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--- docker_notes:ntp [2025-11-09 Sun wk45 19:47] – [ntp servers] baumkp
+++ docker_notes:ntp [2025-11-14 Fri wk46 22:12] (current) – [chronyc] baumkp
@@ Line 11: / Line 11: @@
 ntp servers can be checked using the ''ntpdate'' command, which can be loaded in Debian with ''sudo apt install ntpsec-ntpdate''
-Ranked by testing with ''sudo ntpdate -q {ntp servername/ip}''
 ++++List of local ntp servers|
+Ranked by testing with ''sudo ntpdate -q {ntp servername/ip}''
 ^ sync ^ accuracy ^ server ^ ip address ^ stratum ^ leap status ^
 | +0.018040 | +/- 0.026068 | nets.org.sg | 129.126.239.115 | s1 | no-leap |
@@ Line 37: / Line 37: @@
 ++++
+=====chronyc=====
+chronyc can be used to query chronyd.  The following are some key queries.  Note chrony help will provide a list of available commands.
+  *''sources -v'' will list information about the current sources
+  *''tracking'' Display system time information
+  *''nptdata'' display information about last valid measurement
+  *''activity'' check how many NTP sources are online/offline
+  *''serverstats'' Display statistics of the server
+  *''authdata -v'' Display information about authentication
+++++/etc/chrony/chrony.conf|
+<code># default config
+=====docker chrony=====
+++++Dockerfile|
+<code>FROM alpine:latest
+RUN apk update && \
+apk --no-cache add \
+chrony
+EXPOSE 123/udp
+#ENTRYPOINT [ "/bin/sh" ]
+ENTRYPOINT [ "/usr/sbin/chronyd", "-d" ]
+#ENTRYPOINT [ "/usr/sbin/chronyd", "-d", "-s" ]
+</code>
+++++
+++++docker-compose.yml|
+<code>---
+services:
+  chrony:
+    build: ./
+    image: chrony:latest
+    tty: true
+    stdin_open: true
+    container_name: chrony
+    restart: 'always' # always | unless-stopped | no | on-failure [:max-retries]
+#    volumes:
+#      - '/mnt/docker_store/kea/.config:/app/'
+#      - '/mnt/docker_store/kea/.config/log:/var/log/kea'
+#    network_mode: host
+    cap_add:
+      - SYS_TIME
+#    command: /bin/sh
+</code>
+++++
+  *''docker exec -ti chrony /bin/sh'' to get shell access to container
+pool pool.ntp.org iburst
+initstepslew 10 pool.ntp.org
+driftfile /var/lib/chrony/chrony.drift
+rtcsync
+cmdport 0</code>++++
+=====Reference=====
+  *[[https://www.bodet-time.com/resources/blog/1882-stratums-in-the-ntp-protocol-understanding-the-hierarchy-of-servers.html|STRATUMS IN THE NTP PROTOCOL: Understanding the hierarchy of servers]]
+  *[[https://chrony-project.org/|chrony]]
+  *[[https://github.com/cturra/docker-ntp/tree/main|cturra/ntp]] (crony docker example)
+  *[[https://www.tecmint.com/install-chrony-in-centos-ubuntu-linux/|How to Install and Use Chrony in Linux]]
+  *[[https://krython.com/post/configuring-ntp-server|configuring-ntp-server]]
+  *[[https://wiki.archlinux.org/title/Chrony|Arch chrony]]
+  *[[https://www.golinuxcloud.com/configure-chrony-ntp-server-client-force-sync/|Steps to configure Chrony as NTP Server & Client (CentOS/RHEL 8)]]
+  *[[https://documentation.ubuntu.com/server/how-to/networking/serve-ntp-with-chrony/|How to serve the Network Time Protocol with Chrony]]
+  *[[https://www.howtouselinux.com/post/using-chrony-for-ntp-on-linux|The Essential Guide to Using Chrony for NTP on Linux]]
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