timemaster.8 - pub/scm/linux/kernel/git/bigeasy/linuxptp-hsr - Git at Google

 .TH TIMEMASTER 8 "January 2021" "linuxptp"
 .SH NAME

 timemaster - run NTP with PTP as reference clocks

 .SH SYNOPSIS

 .B timemaster
 [
 .B \-nmqv
 ] [
 .BI \-l " print-level"
 ]
 .BI \-f " file"

 .SH DESCRIPTION
 \fBtimemaster\fR is a program that uses \fBptp4l\fR and \fBphc2sys\fR in
 combination with \fBchronyd\fR or \fBntpd\fR to synchronize the system clock to
 NTP and PTP time sources. The PTP time is provided by \fBphc2sys\fR and
 \fBptp4l\fR via SOCK reference clock to \fBchronyd\fR or SHM reference clock to
 \fBntpd\fR, which can compare all time sources and use the best sources to
 synchronize the system clock.

 On start, \fBtimemaster\fR reads a configuration file that specifies the NTP
 and PTP time sources, checks which network interfaces have and share a PTP
 hardware clock (PHC), generates configuration files for \fBptp4l\fR and
 \fBchronyd\fR/\fBntpd\fR, and start the \fBptp4l\fR, \fBphc2sys\fR,
 \fBchronyd\fR/\fBntpd\fR processes as needed. Then, it waits for a signal to
 kill the processes, remove the generated configuration files and exit.

 .SH OPTIONS

 .TP
 .BI \-f " file"
 Specify the path to the \fBtimemaster\fR configuration file.
 .TP
 .BI \-n
 Don't start the programs, only print their configuration files and the commands
 that would be executed if this option wasn't specified.
 .TP
 .BI \-l " level"
 Set the maximum syslog level of messages which should be printed or sent to
 the system logger. The default value is 6 (LOG_INFO).
 .TP
 .B \-m
 Print messages to the standard output.
 .TP
 .B \-q
 Don't send messages to the system logger.
 .TP
 .B \-v
 Print the software version and exit.
 .TP
 .BI \-h
 Display a help message and exit.

 .SH CONFIGURATION FILE

 The configuration file is divided into sections. Each section starts with a
 line containing its name enclosed in brackets and it follows with settings.
 Each setting is placed on a separate line, it contains the name of the
 option and the value separated by whitespace characters. Empty lines and lines
 starting with # are ignored.

 Sections that can used in the configuration file and options that can be set in
 them are described below.

 .SS [timemaster]

 .TP
 .B ntp_program
 Select which NTP implementation should be used. Possible values are
 \fBchronyd\fR and \fBntpd\fR. The default value is \fBchronyd\fR. Limitations
 of the implementations relevant to the timemaster configuration are listed in
 \fBNOTES\fR.

 .TP
 .B rundir
 Specify the directory where should be generated \fBchronyd\fR, \fBntpd\fR and
 \fBptp4l\fR configuration files and sockets. The directory will be created if
 it doesn't exist. The default value is \fB/var/run/timemaster\fR.

 .TP
 .B first_shm_segment
 Specify the first number in a sequence of SHM segments that will be used by
 \fBptp4l\fR and \fBphc2sys\fR. The default value is 0. Increasing the number
 can be useful to avoid conflicts with time sources that are not started by
 \fBtimemaster\fR, e.g. \fBgpsd\fR using segments number 0 and 1.

 .TP
 .B restart_processes
 Enable or disable restarting of processes started by \fBtimemaster\fR. If the
 option is set to a non-zero value, all processes except \fBchronyd\fR and
 \fBntpd\fR will be automatically restarted when terminated and \fBtimemaster\fR
 is running for at least one second (i.e. the process did not terminate due to a
 configuration error). If a process was terminated and is not started again,
 \fBtimemaster\fR will kill the other processes and exit with a non-zero status.
 The default value is 1 (enabled).

 .TP
 .B use_vclocks
 Enable or disable synchronization with virtual clocks. If enabled,
 \fBtimemaster\fR will create virtual clocks running on top of physical clocks
 needed by configured PTP domains. This enables hardware time stamping for
 multiple \fBptp4l\fR instances using the same network interface. The default
 value is -1, which enables the virtual clocks if running on Linux 5.18 or
 later.

 .SS [ntp_server address]

 The \fBntp_server\fR section specifies an NTP server that should be used as a
 time source. The address of the server is included in the name of the section.

 .TP
 .B minpoll
 .TQ
 .B maxpoll
 Specify the minimum and maximum NTP polling interval as powers of two in
 seconds. The default values are 6 (64 seconds) and 10 (1024 seconds)
 respectively. Shorter polling intervals usually improve the accuracy
 significantly, but they should be used only when allowed by the operators of
 the NTP service (public NTP servers generally don't allow too frequent
 queries). If the NTP server is located on the same LAN, polling intervals
 around 4 (16 seconds) might give best accuracy.

 .TP
 .B iburst
 Enable or disable sending a burst of NTP packets on start to speed up the
 initial synchronization. Possible values are 1 and 0. The default value is 0
 (disabled).

 .TP
 .B ntp_options
 Specify extra options that should be added for this source to the \fBserver\fR
 directive in the configuration file of the selected NTP implementation. No
 extra options are added by default.

 .SS [ptp_domain number]

 The \fBptp_domain\fR section specifies a PTP domain that should be used as a
 time source. The PTP domain number is included in the name of the section. The
 \fBptp4l\fR instances are configured to run in the \fBclientOnly\fR mode. In
 this section at least the \fBinterfaces\fR option needs to be set, other
 options are optional.

 .TP
 .B interfaces
 Specify which network interfaces should be used for this PTP domain. A separate
 \fBptp4l\fR instance will be started for each group of interfaces sharing the
 same PHC and for each interface that supports only SW time stamping. HW time
 stamping is enabled automatically. If an interface with HW time stamping is
 specified also in other PTP domains and virtual clocks are disabled, only the
 \fBptp4l\fR instance from the first PTP domain will be using HW time stamping.

 .TP
 .B ntp_poll
 Specify the polling interval of the SOCK/SHM reference clock reading samples
 from \fBptp4l\fR or \fBphc2sys\fR. It's specified as a power of two in seconds.
 The default value is 2 (4 seconds).

 .TP
 .B phc2sys_poll
 Specify the polling interval used by \fBphc2sys\fR to read a PTP clock
 synchronized by \fBptp4l\fR and update the SOCK/SHM sample for
 \fBchronyd\fR/\fBntpd\fR. It's specified as a power of two in seconds. The
 default value is 0 (1 second).

 .TP
 .B delay
 Specify the maximum assumed roundtrip delay to the primary source of the time
 in this PTP domain. This value is included in the distance used by
 \fBchronyd\fR in the source selection algorithm to detect falsetickers and
 assign weights for source combining. The default value is 1e\-4 (100
 microseconds). With \fBntpd\fR, the \fBtos mindist\fR command can be used to
 set a limit with similar purpose globally for all time sources.

 .TP
 .B ntp_options
 Specify extra options that should be added for this source to the
 \fBrefclock\fR or \fBserver\fR directives in the configuration file of the
 selected NTP implementation. No extra options are added by default.

 .TP
 .B ptp4l_option
 Specify an extra \fBptp4l\fR option specific to this PTP domain that should be
 added to the configuration files generated for \fBptp4l\fR. This option may be
 used multiple times in one \fBptp_domain\fR section.

 .SS [chronyd]

 .TP
 .B path
 Specify the path to the \fBchronyd\fR binary. The default value is
 \fBchronyd\fR to search for the binary in \fBPATH\fR.

 .TP
 .B options
 Specify extra options that should be added to the \fBchronyd\fR command line.
 No extra options are added by default.

 .SS [chrony.conf]

 Settings specified in this section are copied directly to the configuration
 file generated for \fBchronyd\fR. If this section is not present in the
 \fBtimemaster\fR configuration file, the following setting will be added:

 .EX
 makestep 1 3
 .EE

 This configures \fBchronyd\fR to step the system clock in the first three
 updates if the offset is larger than 1 second.

 .SS [ntpd]

 .TP
 .B path
 Specify the path to the \fBntpd\fR binary. The default value is \fBntpd\fR to
 search for the binary in \fBPATH\fR.

 .TP
 .B options
 Specify extra options that should be added to the \fBntpd\fR command line. No
 extra options are added by default.

 .SS [ntp.conf]

 Settings specified in this section are copied directly to the configuration
 file generated for \fBntpd\fR. If this section is not present in the
 \fBtimemaster\fR configuration file, the following settings will be added:

 .EX
 restrict default nomodify notrap nopeer noquery
 restrict 127.0.0.1
 restrict ::1
 .EE

 This configures \fBntpd\fR to use safe default restrictions.

 .SS [phc2sys]

 .TP
 .B path
 Specify the path to the \fBphc2sys\fR binary. The default value is
 \fBphc2sys\fR to search for the binary in \fBPATH\fR.

 .TP
 .B options
 Specify extra options that should be added to all \fBphc2sys\fR command lines.
 By default, \fB\-l 5\fR is added to the command lines.

 .SS [ptp4l]

 .TP
 .B path
 Specify the path to the \fBptp4l\fR binary. The default value is \fBptp4l\fR to
 search for the binary in \fBPATH\fR.

 .TP
 .B options
 Specify extra options that should be added to all \fBptp4l\fR command lines. By
 default, \fB\-l 5\fR is added to the command lines.

 .SS [ptp4l.conf]
 Settings specified in this section are copied directly to the global section of
 the configuration files generated for all \fBptp4l\fR instances. There is no
 default content of this section.

 Other sections (e.g. \fB[unicast_master_table]\fR) may be specified here, but
 lines beginning with the bracket need to be prefixed with the \fB>\fR character
 to prevent \fBtimemaster\fR from parsing it as a beginning of another section.

 .SH NOTES
 For best accuracy, \fBchronyd\fR is usually preferred over \fBntpd\fR, it also
 synchronizes the system clock faster. Both NTP implementations, however, have
 some limitations that need to be considered before choosing the one to be used
 in a given \fBtimemaster\fR configuration.

 The \fBchronyd\fR limitations are:

 .RS
 In version 1.31 and older, the maximum number of reference clocks used at the
 same time is 8. This limits the number of PHCs and interfaces using SW time
 stamping that can be used for PTP.

 Using polling intervals (\fBminpoll\fR, \fBmaxpoll\fR, \fBntp_poll\fR options)
 shorter than 2 (4 seconds) is not recommended with versions before 1.30. With
 1.30 and later values of 0 or 1 can be used for NTP sources and negative values
 for PTP sources (\fBntp_poll\fR) to specify a subsecond interval.
 .RE

 The \fBntpd\fR limitations are:

 .RS
 In versions before 4.2.8p1, only the first two shared-memory segments created by
 the \fBntpd\fR SHM refclock driver have owner-only access. Other segments
 are created with world access, which allows any user on the system to write to
 the segments and disrupt or take control over the synchronization of the clock.
 In 4.2.8p1 the access was made configurable with the mode option, which is set
 by \fBtimemaster\fR for owner-ownly access.

 The shortest polling interval for all sources is 3 (8 seconds).

 Nanosecond resolution in the SHM refclock driver is supported in version
 4.2.7p303 and later, older versions have only microsecond resolution.
 .RE

 .SH EXAMPLES

 A minimal configuration file using one NTP source and two PTP sources would be:

 .EX
 [ntp_server 10.1.1.1]

 [ptp_domain 0]
 interfaces eth0

 [ptp_domain 1]
 interfaces eth1
 .EE

 A more complex example using all \fBtimemaster\fR options would be:

 .EX
 [ntp_server 10.1.1.1]
 minpoll 3
 maxpoll 4
 iburst 1
 ntp_options key 12

 [ptp_domain 0]
 interfaces eth0 eth1
 ntp_poll 0
 phc2sys_poll \-2
 delay 10e\-6
 ntp_options prefer
 ptp4l_option clock_servo linreg
 ptp4l_option delay_mechanism P2P

 [timemaster]
 ntp_program chronyd
 rundir /var/run/timemaster
 first_shm_segment 1
 restart_processes 0
 use_vclocks 0

 [chronyd]
 path /usr/sbin/chronyd
 options

 [chrony.conf]
 makestep 1 3
 logchange 0.5
 rtcsync
 driftfile /var/lib/chrony/drift

 [ntpd]
 path /usr/sbin/ntpd
 options \-u ntp:ntp

 [ntp.conf]
 restrict default nomodify notrap nopeer noquery
 restrict 127.0.0.1
 restrict ::1
 driftfile /var/lib/ntp/drift

 [phc2sys]
 path /usr/sbin/phc2sys
 options \-l 5

 [ptp4l]
 path /usr/sbin/ptp4l
 options

 [ptp4l.conf]
 logging_level 5
 .EE

 .SH SEE ALSO

 .BR chronyd (8),
 .BR ntpd (8),
 .BR phc2sys (8),
 .BR ptp4l (8)
	.TH TIMEMASTER 8 "January 2021" "linuxptp"
	.SH NAME

	timemaster - run NTP with PTP as reference clocks

	.SH SYNOPSIS

	.B timemaster
	[
	.B \-nmqv
	] [
	.BI \-l " print-level"
	]
	.BI \-f " file"

	.SH DESCRIPTION
	\fBtimemaster\fR is a program that uses \fBptp4l\fR and \fBphc2sys\fR in
	combination with \fBchronyd\fR or \fBntpd\fR to synchronize the system clock to
	NTP and PTP time sources. The PTP time is provided by \fBphc2sys\fR and
	\fBptp4l\fR via SOCK reference clock to \fBchronyd\fR or SHM reference clock to
	\fBntpd\fR, which can compare all time sources and use the best sources to
	synchronize the system clock.

	On start, \fBtimemaster\fR reads a configuration file that specifies the NTP
	and PTP time sources, checks which network interfaces have and share a PTP
	hardware clock (PHC), generates configuration files for \fBptp4l\fR and
	\fBchronyd\fR/\fBntpd\fR, and start the \fBptp4l\fR, \fBphc2sys\fR,
	\fBchronyd\fR/\fBntpd\fR processes as needed. Then, it waits for a signal to
	kill the processes, remove the generated configuration files and exit.

	.SH OPTIONS

	.TP
	.BI \-f " file"
	Specify the path to the \fBtimemaster\fR configuration file.
	.TP
	.BI \-n
	Don't start the programs, only print their configuration files and the commands
	that would be executed if this option wasn't specified.
	.TP
	.BI \-l " level"
	Set the maximum syslog level of messages which should be printed or sent to
	the system logger. The default value is 6 (LOG_INFO).
	.TP
	.B \-m
	Print messages to the standard output.
	.TP
	.B \-q
	Don't send messages to the system logger.
	.TP
	.B \-v
	Print the software version and exit.
	.TP
	.BI \-h
	Display a help message and exit.

	.SH CONFIGURATION FILE

	The configuration file is divided into sections. Each section starts with a
	line containing its name enclosed in brackets and it follows with settings.
	Each setting is placed on a separate line, it contains the name of the
	option and the value separated by whitespace characters. Empty lines and lines
	starting with # are ignored.

	Sections that can used in the configuration file and options that can be set in
	them are described below.

	.SS [timemaster]

	.TP
	.B ntp_program
	Select which NTP implementation should be used. Possible values are
	\fBchronyd\fR and \fBntpd\fR. The default value is \fBchronyd\fR. Limitations
	of the implementations relevant to the timemaster configuration are listed in
	\fBNOTES\fR.

	.TP
	.B rundir
	Specify the directory where should be generated \fBchronyd\fR, \fBntpd\fR and
	\fBptp4l\fR configuration files and sockets. The directory will be created if
	it doesn't exist. The default value is \fB/var/run/timemaster\fR.

	.TP
	.B first_shm_segment
	Specify the first number in a sequence of SHM segments that will be used by
	\fBptp4l\fR and \fBphc2sys\fR. The default value is 0. Increasing the number
	can be useful to avoid conflicts with time sources that are not started by
	\fBtimemaster\fR, e.g. \fBgpsd\fR using segments number 0 and 1.

	.TP
	.B restart_processes
	Enable or disable restarting of processes started by \fBtimemaster\fR. If the
	option is set to a non-zero value, all processes except \fBchronyd\fR and
	\fBntpd\fR will be automatically restarted when terminated and \fBtimemaster\fR
	is running for at least one second (i.e. the process did not terminate due to a
	configuration error). If a process was terminated and is not started again,
	\fBtimemaster\fR will kill the other processes and exit with a non-zero status.
	The default value is 1 (enabled).

	.TP
	.B use_vclocks
	Enable or disable synchronization with virtual clocks. If enabled,
	\fBtimemaster\fR will create virtual clocks running on top of physical clocks
	needed by configured PTP domains. This enables hardware time stamping for
	multiple \fBptp4l\fR instances using the same network interface. The default
	value is -1, which enables the virtual clocks if running on Linux 5.18 or
	later.

	.SS [ntp_server address]

	The \fBntp_server\fR section specifies an NTP server that should be used as a
	time source. The address of the server is included in the name of the section.

	.TP
	.B minpoll
	.TQ
	.B maxpoll
	Specify the minimum and maximum NTP polling interval as powers of two in
	seconds. The default values are 6 (64 seconds) and 10 (1024 seconds)
	respectively. Shorter polling intervals usually improve the accuracy
	significantly, but they should be used only when allowed by the operators of
	the NTP service (public NTP servers generally don't allow too frequent
	queries). If the NTP server is located on the same LAN, polling intervals
	around 4 (16 seconds) might give best accuracy.

	.TP
	.B iburst
	Enable or disable sending a burst of NTP packets on start to speed up the
	initial synchronization. Possible values are 1 and 0. The default value is 0
	(disabled).

	.TP
	.B ntp_options
	Specify extra options that should be added for this source to the \fBserver\fR
	directive in the configuration file of the selected NTP implementation. No
	extra options are added by default.

	.SS [ptp_domain number]

	The \fBptp_domain\fR section specifies a PTP domain that should be used as a
	time source. The PTP domain number is included in the name of the section. The
	\fBptp4l\fR instances are configured to run in the \fBclientOnly\fR mode. In
	this section at least the \fBinterfaces\fR option needs to be set, other
	options are optional.

	.TP
	.B interfaces
	Specify which network interfaces should be used for this PTP domain. A separate
	\fBptp4l\fR instance will be started for each group of interfaces sharing the
	same PHC and for each interface that supports only SW time stamping. HW time
	stamping is enabled automatically. If an interface with HW time stamping is
	specified also in other PTP domains and virtual clocks are disabled, only the
	\fBptp4l\fR instance from the first PTP domain will be using HW time stamping.

	.TP
	.B ntp_poll
	Specify the polling interval of the SOCK/SHM reference clock reading samples
	from \fBptp4l\fR or \fBphc2sys\fR. It's specified as a power of two in seconds.
	The default value is 2 (4 seconds).

	.TP
	.B phc2sys_poll
	Specify the polling interval used by \fBphc2sys\fR to read a PTP clock
	synchronized by \fBptp4l\fR and update the SOCK/SHM sample for
	\fBchronyd\fR/\fBntpd\fR. It's specified as a power of two in seconds. The
	default value is 0 (1 second).

	.TP
	.B delay
	Specify the maximum assumed roundtrip delay to the primary source of the time
	in this PTP domain. This value is included in the distance used by
	\fBchronyd\fR in the source selection algorithm to detect falsetickers and
	assign weights for source combining. The default value is 1e\-4 (100
	microseconds). With \fBntpd\fR, the \fBtos mindist\fR command can be used to
	set a limit with similar purpose globally for all time sources.

	.TP
	.B ntp_options
	Specify extra options that should be added for this source to the
	\fBrefclock\fR or \fBserver\fR directives in the configuration file of the
	selected NTP implementation. No extra options are added by default.

	.TP
	.B ptp4l_option
	Specify an extra \fBptp4l\fR option specific to this PTP domain that should be
	added to the configuration files generated for \fBptp4l\fR. This option may be
	used multiple times in one \fBptp_domain\fR section.

	.SS [chronyd]

	.TP
	.B path
	Specify the path to the \fBchronyd\fR binary. The default value is
	\fBchronyd\fR to search for the binary in \fBPATH\fR.

	.TP
	.B options
	Specify extra options that should be added to the \fBchronyd\fR command line.
	No extra options are added by default.

	.SS [chrony.conf]

	Settings specified in this section are copied directly to the configuration
	file generated for \fBchronyd\fR. If this section is not present in the
	\fBtimemaster\fR configuration file, the following setting will be added:

	.EX
	makestep 1 3
	.EE

	This configures \fBchronyd\fR to step the system clock in the first three
	updates if the offset is larger than 1 second.

	.SS [ntpd]

	.TP
	.B path
	Specify the path to the \fBntpd\fR binary. The default value is \fBntpd\fR to
	search for the binary in \fBPATH\fR.

	.TP
	.B options
	Specify extra options that should be added to the \fBntpd\fR command line. No
	extra options are added by default.

	.SS [ntp.conf]

	Settings specified in this section are copied directly to the configuration
	file generated for \fBntpd\fR. If this section is not present in the
	\fBtimemaster\fR configuration file, the following settings will be added:

	.EX
	restrict default nomodify notrap nopeer noquery
	restrict 127.0.0.1
	restrict ::1
	.EE

	This configures \fBntpd\fR to use safe default restrictions.

	.SS [phc2sys]

	.TP
	.B path
	Specify the path to the \fBphc2sys\fR binary. The default value is
	\fBphc2sys\fR to search for the binary in \fBPATH\fR.

	.TP
	.B options
	Specify extra options that should be added to all \fBphc2sys\fR command lines.
	By default, \fB\-l 5\fR is added to the command lines.

	.SS [ptp4l]

	.TP
	.B path
	Specify the path to the \fBptp4l\fR binary. The default value is \fBptp4l\fR to
	search for the binary in \fBPATH\fR.

	.TP
	.B options
	Specify extra options that should be added to all \fBptp4l\fR command lines. By
	default, \fB\-l 5\fR is added to the command lines.

	.SS [ptp4l.conf]
	Settings specified in this section are copied directly to the global section of
	the configuration files generated for all \fBptp4l\fR instances. There is no
	default content of this section.

	Other sections (e.g. \fB[unicast_master_table]\fR) may be specified here, but
	lines beginning with the bracket need to be prefixed with the \fB>\fR character
	to prevent \fBtimemaster\fR from parsing it as a beginning of another section.

	.SH NOTES
	For best accuracy, \fBchronyd\fR is usually preferred over \fBntpd\fR, it also
	synchronizes the system clock faster. Both NTP implementations, however, have
	some limitations that need to be considered before choosing the one to be used
	in a given \fBtimemaster\fR configuration.

	The \fBchronyd\fR limitations are:

	.RS
	In version 1.31 and older, the maximum number of reference clocks used at the
	same time is 8. This limits the number of PHCs and interfaces using SW time
	stamping that can be used for PTP.

	Using polling intervals (\fBminpoll\fR, \fBmaxpoll\fR, \fBntp_poll\fR options)
	shorter than 2 (4 seconds) is not recommended with versions before 1.30. With
	1.30 and later values of 0 or 1 can be used for NTP sources and negative values
	for PTP sources (\fBntp_poll\fR) to specify a subsecond interval.
	.RE

	The \fBntpd\fR limitations are:

	.RS
	In versions before 4.2.8p1, only the first two shared-memory segments created by
	the \fBntpd\fR SHM refclock driver have owner-only access. Other segments
	are created with world access, which allows any user on the system to write to
	the segments and disrupt or take control over the synchronization of the clock.
	In 4.2.8p1 the access was made configurable with the mode option, which is set
	by \fBtimemaster\fR for owner-ownly access.

	The shortest polling interval for all sources is 3 (8 seconds).

	Nanosecond resolution in the SHM refclock driver is supported in version
	4.2.7p303 and later, older versions have only microsecond resolution.
	.RE

	.SH EXAMPLES

	A minimal configuration file using one NTP source and two PTP sources would be:

	.EX
	[ntp_server 10.1.1.1]

	[ptp_domain 0]
	interfaces eth0

	[ptp_domain 1]
	interfaces eth1
	.EE

	A more complex example using all \fBtimemaster\fR options would be:

	.EX
	[ntp_server 10.1.1.1]
	minpoll 3
	maxpoll 4
	iburst 1
	ntp_options key 12

	[ptp_domain 0]
	interfaces eth0 eth1
	ntp_poll 0
	phc2sys_poll \-2
	delay 10e\-6
	ntp_options prefer
	ptp4l_option clock_servo linreg
	ptp4l_option delay_mechanism P2P

	[timemaster]
	ntp_program chronyd
	rundir /var/run/timemaster
	first_shm_segment 1
	restart_processes 0
	use_vclocks 0

	[chronyd]
	path /usr/sbin/chronyd
	options

	[chrony.conf]
	makestep 1 3
	logchange 0.5
	rtcsync
	driftfile /var/lib/chrony/drift

	[ntpd]
	path /usr/sbin/ntpd
	options \-u ntp:ntp

	[ntp.conf]
	restrict default nomodify notrap nopeer noquery
	restrict 127.0.0.1
	restrict ::1
	driftfile /var/lib/ntp/drift

	[phc2sys]
	path /usr/sbin/phc2sys
	options \-l 5

	[ptp4l]
	path /usr/sbin/ptp4l
	options

	[ptp4l.conf]
	logging_level 5
	.EE

	.SH SEE ALSO

	.BR chronyd (8),
	.BR ntpd (8),
	.BR phc2sys (8),
	.BR ptp4l (8)