RESOLV_CONF /etc/origin/node/resolv.conf
       fi
-    done
-
-    # Sort it in case DNS servers arrived in a different order
-    sort $UPSTREAM_DNS_TMP > $UPSTREAM_DNS_TMP_SORTED
-    sort $UPSTREAM_DNS > $CURRENT_UPSTREAM_DNS_SORTED
-
-    # Compare to the current config file (sorted)
-    NEW_DNS_SUM=`md5sum ${UPSTREAM_DNS_TMP_SORTED} | awk '{print $1}'`
-    CURRENT_DNS_SUM=`md5sum ${CURRENT_UPSTREAM_DNS_SORTED} | awk '{print $1}'`
-    if [ "${NEW_DNS_SUM}" != "${CURRENT_DNS_SUM}" ]; then
-      # DNS has changed, copy the temp file to the proper location (-Z
-      # sets default selinux context) and set the restart flag
-      cp -Z $UPSTREAM_DNS_TMP $UPSTREAM_DNS
-      NEEDS_RESTART=1
-    fi
-
-    # compare /etc/origin/node/resolv.conf checksum and replace it if different
-    NEW_NODE_RESOLV_CONF_MD5=`md5sum ${NEW_NODE_RESOLV_CONF}`
-    OLD_NODE_RESOLV_CONF_MD5=`md5sum /etc/origin/node/resolv.conf`
-    if [ "${NEW_NODE_RESOLV_CONF_MD5}" != "${OLD_NODE_RESOLV_CONF_MD5}" ]; then
-      cp -Z $NEW_NODE_RESOLV_CONF /etc/origin/node/resolv.conf
     fi
 
     if ! `systemctl -q is-active dnsmasq.service`; then