dns: deploy dns-updater daemon in place of the shell nsupdate script [HOLD: needs dns-updater RPM published] #482

Merged
benvin merged 1 commits from benvin/dns-updater-daemon into develop 2026-07-17 23:35:00 +10:00
4 changed files with 48 additions and 104 deletions
+48 -21
View File
@@ -23,6 +23,12 @@ class profiles::dns::updater (
Stdlib::AbsolutePath $state_dir = '/var/lib/dns-updater', Stdlib::AbsolutePath $state_dir = '/var/lib/dns-updater',
Stdlib::AbsolutePath $config_dir = '/etc/dns-updater', Stdlib::AbsolutePath $config_dir = '/etc/dns-updater',
Stdlib::AbsolutePath $master_basedir = lookup('profiles::dns::master::basedir'), Stdlib::AbsolutePath $master_basedir = lookup('profiles::dns::master::basedir'),
# dns-updater daemon (replaces the dns-update shell script).
String $package_ensure = 'installed',
Stdlib::AbsolutePath $api_socket = '/run/dns-updater/api.sock',
String $resync = '10m',
Enum['debug', 'info', 'warn', 'error'] $log_level = 'info',
Boolean $watch_interfaces = true,
) { ) {
$state_file = "${state_dir}/applied" $state_file = "${state_dir}/applied"
@@ -91,36 +97,57 @@ class profiles::dns::updater (
})), })),
} }
file { '/usr/local/bin/dns-update': # dns-updater daemon: watches the records file (inotify) and network
# interfaces, pushes TSIG-signed RFC2136 updates to $server natively.
package { 'dns-updater':
ensure => $package_ensure,
}
$env_content = @("ENV")
# Managed by puppet (profiles::dns::updater).
DNS_UPDATER_SERVER=${server}
DNS_UPDATER_KEY_FILE=${key_file}
DNS_UPDATER_RECORDS_FILE=${records_file}
DNS_UPDATER_STATE_FILE=${state_file}
DNS_UPDATER_API=${api_socket}
DNS_UPDATER_RESYNC=${resync}
DNS_UPDATER_WATCH_INTERFACES=${watch_interfaces}
DNS_UPDATER_LOG_LEVEL=${log_level}
| ENV
file { "${config_dir}/env":
ensure => file, ensure => file,
owner => 'root', owner => 'root',
group => 'root', group => 'root',
mode => '0755', mode => '0644',
content => epp('profiles/dns/dns-update.sh.epp', { content => $env_content,
'server' => $server, require => [File[$config_dir], Package['dns-updater']],
'key_file' => $key_file, }
'records_file' => $records_file,
'state_file' => $state_file, # Restart only on config/key change; records-file changes are picked up by
}), # the daemon's own inotify watch, so no service churn on record edits.
service { 'dns-updater':
ensure => running,
enable => true,
subscribe => [File["${config_dir}/env"], File[$key_file]],
require => [Package['dns-updater'], Concat[$records_file], File[$key_file]],
}
# Retire the previous shell-based mechanism.
file { '/usr/local/bin/dns-update':
ensure => absent,
} }
systemd::unit_file { 'dns-update.service': systemd::unit_file { 'dns-update.service':
content => epp('profiles/dns/dns-update.service.epp', { 'script' => '/usr/local/bin/dns-update' }), ensure => absent,
active => false,
enable => false,
} }
# The .path unit watches the records file and triggers the service.
systemd::unit_file { 'dns-update.path': systemd::unit_file { 'dns-update.path':
content => epp('profiles/dns/dns-update.path.epp', { 'records_file' => $records_file }), ensure => absent,
active => true, active => false,
enable => true, enable => false,
}
# Also apply within the puppet run whenever the records change.
exec { 'dns-update-apply':
command => '/usr/local/bin/dns-update',
refreshonly => true,
subscribe => Concat[$records_file],
require => [File['/usr/local/bin/dns-update'], File[$key_file]],
} }
} }
} }
@@ -1,10 +0,0 @@
<%- | String $records_file | -%>
[Unit]
Description=Watch the DNS records file and apply changes
[Path]
PathModified=<%= $records_file %>
Unit=dns-update.service
[Install]
WantedBy=multi-user.target
@@ -1,9 +0,0 @@
<%- | String $script | -%>
[Unit]
Description=Apply host DNS records via nsupdate
After=network-online.target
Wants=network-online.target
[Service]
Type=oneshot
ExecStart=<%= $script %>
@@ -1,64 +0,0 @@
<%- | String $server, String $key_file, String $records_file, String $state_file | -%>
#!/bin/bash
# Managed by puppet (profiles::dns::updater). Applies this host's records to the
# authoritative DNS server via TSIG nsupdate. Only the delta since the last
# successful run is sent; removed records are deleted.
set -euo pipefail
SERVER="<%= $server %>"
KEYFILE="<%= $key_file %>"
RECORDS="<%= $records_file %>"
STATE="<%= $state_file %>"
[ -f "$RECORDS" ] || exit 0
touch "$STATE"
# Format per line: zone|name|type|ttl|value (name is relative to zone, or @).
desired="$(grep -vE '^[[:space:]]*(#|$)' "$RECORDS" | sort -u || true)"
applied="$(grep -vE '^[[:space:]]*(#|$)' "$STATE" 2>/dev/null | sort -u || true)"
[ "$desired" = "$applied" ] && exit 0
fqdn() { # name zone
# $1 may be relative to the zone, "@"/empty for the apex, or already a FQDN
# (trailing dot). Only append the zone in the relative case; appending it to
# an already-qualified name yields a "..", which nsupdate rejects as an
# "invalid owner name: empty label".
case "$1" in
''|'@') printf '%s.' "$2" ;;
*.) printf '%s' "$1" ;;
*) printf '%s.%s.' "$1" "$2" ;;
esac
}
msg="$(mktemp)"
trap 'rm -f "$msg"' EXIT
printf 'server %s\n' "$SERVER" >> "$msg"
# Process per zone so each UPDATE message targets a single zone.
zones="$(printf '%s\n%s\n' "$desired" "$applied" | cut -d'|' -f1 | sort -u | grep -v '^$' || true)"
for zone in $zones; do
printf 'zone %s.\n' "$zone" >> "$msg"
# Additions/updates: replace the RRset for every desired record in this zone.
printf '%s\n' "$desired" | awk -F'|' -v z="$zone" 'NF>=5 && $1==z' | \
while IFS='|' read -r z name type ttl value; do
f="$(fqdn "$name" "$z")"
printf 'update delete %s %s\n' "$f" "$type" >> "$msg"
printf 'update add %s %s %s %s\n' "$f" "$ttl" "$type" "$value" >> "$msg"
done
# Deletions: records present last run but gone now.
comm -23 <(printf '%s\n' "$applied") <(printf '%s\n' "$desired") | \
awk -F'|' -v z="$zone" 'NF>=5 && $1==z' | \
while IFS='|' read -r z name type ttl value; do
f="$(fqdn "$name" "$z")"
printf 'update delete %s %s %s\n' "$f" "$type" "$value" >> "$msg"
done
printf 'send\n' >> "$msg"
done
if nsupdate -k "$KEYFILE" "$msg"; then
printf '%s\n' "$desired" > "$STATE"
else
echo "dns-update: nsupdate to ${SERVER} failed" >&2
exit 1
fi