What I wish I had known when I started developing Lability DevTest Lab Environments

At Black Marble we have been migrating our DevTest labs to from on-premises TFS Lab Management to a mixture of on-premise and Azure hosted Lability defined Labs as discussed by Rik Hepworth on his blog. I have only been tangentially involved in this effort until recently, consuming the labs but not creating the definitions.

So this post is one of those I do where I don’t want to forget things I learnt the hard way, or to put it another way asking Rik or Chris after watching a 2 hour environment deploy fail for the Xth time.

  • You can’t log tool much. The log files are your friends, both the DSC ones and any generated by tools triggered by DSC. This is because most of the configuration process is done during boots so there is no UI to watch.
  • The DSC log is initially created in working folder the .MOF file is in on the target VM; but after a reboot (e.g. after joining a domain) the next and subsequent DSC log files are created in  C:WindowsSystem32ConfigurationConfigurationStatus
  • Make sure you specify the full path for any bespoke logging you do, relative paths make it too easy to lose the log file
  • Stupid typos get you every time, many will be spotted when the MOF file is generated, but too many such as ones in command lines or arguments are only spotted when you deploy an environment. Also too many of these don’t actually cause error messages, they just mean nothing happens. So if you expect a script/tool to be run and it doesn’t check the log and the definition for mismatches in names.
  • If you are using the Package DSC Resource to install an EXE or MSI couple of gotcha’s
    • For MSIs the ProductName parameter must exactly match the one in the MSI definition, and this must match the GUID ProductCode.  Both of these can be found using the Orca tool

      image

    • Package MongoDb {

      PsDscRunAsCredential = $DomainCredentialsAtDomain

      DependsOn = '[Package]VCRedist'

      Ensure = 'Present'

      Arguments = "/qn /l*v c:bootstrapMongoDBInstall.log INSTALLLOCATION=`"C:Program FilesMongoDBServer3.6`""

      Name = "MongoDB 3.6.2 2008R2Plus SSL (64 bit)"

      Path = "c:bootstrapmongodb-win32-x86_64-2008plus-ssl-3.6.2-signed.msi"

      ProductId = "88B5F0D8-0692-4D86-8FF4-FB3CDBC6B40F"

      ReturnCode = 0

      }

    • For EXEs the ProductName does not appear to be as critical, but you still need the Product ID. You can get this with PowerShell on a machine that already has the EXE installed
    • Get-WmiObject Win32_Product | Format-Table IdentifyingNumber, Name, Version
  • I had network issues, they could mostly be put does to incorrect Network Address Translation. In my case this should have been setup when Lability was initially configured, the commands ran OK creating a virtual switch and NetNat, but I ended up with a Windows failback network address of 169.x.x.x when I should have had an address of 192.168.x.x on my virtual switch. So if in doubt check the settings on your virtual switch, in the Windows ‘Networking and Share Center’ before you start doubting your environment definitions.

Hope these pointers help others, as well as myself, next time Lability definitions are written

Creating test data for my Generate Release Notes Extension for use in CI/CD process

As part of the continued improvement to my CI/CD process I needed to provide a means so that whenever I test my Generate Release Notes Task, within it’s CI/CD process, new commits and work item associations are made. This is required because the task only picks up new commits and work items since the last successful running of a given build. So if the last release of the task extension was successful then the next set of tests have no associations to go in the release notes, not exactly exercising all the code paths!

In the past I added this test data by hand, a new manual commit to the repo prior to a release; but why have a dog and bark yourself? Better to automate the process.

This can done using a PowerShell file, run inline or stored in the builds source repo and run within a VSTS build. The code is shown below, you can pass in the required parameters, but I set sensible default for my purposes

For this PowerShell code to work you do need make some security changes to allow the build agent service user to write to the Git repo. This is documented by Microsoft.

The PowerShell task to run this code is placed in a build as the only task

image

This build is then triggered as part of the release process

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Note that the triggering of this build has to be such that it runs on a non-blocking build agent as discussed in my previous posts. In my case I trigger the build to add the extra commits and work items just before triggering the validation build on my private Azure hosted agent.

Now, there is no reason you can’t just run the PowerShell directly within the release if you wanted to. I chose to use a build so that the build could be reused between different VSTS extension CI/CD pipelines; remember I have two Generate Release Note Extensions, PowerShell and NodeJS Based.

So another step to fully automating the whole release process.