Safely running windows automation operations that fail inside winrm or powershell remoting by Matt Wrock

Me and a couple colleagues engaging in our ceremonial preparation for running scheduled tasks. The robes chafe but not as bad as the tasks.

Me and a couple colleagues engaging in our ceremonial preparation for running scheduled tasks. The robes chafe but not as bad as the tasks.

In many ways I like windows powershell more than bash and even powershell remoting over SSH. Please don't hate me. However, in spite of some of the clever things you can do with treating remote sessions as objects and manipulating them as such in powershell, its all fun and games until you start getting HResults thrown in your face trying to do something you'd think was the poster child use case for remoting like installing windows updates on a remote machine.

In this post I'm going to discuss:

  • Some common operations, that I am aware of, that can cause one to get into trouble automating remotely on windows
  • Approaches for working around these issues
  • Using a tool like Boxstarter on  100% windows automation or the Boxstarter cookbook in chef runs on Test-KitchenChef Provisioning or Vagrant provisioning where WinRM is the transport mechanism

To be clear 95% of all things local can be done remotely without incident on windows if not more. This post gives voice to the remaining 5%.

Things that don't work

This may come as a surprise to those used to working over ssh where things pretty much behave just as they do locally, but in the world of remote shells on windows, there are a few gotchas that you should be aware of. Quickly here are the big ones:

  • Working with the windows update interfaces simply don't work
  • Accessing network resources like network shares, databases or web sites that normally leverage your current windows logon context will fail unless using the correct authentication protocol
  • Installing MSIs or other installers that depend on either of the above resources (SQL Server, most .Net Framework installers) will not install successfully
  • Accessing winrm client configuration information like max commands per shell and user, max memory per shell, etc. on windows OS versions below win 8/2012 result in Access Denied errors.

What does failure look like?

I can say this much. Its not pretty.

Windows update called in an installer

Lets try to install the .net framework v 4.5.2. I'm going to do this via a normal powershell remoting session on windows v 8.1 that ships with .net v 4.5.1 but if you are not on a windows box, you can certainly follow along by running this through the WinRM ruby gem or embedding it in a Chef recipe:

function Get-HttpToFile ($url, $file){
    Write-Verbose "Downloading $url to $file"
    if(Test-Path $file){Remove-Item $file -Force}
    $downloader=new-object net.webclient
    try {
        $downloader.DownloadFile($url, $file)
        if($VerbosePreference -eq "Continue"){
            Write-Error $($_.Exception | fl * -Force | Out-String)
        throw $_

Write-Host "Downloading .net 4.5.2.."
Get-HttpToFile `
Write-Host "Installing .net 4.5.2.."
$proc = Start-Process "$env:temp\net45.exe" `
  -verb runas -argumentList "/quiet /norestart /log $env:temp\net45.log"`
while(!$proc.HasExited){ sleep -Seconds 1 }

This should fail fairly quickly. A look at the log file - the one specified in the installer call (note that this will be output in html format and given an html extension) reveals the actual error:

Final Result:
Installation failed with error code: (0x00000005), "Access is denied."

If you investigate the log further you will find:

WU Service: EnsureWUServiceIsNotDisabled succeeded
Action: Performing Action on Exe at C:\b723fe7b9859fe238dad088d0d921179\x64-Windows8.1-KB2934520-x64.msu
Launching CreateProcess with command line = wusa.exe "C:\b723fe7b9859fe238dad088d0d921179\x64-Windows8.1-KB2934520-x64.msu" /quiet /norestart

Its trying to download installation bits using the Windows Update service. This not only occurs in the "web installer" used here but also the full offline installer as well. Note that this script should run without incident locally on the box. So quit your crying and just logon to your 200 web nodes and run this. What's the freaking problem?

So its likely that the .net version you plan to run is pre baked in your base images already, but what this illustrates is that regardless of what you are trying to do, there is no guarantee that things are going to work or even fail in a comprehensible manner. Even if everyone knows what wusa.exe is and what an exit code of 0x5 signifies.

No access to network resources

To quickly demonstrate this, I'll list the C:\ drive of my host computer from a local session using a Hyper-V console:

PS C:\Windows\system32> ls \\ultrawrock\c$

    Directory: \\ultrawrock\c$

Mode                LastWriteTime     Length Name
----                -------------     ------ ----
d----         1/15/2015   9:32 AM            chef
d----        12/12/2014  12:51 AM            dev
d----         9/10/2014   3:44 PM            Go
d----         11/5/2014   7:24 PM            HashiCorp
d----        12/10/2014  12:13 AM            Intel
d----        11/16/2014  11:10 AM            opscode
d----         11/4/2014   5:23 AM            PerfLogs
d-r--         1/10/2015   4:30 PM            Program Files
d-r--         1/17/2015   1:11 PM            Program Files (x86)
d----        12/11/2014  12:33 AM            RecoveryImage
d----        11/16/2014  11:40 AM            Ruby21-x64
d----        12/11/2014  10:26 PM            tools
d-r--        12/11/2014  12:31 AM            Users
d----        12/26/2014   5:24 PM            Windows

Now I'll run this exact same command in my remote powershell session:

[]: PS C:\Users\Matt\Documents> ls \\ultrawrock\c$
ls : Access is denied
    + CategoryInfo          : PermissionDenied: (\\ultrawrock\c$:String) [Get-ChildItem], UnauthorizedAccessException
    + FullyQualifiedErrorId :
 ItemExistsUnauthorizedAccessError, Microsoft.PowerShell.Commands.GetChildItemCommand

ls : Cannot find path '\\ultrawrock\c$' because it does not exist.
    + CategoryInfo          : ObjectNotFound: (\\ultrawrock\c$:String) [Get-ChildItem], ItemNotFoundException
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.GetChildItemCommand

Note that I am logged into both the local console and the remote session using the exact same credentials.

It should be pretty easy to see how this could happen in many remoting scenarios.

Working around these limitations

To be clear, you can install .net, install windows updates and access network shares remotely on windows. Its just kind of like Japanese Tea Ceremony meets automation but stripped of beauty and cultural profundity. You are gonna have to pump out a bunch of boiler plate code to accomplish what you need.

What?...I'm not bitter.

Solving the double hop with CredSSP

This solution is not so bad but will only work for 100% windows scenarios using powershell remoting (as far as I know). That may likely work for most but breaks if you are managing windows infrastructure from linux (read on if you are).

You need to create your remote powershell session using CredSSP authentication:

Enter-PSSession -ComputerName MyComputer `
                -Credential $(Get-Credential user) `
                -Authentication CredSSP

This also requires CredSSP to be enabled on both the host (client) and guest (server):


Enable-WSManCredSSP -Role Client -DelegateComputer * -Force

This states I can delegate my credential via any server. I could also provide an array of hosts to allow.


Enable-WSManCredSSP -Role Server -Force

If you are not in a windows domain, you must also edit the local Group Policy (gpedit from any command line) on the host and allow delegating fresh credentials:

After invoking the Group Policy Editor with gpedit.msc, navigate to Local Computer Policy/Computer Configuration/Administrative Templates/System/Credential Delegation. Then select Allow delegating fresh credentials in the right pane. In the following window, make sure this policy is enabled and specify the servers to authorize in the form of "wsman/{host or IP}". The hosts can be wild carded using domain dot notation. So * would effectively allow any host in that domain.

In case you want to automate the clicking and pointing, see this script I wrote that does just that.

Now here is a kicker: you cant use the Enable-WSManCredSSP cmdlet in a remote session. The server needs to be enabled locally. Thats ok. You could use the next work around to get around that.

Run locally with Scheduled Tasks

This is a fairly well known and somewhat frequent work around to get by this whole dilemma. I'll be honest here, I think the fact that one has to do this to accomplish such routine things as installing updates is ludicrous and I just don't understand why Microsoft does not remove this limitation. Unfortunately there is no way for me to send a pull request for this.

As we get into this, I think you will see why I say this. Its a total hack and a general pain in the butt to implement.

A scheduled task is essentialy a bit of code you can schedule to run in a separate process at a single time or interval. You can invoke them to run immediately or upon certain events like logon. You can provide a specific identity under which the task should run and the task will run as if that identity is logged on locally. There is full GUI interface for maintaining and creating them as well as a command line interface (schtasks) and also a set of powershell cmdlets in powershel v3.0 forward.

To demonstrate how to create, run and remove a task, I'll be pulling code from Boxstarter, an OSS project I started to address windows environment installs. Boxstarter uses the schtasks executable to support earlier powerhell versions (pre 3.0) before the cmdlets were created.

Creating a scheduled task

schtasks /CREATE /TN 'Temp Boxstarter Task' /SC WEEKLY /RL HIGHEST `
         /RU "$($Credential.UserName)" /IT `
         /RP $Credential.GetNetworkCredential().Password `
         /TR "powershell -noprofile -ExecutionPolicy Bypass -File $env:temp\Task.ps1" `

#Give task a normal priority
$taskFile = Join-Path $env:TEMP RemotingTask.txt
Remove-Item $taskFile -Force -ErrorAction SilentlyContinue
[xml]$xml = schtasks /QUERY /TN 'Temp Boxstarter Task' /XML

schtasks /CREATE /TN 'Boxstarter Task' /RU "$($Credential.UserName)" `
         /IT /RP $Credential.GetNetworkCredential().Password `
         /XML "$taskFile" /F | Out-Null
schtasks /DELETE /TN 'Temp Boxstarter Task' /F | Out-Null

This might look a little strange so let me explain what this does (see here for original and complete script). First it uses the CREATE command to create a task that runs under the given identity to run whatever script is in Task.ps1. One important parameter here is /RL, the Run Level. This can be set to Highest or Limited. We want to run with highest privileges. Finally, note the use of /IT - interactive. This is great for debugging. If the identity specified just so happens to be logged into a interactive session when this task runs, any GUI elements will be seen by that user.

Now for some reason the schtasks CLI does not expose the priority to run the task with. However you can serialize any task to XML and then manipulate it directly. I found that this was important for Boxstarter which often invoked immediately after a fresh OS install. Things like Windows Updates or SCCM installs quickly take over and Boxstarter may get significantly delayed waiting for its turn so it at least asks to run with a normal priority.

After we save this file, that's not enough to simply change the priority. We now have to recreate a new task based on that XML using schtasks otherwise our identity is lost. Boxstarter will create this task once and then reuse it for any command it needs local rights for. It then deletes it in a finally block when it is done.

Running the Scheduled Task

I'm not going to cover all of the event driven mechanics or interval syntax since I am really referring to the running of ad hoc tasks. To actually cause the above task to run is simple:

$taskResult = schtasks /RUN /I /TN 'Boxstarter Task'
if($LastExitCode -gt 0){
    throw "Unable to run scheduled task. Message from task was $taskResult"

Since schtasks is a normal executable, we check the exit code to determine if it was successful. Note that this does not indicate if the script that the task runs is successful, it simply indicates that the task was able to be launched. For all we know the script inside the task fails horribly. The /I argument informs RUN to run immediately.

I'm going to spare all the code details for another post, but boxstarter does much more than just this when running the task. At the least you'd want to know when the task ends and have access to output and error streams of that task. Boxstarter finds the process, pumps its streams to a file and interactively reads from those streams back to the console. It also includes hang detection logic in the event that the task gets "stuck" like with a dialog box and is able to kill the task along with all child processes. You can see that code here in its Invoke-FromTask command.

An example usage of that function is when Boxstarter installs .net 4.5 on a box that does not already have it:

if(Get-IsRemote) {
  Invoke-FromTask @"
    Start-Process "$env:temp\net45.exe" -verb runas -wait `
      -argumentList "/quiet /norestart /log $env:temp\net45.log"

This will block until the task completes and ensure stdout is streamed to the console and stderr is captured and bubbled back to the caller.

The Boxstarter cookbook for x-plat use

I developed Boxstarter with a 100% windows world in mind. That was my world then but my world is now mixed. I wanted to leverage some of the functionality in boxstarter for my chef runs without rewriting it (yet). So I created a Chef Boxstarter Cookbook that could install the powershell modules on a converging chef node and convert any block of powershell in a recipe into a Boxstarter "package" (a chocolatey flavored package) that can run inside of a boxstarter context within a chef client run. This can be placed inside a client run launched from Test-Kitchen or Chef-Provisioning both which can run via WinRM on a remote node. One could also use it to provision vagrant boxes with the chef zero provisioner plugin.

Here is an example recipe usage:

include_recipe 'boxstarter'
default['boxstarter']['version'] = "2.4.159"

boxstarter "boxstarter run" do
  password default['my_box_cookbook']['my_secret_password']
  disable_reboots false
  code <<-EOH
    cinst console2
    cinst fiddler4
    cinst git-credential-winstore
    cinst poshgit
    cinst dotpeek

    Install-WindowsUpdate -acceptEula

You can learn more about boxstarter scripts at but they can contain ANY powershell and have the chocolatey modules loaded so all chocolatey commands exist and also expose some custom boxstarter commands for customizing windows settings (note the first two commands) or installing updates. Boxstarter will detect pending reboots and unless asked otherwise, it will reboot upon detecting a pending reboot - bad for production nodes but great for a personal dev environment.

A proof of concept and a bit rough

The boxstarter cookbook is still rough around the edges. It does what I need it to do and I have not invested much time in it. The output handling over WinRM is terrible and it needs more work making sure errors are properly bubbled up.

At any rate, this post is not intended to be a plug for boxstarter but it demonstrates how to get around the potential perils one may encounter inside of a remote windows session either in powershell directly or from raw WinRM from linux.

Installing user gems using chef by Matt Wrock

In my experience installing server infrastructure using Chef, I usually use the chef_gem resource to install a gem that's needed in order to orchestrate the setup process. These are gems that are consumed by chef, or a chef resource to converge a node. However last night I was editing a chef recipe that's included in a chef_workstation cookbook that my team at CenturyLink Cloud uses for provisioning developer vagrant boxes and our TeamCity build agents. I have bloged about that in more detail here. The recipe I was working on is responsible for installing all of the gems we use in our chef dev process. They include both publicly available knife plugins and internally authored tools as well. These gems are consumed by the user of the vagrant box and not chef directly.

The bash force approach

This was one of the first cookbooks we created when we had limited knowledge of chef, ruby and how gems worked in general - alas our knowledge still has limits but they are much less restrictive. So this recipe looked something like this:

bash "install chef gems" do
  code <<-EOS
    su - #{node["chef_workstation"]["user"]} -c "chef gem install my-gem-1"
    su - #{node["chef_workstation"]["user"]} -c "chef gem install my-gem-2"
    su - #{node["chef_workstation"]["user"]} -c "chef gem install my-gem-3"

As you can see we were just running this via bash. Really this is fine and it worked. There is alot to be said for something that works. When we were putting this cookbook together we found that using chef_gem or gem_package installed the gems into the root user's directory making them inaccesible to the vagrant user. So using su was our workaround.

Recently we started using Nexus as an internal gem repository that seems to have slightly different install behavior from rubygems or artifactory. The former repositories would always install the latest gem assuming we had no constraints. Nexus would not install anything if any version of the requested gem was already installed. This did not work well for our internal gem workflow where we expect a vagrant provision to always install the latest gem.

Using gem_package

My first thought was to use the raw ruby gem modules to check for updates, install if the gem was missing or run an update if there was a newer version. That could have worked but it just seemed like I must be reinventing a wheel so I revisited the gem_package docs. Not sure why, but I didn't find anything meeting my needs on StackOverflow or the other google results I was turning up.

After reviewing the docs and a couple of initial failed attempts I landed on the right attribute values that yielded what worked:

%w[clc-gem1 clc-gem2 clc_gem-amazing].each do |gem|
  gem_package gem do
    source node["clc_nexus"]["repo"]["localgems"]
    gem_binary "/opt/chefdk/embedded/bin/gem"
    options "--no-user-install"
    action :upgrade

The key attributes here are gem_binary and options. Because I lean toward the idiot side of the intelligence spectrum, I had initially written off the gem_binary attribute thinking it was pointing to where to install binary gems. Nope, its intended to point to the location of the gem bin you want to use. Handy when you have multiple ruby installs. We use the chefdk on our vagrant boxes so that's where I point the gem_binary attribute.

The other not so obvious thing to add is the --no-user-install option. Since chef is running as root, if this is not specified, the gems are installed in /home/root. By specifying --no-user-install, the gems are installed in the shared ruby gems location. This may not be ideal and I'm sure there must be a way to get it in the vagrant user directory, but for the purposes of our vagrant environments, this works well.

Building, signing and deploying click-once and Azure web sites without Visual Studio installed by Matt Wrock

A few weeks ago, I repaved my windows laptop with the technical preview of windows 10. As I explained in last week's post, I have not been doing a whole lot of .net development these days and therefore have not been using Visual Studio much either. So I removed Visual Studio, Sql Server and a couple other heavy installs from my boxstarter script that I do not use. However, I do still actively maintain a project that is largely a collection of powershell modules but also includes a small click-once installer and a Razor based web site hosted on Azure that serves the documentation and latest download.

Both the click-once and web application are housed within Visual Studio projects and each include a .csproj file that drives the build. In the past I have always had Visual Studio installed and therefore had all the build tools on hand such as msbuild.exe, signtool.exe and web deploy that my build script could call to build and deploy the bits.

Well it was time to push out a maintenance release the other day and I wanted to do so without installing Visual Studio. Don't get me wrong, Visual Studio is an incredible tool but if you don't need it, why install it? Its quite large and my 128GB SSD is rather greedy. This is not only sound reasoning for a developer machine but it is even more applicable to a build server. I have known lots of folks who think they need to install Visual Studio on the build server in order to build their .net apps. Perhaps there are a couple edge cases where this is so but for most build and deploy tasks, the tools you need can be downloaded separately.

I'll cover the pieces I use to build and deploy Boxstarter here and walk you through the key build tasks. You can find the entire build script here which includes tasks for building and running Pester tests as well as the one task I run that deploys the packages to Chocolatey, creates a github release with zip file and deploys the web bits and click-once installer to Azure. Let me tell you it is very convenient to deploy everything with a single command. There is no database so its easy.

Compiling with msbuild

Both my click-once install and my web project need to be compiled to a .dll. This is done via msbuild. While msbuild does come included with visual studio, it can be downloaded separately with the Microsoft Build Tools. I get this and most other build prerequisites from Chocolatey:

task Install-MSBuild {
    if(!(Test-Path "$msbuildExe")) { cinst microsoft-build-tools }

task Build-Web -depends Install-MSBuild, Install-WebAppTargets {
    exec { .$msbuildExe "$baseDir\Web\Web.csproj" /t:Clean /v:minimal }
    exec { .$msbuildExe "$baseDir\Web\Web.csproj" /t:Build /v:minimal /p:DownloadNuGetExe="true" }
    copy-Item -Path "$baseDir\packages\bootstrap.3.0.2\content\*"`
      -Destination "$baseDir\Web" -Recurse -Force `
      -ErrorAction SilentlyContinue

Note that my build uses psake which compose the build from calls to a powershell function, Task, that define a script block to specify the code that the task actually runs. These tasks can optionally include dependencies which must be run prior to the task. Here my Build-Web task depends on Install-MSBuild to check and install the msbuild tools if they are not already installed.

Web application targets

Plain msbuild comes with most of the standard target files needed to build most visual studio project types. For whatever reason, web projects reference target files located in the visual studio install. However you can obtain these files by installing the MSBuild.Microsoft.VisualStudio.Web.targets nuget package. This check and potential install is handled in the Install-WebAppTargets task of my build script:

task Install-WebAppTargets {
    if(!(Test-Path "$env:ChocolateyInstall\lib\MSBuild.Microsoft.VisualStudio.Web.targets.12.0.4\tools\VSToolsPath\WebApplications\Microsoft.WebApplication.targets")) { 
        cinst MSBuild.Microsoft.VisualStudio.Web.targets -source -version '12.0.4'

I also edit the path to Microsoft.WebApplication.targets at the end of my web project's .csproj file to reference these targets from the chocolatey lib directory:

<Import Project="$(ChocolateyInstall)\lib\MSBuild.Microsoft.VisualStudio.Web.targets.12.0.4\tools\VSToolsPath\WebApplications\Microsoft.WebApplication.targets" Condition="'$(VSToolsPath)' != ''" />

Code signing the click-once payload

Boxstarter can be invoked from a URL which leverages "click-once" technology. Click-once apps must be signed with a valid code signing certificate. Although I invoke the click-once build with msbuild.exe:

task Build-ClickOnce -depends Install-MSBuild, Install-Win8SDK {
    Update-AssemblyInfoFiles $version $changeset
    exec { .$msbuildExe "$baseDir\Boxstarter.ClickOnce\Boxstarter.WebLaunch.csproj" /t:Clean /v:minimal }
    exec { .$msbuildExe "$baseDir\Boxstarter.ClickOnce\Boxstarter.WebLaunch.csproj" /t:Build /v:minimal }

Boxstarter.WebLaunch.csproj includes a post build step that signs the click once payload with my certificate:

<PostBuildEvent>"$(WindowsSDK80Path)bin\x64\signtool.exe" sign /n "Open Source Developer," "$(ProjectDir)obj\debug\Boxstarter.WebLaunch.exe"</PostBuildEvent>

Note that this assumes that I have imported a certificate into my user certificate store that has the subject name: "Open Source Developer," and that it includes the private key.

As you can see, signtool.exe lives in the Windows 8.1 SDK which is not included with the build tools that provide msbuild. You will need to install the windows 8.1 SDK available here. I install it via chocolatey like most others in polite society:

task Install-Win8SDK {
  if(!(Test-Path "$env:ProgramFiles\Windows Kits\8.1\bin\x64\signtool.exe")) {
    cinst windows-sdk-8.1 

Deploying to Azure Websites

When I initially created the web project in Visual Studio, I used to use the visual studio UI to deploy the files to my azure website. That works well but I wanted to include it as a step in my command line build. This is accomplished by calling msbuild with the correct properties describing the publish properties and password to use:

task Publish-Web -depends Install-MSBuild, Install-WebDeploy {
    exec { .$msbuildExe "$baseDir\Web\Web.csproj" /p:DeployOnBuild=true /p:PublishProfile="boxstarter - Web Deploy" /p:VisualStudioVersion=12.0 /p:Password=$env:boxstarter_publish_password }

The key properties here are the profile name and password. I keep my password in an environment variable so I don't store it in clear text on github. You can get both the profile name and password from the azure portal:

This downloads an xml file with both the name and password embedded inside.

In order for this to work without visual studio installed, you will need to install Web Deploy available here. Because I'm not a barbarian, I grab this from Chocolatey:

task Install-WebDeploy {
    if(!(Test-Path "$env:ProgramW6432\IIS\Microsoft Web Deploy V3")) { 
      cinst webdeploy 

Wrapping up with psake

As mentioned above, I use psake to drive the build and manage all of the task dependencies. If you don't care for programming in xml and especially if you are comfortable with powershell, you may find psake much more palatable than dressing up csproj and target files.

I've wrapped the call to invoke psake in a simple batch file, build.bat, so that the build can be invoked either from powershell or the Fisher-Price style command line CMD.exe making it compatible with any build server.

So simply typing build followed by the task name I want to run, kicks off my build:

build deploy # runs build, tests and packages everything for deployment
build Push-Public # deploys to chocolatey, github and azure

From full microsoft stack to cross platform development by Matt Wrock

I've been wanting to write about this for some time. About 8 months ago I not only left my software engineering position at Microsoft but I pivoted technology stacks all together and plunged into an entirely new and different technology ecosphere.  This was not a calculated move to abandon the Microsoft platforms (windows, .net, powershell, visual studio, etc, etc...) nor was it a reactionary vote of no confidence in the Microsoft based developer community. Over the past few years I have developed a growing passion and involvement in automation tooling. Over time this involvement consumed my "after hours" time and while it certainly occupied a fair amount of my work at Microsoft, I was presented with a super compelling opportunity at CenturyLink Cloud where I could cultivate this passion all day long (not JUST nights and weekends). Like many companies that are not Microsoft, it so happens that we use tools, infrastructure and development stacks that are not entirely Microsoft based.

Much of our back end runs on linux, there is no hyper-v here,  and our automation leverages Chef and is therefore saturated with ruby based tools. As a result, I have not written a line of C# or SQL in the last six months and I have opened visual studio no more than a handful of times. I read and write ruby everyday and have been contributing much of my spare time to ruby based open source projects like Vagrant, Test-Kitchen, and the ruby WinRM gem, my primary IDE is a text editor (sublime text 3), and my work funded laptop natively runs an Ubuntu 14.04 desktop. Let me tell you - this is a very different world and this post will attempt to describe some of the ways in which it is different from my experiences in the Microsoft world.

Again, I want to make it clear that I do not see this "pivot" as a conversion or even evolution to something better. While I do absolutely feel that some of the technologies I am working with are "better," there is alot that I miss and other areas that are just plain "grey." For example, I love just opening a text editor and writing code in a much simpler and snappier environment but there are moments that I yearn for some of the debugging and refactoring effeciencies that visual studio (and its plugins like resharper) provided. I'll probably dedicate a separate post to C# vs ruby but I still think C# is one kick ass language and while there are areas of ruby I have learned to love (and I am appreciating it more over time) I'd prefer a statically typed compiler aided language for not all but certainly my larger projects.

Differences are more cultural than technical

As I review the nuances that strike me as most profoundly different between the cross-platform world (this may not be the best term to use here but I'm sticking with it) and the MS-centric world, these tend to gravitate more strongly toward cultural differences than technical differences. Sure there are some fundamental distinctions to be found in the underlying architecture of linux and windows. If I were writing this just 5 years ago I'd be more tempted to give these differences more discussion but Microsoft has filled in some significant gaps and while its still "different," its really the culture that captures my attention.

What do I mean by culture? Well its just not interesting to compare and contrast these tools in terms of differing feature sets (but I will). Rather, there is a distinct and unique ethos in how these tools are composed and how their users value this composition and how they expect to interact with the tooling ecosystem that I find fascinating. Why is linux better than windows, why is C# better than GO, how do ruby gems differ from nuget packages? There is definitely some juice in all of these discussions but they will all eventually lead any observer of these debates to notice key character differences between these communities and what they value in the technology they build and consume.

So I am going to point out some of the characteristics of the cross platform community that I have found personally most notable. Look, this is a broad group and it is impossible to justifiably lump them into a cohesive community like I am doing here. More so today than ever there is growing "cross over" between this "cross-platform" community and the Microsoft stack developer communities. However, anyone who has spent any significant amount of time interacting with both camps will likely agree that the experience of interacting with one compared to the other evokes similar comparisons to groups that share different political or religious affiliations.

Open Source is normal

Yes...yes...I know Microsoft has recently made several announcements regarding the open sourcing of several significant formerly proprietary closed source technologies they own. What I think is key here is how in 2014, that is such a big deal. In so many pockets of the cross-platform world, its just how teams work. I personally share this value and I applaud those at Microsoft who have worked very hard to make this happen. But trust me, cultural wars have been raging inside the walls of Microsoft to push these projects to OSS and I assure you some of the coals are still quite hot.

Microsoft is in no way alone its struggle to open source its source code. Many, particularly larger, companies find themselves needing to wage internal campaigns to do the same. But my experience in the ruby community where I am most involved right now and its java, go and node cousins is that open sourcing and in many cases even your company's core IP is common place. Now I could go off on the virtues of why I think this is a wonderful thing and maybe, just maybe, unicorns and humans would peacefully coexist within the same halls if all code were open source, but instead I want to point out that differing attitudes of open source development reflect different mindsets and ways of viewing outside developers and development teams.

The open source adverse, may see OSS projects as the fruit of the "hobbyist" or "enthusiast" developer and not necessarily the product of highly skilled developer teams. This group may also see OSS as a threat either because it would expose "secret sauce" IP or sacrifice revenue opportunities because now the very thing you would charge for is freely available. I'm not "exposing" these views as unfounded at all. One has to walk carefully here but there are going to be distinct differences in the work habits and collaboration patterns of those who embrace open source and those that resist it or even just choose not to participate.

Personally my experience here has been largely positive. Even though someone else may be technically profiting from the contributions of my "work product," my contributions give me a voice in the direction of software that may not be "mine" but provides core services to my own product. It also gives full transparency into how a body of code works and exposes to myself and everyone else any key flaws that might exist in tools that I use and provide a way for me to either fix or work around problems.

Whether I pay for this software that I do not have time to write or not, the fact that I can read the source often proves itself to be invaluable to me in order to learn how to best use it or to solve blocking problems I might be facing as I use the software.

Now I will admit that there have been times of utter frustration where I just want the software to work as advertised and I'm pissed that I have to spend hours deep diving through someone else's code to figure out why I'm getting an UnspecifiedParameterException. But you know, I'd rather do that and learn some things in the process than spend the same amount of time on phone calls and emails with customer support. It also feels good to look at the code and see my github icon on the contributor list knowing that my fix is helping others perhaps in the same bind.

More granular projects and plugins over monoliths

 This is reflective all over in the *Nix universe. You tend to see lots of tools that can be composed alongside of one another and each has a bounded scope of responsibility. Overall this is definitely a software design principle I appreciate. Historically, larger software vendors may try to sell a "one tool does everything" sort of tool chain. Sure its nice to just have to buy one thing and deal with one vendor but this often also means "settling" for inferior functionality on some part if not all of the tool.

Not just at my current gig but in several other projects I have found that its usually more efficient in the end to get the best tool for the job even if that means having to license several tools.

The Chef ecosystem is a great example here. There are literally hundreds of different pieces one can compose to build an infrastructure automation strategy. You are not hand fed a single tool to orchestrate provisioning, installations, security, testing and reporting that includes compatibility with all hypervisors, clouds, containers and bare metal.

The result can be quite mixed. At first one is overwhelmed by choice. You spend alot of time understanding the benefits of different workflows and tool chains. However in the end, you gain a deeper understanding into how the tools fit together.

What I have also found here is that this granularity can make the individual pieces much easier to understand and troubleshoot. It means I may just need to grok a few dozen files to fully understand how the core testing infrastructure works without having to worry that some Digital Ocean based provisioner is coupled to this infrastructure in such a way that is gonna mess with my VMWare driven scenario.

Finding the right abstraction boundaries can be more art than science and can potentially clutter or over complicate an API but more often than not it guides towards better flexibility and composability. It also assumes that its consumers are more technically adept. A jr. engineer is not going to be able to wire everything up to take advantage of this flexibility. Again, this can be for better or for worse. I think it also explains cultural differences in the communities that consume these different kind of products.

Compare the consumer of a large chef or puppet based infrastructure to say a vmware vcac (or whatever they are calling this at the time you are reading this) or a Microsoft system center solution. The same analogy might be drawn comparing web forms vs MVC consumers of ASP.NET. I am not saying that one is better because it has more flexibility and you should therefore NOT use the other. Especially if you do not need the flexibility, there is alot to be said for buying the "packaged" deal if it meets your needs so that you can focus your expertise elsewhere. I am stating that in large part, I have found that the cross-platform world tends to steer towards more smaller, composable parts that take some effort and know how to wire/script together than a monolithic "out of the box" solution.

Less IDE-centric programming platforms

I've already spent some time on this topic above. Certainly ruby, go and node lend themselves toward a text editor over a full blown IDE for ones primary development environment. Until recently, it was simply not practical to write C# outside of Visual Studio and it has been a long time since I wrote java but I remember having the same dependence on an IDE when I was a java developer. 

Like everything else this has its upsides and downsides. You get lighter weight tools that provide 90% of the features you may actually use in an IDE. Many may find they do just fine without that extra 10%. Personally I find that there are certain times especially when debugging that I wish I had a richer debugging toolset. Actually these toolsets (like RubyMine) are available and may augment a text editor but can be tough to get used to them if you don't use them day in/day out. An IDE and "real" Intellisense can also be a real boon in discovering APIs without reading alot of source code. Then again, there is something to be said for reading source code. I have a better understanding for the API. Also, BONUS: as a new ruby developer, this is an excellent way to learn the idioms of a new language.

The command line is king

Historically products sold by Microsoft tend to be GUI heavy and in fact, its consumer base expect this. Often you get a v1 product with a GUI and need to wait for future versions for an API. The cross-platform world is filled with tools that have no GUI and will never have a GUI. Again, the consumer base expects this and values the command line.

Now I am the slowest typist I know and I say that, sadly, sans hyperbole. However I discovered years ago that I was more efficient with git on the commandline than using a GUI. For one thing I use source control all day, every day. I eventually found that using commandline tools even in the Microsoft world had a ton of value. Lots of Microsoft stack developers find this to be the case. However, I would not say this was nearly as prevalent among Microsoft stack developers largely because tooling simply did not lend itself to this. Just like it takes descent designers to write good GUIs, good command line tools also require a special skill.

Once you spend a certain amount of time immersed in the cross platform ecosystem, you learn some common patterns shared in most CLIs that allow you to navigate most others fairly quickly. The descent CLIs either have really good command line help or point to good READMEs on github or a product website. Note that there are some that are absolutely horrible. Oddly one of the most popular, git, does not rank highly in this regard. Others will scoff, but I think powershell is excellent in providing a discoverable command line interface with quality help. Its just too easy to get by in windows without ever opening a powershell window so many never learn it or use it consistently enough to pick it up.

More mature automation tooling

One thing that I and many of my colleagues note is that everything is harder and wrought with more friction when it comes to automating windows vs. linux. This has gotten much better since powershell and is getting rapidly better but this is still very much true today on the latest windows server OS (2012 R2 at the time of this post).

On linux, SSH is "just there" and their are no odd list of exceptions when it comes to running commands locally vs. remotely. Sure you can manage anything remotely on a windows machine but may have to jump through rings of fire to do so. However have you actually ever jumped through rings of fire? Neither have I but I have watched other do so and when they do they tend to stand tall afterwards with their arms up in the air and look extremely proud. So there is that...

Package management and configuration management have long been part of the linux lexicon but are novelties to windows. At least they are now novelties and not nonexistent. There are a rich set of automation tools in the linux world. Many, if not most of these are advertised to work with windows. However, there are often tears involved. I am confident Windows is going to catch up here and that the leaders behind Windows server want to do the right thing and understand the space.

I wrote an article for InfoQ a few months back describing the state of this tooling in the Windows world today. I'm really excited about where things are heading and have been an active participant in this space.

The gap is closing but there will always be a gap

I've hinted at this several times, but in areas where I think there are solid technical shortcomings, windows is catching up. I do think there will be a day for instance where the automation story will be at least very nearly as good as it is for linux. That said, I do think there will always be a cultural gap between these two platforms and their communities.

This is not necessarily a bad thing and I suppose that depends largely on your own developer ideologies and personal style. Even regardless of those, there will always be large pockets on either side that share very different values. personally, I enjoy both platforms for different reasons and I have good friends that develop for both stacks. Besides, what fun would the world be if windows and mac/linux users didn't argue? And in this world, how would you be able to identify the hipsters?

Accessing chef node attributes from kitchen tests by Matt Wrock

This should not happen often and maybe never, but there have been a few occasions where I needed the attribute values stored in the "node under test" to verify my kitchen test verifications. For example, maybe your recipe uses the node's IP or machine names as part of writing a config file and your kitchen driver uses dhcp to obtain an IP and auto generates unique machine names. In this case, you cant know the IP or machine name at the time you are authoring your test to check that the correct text was used in the config file.

This post demonstrates a very small and simple technique to retrieve this data inside of the test in order to dynamically verify the correct values were used in your recipe that you are testing.

At CenturyLink Cloud we use this in a few serverspec tests. One place we use this is in testing our haproxy configuration. Some values we need to inject into the configuration include the subnet of the current node and its chef environment which we include in the server names. Depending on where the kitchen test is being run, a different environment may be used so we cant be sure what the names of the subnet or chef environment will be while writing the test.

We solve this by adding a recipe to the end of our kitchen run list called "export-node":

  - name: my-suite
      - recipe[cookbook-under-test]
      - recipe[export-node]

This is a very simple recipe that simply converts the current node's attributes to json and writes it to a known location in /tmp/kitchen on the node.

ruby_block "Save node attributes" do
  block do
    if Dir::exist?('/tmp/kitchen')
      IO.write("/tmp/kitchen/chef_node.json", node.to_json)

Then our test can read that file and parse its json to a hash to be used throughout the test.

require 'json'
require 'serverspec'

set :backend, :exec

describe file('/etc/haproxy/haproxy.cfg') do
  let(:node) { JSON.parse('/tmp/kitchen/chef_node.json')) }
  let(:subnet) {
    ip = node["automatic"]["ipaddress"]
  let(:env) { node["chef_environment"].upcase}

  it { should be_a_file }
  its(:content) {
    should match <<-EOS
      backend elasticsearch_backend
        mode http
        balance roundrobin
        server #{env}SRCH01 #{subnet}.121:92 weight 1 check port 92
        server #{env}SRCH02 #{subnet}.122:92 weight 1 check port 92
        server #{env}SRCH03 #{subnet}.123:92 weight 1 check port 92

      backend web_backend
        mode http
        balance roundrobin
        timeout server 5m
        server #{env}WEB01 #{subnet}.131:80 weight 1 check port 80
        server #{env}WEB02 #{subnet}.132:80 weight 1 check port 80

      backend rabbit_backend
        mode http
        balance roundrobin
        server #{env}RABBIT01 #{subnet}.141:1567 weight 1 check port 1567
        server #{env}RABBIT02 #{subnet}.142:1567 weight 1 check port 1567
        server #{env}RABBIT03 #{subnet}.143:1567 weight 1 check port 1567

Above is a serverspec test that parses the node json to a hash. That hash is then accessible to our it blocks.

I have extracted the handful of lines in the export-node recipe to its own cookbook so you can grab it here.