Category: Containers

Andrew Pruski shows how to save a Docker image:

What I’m going to do now is save my custom image to a location [C:\temp] on my host server. So I’ll run: –

1	docker save -o myfirstimage.tar myfirstimage

N.B. – I’m saving the file as a .tar as this seems to be the format that works best for loading the image. I’ve tried exporting to other formats (.zip) but it always seems to become corrupt. The .tar format has always worked for me so I’ll stick with it.

If I’m understanding Andrew correctly, that’s because docker save will only generate a tar archive.  Keep reading for more details, including how to restore a Docker image to another machine.

Andrew Pruski demos Portainer, a user interface for Docker:

So let’s run through the setup and then look at the system. There’s a couple of pre-requisities to this I’m afraid, the first one is that you must setup remote administration using TLS on the Docker host that you want to manage via Portainer. I’ve detailed how to do this here.

Also, Portainer doesn’t support managing a local Docker Engine running on Windows so the way I’ve set it up is to run Portainer locally on Windows 10 and then point it at a server running the Docker Engine I want to manage. This means that you’ll need to install Docker locally, you can do that here.

Of course you get it in a container.  How else would you get the container interface…?

It looks like a nice UI for getting started with Docker.

Andrew Pruski shows how to perform remote Docker administration:

Continuing on my series in working with Docker on Windows, I noticed that I always open up a remote powershell window when working with Docker on servers. Nothing wrong with this, if you want to know how to do that you can follow my instructions here.

However what if we want to connect to the Docker engine remotely? There’s got to be a way to do that right? Well it’s not quite so straightforward, but there is a way to do it involving a custom image downloaded from the Docker Hub (built by Stefan Scherer [g|t]) whichs creates TLS certs to allow remote connections.

Let’s go through the steps.

Read on for the steps.

Andrew Pruski shows how simple it is to view Docker logs:

I have to run the docker ps command with the -a flag (to show all containers, the default is to only show running containers). Which means my container isn’t running, something’s gone wrong.

So to see what’s happening I can run the docker logs command to see what’s up: –

Click through for an example that Andrew ran through.

Andrew Pruski builds up a custom dockerfile with his SQL Server configuration and custom databases:

And there you have it. One newly built SQL container from a custom image running our databases.

Imagine being able to spin up new instances of SQL with a full set of databases ready to go in minutes. This is main advantage that container technology gives you, no more waiting to install SQL and then restore databases. Your dev or QA person can simply run one script and off they go.

I really think this could be of significant benefit to many companies and we’re only just starting to explore what this can offer.

The best part is that it’s quite easy to do, meaning you could set up a guaranteed clean QA image for each continuous integration deployment and know that some process oddity didn’t fail to clean up after itself and thereby wrecked the automated build process.

Andrew Pruski explains how Docker containers interact with the network:

Anyway, during the podcast one of the questions that came up was “How do containers interact with the network resources on the host server?”

To be honest, I wasn’t sure. So rather can try and give a half answer I said to the guys that I didn’t know and I’d have to come back to them.

Click through for the answer.

Andrew Pruski demonstrates WinDocks, for people without Windows Server 2016 available:

So the first thing to do is get a new server with Windows Server 2012 R2 installed. Then once that’s up and running, you need to install SQL Server…

…wait, what??

The WinDocks software is different from the previous docker software that we’ve worked with in that it needs an instance of SQL installed on the host in order to use it’s binaries to create SQL within the containers. The instance won’t need to be running, it just needs to be installed.

Check out WinDocks; it’s focused around Dockerizing older versions of SQL Server.

Andrew Pruski walks us through pushing an image up to Docker so we can use it later:

And there it is, our image in our repository tagged as v1! The reason that I’ve tagged it as v1 is that if I make any changes to my image, I can push the updated image to my repository as v2, v3, v4 etc…

Still with me? Awesome. Final thing to do then is pull that image down from the repository on a different server. If you don’t have a different server don’t worry. What we’ll do is clean-up our existing server so it looks like a fresh install. If you do have a different server to use (lucky you) you don’t need to do this bit!

Read the whole thing.