Now I’ve got the Synology NAS up and running, I thought it would be interesting to see what the Docker support is like. You can essentially run Docker container instances on the NAS box which also means you can deploy your own custom .NET Core apps to the Synology box.

This post is organized into 3 parts:

1. Creating and testing a Docker-enabled ASP.NET Core app locally
2. Deploying the app to the Synology NAS via Docker Hub
3. Deploying the app locally to the NAS

Part 1: Creating and Testing a Docker ASP.NET Core App Locally

There’s a few things to setup to allow you to deploy and Test  Docker containers locally.

The first is to enable Hyper-V in Windows, this is a prerequisite of Docker Desktop for Windows:

Once you’ve enabled Hyper-V (a restart will probably be required) you can go and download and install Docker Desktop for Windows – this will allow you to enable Docker support when you create the project in Visual Studio.

Once Docker Desktop is installed and running you can check it’s running with PowerShell:

PS C:\Users\Admin> docker version
Client: Docker Engine - Community
 Version:           19.03.8
 API version:       1.40
 Go version:        go1.12.17
 Git commit:        afacb8b
 Built:             Wed Mar 11 01:23:10 2020
 OS/Arch:           windows/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          19.03.8
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.12.17
  Git commit:       afacb8b
  Built:            Wed Mar 11 01:29:16 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.2.13
  GitCommit:        7ad184331fa3e55e52b890ea95e65ba581ae3429
 runc:
  Version:          1.0.0-rc10
  GitCommit:        dc9208a3303feef5b3839f4323d9beb36df0a9dd
 docker-init:
  Version:          0.18.0
  GitCommit:        fec3683
PS C:\Users\Admin>

Now you can fire up Visual Studio and create a new ASP.NET Core web application and tick the Enable Docker Support checkbox:

Once the project is created, you can click the Run button in Visual Studio (it should say “Docker” next to it).

Checking  the Output window for Container Tools you should can see something like:

========== Checking for Container Prerequisites ==========
Verifying that Docker Desktop is installed...
Docker Desktop is installed.
========== Verifying that Docker Desktop is running... ==========
Verifying that Docker Desktop is running...
Docker Desktop is running.
========== Verifying Docker OS ==========
Verifying that Docker Desktop's operating system mode matches the project's target operating system...
Docker Desktop's operating system mode matches the project's target operating system.
========== Pulling Required Images ==========
Checking for missing Docker images...
Pulling Docker images. To cancel this download, close the command prompt window.
docker pull mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim

After a while the build might fail with the following error: Error    CTC1001    Volume sharing is not enabled. On the Settings screen in Docker Desktop, click Shared Drives, and select the drive(s) containing your project files.  

To fix this, open up the Docker Desktop UI, and find the File Sharing section and enable C: drive if you want to make it available to Docker – this should fix the error:

Once this this change is applied and Docker Desktop restarted, click the Start button again in Visual Studio and after accepting dialog boxes to do with firewall and local certificate the web app should start up and run successfully and Docker Desktop should show the web app container running:

So now you have a Docker-enabled .NET Core web app and have tested it locally you can deploy it to the Synology NAS.

Part 2: Deploying an ASP.NET Core Docker App To a Synology NAS Via Docker Hub (AKA There And Back Again – a Docker Hub Tale)

Docker Hub is place (“registry”) where you can store and manage Docker images. These images can then be pulled (downloaded) by  a Docker host and then a container started from this image.

Visual Studio has built-in support for pushing an image to Docker Hub and the Synology Docker app has the ability to pull images from Docker Hub. Images on Docker Hub can be public or private (depending on what plan you are using).

Once you’ve created a Docker Hub account, in Visual Studio go to the Build menu and choose Publish WebApplication1 (or whatever the name of your project is) and click Start. You will need to choose a publish target of Container Registry and choose Docker Hub:

Click Create Profile - you’ll need to supply your Docker Hub user name and password and click save.

You can now click the Publish button and wait for a little while:

You should see the app being pushed to Docker Hub:

Once the publish is complete you can head over to Docker Hub and you should see your image:

Now the image is in Docker Hub, you can enable Docker support on the Synology NAS, pull the image from Docker Hub, and start a container on the NAS.

First log into the Synology as an admin account and open the Package Center. Here you can search for “Docker” and install the Docker app:

Once you’ve installed the Docker app, open it and head to the Image section, click the Add button and choose Add From Url. Now you can head over to Docker Hub and copy the URL for your image, for example it will look something like this: https://hub.docker.com/r/jrdontcodetired/webapplication1:

Click Add and the image will be downloaded from Docker Hub to the NAS.

Once the image has downloaded, click on it and click the Launch button. This will enable you to start a container instance from the image.

You’ll need to click on Advanced Settings and go to the Port Settings tab. In the Dockerfile in Visual Studio, the image is set to use port 80. We need to map a port on the NAS to this port 80 in the container. For example you could set up port 7500 on the NAS itself to map traffic to port 80 in the container:

Click Apply and then Next. You will be given a summary of the settings (the “Run this container after the wizard is finished” box is ticked) and click Apply to finish the wizard and start the container.

You should now be able to see the container running in the Container section:

You can now point your browser to your NAS IP and the port your chose when staring the container, for example: http://192.168.20.17:7500/

You should now see your ASP.NET Core web app being served from the Docker container on the Synology NAS:

Part 3: Directly Deploying Docker Container to a Synology NAS

The first step is to publish the web app and copy the published files to the Synology. You could also publish directly to a folder on the NAS such as: \\SYN001\Test1\DockerPublish

In Visual Studio from the Build menu choose Publish WebApplication1. Create a new Publish Profile this time using a Folder Target and as the folder choose a folder on the Synology:

Click Create Profile and then click Publish. Once this is finished you should see the web app files published to the Synology folder.

In the DockerPublish folder (this is an arbitrary name) on the NAS create a new Dockerfile with the following contents:

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim
COPY . /app
WORKDIR /app
EXPOSE 80
ENTRYPOINT ["dotnet", "WebApplication1.dll"]

Your folder on the Synology should now look like something like this:

The next step is to build the Docker image on the Synology NAS. To do this you can SSH into the NAS and use Docker build.

The first step is to enable SSH access on the Synology, you can do this from the Synology Control Panel in the Terminal & SNMP section – tick the Enable SSH Service box and click Apply:

Next in Windows, open a new PowerShell window and enter:

ssh Jason@192.168.20.17

Replace “Jason” with the name of one of your admin users and the IP address with the address of your Synology NAS – you will then need to enter the user’s password.

We need to SSH in as root (or set up a new user on the NAS). Be careful working in root or you could seriously mess your NAS up or introduce security problems. To get root access enter:

sudo -i

And once again enter the password.

You can now change to the folder that contains the published web app and Dockerfile:

cd /volume1/Test1/DockerPublish

And now build the image:

docker build -t manualwebapp .

This will produce the following output:

Sending build context to Docker daemon  4.706MB
Step 1/5 : FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim
3.1-buster-slim: Pulling from dotnet/core/aspnet
c499e6d256d6: Pull complete
251bcd0af921: Pull complete
852994ba072a: Pull complete
f64c6405f94b: Pull complete
9347e53e1c3a: Pull complete
Digest: sha256:a9e160dbf5ed62c358f18af8c4daf0d7c0c30f203c0dd8dff94a86598c80003b
Status: Downloaded newer image for mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim
 ---> c819eb4381e7
Step 2/5 : COPY . /app
 ---> 0beff55307c9
Step 3/5 : WORKDIR /app
 ---> Running in e731c0fa1d6e
Removing intermediate container e731c0fa1d6e
 ---> b64c09a9d51e
Step 4/5 : EXPOSE 80
 ---> Running in 6fddd1f77f4e
Removing intermediate container 6fddd1f77f4e
 ---> 9aa4035379dc
Step 5/5 : ENTRYPOINT ["dotnet", "WebApplication1.dll"]
 ---> Running in 4f0b086e44d3
Removing intermediate container 4f0b086e44d3
 ---> ead6395bf486
Successfully built ead6395bf486
Successfully tagged manualwebapp:latest

If you now head to the Docker app on the Synology you will see the manualwebapp image:

You can start a container from this image as we did before using the Synology GUI or from the PowerShell prompt - we can start it with the following command (notice we’re mapping port 7501 on the NAS to port 80 in the container):

docker run --name manualtestcontainer -p 7501:80 -d manualwebapp

Now heading back the the Synology GUI you should see a container called manualtestcontainer running:

Now you can head to the URL in a browser (e.g. http://192.168.20.17:7501/) and see the ASP.NET Core web app running in the Docker container:

Summary

The ability to run Docker containers on a NAS is really nice, not only can you develop your own apps and deploy them as containers, you can also use images from a registry such as Docker Hub, for example MySQL, ghost blogging engine, etc. You should of course only use images you trust.

If you have any cool containers running on your Synology let me know in the comments!

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Early this year I tweeted this:

Think 2020 is the year to my first NAS. Would you still recommend a @Synology NAS mr @shanselman - if so what CPU/RAM would you recommend so I can run max apps on the NAS etc??

— Jason Roberts (@robertsjason) January 17, 2020

After seeing this, Synology reached out to me and asked if they could give me a unit to review. The contents of this post are my opinions based purely on my experience and this article was not pre-approved or edited by Synology.

What is a NAS?

A NAS device or Network Attached Storage device allows you to serve files over a network. A NAS can be a purpose built piece of hardware (like the Synology unit being discussed in this article) or a server set up with specific software to make it act like a NAS.

A NAS is like a hard disk that you can access over the network (potentially by multiple users) but depending on the hardware/software it can do a lot more. For example a NAS can enable you to fit multiple individual hard disks in a RAID configuration. RAID (Redundant Array of Inexpensive Disks or Redundant Array of Independent Disks) allows you to combine multiple disks/SSDs in a number of different ways.

RAID comes in a number of flavours (“levels”) with  names such as RAID 0 or RAID 10. Each RAID level has its own benefit/trade-offs in terms of number of redundant disks, read/write speeds, and storage efficiency. For example, given 4 hard disks you could set up RAID to allow 2 disks to fail without loosing data, but you will not be able to use all the disk space on all the drives for your own storage.

In summary, a NAS is a network device that exposes file storage from one or more drives and may also use RAID for some redundancy.

One thing to bear in mind is RAID is not the same as backup. RAID gives you redundancy for hardware (drive) failure. If a drive fails in a RAID array you can usually keep working and just replace the damaged drive with a new one. You should still have a good backup strategy in place that backups data on the NAS, for example making sure you have off-site backups in case the building where the NAS is burns down, gets flooded, etc.. There are a number of ways you could do this on the Synology such as setting up Cloud Sync to Dropbox/Onedrive/etc or using an actual backup service that integrates with the Synology such as Synology C2, Backblaze, etc.

Setting Up a Synology DS1618+

The first think is to decide what redundancy characteristics  you want for your data that you’ll be storing on the Synology. Synology have a handy RAID calculator to help you work out how many drives will give you what amount of storage for different RAID levels.

For this device I decided I wanted 2 disk redundancy. This mean that even if 2 disks fails no data will be lost (using SHR-2). SHR (Synology Hybrid Raid) and SHR-2 are RAID-like configurations but allow mixing disks of different sizes.

I decided I wanted to start with 6 TB of accessible storage to start with to keep initial costs low. This means with 2 redundant disks (using SHR-2) I need a total of 4 drives each one being 3 TB in size.

There are hard drives that are designed for NAS applications and offer features such as rotational vibrational sensors and other features that make them more suitable than normal desktop hard drives. I decided for this Synology NAS I would go with 2 Western Digital Red NAS drives and 2 Seagate IronWolf NAS drives. The reason I went with 2 different brands is to minimize the chance of a manufacturing error in a single batch failing all the drives at once. This might however be overkill.

For maximum compatibility you should choose drives that have been verified as compatible, there is a handy compatibility list you can use though I found it almost impossible to find drives here in Australia that exactly matched the drive model numbers/firmware/etc. On the compatibility list you can also see drives that are explicitly incompatible. Before ordering the drives I checked that they were not explicitly marked as incompatible even though they also did not match exactly the drives on the compatible list.

Out of the box, the DS1618+ comes with a couple of network cables, a power cord, some mounting screws if you are using 2.5” drives.

Installing Drives

Installing the drives is pretty easy, each bay pops open and the tray slides out into which the hard drive is inserted. For 3.5” drives no screws are required, instead the drives are help in place by a plastic strip on each side. These plastic were a bit fiddly however and felt a bit fragile and I was worried that I was going to snap them when trying to remove them from the tray. When the drive is inserted and the plastic strips clipped back in they feel like they hold the drive solidly in place however. Once the drive is held in place it can be slotted back into the NAS.

The drives can be secured in place using the supplied “key” to prevent the drives from accidentally being removed.

DS1618+ Setup

Once all 4 disks were installed, I connected the power cord and the network cable to the modem/router.

Back on my PC in a browser I navigated to http://find.synology.com – this then forwarded the browser to the NAS.

A wizard like setup process leads you through the required steps to install the NAS OS, create an admin user account, and optionally enable QuickConnect that allows you to access the management interface on your NAS over the Internet without needing to setup complex port forwarding rules which is a nice feature.

Once the setup is complete the web interface opens.

From here you can manage the NAS and install additional packages such as Dropbox/Onedrive/etc cloud sync. This ability to install “apps” onto the NAS is a powerful feature that helps to add extra value to the NAS proposition.

At this point I had not actually setup or chosen a RAID level so I wasn’t sure what to do next.

Eventually I found the Main Menu button at the top left that allowed be to open the Storage Manager app that allows the setup of disks – it would have been nice if this was part of the initial setup wizard/guided workflow – at least for beginner users like myself.

There are 2 key concepts: Storage Pools and Volumes.This is where things started to get a little confusing for as a first-time NAS user, I knew that I wanted a single volume using SHR-2 but was not sure how to get there.

After a few minutes looking at the documentation I understood that a storage pool is a collection of drives. There are 2 types of storage pools: “Storage pool for better performance” and “Storage pool for higher flexibility” with the performance pool “better performance but less storage management flexibility” –unfortunately the doc I was looking at didn’t link to what this “storage management flexibility” refers to.

So I decided to just go and click the create storage pool button and see what happens. The popup then told me that the “flexible” pool is the one that supports SHR so I chose that option.

I gave the pool a not very original name of “MainPool” and chose SHR-2 as the RAID type. Then I proceed through the wizard and selected the 4 drives I installed to be part of this pool.

Next I clicked on the create new volume button and chose the storage pool I just created. I set the volume size to max because I only want 1 volume for all the 4 drives and then I was offered the choice of file system: Btrfs or ext – I went with the Btrfs option as it was the recommended option..

Once all this was done the NAS started running a parity consistency check check on the drives.

Setting Up A Share

Now the pool and volume are up and running it’s time to store some files!

I went to the Shared Folder Creation wizard and created a test share and then setup read/write permissions for myself.

Now heading over to Windows File Explorer and navigating to the NAS I had to provide credentials which I did for the user I created earlier:

Now I can navigate to the Test1 share and create my first NAS-ed file :)

Setup Summary and First Impressions

One thing to bear in mind is that setting up a NAS is not the same as just plugging in an external USB. The Synology DS1618+ offers loads of configuration options and other than a short stumble where I learned about Storage Pools and Volumes the process was pretty painless. I now have the ability to store and retrieve files from anywhere in the house and also know that even if 2 of the 4 hard disks failed I would not lose data.

At this point I have not setup any backups so I won’t be putting any critical files on the NAS yet, I’m also looking forward to setting up things such as Cloud Sync that will sync Dropbox, Onedrive, etc to the NAS – at the moment due to smaller SSD sizes on my machines I’m having to make use of Dropbox selective sync all the time which is a bit annoying – having my entire Dropbox account on my local network will hopefully make things a lot nicer!.

I’m also looking forward to playing with the Synology Docker container support.

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