NTP Service Fails to Start or Hangs on SLES12

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Environment

SUSE Linux Enterprise Server 12 GA

Situation

Upon completing the NTP configuration in yast2 and clicking Finish, an error "Error: Cannot restart the NTP daemon" appears on the screen.

Running systemctl start ntpd.service fails or hangs.

The error persists whether NTP is configured in a chroot jail or not.

The system log /var/log/messages contains the errors:
'kernel: [ 657.760204] type=1400 audit (1415376571.756:44): apparmor="DENIED" operation="file_mmap" parent=1 profile="/usr/sbin/ntpd" name="/run/nscd/group" pid=2879 comm="ntpd" requested_mask="r" denied_mask="r" fsuid=0 ouid=0'

"systemd[1]: Failed to start NTP Server Daemon."

# ntpq -p
ntpq: read: Connection refused

The following services are enabled.

# apparmor_status
apparmor module is loaded.
39 profiles are loaded.
39 profiles are in enforce mode.
   /sbin/klogd
   /sbin/syslog-ng
   /sbin/syslogd
   /usr/lib/apache2/mpm-prefork/apache2
   /usr/lib/apache2/mpm-prefork/apache2//DEFAULT_URI
   /usr/lib/apache2/mpm-prefork/apache2//HANDLING_UNTRUSTED_INPUT
   /usr/lib/apache2/mpm-prefork/apache2//phpsysinfo
   /usr/lib/dovecot/anvil
   /usr/lib/dovecot/auth
   /usr/lib/dovecot/config
   /usr/lib/dovecot/deliver
   /usr/lib/dovecot/dict
   /usr/lib/dovecot/dovecot-auth
   /usr/lib/dovecot/dovecot-lda
   /usr/lib/dovecot/imap
   /usr/lib/dovecot/imap-login
   /usr/lib/dovecot/lmtp
   /usr/lib/dovecot/log
   /usr/lib/dovecot/managesieve
   /usr/lib/dovecot/managesieve-login
   /usr/lib/dovecot/pop3
   /usr/lib/dovecot/pop3-login
   /usr/lib/dovecot/ssl-params
   /usr/lib64/libvirt/virt-aa-helper
   /usr/sbin/avahi-daemon
   /usr/sbin/dnsmasq
   /usr/sbin/dovecot
   /usr/sbin/identd
   /usr/sbin/libvirtd
   /usr/sbin/mdnsd
   /usr/sbin/nmbd
   /usr/sbin/nscd
   /usr/sbin/ntpd
   /usr/sbin/smbd
   /usr/sbin/smbldap-useradd
   /usr/sbin/smbldap-useradd///etc/init.d/nscd
   /usr/sbin/winbindd
   /usr/{sbin/traceroute,bin/traceroute.db}
   /{usr/,}bin/ping
0 profiles are in complain mode.
3 processes have profiles defined.
3 processes are in enforce mode.
   /usr/sbin/avahi-daemon (892) 
   /usr/sbin/libvirtd (1425) 
   /usr/sbin/nscd (896) 
0 processes are in complain mode.
0 processes are unconfined but have a profile defined.

# systemctl status ntpd
ntpd.service - NTP Server Daemon
   Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled)
   Active: activating (auto-restart) (Result: timeout) since Fri 2014-11-07 09:26:57 MST; 1min 38s ago
     Docs: man:ntpd(1)
  Process: 4584 ExecStart=/usr/sbin/start-ntpd start (code=exited, status=0/SUCCESS)

Nov 07 09:26:57 sles12 systemd[1]: Failed to start NTP Server Daemon.

Rebooting the server seems to start the NTP service daemon just fine, but it terminates after some time attempting to activate the service.

# systemctl status ntpd
ntpd.service - NTP Server Daemon
   Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled)
   Active: activating (start) since Fri 2014-11-07 09:59:14 MST; 45s ago
     Docs: man:ntpd(1)
  Process: 1428 ExecStart=/usr/sbin/start-ntpd start (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/ntpd.service
           └─1444 /usr/sbin/ntpd -p /var/run/ntp/ntpd.pid -g -u ntp:ntp -i /v...

Nov 07 09:59:14 sles12 ntpd[1444]: pid file /var/run/ntp/ntpd.pid: Permission denied
Nov 07 09:59:14 sles12 ntpd[1444]: ntp_io: estimated max descriptors: 102...

Resolution

Update the AppArmor /usr/sbin/ntpd profile with logprof to allow read access to /run/nscd/group and write access to /var/lib/ntp/var/run/ntp/ntpd.pid. Once the AppArmor ntpd policy has been saved, you can restart the NTP service.

Login as root on the command line and run:

# logprof
Reading log entries from /var/log/messages.
Updating AppArmor profiles in /etc/apparmor.d.
Enforce-mode changes:

Profile:  /usr/sbin/ntpd
Path:     /run/nscd/group
Mode:     r
Severity: unknown

 [1 - /run/nscd/group]

(A)llow / [(D)eny] / (G)lob / Glob w/(E)xt / (N)ew / Abo(r)t / (F)inish / (O)pts
Adding /run/nscd/group r to profile.

Profile:  /usr/sbin/ntpd
Path:     /var/lib/ntp/var/run/ntp/ntpd.pid
Mode:     w
Severity: unknown

 [1 - /var/lib/ntp/var/run/ntp/ntpd.pid]

(A)llow / [(D)eny] / (G)lob / Glob w/(E)xt / (N)ew / Abo(r)t / (F)inish / (O)pts
Adding /var/lib/ntp/var/run/ntp/ntpd.pid w to profile.

= Changed Local Profiles =

The following local profiles were changed.  Would you like to save them?

 [1 - /usr/sbin/ntpd]

(S)ave Changes / [(V)iew Changes] / Abo(r)t
Writing updated profile for /usr/sbin/ntpd.

# systemctl restart ntpd.service
# systemctl status ntpd.service

Cause

Apparmor is restricting the NTP service from reading /run/nscd/group and from writing to /var/lib/ntp/var/run/ntp/ntpd.pid.

Additional Information

Problem is fixed since: apparmor-2.8.2-28.2

Disclaimer

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