18. September 2017
In the previous posts, I have talked about everything from what Docker is, to how you can set up a stack of containers using docker-compose, but all of the posts have been about setting up containers on a single machine. Something that can be really useful, but imagine being able to deploy your containers just as easily to a cluster of machines. That would be awesome!
With Docker Swarm, this is exactly what you can do. You can set up a cluster of Docker hosts, and deploy your containers to them in much the same way that you would deploy to a single machine. How cool is that!
Creating a cluster, or swarm
To be able to try out what it’s like working with a cluster of machines, we need a cluster of machines. and by default, Docker for Windows/Mac includes only a single Docker host when it’s installed. However, it also comes with a tool called docker-machine that can be used to create more hosts very easily.
In the previous posts about Docker, here, here and here, we’ve looked at what Docker is, how to set up a basic container and how to set up a stack of containers using docker-compose. One thing we haven’t talked about is the fact that most projects use some form of persistent data store, and the most common store, at least in my world, is a relational database of some sort. So this time, I want to cover something that might seem slightly odd…setting up an MS SQL Server…on Linux…in Docker.
Yes, you heard me right… I’m going to show you how to set up an MS SQL Server instance in a Linux-based Docker container. Something that wouldn’t have been possible, in any way, not too long ago, but Microsoft “recently” released a version of MS SQL Server that runs on Linux, which is really cool. And running it in Docker just makes sense!
Running MS SQL Server in a Docker container
Starting a SQL Server instance in a Docker isn’t that hard, but there are a couple of things that need to be set up for it to work.
So far in this little blog series about Docker, I have covered what Docker is, how it works, how to get a container up and running using pre-built images, as well as your own images. But so far, it has all been about setting up a single container with some form of application running inside it. What if we have a more complicated scenario? What if we have a couple of different things we want to run together? Maybe we want to run our ASP.NET Core app that we built in the previous post behind an nginx instance instead of exposing the Kestrel server to the internet… Well, obviously Docker has us covered.
However, before we go any further, I just want to mention that I will only be covering something called docker-compose in this post. This can be used to create a stack of containers that are set started and stopped together. I will not be covering distributing the application accross several nodes this time. There will be more about that later. And even if that is probably the end goal in a lot of cases, being able to just run on a single host can be useful as well. Especially while developing stuff.
What is docker-compose?
When you installed Docker for Windows or Docker for Mac, you automatically got some extra tools installed. One of them is docker-compose, which is a tool for setting up several containers together in a stack, while configuring their network etc. Basically setting up and configuring a set of containers/apps that work together.
25. October 2015
ASP.NET , Azure
I recently did a blog post about how to get an ASP.NET 5 application to run in a Windows Server container using Docker. However, I kept thinking about that solution, and started wondering if I could add IIS Application Request Routing to the mix as well. What if I could have containers at different ports, and have IIS and ARR routing incoming requests to different ports based on the host for example. And apparently I could. So I decided to write another post about how I got it going.
Disclaimer: There is still some kinks to work out regarding the routing. Right now, I have to manually change the routing to point to the correct container IP every time it is started, as I don’t seem to find a way to assign my containers static IP addresses…
Disclaimer 2: I have no clue about how this is supposed to be done, but this seems to work… More...
A couple of days ago, I ended up watching a video about Windows Server 2016 at Microsoft Virtual Academy. I think it was A Deep Dive into Nano Server, but I’m not sure to be honest. Anyhow, they started talking about Windows Server Containers and Docker, and I got very interested.
I really like the idea of Docker, but since I’m a .NET dev, the whole Linux dependency is a bit of a turn-off to be honest. And yes, I know that ASP.NET 5 will be cross-platform and so on, but in the initial release of .NET Core, it will be very limited. So it makes it a little less appealing. However, with Windows Server Containers, I get the same thing, but on Windows. So all of the sudden, it got interesting to look at Docker. So I decided to get an ASP.NET 5 app up and running in a Windows Server Container. Actually, I decided to do it in 2 ways, but in this post I will cover the simplest way, and then I will do another post about the other way, which is more complicated but has some benefits…More...