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🐳 First Container Guide

Run Your First Container on Synology NAS the Safe Way

The first container teaches you everything — how images download, how ports open, where data lives, and how logs confess problems. Run it as a deliberate small test and every container after it becomes routine. Run your most important app first, and the same lessons arrive at the worst possible time.

✍️ Technical Anshu🐳 Synology DSM 7⏱️ 15 minute exercise
🎥 Watch the complete installation in the video — Docker on a Synology NAS, step by step

Ask experienced NAS owners what their first container was and most will name something small and slightly pointless. That is not an accident. The first container is practice. Its job is to prove four links in a chain: the NAS can download an image, the container starts, you can reach it from your browser, and its data survives being deleted. This guide walks that chain in order, using Container Manager's own screens, and finishes with the one upgrade most people install next.

The first container — four links to prove
1. Image downloads from the registryPULL
2. Container starts and stays runningRUN
3. Its page opens in your browserREACH
4. Delete it — shared folder data survivesPROOF
A first container is a test of the whole chain. If all four links hold, you understand Docker on your NAS better than most tutorials teach.
1

Choose a Genuinely Small First Image

Pick an image that is small to download, starts instantly, and shows a page in the browser so success is visible. A tiny static web server image is ideal. Avoid databases, media servers and anything that wants several containers working together — those are second-week projects.

  1. Open Container Manager → Registry and search for your test image.
  2. Prefer images published by the official project or a well-known maintainer. The registry shows who published an image — random re-uploads by strangers are the supply-chain equivalent of a stranger's pen drive.
  3. Download the image and watch it land under Image. Note its size; small images forgive slow connections and small disks.
2

Create the Container — Name, Port, Folder

Select the image and choose Run. The wizard asks for the few decisions that actually matter.

  1. Name: something you will recognise in six months — the app name is enough.
  2. Port: the container's own port is fixed by the app; your job is the local (host) port. DSM already uses 5000 and 5001 for its own web interface, so choose a clear number like 8080 and write it down.
  3. Volume: if the app stores anything, map its data path to a folder inside your docker shared folder — for a test app, docker/test is fine. The port and volume guides in this series go deeper.
  4. Restart: leave automatic restart off for a test container. You want to see it fail if it fails, not watch it loop forever.
3

Start It and Read the Log Before Anything Else

Start the container, then open its Log tab before you touch your browser. The log is the app talking to you.

  1. A healthy app prints its ready line — often the address and port it is listening on.
  2. A container that starts and stops in a loop is telling you something is missing: a folder it cannot write to, a setting it needs, a port already taken. The last few log lines usually name it plainly.
  3. Only now open your browser to http://your-nas-address:8080 (using the port you chose). Seeing the app's page closes link three of the chain.
4

The Deletion Test — The Real Lesson

Now the step nobody wants to do and everybody should. Put one throwaway file or setting into the app, then stop the container and delete it completely.

  1. Open your docker shared folder in File Station. The data you mapped is still there — because it was never inside the container at all.
  2. Recreate the container with the same volume mapping and the same setting reappears. The app was disposable; the data was not.
  3. If instead the data vanished, you have learned the most valuable container lesson at the cheapest possible price: that app was storing data in the container's own temporary layer, and it needs a volume mapping before it can be trusted with anything real.
5

The Popular Next Step — Portainer

After the test, many people install Portainer as their first real container. It is a free web dashboard that manages Docker itself — containers, images, volumes and logs in one tidy interface — and it runs happily on a Synology NAS as a container managing its siblings.

Be clear about what it is: a nicer steering wheel, not a second engine. Everything Portainer shows is the same Docker underneath, and everything learned in Container Manager still applies. Plenty of owners never install it and lose nothing. If you do, it becomes an excellent second exercise: it needs a volume for its own data and its own port, exactly like the test — only now the steps mean something.

🐳 Beginner's rule: never let an app's first run also be its only copy of anything. Test containers are for learning; an app graduates to real data only after it has survived the deletion test with its data intact in a shared folder.

🎥 Watch the Complete Video

The full Docker on Synology NAS installation, shown live on a real NAS from package install to a running container.

▶️ Watch Full Video
❓ Common Questions (FAQ)

My container keeps restarting. Where do I look first?

The container's Log tab in Container Manager. A restart loop almost always means the app is missing something it needs — most often a folder it cannot write to, a required setting, or a port conflict. The last lines of the log usually say which one, in plain language.

Do I need Portainer to use Docker on Synology?

No. Portainer is an optional free dashboard that manages the same Docker engine through a different interface. Container Manager does everything needed — images, containers, volumes, projects and logs. Many people install Portainer because they prefer its layout, but it is a preference, not a requirement.

What port should I choose for a container?

Pick a host port that nothing else on the NAS is using, and write it down. Avoid 5000 and 5001, which DSM itself uses, and avoid the app ports of services you already run. Numbers in the 8000 to 9000 range are the common habit — for example 8080 for a first web app.

This guide is based on the Technical Anshu video on installing Docker on a Synology NAS • Stuck on a step? Ask in the video comments 🙏