Merge ~hloeung/ntp-charm:master into ntp-charm:master

[Haw Loeung]

Ignore IPv6 link-local interfaces

Ignore IPv6 link-local interfaces

For hosts with lots of VMs (e.g. OpenStack compute nodes), this makes
ntp listen on a bunch of interfaces and restart whenever they change.

[Paul Gear (paulgear)]

Can you show an example of ntp restarting when these interfaces change? As I understand it, ntpd will listen when it finds a new interface, but this shouldn't require a restart.

review: Needs Information

[Haw Loeung (hloeung)]

Ah, I was mis-remembering and that was ntpdate's ifup scripts that was bouncing ntpd on interface changes - LP: #1593907.

I still think this change should be landed reducing the interfaces ntpd listens on. It's not likely hosts would query ntp servers on the same network using their link-local address.

[Paul Gear (paulgear)]

I'd have to look up the exact behaviour of the 'interface ignore' directive, but it may have implications for receiving replies sent to servers on such interfaces.

[Haw Loeung (hloeung)]

Revisiting this:

Oct 27 21:44:51 bagon ntpd[148367]: Listen normally on 111928 qvbd9672bb7-c2 [fe80::5c2d:6eff:fea5:ccfb%641987]:123
Oct 27 21:44:51 bagon ntpd[148367]: Listen normally on 111929 tapd9672bb7-c2 [fe80::fc16:3eff:fe03:719a%641988]:123
Oct 27 21:44:51 bagon ntpd[148367]: Deleting interface #111876 qvo9c34b0d9-ce, fe80::bcb5:97ff:fe22:bf8c%641926#123, interface stats: received=0, sent=0, dropped=0, active_time=134 secs
Oct 27 21:44:51 bagon ntpd[148367]: Deleting interface #111877 qvb9c34b0d9-ce, fe80::c58:9dff:feb9:32ee%641927#123, interface stats: received=0, sent=0, dropped=0, active_time=134 secs
Oct 27 21:44:51 bagon ntpd[148367]: Deleting interface #111891 tapa2a325c3-04, fe80::fc16:3eff:fe41:bc52%641943#123, interface stats: received=0, sent=0, dropped=0, active_time=105 secs
Oct 27 21:44:51 bagon ntpd[148367]: Deleting interface #111919 tap9c34b0d9-ce, fe80::fc16:3eff:fed0:fbd6%641976#123, interface stats: received=0, sent=0, dropped=0, active_time=41 secs
Oct 27 21:44:51 bagon ntpd[148367]: new interface(s) found: waking up resolver
Oct 27 21:44:57 bagon ntpd[148367]: ./../lib/isc/unix/ifiter_getifaddrs.c:163: INSIST(ifa->ifa_name != ((void *)0)) failed
Oct 27 21:44:57 bagon ntpd[148367]: exiting (due to assertion failure)

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

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[Haw Loeung (hloeung)]

Oct 27 22:19:26 bagon ntpd[27598]: Listen and drop on 0 v6wildcard [::]:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen and drop on 1 v4wildcard 0.0.0.0:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 2 lo 127.0.0.1:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 3 enP5p9s0f0 10.189.0.37:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 4 enP5p9s0f1 10.189.4.40:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 5 qvbc2a16872-4b [fe80::6878:b2ff:feac:1e1e%178432]:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 6 lo [::1]:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 7 enP5p9s0f0 [fe80::9abe:94ff:fe01:4adc%2]:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 8 qvo56d9a306-7c [fe80::f012:54ff:fe37:e8ed%233731]:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 9 qvoe79559da-6c [fe80::f4b7:50ff:feb7:c857%69891]:123
Oct 27 22:19:26 bagon ntpd[27598]: Listen normally on 10 enP5p9s0f1 [fe80::9abe:94ff:fe01:4add%3]:123

vs.

Oct 27 22:27:54 bagon ntpd[60944]: Listen and drop on 0 v6wildcard [::]:123
Oct 27 22:27:54 bagon ntpd[60944]: Listen and drop on 1 v4wildcard 0.0.0.0:123
Oct 27 22:27:54 bagon ntpd[60944]: Listen normally on 2 lo 127.0.0.1:123
Oct 27 22:27:54 bagon ntpd[60944]: Listen normally on 3 enP5p9s0f0 10.189.0.37:123
Oct 27 22:27:54 bagon ntpd[60944]: Listen normally on 4 enP5p9s0f1 10.189.4.40:123
Oct 27 22:27:54 bagon ntpd[60944]: Listen normally on 5 lo [::1]:123
Oct 27 22:27:54 bagon ntpd[60944]: Listening on routing socket on fd #22 for interface updates

[Barry Price (barryprice)]

Makes sense, +1

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Merge proposal is approved, but source revision has changed, setting status to needs review.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Merge proposal is approved, but source revision has changed, setting status to needs review.

[Barry Price (barryprice)]

Yup

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 9543527ad8a294cce74cfb77be41b92a76076525

diff --git a/templates/ntp.conf b/templates/ntp.conf
index 1a38ecf..6c64ca4 100644
--- a/templates/ntp.conf
+++ b/templates/ntp.conf
@@ -14,6 +14,8 @@ restrict -6 default kod notrap nomodify nopeer noquery limited
 restrict source notrap nomodify noquery
 restrict 127.0.0.1
 restrict ::1
+interface listen all
+interface ignore fe80::/10
 
 {%- if is_container == 1 %}
 # running in a container - time adjustments disabled