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Category: Containers

Running Confluent Platform with .NET

Published 2019-06-20 by Kevin Feasel

Niels Berglund shows how you can install Confluent Platform as a Docker container and use the .NET client against it:

What we see in Figure 16 are the various project related files, including the source file Program.cs. What is missing now is a Kafka client. For .NET there exists a couple of clients, and theoretically, you can use any one of them. However, in practice, there is only one, and that is the Confluent Kafka DotNet client. The reason I say this is because it has the best parity with the original Java client. The client has NuGet packages, and you install it via VS Code’s integrated terminal: dotnet add package Confluent.Kafka --version 1.0.1.1:

Definitely use the Confluent client. The others were from a time when there was no official driver; most aren’t even maintained anymore.

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Docker Desktop Resource Limits

Published 2019-06-20 by Kevin Feasel

Andrew Pruski lays out the default resource limits for Linux and Windows containers using Docker Desktop on Windows:

Docker Desktop is a great product imho. The ability to run Windows and Linux containers locally is great for development and has allowed me to really dig into SQL Server on Linux. I also love the fact that I no longer need to install SQL 2016/2017, I can run it in Windows containers.

However there are some differences between how Windows and Linux containers run in Docker Desktop. One of those differences being the default resource limits that are set.

Read on to see how they differ and how to deal with Windows container resources.

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The Banality of Containers

Published 2019-06-19 by Kevin Feasel

Grant Fritchey points out that containers hosting SQL Server are, in and of themselves, banal:

I’m only half joking when I say containers are boring and dull. They’re not. The technology is amazing. However, that technology doesn’t fundamentally change what you’re dealing with. It’s SQL Server. How do you capture detailed performance metrics in a container? Extended Events. How do you capture aggregated performance metrics and query plans in a container? Query Store. What’s the backup syntax for a database in a container? BACKUP DATABASE. We can keep going on this, but I won’t.

To a great extent, this is the same as SQL Server on Linux: once you have it installed, it works just like the Windows version (well, save for the things which aren’t there yet). All of the magical parts are in getting there.

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Containers and Data

Published 2019-06-13 by Kevin Feasel

Randolph West argues that you should keep data and containers separated:

Where it gets interesting is that the SQL Server container is also where the database files are stored by default. I raised a point (which Grant and others have already noted in the past) that persisted storage volumes allow us to throw away a SQL Server container without throwing away the database files, provided that the container is set up to use that persisted storage.

For example, I can map the SQL Server container to a local directory on my Ubuntu or Windows Server, or — as is the case with Kubernetes — a second container can serve as the storage volume. SQL Server is then just a compute engine, or a “service” as Anthony points out in the Twitter thread.

Because every rule has a counter-example (even this one), there are cases when you do want the data to live with the container. For example, a test database for a unit test runner should probably live inside the container rather than being a persisted volume. The reason is that you can blow away the database after a test run and start over for the next run. Putting together a database for a hackathon or user group can be another exception for the same reason. But for pretty much every other purpose, I’d rather have a persisted volume.

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Kubernetes + AGs + SQL Server 2019 CTP 3

Published 2019-06-11 by Kevin Feasel

Allan Hirt has a fix for an annoying bug in the latest CTP of SQL Server 2019:

I haven’t written much about them yet (key emphasis there …) but AGs now being supported for containers in SQL Server 2019 is a big deal. Recently, SQL Server 2019 CTP 3.0 was released, but there’s a slight problem: if you try to deploy an AG with Kubernetes, you may see the following errors when trying to deploy the pods with the YAML that contains their definition. The services (i.e. instances of SQL Server) get created, but the pods do not.

Read on for the root cause and the solution.

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SQL Server Containers: MCR vs Docker Hub

Published 2019-05-30 by Kevin Feasel

Randolph West notes that Microsoft is no longer updating SQL Server images on Docker Hub:

In October 2018, Microsoft announced a change to the source of their Docker containers. You should be using the new Microsoft Container Registry (MCR) as the source for official Docker container images for Microsoft products.

While existing container images in the Docker Hub are not affected, you may not get updated images unless you switch.

On the Docker Hub website, there are instructions on hitting the MCR:

Start a mssql-server instance using the latest update for SQL Server 2017

docker run -e 'ACCEPT_EULA=Y' -e 'SA_PASSWORD=yourStrong(!)Password' -p 1433:1433 -d mcr.microsoft.com/mssql/server:2017-latest

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Customizing a Docker Container

Published 2019-05-28 by Kevin Feasel

Grant Fritchey shows how you can take a Docker container and save modifications:

There are much more sophisticated ways to get this done using Docker Files. However, this illustrates the point quite simply. You can customize your servers and then use those customizations. You don’t have to re-customize every time. Again, this is just a small slice of why containers are so powerful.

This method is great when you want to build out a sample data set, like when you’re running through automated testing and want to start from the same known point each time.

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Creating Containers and Volumes

Published 2019-05-24 by Kevin Feasel

Grant Fritchey continues a dive into containers. First up is running a Docker container:

Let’s break this down a bit so you know what you just did. The two ‘-e’ statements are setting environment variables. The first is accepting Microsoft’s end user license agreement, EULA. The second is setting the SA password. By default, we’re running a Developer Edition of SQL Server here. If you want to, you can change to a version that you have a specific license for using the MSSQL_PID environment variable. Documentation for that is located here.

Next is using volumes:

Now, let’s create a new container, but, let’s use the same volume:
docker run -e 'ACCEPT_EULA=Y' ` -e 'SA_PASSWORD=$cthulhu1988' ` -p 1450:1433 ` --name DockerDemo19 ` -v sqlvol:/var/opt/mssql ` -d mcr.microsoft.com/mssql/server:2019-CTP2.5-ubuntu

What happens next is marvelous. 

It’s an exciting time to get into containers and if you’re feeling a little trepidatious, they’re containers—the worst thing you can do is mess one up and then you just blow it away and start over.

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Pulling Docker Images

Published 2019-05-22 by Kevin Feasel

Grant Fritchey starts us off slowly with containers:

The first command you have to learn is ‘docker pull’. You then have to supply something for it to pull, an image that will be used to create your containers. I’m using Powershell for the commands I’m posting this week. Here’s how you get an image with SQL Server 2017:

docker pull mcr.microsoft.com/mssql/server:2017-latest

Click through to learn more.

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SQL Server and Terraform

Published 2019-05-16 by Kevin Feasel

Andrew Pruski continues a series on using Terraform to deploy to Azure Container Instances:

In a previous post I went through how to deploy SQL Server running in an Azure Container Instance using Terraform.

In that post, I used hardcoded variables in the various .tf files. This isn’t great to be honest as in order to change those values, we’d need to update each .tf file. It would be better to replace the hardcoded values with variables whose values can be set in one separate file.

So let’s update each value with a variable in the .tf files.

Click through for a demo.

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