Enable the Stratum (1) GNSS time server.
Type: boolean
Default:
true
Declared by:
In some cases a GNSS device can be deactived only to return a few seconds later (with some modules more than others). However, by this time gpsd has often already removed the device and because gpsd drops root priviliges after initialization it is unable to re-initialize the device.
The proper solution would be to fix the issue of why your GPS module resets (faulty cabling, faulty module, another device using the same GPIO pins, etc).
See this gpsd issue for more details.
This option will enable a watchdog that will monitor chrony & gpsd and restart gpsd when it detects that gpsd hasn’t been forwarding the NMEA and PPS signals for a while.
Type: boolean
Default:
true
Declared by:
Most GNSS devices will transmit data on the serial port before being talked to, making u-boot and the bootloader think the user pressed a keyboard button to interrupt autoboot.
Because we’d like our device to boot without interaction we force the bootloader to not prompt the user. Because we override a generated config file, we take care to “fix” this everytime this file gets overwritten.
Ideally we would fix this properly, so we can rely on the bootloader for fault-recovery.
Type: boolean
Default:
true
Declared by:
The NTP Reference ID (refid) of another reference clock to lock the PPS clock to.
Because the PPS device only tells us the (quite exact) edge of a second but not what second that is, we need another clock source to be able to actually tell the time of day.
This option allows us to “lock” the PPS signal to another refclock, adding the precision of the PPS signal to the more complete but (presumably) less accurate other refclock.
Type: string
Default:
"NMEA"
Declared by:
Path to the GNSS PPS device
Note that some GNSS receivers will only initialize the PPS device after being talked to by gpsd.
Type: string
Default:
"/dev/pps0"
Declared by:
The NTP Reference ID (refid) for the PPS clock.
In the NTP response message this is a field that in the case of a stratum 1 server (like us) indicates what their stratum 0 clock is. There is an authoritative list of Reference Identifiers maintained by IANA, see here for an overview.
If you’ve configured your GNSS receiver to only use a particular constellation, other values of interest might be GOES, GPS or GAL. The default value of PPS indicates a generic pulse-per-second refclock.
Type: unspecified value
Default:
"PPS"
Declared by:
The known constant offset of this device (not including the PPS signal)
After monitoring your situation for a bit you’ll probably notice the serial-connected device as a somewhat-constant offset from the PPS signal, which you can configure here for extra clean output.
Type: null or string
Default:
null
Example:
"0.120"
Declared by:
Path to the GNSS/GPS UART/serial device
Type: string
Default:
"/dev/ttyS1"
Declared by:
The NTP Reference ID (refid) for this device
In the NTP message the server returns to the client, this is a field that can be used by stratum 1 servers (like us) to indicate what their stratum 0 clock is. There is an authoritative list of Reference Identifiers maintained by IANA, see here for an overview.
In addition to enabling clients to tell the source of their time, the refid can also be used to lock a PPS reference clock to another clock.
This is the refid for the UART device which we will actually not broadcast to clients, so it doesn’t matter that much what you set this to. Do keep in mind restrictions apply (e.g. only ascii, max 4 chars).
Type: string
Default:
"NMEA"
Declared by:
Whether to enable I2C Real Time Clock support.
Type: boolean
Default:
false
Example:
true
Declared by:
The I²C address of the RTC
Detect with i2cdetect <bus>
Type: string
Default:
"0x68"
Declared by:
The I²C bus the RTC is connected to.
Type: positive integer, meaning >0
Default:
3
Declared by:
RTC model
This will be passed to the kernel driver. If your model isn’t directly known by the kernel, you might get lucky using the “ds1307” model string as fallback.
Type: string
Default:
"ds3231"
Example:
"ds1307"
Declared by:
Enable the (chrony) NTP Server
Type: boolean
Default:
true
Declared by:
The IPv6 Ranges that will be allowed to query our NTP server.
This will open the firewall and configure the ACL’s in chrony.
Type: unspecified value
Default:
[
{
address = "fe80::";
prefixLength = 10;
}
]
Example:
[
{
address = "fe80::";
prefixLength = 10;
}
{
address = "2001:db8::";
prefixLength = 32;
}
]
Declared by:
Enable redirects for web requests to *.ntppool.org to www.nttppool.org
This is requested on https://www\.ntppool\.org/en/join\.html because people sometimes don’t type the ‘www.’, causing them to end up on some ntp servers like, perhaps, yours. This will help them be where they want to be :)
This is enabled by default when ACME is enabled because that means we’ll have a public webserver anyway (to solve the ACME challenge); might as well be the best NTP-guardian we can be and redirect these requests as requested.
Type: boolean
Default:
true
Declared by:
Whether to enable NTS (authenticated NTP) support.
Type: boolean
Default:
false
Example:
true
Declared by:
Enable ACME integration
This will enable a nginx server on port 80 to solve the ACME challenges and sync the key & certificate with chrony.
This requires your fqdn to be resolvable by the ACME servers and if you’re behind a NAT perhaps additionally port-forwarding.
Type: boolean
Default:
true
Declared by:
E-mail to use for the NTS ACME certificates
Type: unspecified value
Default:
"[email protected]"
Example:
"[email protected]"
Declared by:
The FQDN that will be used for the NTS certificates
Type: string
Default:
"strings.concatStrings [ config.networking.hostName \".\" config.networking.domain ]"
Example:
"time.example.com"
Declared by:
Certificate to use for the NTS KE
Type: string
Default:
"config.services.chrony.directory + \"/fullchain.pem\""
Example:
"/var/lib/chrony/fullchain.pem"
Declared by:
Key to use for the NTS KE
Type: unspecified value
Default:
"config.services.chrony.directory + \"/key.pem\""
Example:
"/var/lib/chrony/key.pem"
Declared by:
List of NTP servers to use for monitoring.
These servers are strictly optional and not used by chrony to adjust
the clock. Instead they can be monitored (e.g. with chronyc sources)
to get a sense of our time compared to the community.
Type: unspecified value
Default:
[
"0.nixos.pool.ntp.org"
"1.nixos.pool.ntp.org"
"2.nixos.pool.ntp.org"
"3.nixos.pool.ntp.org"
"4.nixos.pool.ntp.org"
]
Declared by: