diff options
Diffstat (limited to 'roles/openshift_node/files')
| -rwxr-xr-x | roles/openshift_node/files/networkmanager/99-origin-dns.sh | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/roles/openshift_node/files/networkmanager/99-origin-dns.sh b/roles/openshift_node/files/networkmanager/99-origin-dns.sh new file mode 100755 index 000000000..f4e48b5b7 --- /dev/null +++ b/roles/openshift_node/files/networkmanager/99-origin-dns.sh @@ -0,0 +1,128 @@ +#!/bin/bash -x +# -*- mode: sh; sh-indentation: 2 -*- + +# 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, +# - If this host is also a master, reconfigure master dnsConfig to listen on +# 8053 to avoid conflicts on port 53 and open port 8053 in the firewall +# - 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 [[ $2 =~ ^(up|dhcp4-change|dhcp6-change)$ ]]; then + # If the origin-upstream-dns config file changed we need to restart + NEEDS_RESTART=0 + UPSTREAM_DNS='/etc/dnsmasq.d/origin-upstream-dns.conf' + # We'll regenerate the dnsmasq origin config in a temp file first + UPSTREAM_DNS_TMP=`mktemp` + UPSTREAM_DNS_TMP_SORTED=`mktemp` + CURRENT_UPSTREAM_DNS_SORTED=`mktemp` + NEW_RESOLV_CONF=`mktemp` + NEW_NODE_RESOLV_CONF=`mktemp` + + + ###################################################################### + # 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} == ${def_route_int} ]]; then + if [ ! -f /etc/dnsmasq.d/origin-dns.conf ]; then + cat << EOF > /etc/dnsmasq.d/origin-dns.conf +no-resolv +domain-needed +server=/cluster.local/172.30.0.1 +server=/30.172.in-addr.arpa/172.30.0.1 +enable-dbus +dns-forward-max=5000 +cache-size=5000 +EOF + # New config file, must restart + NEEDS_RESTART=1 + fi + + # If network manager doesn't know about the nameservers then the best + # we can do is grab them from /etc/resolv.conf but only if we've got no + # watermark + if ! grep -q '99-origin-dns.sh' /etc/resolv.conf; then + if [[ -z "${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 $NEW_NODE_RESOLV_CONF /etc/origin/node/resolv.conf + fi + fi + + if ! `systemctl -q is-active dnsmasq.service`; then + NEEDS_RESTART=1 + fi + + ###################################################################### + if [ "${NEEDS_RESTART}" -eq "1" ]; then + systemctl restart dnsmasq + fi + + # Only if dnsmasq is running properly make it our only nameserver and place + # a watermark on /etc/resolv.conf + if `systemctl -q is-active dnsmasq.service`; then + if ! grep -q '99-origin-dns.sh' /etc/resolv.conf; then + echo "# nameserver updated by /etc/NetworkManager/dispatcher.d/99-origin-dns.sh" >> ${NEW_RESOLV_CONF} + fi + sed -e '/^nameserver.*$/d' /etc/resolv.conf >> ${NEW_RESOLV_CONF} + echo "nameserver "${def_route_ip}"" >> ${NEW_RESOLV_CONF} + if ! grep -qw search ${NEW_RESOLV_CONF}; then + echo 'search cluster.local' >> ${NEW_RESOLV_CONF} + elif ! grep -q 'search.*cluster.local' ${NEW_RESOLV_CONF}; then + sed -i '/^search/ s/$/ cluster.local/' ${NEW_RESOLV_CONF} + fi + cp -Z ${NEW_RESOLV_CONF} /etc/resolv.conf + fi + fi + + # Clean up after yourself + rm -f $UPSTREAM_DNS_TMP $UPSTREAM_DNS_TMP_SORTED $CURRENT_UPSTREAM_DNS_SORTED $NEW_RESOLV_CONF +fi |