Syncthing (container)

Syncthing replaces proprietary sync and cloud services with something open, trustworthy and decentralized. Your data is your data alone and you deserve to choose where it is stored, if it is shared with some third party and how it's transmitted over the Internet.

Image details

Pulls: 209.3M

Architecture: amd64, arm64

Image size: 24 MB

Latest: 2.1.3

User: linuxserver

Created: Oct 14, 2015

Updated: 7 hours ago

Status: active

Configuration

Type

Container

Platform

linux

Image

linuxserver/syncthing:latest

Ports

8384:8384/tcp22000:22000/tcp22000:22000/udp21027:21027/udp

Volumes

/config : /srv/lsio/syncthing/config/data1 : /srv/lsio/syncthing/data1/data2 : /srv/lsio/syncthing/data2

Env vars

PUID=1000PGID=1000TZ=Etc/UTC

Restart

unless-stopped

Template by technorabilia

Notes

Portainer App Templates by Technorabilia, based on data provided by LinuxServer.io.

Ensure to create the following volume directories on the host file system, or modify the paths in the volume mapping section under the advanced options below, as needed.

mkdir -p /srv/lsio/syncthing/config
mkdir -p /srv/lsio/syncthing/data1
mkdir -p /srv/lsio/syncthing/data2

Standalone Install

Select an install method, to see config/commands for deploying Syncthing (container)

Install on Portainer

Import all app templates into your Portainer instance, for easy 1-click deploys

Ensure both Docker and Portainer are installed, and up-to-date
Log into your Portainer web UI
Under Settings → App Templates, paste the below URL
Head to Home → App Templates, and the list of apps will show up
Select Syncthing (container), fill in any config options, and hit Deploy

Template Import URL

https://raw.githubusercontent.com/Lissy93/portainer-templates/main/templates.json

Show Me

More install options in our documentation.

The LinuxServer.io team brings you another container release featuring:

regular and timely application updates
easy user mappings (PGID, PUID)
custom base image with s6 overlay
weekly base OS updates with common layers across the entire LinuxServer.io ecosystem to minimise space usage, down time and bandwidth
regular security updates

Find us at:

Blog - all the things you can do with our containers including How-To guides, opinions and much more!
Discord - realtime support / chat with the community and the team.
Discourse - post on our community forum.
GitHub - view the source for all of our repositories.
Open Collective - please consider helping us by either donating or contributing to our budget

linuxserver/syncthing

Supported Architectures

We utilise the docker manifest for multi-platform awareness. More information is available from docker here and our announcement here.
Simply pulling lscr.io/linuxserver/syncthing:latest should retrieve the correct image for your arch, but you can also pull specific arch images via tags.
The architectures supported by this image are:

Architecture	Available	Tag
x86-64	✅	amd64-\
arm64	✅	arm64v8-\

Application Setup

Note: The Syncthing devs highly suggest setting a password for this container as it listens on 0.0.0.0. To do this go to Actions -> Settings -> set user/password for the webUI.

Usage

To help you get started creating a container from this image you can either use docker-compose or the docker cli.
>!NOTE >Unless a parameter is flagged as 'optional', it is mandatory and a value must be provided.

docker-compose (recommended, click here for more info)

---
services:
  syncthing:
    image: lscr.io/linuxserver/syncthing:latest
    container_name: syncthing
    hostname: syncthing #optional
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Etc/UTC
    volumes:
      - /path/to/syncthing/config:/config
      - /path/to/data1:/data1
      - /path/to/data2:/data2
    ports:
      - 8384:8384
      - 22000:22000/tcp
      - 22000:22000/udp
      - 21027:21027/udp
    restart: unless-stopped

docker cli (click here for more info)

docker run -d \
  --name=syncthing \
  --hostname=syncthing `#optional` \
  -e PUID=1000 \
  -e PGID=1000 \
  -e TZ=Etc/UTC \
  -p 8384:8384 \
  -p 22000:22000/tcp \
  -p 22000:22000/udp \
  -p 21027:21027/udp \
  -v /path/to/syncthing/config:/config \
  -v /path/to/data1:/data1 \
  -v /path/to/data2:/data2 \
  --restart unless-stopped \
  lscr.io/linuxserver/syncthing:latest

Parameters

Containers are configured using parameters passed at runtime (such as those above). These parameters are separated by a colon and indicate <external>:<internal> respectively. For example, -p 8080:80 would expose port 80 from inside the container to be accessible from the host's IP on port 8080 outside the container.

Parameter	Function
`--hostname=`	Optionally the hostname can be defined.
`-p 8384:8384`	Application WebUI
`-p 22000:22000/tcp`	Listening port (TCP)
`-p 22000:22000/udp`	Listening port (UDP)
`-p 21027:21027/udp`	Protocol discovery
`-e PUID=1000`	for UserID - see below for explanation
`-e PGID=1000`	for GroupID - see below for explanation
`-e TZ=Etc/UTC`	specify a timezone to use, see this list.
`-v /config`	Configuration files.
`-v /data1`	Data1
`-v /data2`	Data2

Environment variables from files (Docker secrets)

You can set any environment variable from a file by using a special prepend FILE__.
As an example:

-e FILE__MYVAR=/run/secrets/mysecretvariable

Will set the environment variable MYVAR based on the contents of the /run/secrets/mysecretvariable file.

Umask for running applications

For all of our images we provide the ability to override the default umask settings for services started within the containers using the optional -e UMASK=022 setting. Keep in mind umask is not chmod it subtracts from permissions based on it's value it does not add. Please read up here before asking for support.

User / Group Identifiers

When using volumes (-v flags), permissions issues can arise between the host OS and the container, we avoid this issue by allowing you to specify the user PUID and group PGID.
Ensure any volume directories on the host are owned by the same user you specify and any permissions issues will vanish like magic.
In this instance PUID=1000 and PGID=1000, to find yours use id your_user as below:

id your_user

Example output:

uid=1000(your_user) gid=1000(your_user) groups=1000(your_user)

Docker Mods

We publish various Docker Mods to enable additional functionality within the containers. The list of Mods available for this image (if any) as well as universal mods that can be applied to any one of our images can be accessed via the dynamic badges above.

Support Info

Shell access whilst the container is running:

```bash
docker exec -it syncthing /bin/bash
```

To monitor the logs of the container in realtime:

```bash
docker logs -f syncthing
```

Container version number:

```bash
docker inspect -f '{{ index .Config.Labels "build_version" }}' syncthing
```

Image version number:

```bash
docker inspect -f '{{ index .Config.Labels "build_version" }}' lscr.io/linuxserver/syncthing:latest
```

Updating Info

Most of our images are static, versioned, and require an image update and container recreation to update the app inside. With some exceptions (noted in the relevant readme.md), we do not recommend or support updating apps inside the container. Please consult the Application Setup section above to see if it is recommended for the image.
Below are the instructions for updating containers:

Via Docker Compose

Update images:

* All images:

    ```bash
    docker-compose pull
    ```

* Single image:

    ```bash
    docker-compose pull syncthing
    ```

Update containers:

* All containers:

    ```bash
    docker-compose up -d
    ```

* Single container:

    ```bash
    docker-compose up -d syncthing
    ```

You can also remove the old dangling images:

```bash
docker image prune
```

Via Docker Run

Update the image:

```bash
docker pull lscr.io/linuxserver/syncthing:latest
```

Stop the running container:

```bash
docker stop syncthing
```

Delete the container:

```bash
docker rm syncthing
```

Recreate a new container with the same docker run parameters as instructed above (if mapped correctly to a host folder, your /config folder and settings will be preserved)
You can also remove the old dangling images:

```bash
docker image prune
```

Image Update Notifications - Diun (Docker Image Update Notifier)

>!TIP >We recommend Diun for update notifications. Other tools that automatically update containers unattended are not recommended or supported.

Building locally

If you want to make local modifications to these images for development purposes or just to customize the logic:

git clone https://github.com/linuxserver/docker-syncthing.git
cd docker-syncthing
docker build \
  --no-cache \
  --pull \
  -t lscr.io/linuxserver/syncthing:latest .

The ARM variants can be built on x8664 hardware and vice versa using lscr.io/linuxserver/qemu-static
docker run --rm --privileged lscr.io/linuxserver/qemu-static --reset

Once registered you can define the dockerfile to use with -f Dockerfile.aarch64.
Versions
03.03.26: - Rebase to Alpine 3.23.
16.08.25: - Rebase to Alpine 3.22.
13.08.25: - Use double-dash long options for syncthing v2.0.0.
03.12.24: - Rebase to Alpine 3.21.
06.06.24: - Rebase to Alpine 3.20.
05.03.24: - Rebase to Alpine 3.19.
05.09.23: - Rebase to Alpine 3.18.
01.07.23: - Deprecate armhf. As announced here
13.02.23: - Rebase to Alpine 3.17, migrate to s6v3.
17.08.22: - Build on alpine 3.16 for go 1.18).
03.05.22: - Rebase to alpine 3.15 (builds on edge for go 1.18).
05.10.21: - Rebase to alpine 3.14.
12.05.21: - Remove sysctl parameter again
03.05.21: - Raise maximum UDP buffer size.
03.05.21: - Add port mapping for 22000/udp.
29.01.21: - Deprecate UMASK_SET in favor of UMASK in baseimage, see above for more information.
23.01.21: - Rebasing to alpine 3.13.
15.09.20: - Use go from alpine edge repo to compile. Remove duplicate UMASK env var. Add hostname setting.
01.06.20: - Rebasing to alpine 3.12.
19.12.19: - Rebasing to alpine 3.11.
28.06.19: - Rebasing to alpine 3.10.
23.03.19: - Switching to new Base images, shift to arm32v7 tag.
05.03.19: - Update Build process for v1.1.0 release.
22.02.19: - Rebasing to alpine 3.9.
16.01.19: - Add pipeline logic and multi arch.
30.07.18: - Rebase to alpine 3.8 and use buildstage.
13.12.17: - Rebase to alpine 3.7.
25.10.17: - Add env for manual setting of umask.
29.07.17: - Simplify build structure as symlinks failing on > 0.14.32
28.05.17: - Rebase to alpine 3.6.
08.02.17: - Rebase to alpine 3.5.
01.11.16: - Switch to compiling latest version from git source.
14.10.16: - Add version layer information.
30.09.16: - Fix umask.
09.09.16: - Add layer badges to README.
28.08.16: - Add badges to README.
11.08.16: - Rebase to alpine linux.
18.12.15: - Initial testing / release (IronicBadger)
24.09.15: - Inital dev complete (Lonix)

Serve Syncthing (container) on your own domain behind Caddy, Nginx or Traefik. Fill in your domain and copy the result. It's a starting point, some apps need their own base URL or extra headers set too.

Proxy Domain App port Upstream

Proxying syncthing-container.example.com to http://Syncthing:8384

Add this to your Caddyfile

syncthing-container.example.com {
	reverse_proxy http://Syncthing:8384
}

Check the logs first

Nine times out of ten the logs tell you exactly what went wrong.

In Portainer, go to Containers, click the container, then Logs. Or run docker logs Syncthing
Exit codes help too: 137 means killed, usually out of memory. 126 or 127 means the command inside the image is broken.

Port already in use

If deployment fails with "Bind for 0.0.0.0:8384 failed: port is already allocated", something else on your server is using that port.

Find what's using it: sudo ss -tlnp | grep :8384
Stop the other service, or pick a different host port. In 8384:8384 only the left number is yours to change, the right one belongs to the app.

Running but the page won't load

The container is up but nothing appears in your browser.

Use your server's real IP: http://your-server-ip:8384. The 0.0.0.0 link Portainer shows isn't a real address.
Give it a minute after first deploy, Syncthing can take a while to initialise.
Make sure your firewall allows the port, e.g. sudo ufw allow 8384

Permission denied on volumes

If the logs show "permission denied", the app can't write to its data folder on the host.

Fix the ownership: sudo chown -R 1000:1000 /srv/lsio/syncthing/config (and the same for the other mapped folders)
Or set the PUID and PGID variables (defaults 1000:1000) to match your own user, found with id $USER

Image won't pull

Test the pull directly on the host: docker pull linuxserver/syncthing:latest

"manifest unknown" means the tag no longer exists. This template uses latest, so try pinning a specific version instead.
"toomanyrequests" is the Docker Hub rate limit. Log in with docker login to raise it.
"no space left on device" means a full disk. Reclaim space with docker system prune

"exec format error"

This means the image was built for a different CPU architecture than your server.

This image supports: amd64, arm64
Check yours with uname -m: x86_64 is amd64, aarch64 is arm64. Raspberry Pi and other ARM boards are the usual culprits.

Container keeps restarting

The unless-stopped restart policy relaunches the app after every crash, so the real error can scroll past.

Check the logs right after a restart, the last few lines before it died are the useful ones.
Get the exit code with docker inspect Syncthing --format '{{.State.ExitCode}}'
Still stuck? Redeploy once with the restart policy set to no so the failure stays visible.

Raise an issue

Found something which isn't working as it should? Here's how to report it.

Bug within the app: Open an issue within Syncthing's repo
Template not working: Open an issue on technorabilia/portainer-templates
This website not working: Open an issue on lissy93/portainer-templates

A single container

Syncthing (container) runs as one container, the simplest kind of app here. Just the one image to pull and nothing else wired up alongside it.

The app image

An image is the app packed up ready to go, everything Syncthing (container) needs bundled into one download. This template pulls linuxserver/syncthing:latest, which Docker fetches once (about 24 MB) and then starts your own copy from.

Where the image comes from

Docker pulls its images from registries, public libraries of ready-built apps. Syncthing (container)'s comes from Docker Hub, published by linuxserver.

Version tags

The bit after the colon in the image name is the version tag. Here it's latest, which always points at the newest build, so a redeploy can bump you to a newer release without you asking. Newest right now is 2.1.3. Pin a specific tag if you would rather stay on one version.

Which machines it runs on

Every image is built for particular CPU types. This one ships for amd64, arm64, so it runs on both regular x86 servers and ARM boards like a Raspberry Pi.

Ports

A port is the door the app answers on. A mapping like 8384:8384 means it's reachable on port 8384 of your server, where the left number is yours to change and the right one belongs to the app. It opens:

8384:8384
22000:22000
22000:22000 over UDP
21027:21027 over UDP

Volumes

A volume is where Syncthing (container) keeps its files so they survive an update or a restart. Without one, anything it saves would sit inside the container and vanish the moment it's recreated. This template mounts:

/config from /srv/lsio/syncthing/config on the host
/data1 from /srv/lsio/syncthing/data1 on the host
/data2 from /srv/lsio/syncthing/data2 on the host

Environment variables

Environment variables are the settings you hand over when you deploy, things like a password or a timezone. Syncthing (container) takes 3 of them, all with defaults you can leave alone or tweak:

PUID, defaults to 1000. Run 'id [USER]' for the owner of the host volume directories to get the UID to use here.
PGID, defaults to 1000. Run 'id [USER]' for the owner of the host volume directories to get the GID to use here.
TZ, defaults to Etc/UTC. Specify a timezone to use, see this list.

Restart policy

The restart policy here is unless-stopped, so Docker restarts Syncthing (container) after a crash or reboot, but leaves it off when you stop it on purpose. You can change this on the deploy screen. The choices are no (never restart), on-failure (only after a crash), unless-stopped (restart unless you stop it), and always (bring it back no matter what).

Users and permissions

The PUID and PGID settings tell it which user and group to act as on your host. Point them at your own account (find yours with id $USER) so the files it writes into your mounted folders come out owned by you rather than root.

Networking

Nothing custom is set, so Syncthing (container) sits on Docker's default bridge network: its own private space that reaches the outside world only through the ports it publishes.

Container name

Once it's deployed, Portainer names the container Syncthing. That's what you'll spot in the containers list and use in commands like docker logs Syncthing.

Platform

The platform is linux, the kind of system the container is built to run on. Docker and Portainer handle this on a normal Linux server.

Portainer app templates

Zooming out, this whole page comes from a Portainer app template: a short recipe telling Portainer how to set Syncthing (container) up. Add the template list to Portainer once, then deploying Syncthing (container) is a click rather than a wall of config.

Syncthing (container)

Image details

Configuration

Notes

Standalone Install

Install on Portainer

Template Import URL

Container Documentation

linuxserver/syncthing

Supported Architectures

Application Setup

Usage

docker-compose (recommended, click here for more info)

docker cli (click here for more info)

Parameters

Environment variables from files (Docker secrets)

Umask for running applications

User / Group Identifiers

Docker Mods

Support Info

Updating Info

Via Docker Compose

Via Docker Run

Image Update Notifications - Diun (Docker Image Update Notifier)

Building locally

Versions

Recent versions

Proxy configurator

Troubleshooting

Check the logs first

Port already in use

Running but the page won't load

Permission denied on volumes

Image won't pull

"exec format error"

Container keeps restarting

Raise an issue

Config glossary

A single container

The app image

Where the image comes from

Version tags

Which machines it runs on

Ports

Volumes

Environment variables

Restart policy

Users and permissions

Networking

Container name

Platform

Portainer app templates

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