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Keeping time is important. Especially when debugging an issue between servers. It is a pain comparing logfiles with a time skew. For that reason we will configure two NTP servers that all clients will synchronize their clock to. | Keeping time is important. Especially when debugging an issue between servers. It is a pain comparing logfiles with a time skew. For that reason we will configure two NTP servers that all clients will synchronize their time to. |
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== Network == The NTP servers will have fixed IP-addresses. That is configured in the DHCP servers list of statically assigned IP-adresses by using the Domains MAC address. * 192.168.1.38 ntp01 * 192.168.1.39 ntp02 |
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=== Set the Time === {{{ apt-get install ntpdate ntpdate pool.ntp.org hwclock --systohc }}} === DHCP === Jan 30 22:02:30 haproxy01 ntpd[759]: receive: KoD packet from 192.168.1.40 has inconsistent xmt/org/rec timestamps. Ignoring. Jan 30 07:03:09 ntp02 ntpd[511]: receive: KoD packet from 192.168.1.40 has inconsistent xmt/org/rec timestamps. Ignoring. While getting its IP-address via DHCP, the system will also ask the DHCP-server for any available NTP-servers. This causes the NTP server to synchronize time against itself, which again causes it to loose track of time. The solution is to tell its DHCP-client to not request the NTP informatino from the DHCP-server. Make the following changes in `/etc/dhcp/dhclient.conf` #rfc3442-classless-static-routes, ntp-servers; # Begin added by Kallenberg rfc3442-classless-static-routes; # End added by Kallenberg As we are getting the NTP server via DHCP. This will create a loop, where the NTP server synchronises its time from itself. The solution is to remove the NTP part from the DHCP client configuration. === Install the NTP Daemon === {{{ apt-get install ntp }}} |
NTP
Keeping time is important. Especially when debugging an issue between servers. It is a pain comparing logfiles with a time skew. For that reason we will configure two NTP servers that all clients will synchronize their time to.
Configuring a redundant NTP server does not really make any sense. The DHCP server sends option ntp-servers to the DHCP clients, so if one NTP server is down, then the other will get the request instead.
Network
The NTP servers will have fixed IP-addresses. That is configured in the DHCP servers list of statically assigned IP-adresses by using the Domains MAC address.
- 192.168.1.38 ntp01
- 192.168.1.39 ntp02
Software
Set the Time
apt-get install ntpdate ntpdate pool.ntp.org hwclock --systohc
DHCP
Jan 30 22:02:30 haproxy01 ntpd[759]: receive: KoD packet from 192.168.1.40 has inconsistent xmt/org/rec timestamps. Ignoring.
Jan 30 07:03:09 ntp02 ntpd[511]: receive: KoD packet from 192.168.1.40 has inconsistent xmt/org/rec timestamps. Ignoring.
While getting its IP-address via DHCP, the system will also ask the DHCP-server for any available NTP-servers. This causes the NTP server to synchronize time against itself, which again causes it to loose track of time. The solution is to tell its DHCP-client to not request the NTP informatino from the DHCP-server.
Make the following changes in /etc/dhcp/dhclient.conf
- #rfc3442-classless-static-routes, ntp-servers; # Begin added by Kallenberg rfc3442-classless-static-routes; # End added by Kallenberg
As we are getting the NTP server via DHCP. This will create a loop, where the NTP server synchronises its time from itself. The solution is to remove the NTP part from the DHCP client configuration.
Install the NTP Daemon
apt-get install ntp