Voice of the DBA

Tag: DevOps

  • DevOps – Downloading a File from the Internet with PoSh

    One of the things we need to do as data professionals is move data files around. Often we’ll get a local path, but in looking for public data sets, I wanted to get a file from the Internet. In this case, a rather large file.

    I could have put the URL in a browser, but the file was slow to load, and while waiting ten minutes or so for the download to complete and doing a “Save As” is quick, it isn’t easily repeatable. Plus, since I needed to get a few files, and might need to do it again, I thought a PoSh download would be better.

    A quick search turned up a few options. I could use System.Net.WebClient, or I could use Invoke-WebRequest. I decided to use the latter because it could use credentials or even parse the file prior to doing some save.

    I just had a simple item, so I used:

    Invoke-WebRequest -Uri “http://labrosa.ee.columbia.edu/millionsong/sites/default/files/AdditionalFiles/unique_tracks.txt” -OutFile “e:\Downloads\unique_tracks.txt”

    I could easily have wrapped this in a function to simulate a copy command, and I may do that at some point. For now, I can drop this in a file, copy/paste, and change a few filenames.

    If this were part of a regular process, such as getting files from a remote web server, I could easily automate this in a task on some server. For now, this is a quick, easy way to get a file from the Internet without a browser.

  • DevOps Can Help

    Amazon had a load balancer failure in 2012. The analysis of the event shows that there were missing data in the devices that caused issues. The restore of data from these devices is complex, way more complex with less mature tools than most database platforms. The result was a nearly 10 hour period of time when some customers were experiencing issues.

    In 2016, Gliffy had three days of downtime from a database error. In this case, an admin was updating a replicated system, but failed to sever a link with the primary node. Forgetting this step caused a data removal on the node, which replicated to the secondary nodes. They discovered the restore and replay of logs would take many days due to the size. They hadn’t practiced a DR situation in some time, and were not prepared for the delays.

    Digital Ocean received alerts earlier in 2017 that some services were not functioning. They traced this down to the primary database being deleted. The issue was a process used the wrong credentials for automated testing, and I’m guessing that part of the testing was removing and rebuilding a database. Five hours across the middle of the night resulted in the main database being restored, and a couple more hours to get replicas caught up.

    In the first two cases, there were issues with the deployment of changes to systems, as well as inadequate backup and restore processes. In both of these cases, I would argue that a good DevOps process would have automated the way the code was deployed, including ensuring that steps weren’t forgotten or predeployment backups captured the state of configuration. DevOps includes the “Ops” changes and should ensure that all state information is captured and stored in a VCS. If this had been done, it’s possible that these companies wouldn’t have had these issues.

    In the last case, certainly whoever sets up a system is responsible for using the correct credentials. While it’s easy to say that a developer or tester shouldn’t know the production credentials, but it’s entirely possible that the person that configured the process would have the credentials. I don’t know what to do here, as the first test of this might cause the issue. Maybe a second set of eyes is important for security changes in automated systems? That certainly could be part of your DevOps process. What I’d like here is two factor authentication for all security setup, including for SQL Server.

    DevOps isn’t a prescriptive set of things that someone does. Whenever I talk with people about DevOps and they give reasons why a particular step I’ve demonstrated won’t work for them, I tell them to stop doing that step. After all, the way you implement DevOps doesn’t have to match what I did. We each need to do what works for our environment, and ensure we have some consistency and repeatability in our process. Hopefully preventing downtime from simple mistakes.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 4.2MB) podcast or subscribe to the feed at iTunes and Libsyn.

  • T-SQL Tuesday #91–Early DevOps

    tsqltuesdayThis month the T-SQL Tuesday invitation is from Grant Fritchey, my colleague at Redgate Software. Surprise, surprise, the topic is DevOps.

    I write and talk about this a lot, but for this month I’ll look back at DevOps for me in 2001.

    If you want to participate in the blog party, you need to publish on the second Tuesday of the month, GMT time. You can see the invitations at tsqltuesday.com.

    2001, A DBA’s Journey

    I started working for a small startup in 2001. I was the DBA (dev and production) with 4-5 developers. Eventually we grew to 10 developers, a couple QA people, and a UX person. Our goal was to release code every Wednesday night, and developers would work from Tues-Mon am on that week’s changes.

    The initial plan when I started was to get together with the lead dev and produce the scripts to upgrade our web application as well as the database. Early on we had a small system, so it was a few hours on Monday afternoon putting together a script for the QA server. Inevitably we’d make changes if QA found issues, and then Wednesday night we’d go into the office and usually spend a few hours deploying and fixing things. Often we had another developer or two with us to ensure that we could get the changes out.

    Over a few months we started to try and smooth our process. We talked about the issues, and started small. First with version control, Visual SourceSafe at that time. We’d get everyone to check in changes, which let us more easily determine what had changed that week.

    We also talked about what made life easier for the lead dev and me. How could we package code to easily ensure it gets deployed. For the database, this meant ensuring all files were named easily and branched to a folder.

    Ultimately, the technical challenges were few. A few scripts that automatically packaged changes for us and deployed them. However, the biggest challenge was cultural. Getting all the developers to think forward about what was needed to get code to production and slightly alter their behavior. We also had to break habits of “fixing” code in QA. We had to learn to reset QA, change our scripts in version control, and then redeploy.

    Sharing information, communicating, and adhering to a consistent process for deployments, ensuring that we practiced our production deployment on QA, helped us move to a release process that consisted of a phone call and a few minutes instead of a late night at the office.

    DevOps works, but you have to work at building a process for your environment.

  • VSTS–Changing the Default Build Queue

    I wrote recently about the Release agent using the hosted queue as the default, which is sometimes a problem. The Build process has the same issue, though the way you change things is different.

    In a build, you see a set of tasks with various menu items across the top, as shown here.

    2017-06-01 19_48_11-Build-CI - Visual Studio Team Services

    If you click on Options, which will then be underlined, on the right side the Agents options appear. The default, as with releases, is the hosted agent. Change this to another pool if you want local builds.

    2017-06-01 19_48_19-Build-CI - Visual Studio Team Services

    Microsoft makes this the default for a couple reasons. One, it’s easier. No need to install an agent, which might be an issue for some people. I think it’s simple, but for some teams, you might not want this.

    The other reason is that while you get 240 minutes per month, if you’re like me and built often, you can blow by this. Also, I have machines available, so I’d rather build locally, and I wish I could make this a default.

    Microsoft wants to make money, and that’s fine. I like the service, and in a commercial environment I’d weight the cost here v purchasing something like TeamCity + add-ons, and then make a decisions. Since I dislike uncertainty, and not knowing the costs, I lean towards local builds always. YMMV.