Add openshift_node_dnsmasq

1 files changed, 55 insertions, 0 deletions

diff --git a/roles/openshift_node_dnsmasq/files/networkmanager/99-origin-dns.sh b/roles/openshift_node_dnsmasq/files/networkmanager/99-origin-dns.sh
new file mode 100755
index 000000000..51e0751e9
--- /dev/null
+++ b/roles/openshift_node_dnsmasq/files/networkmanager/99-origin-dns.sh
@@ -0,0 +1,55 @@
+#!/bin/bash -x
+
+# This NetworkManager dispatcher script replicates the functionality of
+# NetworkManager's dns=dnsmasq  however, rather than hardcoding the listening
+# address and /etc/resolv.conf to 127.0.0.1 it pulls the IP address from the
+# interface that owns the default route. This enables us to then configure pods
+# to use this IP address as their only resolver, where as using 127.0.0.1 inside
+# a pod would fail.
+#
+# To use this,
+# Drop this script in /etc/NetworkManager/dispatcher.d/
+# systemctl restart NetworkManager
+# Configure node-config.yaml to set dnsIP: to the ip address of this
+# node
+#
+# Test it:
+# host kubernetes.default.svc.cluster.local
+# host google.com
+#
+# TODO: I think this would be easy to add as a config option in NetworkManager
+# natively, look at hacking that up
+
+cd /etc/sysconfig/network-scripts
+. ./network-functions
+
+[ -f ../network ] && . ../network
+
+if [[ $2 =~ ^(up|dhcp4-change)$ ]]; then
+  # couldn't find an existing method to determine if the interface owns the 
+  # default route
+  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} ]]; then
+    if [ ! -f /etc/dnsmasq.d/origin-dns.conf ]; then
+      cat << EOF > /etc/dnsmasq.d/origin-dns.conf
+strict-order
+no-resolv
+domain-needed
+server=/cluster.local/172.30.0.1
+server=/30.172.in-addr.arpa/172.30.0.1
+EOF
+    fi
+    # zero out our upstream servers list and feed it into dnsmasq
+    echo '' > /etc/dnsmasq.d/origin-upstream-dns.conf
+    for ns in ${DHCP4_DOMAIN_NAME_SERVERS}; do
+       echo "server=${ns}" >> /etc/dnsmasq.d/origin-upstream-dns.conf
+    done
+    echo "listen-address=${def_route_ip}" >> /etc/dnsmasq.d/origin-upstream-dns.conf
+    systemctl restart dnsmasq
+
+    sed -i 's/^nameserver.*$/nameserver '"${def_route_ip}"'/g' /etc/resolv.conf
+    echo "# nameserver updated by /etc/NetworkManager/dispatcher.d/99-origin-dns.sh" >> /etc/resolv.conf
+  fi
+fi