[Bug 1257082] Re: MAAS does not use NTP servers specified in DHCPD options

Robie Basak 1257082 at bugs.launchpad.net
Mon Dec 16 12:48:53 UTC 2013


Setting to Medium priority as a workaround is available.

Debian is considering making NTP available by default in
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731594.

I'm also concerned that though changing NTPDATE_USE_NTP_CONF to default
to "no" if /etc/ntp.conf doesn't exist seems to be right solution right
now, it may have a negative impact to non-MAAS users, and so this needs
to be considered carefully.

So it seems like we're still figuring out what the right solution should
be. Some discussion in Ubuntu at: https://lists.ubuntu.com/archives
/ubuntu-devel/2013-December/037895.html

Given that there's a workaround, I think we should probably wait to see
what Debian wants to do with ntp by default before we tackle this. If
this takes too long, then I suppose we could patch the behaviour above,
or even send that to Debian.

** Description changed:

+ [Impact]
+ 
+ MAAS-deployed systems *that do not have persistent RTCs* (unusual) have
+ difficulty with time and authentication, generally making these nodes
+ unusable.
+ 
+ [Workaround]
+ 
+ See comment #8.
+ 
+ [Original Description]
+ 
  I have tried setting up NTP servers as DHCP options to MAAS nodes
  because I am behind a proxy here at work that cannot contact
  ntp.ubuntu.com. Here is the top of the dhcpd.conf file on on my MAAS
  head node, maas01:
  
  root at maas01:/etc/dhcp# less dhcpd.conf
  default-lease-time 600;
  max-lease-time 7200;
  
  subnet 192.168.0.0 netmask 255.255.0.0 {
-   option domain-name "mgmt";
-   option domain-name-servers 192.168.255.254;
-   option routers 192.168.255.254;
+   option domain-name "mgmt";
+   option domain-name-servers 192.168.255.254;
+   option routers 192.168.255.254;
  
-   pool {
-     range 192.168.0.1 192.168.255.253;
-     deny unknown-clients;
-   }
+   pool {
+     range 192.168.0.1 192.168.255.253;
+     deny unknown-clients;
+   }
  }
  
  subnet 10.255.0.0 netmask 255.255.0.0 {
-   option domain-name "maas";
-   option domain-name-servers 10.255.0.1;
-   option routers 10.255.0.1;
-   option ntp-servers 172.31.22.1, 172.31.23.1, 172.31.20.104;
-   next-server 10.255.0.1;
+   option domain-name "maas";
+   option domain-name-servers 10.255.0.1;
+   option routers 10.255.0.1;
+   option ntp-servers 172.31.22.1, 172.31.23.1, 172.31.20.104;
+   next-server 10.255.0.1;
  
-   pool {
-     range 10.255.1.0 10.255.255.254;
-     deny unknown-clients;
-   }
+   pool {
+     range 10.255.1.0 10.255.255.254;
+     deny unknown-clients;
+   }
  }
  
  I have also verified the parameter is being sent to a client’s DHCP
  lease:
  
  ubuntu at sled204n0:/var$ cat /var/lib/dhcp/dhclient.eth0.leases
  lease {
-   interface "eth0";
-   fixed-address 10.255.4.44;
-   option subnet-mask 255.255.0.0;
-   option routers 10.255.0.1;
-   option dhcp-lease-time 600;
-   option dhcp-message-type 5;
-   option domain-name-servers 10.255.0.1;
-   option dhcp-server-identifier 10.255.0.1;
-   option ntp-servers 172.31.22.1,172.31.23.1,172.31.20.104;
-   option domain-name "maas";
-   renew 4 2000/01/06 19:40:51;
-   rebind 4 2000/01/06 19:40:51;
-   expire 4 2000/01/06 19:40:51;
+   interface "eth0";
+   fixed-address 10.255.4.44;
+   option subnet-mask 255.255.0.0;
+   option routers 10.255.0.1;
+   option dhcp-lease-time 600;
+   option dhcp-message-type 5;
+   option domain-name-servers 10.255.0.1;
+   option dhcp-server-identifier 10.255.0.1;
+   option ntp-servers 172.31.22.1,172.31.23.1,172.31.20.104;
+   option domain-name "maas";
+   renew 4 2000/01/06 19:40:51;
+   rebind 4 2000/01/06 19:40:51;
+   expire 4 2000/01/06 19:40:51;
  }
  
  Even so, the date on the target node is still incorrect.
  
  ubuntu at sled204n0:/etc$ date
  Thu Jan  6 19:52:29 UTC 2000
  
  The ntpdate defaults are the following (unchanged from MAAS defaults):
  
  ubuntu at sled204n0:/etc$ cat /etc/default/ntpdate
  # The settings in this file are used by the program ntpdate-debian, but not
  # by the upstream program ntpdate.
  
  # Set to "yes" to take the server list from /etc/ntp.conf, from package ntp,
  # so you only have to keep it in one place.
  NTPDATE_USE_NTP_CONF=yes
  
  # List of NTP servers to use  (Separate multiple servers with spaces.)
  # Not used if NTPDATE_USE_NTP_CONF is yes.
  NTPSERVERS="ntp.ubuntu.com"
  
  # Additional options to pass to ntpdate
  NTPOPTIONS=""
  
  And the DHCP generated NTP server file is correct:
  
  ubuntu at sled204n0:/etc$ cat /var/lib/ntpdate/default.dhcp
  # NTP server entries received from DHCP server
  NTPSERVERS='172.31.22.1 172.31.23.1 172.31.20.104'
  
  The culprit seems to be in how ntpdate-debian is programmed. the logic
  ignores /var/lib/ntpdate/default.dhcp if /etc/default/ntpdate sets
  NTPDATE_USE_NTP_CONF=yes (the default).
  
  After examining the script further my recommendation would be for the
  /etc/dhcp/dhclient-exit-hooks.d/ntpdate to create the file
  /var/lib/ntp/ntp.conf.dhcp. By doing so ntpdate-debian will work
  transparently with /etc/defaults/ntpdate and NTP servers advertised by
  DHCPD.
  
- 
  -------------------------------------------------------------------------
  (contents of /var/log/maas/* is 125MB in size, will post data from there if requested)
  
  # dpkg -l '*maas*'|cat
  Desired=Unknown/Install/Remove/Purge/Hold
  | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
  |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
  ||/ Name                               Version                                Architecture Description
  +++-==================================-======================================-============-==========================================================================
  ii  maas                               1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Server
  ii  maas-cli                           1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Client Tool
  ii  maas-cluster-controller            1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Cluster Controller
  ii  maas-common                        1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Server
  un  maas-dhcp                          <none>                                              (no description available)
  un  maas-dns                           <none>                                              (no description available)
  ii  maas-region-controller             1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Server
  ii  python-django-maas                 1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Server - (django files)
  ii  python-maas-client                 1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS API Client - (python files)
  ii  python-maas-provisioningserver     1.3+bzr1461+dfsg-0ubuntu2.2+tay.8      all          Ubuntu MAAS Server

** Bug watch added: Debian Bug tracker #731594
   http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731594

** Changed in: ntp (Ubuntu)
   Importance: High => Medium

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https://bugs.launchpad.net/bugs/1257082

Title:
  MAAS does not use NTP servers specified in DHCPD options

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