SQL Server

Yesterday in this post I described a method to correct permissions when upgrading a SQL Server 2017 container using Data Volumes to 2019’s non-root container on implementations that use the Moby or HyperKit VM. My friend Steve Jones’ on Twitter wondered if you could do this in one step by attaching a shell (bash) in the 2017 container prior to shutdown. Absolutely…let’s walk through that here in this post.  I opted to use an intermediate container in the prior post out of an abundance of caution so that I was not changing permissions on the SQL Server instance directory and all of the data files while they were in use. Technically this is a-ok, but again…just being paranoid there.

Recently Microsoft released a Non-Root SQL Server 2019 container and that’s the default if you’re pulling a new container image. But what if you’re using a 2017 container running as root and want to upgrade your system the SQL Server 2019 container…well something’s going to break. As you can see here, my friend Grant Fritchey came across this issue recently and asked for some help on Twitter’s #sqlhelp. This article describe a solution to getting things sorted and running again. The scenario below is if you’re using a Linux based SQL Server container on Windows or Mac host where the container volumes are backed by a Docker Moby or HyperKit virtual machine. If you’re using Linux container on Linux, you’ll adjust the file system permissions directly.

I’m very pleased to announce that I will be speaking at PASS Summit 2019!  This is my second time speaking at PASS Summit and I’m very excited to be doing so! What’s more, is I get to help blaze new ground with an emerging technology,** Kubernetes and how to run SQL Server in Kubernetes**!

My session is “Inside Kubernetes – An Architectural Deep Dive” if you’re a just getting started in the container space and want to learn how Kubernetes works and dive into how to deploy SQL Server in Kubernetes this is the session for you. I hope to see you there!

People often ask me what’s the number one thing to look out for when running SQL Server on Kubernetes…the answer is memory settings. In this post, we’re going to dig into why you need to configure resource limits in your SQL Server’s Pod Spec when running SQL Server workloads in Kubernetes. I’m running these demos in Azure Kubernetes Service (AKS), but these concepts apply to any SQL Server environment running in Kubernetes.

Recently I needed to write a PowerShell script that could build a backup set from a collection of backups stored in Azure Blob Storage without any backup history available from MSDB. And as with all things SQL Server and PowerShell related I went straight to dbatools.io to see if Restore-DbaDatabase was up to the task…and of course, it is…let’s talk about how I solved this challenge.

When restoring from Azure Blob, the main challenge you have is accessing the blobs and building a backup set. For this process, you’ll need access to the Storage Account via PowerShell and you’ll have to have define a Credential on your SQL Instance that has access to the Storage Account. Here’s the code I used to connect to my Storage Account in Azure.

When working with SQL Server running containers the Error Log is written to standard out. Kubernetes will expose that information to you via kubectl. Let’s check out how it works.

If we start up a Pod running SQL Server and grab the Pod name

kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
mssql-deployment-56d8dbb7b7-hrqwj   1/1     Running   0          22m

We can usefollow flag and that will continuously write the error log to your console, similar to using tail with the -f option. If you remove the follow flag it will write the current log to your console. This can be useful in debugging failed startups or in the case below, monitoring the status of a database restore. When finished you can use CTRL+C to break out and return back to your prompt.

Pre-conference Workshop at SQLSaturday Denver

I’m proud to announce that I will be be presenting an all day pre-conference workshop at SQL Saturday Denver on October 11th 2019! This one won’t let you down!

The workshop is **“Kubernetes Zero to Hero – Installation, Configuration, and Application Deployment” **

    <a href="https://www.eventbrite.com/e/kubernetes-zero-to-hero-installation-configuration-and-application-deployment-tickets-70529350185"><img loading="lazy" style="display: block; margin-left: auto; margin-right: auto;" title="NewImage.png" src="/images/2019/01/Availability-Group-StatusNewImage-1.png" alt="NewImage" width="129" height="126" border="0" /></a>

    **Here’s the abstract for the workshop**

  <blockquote>

      Modern application deployment needs to be fast and consistent to keep up with business objectives and Kubernetes is quickly becoming the standard for deploying container-based applications, fast. In this day-long session, we will start with an architectural overview of a Kubernetes cluster and how it manages application state. Then we will learn how to build a production-ready cluster. With our cluster up and running, we will learn how to interact with our cluster, common administrative tasks, then wrap up with how to deploy applications and SQL Server. At the end of the session, you will know how to set up a Kubernetes cluster, manage a cluster, deploy applications and databases, and how to keep everything up and running.

  </blockquote>

Session Objectives

So, if you’ve been following my blog you know my love for internals. Well, I needed to find out exactly how something worked at the startup of a SQL Server process running inside a docker container and my primary tool for this is <a href="http://man7.org/linux/man-pages/man1/strace.1.html">strace</a>, well how do you run strace against processes running in a container? I hadn’t done this before and needed to figure this out…so let’s go through how I pulled this off.

A quick post about pulling docker containers (this applies to docker run too)…when specifying the container image, the container image name and tag are case sensitive. We’re not going to discuss how much time troubleshooting it too me to figure this out…but let’s just say it’s more than I care to admit publicly.

In this code you can see I’m specifying the following image and tag server:2019-rc1-ubuntu (notice the lowercase rc in the tag)

In the first two posts in this series we discussed the need for data persistency in containers then we discussed where the data actually lives on our systems. Now let’s look at specifying the location of the data on the underlying file system of the base OS.

This is the third post in a three part series on Persisting SQL Server Data in Docker Containers. The first post introducing Docker Volumes is here. The second post on where Docker actually stores your data is here.