Chrony NTP server based on Alpine Linux

Versions

latest, 4.1 - Alpine 3.14, chrony 4.1 3.2 - Alpine 3.7, chrony 3.2

Getting The Image

Docker Hub

docker pull cwadley/alpine-chrony:latest

Build

git pull https://github.com/cwadley/alpine-chrony.git docker build --tag cwadley/alpine-chrony .

Usage

Default Config

docker run -d                       \
            --name chrony           \
            -p 123:123/udp          \
            --cap-add SYS_NICE      \
            --cap-add SYS_TIME      \
            --cap-add SYS_RESOURCE  \
            cwadley/alpine-chrony

Custom Config

docker run -d                                                       \
            --name chrony                                           \
            -p 123:123/udp                                          \
            --cap-add SYS_NICE                                      \
            --cap-add SYS_TIME                                      \
            --cap-add SYS_RESOURCE                                  \
            -v <path_to_chrony.conf>:/etc/chrony/chrony.conf:ro     \
            cwadley/alpine-chrony

Logs

Chrony runs in un-detached mode in this image, which means that it does not send its logs to a file in the container, but to stdout. To view chrony logs, use docker logs chrony.

Testing

ntpdate or sntp can be used to query the running container for the time:

If you have mapped port 123 to the host:

ntpdate -q localhost

From another container on the same Docker network:

ntpdate -q <chrony_ip>

Both ntpdate and sntp are included in the image to debug NTP source server connections.