# NTP

NTP is a Docker container that runs chrony on Alpine Linux, letting homelab users synchronise system clocks with upstream Network Time Protocol (NTP) servers and provide time to other devices on the network. It is open source and self-hosted, installable on Docker Hub and Unraid.

Canonical page: https://ourlocalhost.com/app/513/ntp

## Description

NTP is a Docker container that runs chrony on Alpine Linux, letting homelab users synchronise system clocks with upstream Network Time Protocol (NTP) servers and provide time to other devices on the network.

## Platform availability

Available on 1 of 9 platforms: Unraid.

## Health score

30/100 (Low), based on 3 of 4 factors.
- Maintained: 14 (last commit 587 days ago)
- Popular: 53 (443 GitHub stars)
- Easy to install: 35 (1 install platform, install notes, Docker image)

## Links

- GitHub: https://github.com/cturra/docker-ntp
- Docker Hub: https://hub.docker.com/r/cturra/ntp
- Unraid: https://ca.unraid.net/apps/ntp-1gdxqob1vxnt9r?q=ntp
- Official website: https://www.advtimesync.com

## Common questions

### Which port should I expose for NTP clients?

Publish UDP port 123, for example with --publish=123:123/udp.

### How do I configure different upstream NTP servers?

Set the NTP_SERVERS environment variable to a comma-delimited list without spaces.

### Can I run the container with a more restrictive filesystem?

Yes, run it read-only and mount /etc/chrony, /run/chrony, and /var/lib/chrony as writable tmpfs mounts with mode 1750.

### Does the included Compose file have a Docker Engine requirement?

The included file uses Compose format 3.9, which requires Docker Engine 19.03.0 or newer.

### Can this container provide time to other devices on my network?

Yes, chrony can operate as an NTPv4 server and peer to provide a time service to other computers in the network.

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Source: Our Local Host (https://ourlocalhost.com/app/513/ntp), the self-hosted and open-source app directory.