53 lines
1.3 KiB
Markdown
53 lines
1.3 KiB
Markdown
# Chrony
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Setup alternative ntp that does well with systems that may or may not always be online.
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## Inspiration / Further Reading
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- [https://wiki.archlinux.org/index.php/Chrony](https://wiki.archlinux.org/index.php/Chrony)
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- [https://insights.ubuntu.com/2018/04/09/ubuntu-bionic-using-chrony-to-configure-ntp](https://insights.ubuntu.com/2018/04/09/ubuntu-bionic-using-chrony-to-configure-ntp)
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- [http://manpages.ubuntu.com/manpages/trusty/man5/chrony.conf.5.html](http://manpages.ubuntu.com/manpages/trusty/man5/chrony.conf.5.html)
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## Install
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``` bash
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apt update
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apt install chrony
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systemctl enable chrony # Enable service
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systemctl start chrony # Start service
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chronyc activity # Verify install successful
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systemctl disable ntp.service # Disable std ntpd (replaced by chrony)
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```
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## Configuration
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``` bash
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cat >> /etc/chrony/chrony.conf <<EOF
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allow 172.16.16.0/24
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allow 172.17.17.0/24
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allow 172.18.18.0/24
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allow 172.30.0.0/16
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# Allow large clock adjustments (you want this as there is no RTC on most SBCs)
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makestep 1 -1
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EOF
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```
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Run ```systemctl restart chrony``` to pickup the changes.
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## Allow NTP access via internal/trusted networks
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``` bash
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firewall-cmd --permanent --zone=internal --add-service ntp
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firewall-cmd --permanent --zone=trusted --add-service ntp
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firewall-cmd --reload
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firewall-cmd --info-zone internal
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firewall-cmd --info-zone trusted
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```
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