Docker on Ubuntu on Hyper-V 2012 R2

I recently read through an MSDN article that described running Docker in a VM on Hyper-V.

Frankly, I was less than impressed at the complexity of the solution.  Especially since the concept here is not a huge leap.

The basic steps are:

1. Build a VM on Hyper-V
2. Install Docker into that VM
3. Run containers in that VM

This achieves a couple things.

• Your Docker containers are isolated within a VM. 

This is actually an important thing.  Docker has its own networking stack, but it also allows exposing the underlying storage to the VM to support things like databases and configurations or even updating source easily. 
The model here is one VM per tenant.  Thus forming that boundary and still getting the flexibility of both containers and VMs.

• You can run the OS of your choice.

In my experimentation I have been using Ubuntu.  Mainly because it has good support, but primarily because they are right up to date with the kernel.  This gives me the latest Hyper-V support within that VM.

So, you want to setup Docker in a VM.  There are a few steps as I am outlining this in gory detail.  Here is goes:

1. Install Ubuntu in the VM (14.04 LTS Server) or 14.10
2. Add OpenSSH Server
3. Determine IP
4. Connect over SSH
5. Update
1. sudo apt-get update
6. Upgrade the components (aka patch the OS)
1. sudo apt-get upgrade -y
7. Add Docker gpg key (that is 'qO' not 'qZero')
1. sudo sh -c "wget -qO- https://get.docker.io/gpg | apt-key add -" 
8. Update the app list
1. sudo sh -c "echo deb http://get.docker.io/ubuntu docker main\ >> /etc/apt/sources.list.d/docker.list"
9. Update the local apt repository after adding the docker reference
1. sudo apt-get update
10. Install (latest) Docker (on 12/15/14 this is 1.4.0)
1. sudo apt-get install lxc-docker -y

Now you are ready to play with the magic of Containers.

 

I am tired of the Azure vs AWS argument

I had the pleasure this morning of catching up on some email and ran across a scathing comment about Azure.  How horrible it was, how it could never catch up, how it was all around inferior.  The context was in comparison to AWS.

Now, I have to say - I have never (not one) done anything with AWS.  But, I have talked to a lot of folks that love AWS and hate Azure (lots).  And I counter that with the fact that I have been working with legacy enterprise software on Azure since 2011.  And, those of us that work with Azure know that it is never done and it has constantly been evolving.

I am not here to say that Azure is better, I am here to say it is different.  And if you can't accept that a platform is different and learn about its differences, and adapt as you need to, then be the bigot.

Since this is an AWS thread, then the context here is Infrastructure as a Service.  And most folks that I know that hold AWS up as better are folks that have no desire to change the legacy ways and thinking that they already know.

I am still describing the MSFT model of VM Templates and machine composition.  Which SCVMM introduced in 2010.  The concept of taking a generalized OS image and specializing it on deployment.  And storing these properties as separate things, thus granting the ability to re-use, mix and match, and so forth.

SCVMM further extended this concept in 2012 with the introduction of Service Templates - now you can group machines, customize application tiers, and even install applications and thus build out an entire distributed enterprise application.  With one OS disk image.

I prototyped this with XenDesktop - building out a scalable deployment.  No custom templates for each role, no pre-installation of any software - it all happens on the fly. 

MSFT has been moving in this direction of machine composition - layering settings and applications onto an OS at deployment - since 2008.  Azure PaaS has done it forever and SCVMM brought the concept to the enterprise and features of Azure IaaS keep it moving.

Desired State Configuration is the latest supporting feature that enables this (and more).  I have a resource for XenDesktop to use with that as well.

My point, things are different now than 5 or 10 years ago in IT.  And the models and whitepapers and testing and legacy applications need to change along with it.

Now, back to AWS and Azure.  The only argument I ever hear are two; firewalling rules, and the composition / deployment process of AWS.

MSFT is on the way to handing the deployment stuff.  Firewalling?  That is a lazy argument in my mind.  I have invested time in hardening machines, properly setting firewalls rules in the OS, IPsec rules and the like.  This is harder than setting rules at the network layer, but just as effective.

Someone has to choose which platform to get into bed with.  And if the software folks can't get past the traditional datacenter style deployment to a modern cloud model of software development - then maybe the platform is not the problem.  Maybe the issue is an open-ness to new ideas and new ways of looking at old problems.

Testing and Checking in the cloud service era

Services.  DevOps. Cloud Services. Rapid prototyping. Start-up methodologies. Agile development.

These are all terms that we hear in the software business.  And they generally all point to what some folks consider a reduction in testing.  And what many customers consider a reduction in overall quality.

If you follow some of the big names in the software testing world ( Michael Bolton, Rex Black, James Bach, and others ) one theme that resonates with all of this is testing vs checking.

And in my experience what I see happening in this cloud service era and the rise of DevOps is that there has been a shift away from 'testing' and a greater focus on 'checking'. 
Some say that this makes the developer more accountable instead of them blaming test for missing it.  I don't argue that quality was always the developers responsibility anyway.

In my words, checking is more like unit testing.  Did this thing respond in the way it was designed to?  Everything is positive, everything is looking for the intended desired outcome.

Where testing is checking plus looking at and driving appropriate failures.  Not only did this thing do the positive action, but when I send a negative action - what happens.  Did it fall over, did it respond with a proper error, did something totally unexpected happen.  And then there are other studies; load, scaling, fuzzing, chaos monkey, etc.

In fact, I would argue that in this cloud service world, this shift to a greater emphasis on checking is actually a bad thing.  I tis good for development in that it gets more code out the door, and in theory more features and quicker fixes.  However, it ends up making for very fragile applications, and I know of few cloud applications that don't have a high number of dependencies on other cloudy services.

Now, why does this matter?  Because, customers have an emotional connection to your product.  Not a factual relationship with it.

Any small issue that blows up into a large issue, or a planned two hour outage that becomes a 4 to 8 hour outage impacts the feelings of the customer in regards to your service.  This impacts their perception of your quality.  As the customer sees quality as a value judgment.  No different than excellent service at a restaurant.  The more expensive the restaurant, the better everything must be.

This gets messy in the cloud service era.  Because of pricing competition.  The model is closer to that of a bank.  If a customer only consumes one of your services, it is easy to switch.  So you upsell them with more and more services and possibly take a loss in doing it.  This generates a type of lock-in as it becomes more and more difficult for a customer to leave and go somewhere else.  The tipping point.

Anyone who has been involved in IT purchasing decisions knows that software is brought into the enterprise through some corporate division.  Then it gets handed to IT to evaluate.  And in very rare cases, IT actually gets to give feedback or get the corporate division to consider alternate options.
The other side to this is that IT is the one doing the evaluation and choice.  When this is the case the judgment is all about the getting started experience - if I have to crack a manual to get started, something is not right.

Again, checking would focus on the binary functions of the software where testing should be looking at the overall experience.
Just something to keep in mind in this rapid software era.

XenDesktop DSC resource and the Azure DSC VM Extension

After all of the previous blog posts, I thought that I would climax with a few real examples of using the DSC resource for XenDesktop.

Earlier this year (just a few++ weeks ago) Microsoft released the VM extensions for Virtual Machines.  This is the IaaS style VM role.  The VM Extensions are small modules that you can inject into your VM and you can interface with them.  The simplest way to think of it is they are purpose built agents.  You can configure them on provisioning, but also nifty is that you can update the configuration of an extension after deployment and do something else.

There is a script extension that can be used to download and execute any script(s) inside of your VM.  Handy for performing a number of things. You can use this to drive DSC if you like.
After that the DSC extension was released.  This one is purpose built just for DSC and the one this post will be focusing on.

I will warn you, I am going to expose a few warts of the process as I do this, just because the extension is built to support DSC and only the DSC packages.  And this process requires external media - yes, the media could be bundled into the DSC resource (the only workaround to this process at the moment), but that would make the resource really fat.  So, why not continue to think of it as two problems.

One thing - the DSC provider for XenDesktop expects media to be on the machine where it runs or a DVD attached ISO.  So a ZIP or ISO (DVD attached or downloaded to the machine) or folder.  This way there is no requirement to save credentials for connecting to some share or other store.

Now, let get everything set up.  (I am experimenting with a slightly different writing format here, so you will have to let me know if it works for you)

First of all, I am going to assume that you are sitting at your 'configuration computer' - that management computer that you use that has all of the consoles and what not installed.  In this case it is where you build all of your configurations that you later push to machines or place on your pull server.  Your configuration computer needs the XenDesktop resource module installed under the path "%ProgramFiles%\WindowsPowerShell\Modules" so a later cmdlet for the DSC script provider can automagically pick it up and bundle it for you.

Begin by connecting to your Azure subscription and set the storage account you will be using ( Set-AzureStorageAccount -StorageAccountName "YourCoolStorageAccount" )

Then upload the XenDesktop media.  ( the media is created from the ISO, simply ZIP the contents of the ISO - don't add any folders into the path)

Be sure that your container security is set to public blob (not public container) since we don't want folks discovering it.

For a later step you will need the URI to the blob that you just uploaded.

Now, we need to define the configuration (the DSC one) that will be applied to the VM.

For that I created a PowerShell script that accepts two parameters; the URI to the media and the role to be installed.

The DSC extension will run this and then apply the configuration.

Now that the configuration script exists, this must be packaged up, with the module, for the Azure DSC extension to use.  I saved mine with the name "XenDesktopInAzure.ps1".

The Azure PowerShell cmdlets have created a cmdlet just for this action; Publish-AzureVMDscConfiguration

After running the Publish-AzureVMDscConfiguration cmdlet, go check out your Azure management portal and look into the container and you will find a ZIP archive with a name that matches your script.  What the Public- command does is package the script and the modules that are used into the ZIP, then uploads them to Azure for you.

Now, define the VM, so that can be created.

First needed is an Azure VM Image - an 'image' is a virtual disk that is installed with an OS and prepared with sysprep and registered with Azure as an image - to the management platform, this means that it can specialize the OS on provisioning through mini-setup and the use of an unattended answer file.

Moving forward to the next step of building the VM configuration.

First, begin with a base VM configuration.

Then add the provisioning configuration ( these are the specialization settings ).
Then configure the Azure DSC VM extension.

Then create the VM.  Azure and the VM extension take care of processing the configuration script, and the configuration script downloads the ZIP, unpacks it, and installs the role.

One really cool thing about DSC is that you can keep applying configurations.  The last applied settings to a specific thing win, configurations are not undone when a new one is added, simply the changes defined in the new configuration are applied.  So, if you have some management layer, it can apply configuration after configuration if it so wanted to, or change a configuration over time to modify something.

As an option for delivering media, you can use a data disk with the XenDesktop media within it.  Then you can attach that to a new VM and have DSC mount the disk (rather, make sure it is mounted at a specific drive letter) and then perform the installation.

If you are using SCVMM, you can have an ISO attached to the VM as part of the template.  You could even use DSC to map a drive if that is what fits for your environment.  They are all possibilities.

Have fun! And please, send feedback!

Using the XenDesktop DSC resource

In my last article I covered using the built-in desired state configuration (DSC) resources to stand up a Citrix License server.  All but one of the resources I used shipped in the box with Server 2012 R2 - and you could argue that I really didn't have to use the custom resource to fetch and install my license file.

I used the package resource to install the Citrix License server. 

The package resource works great for the License Server, which is a really quick and simple install.  But what do you do when you have an installer that requires reboots mid-stream?  Or even multiple reboots? 

Some of you who have installed XenApp or XenDesktop over the years know that this takes extra time and you have to follow your checklist or the wizard to make sure you didn't miss a step.  What if you didn't need to do that?  Or what if we could greatly simplify the entire process?

Here is an example I think you will like.

Recently released is a Technology Preview of a desired state configuration resource for XenDesktop.  You can find it here: http://www.citrix.com/go/xendesktop-for-the-private-cloud.html

Follow the admin guide and place the module in the PowerShell path on your target (and the machine where you create configurations) and move forward.

Since I will be using this in upcoming examples, lets give it a quick description.

This brings together a few of the previous articles.

Lines 9 - 12 coupled with line 47 sets the local configuration manager (LCM) to handle reboots on its own.

Lines 15 - 20 creates my unzip and logging path

Lines 24 - 30 unzips my media.  I know what the name of my media is and I expect that media to be delivered to the same path where this script is being run by some other agent or process - such as an external process that downloads the media plus this script to the same path and then runs this script.

Lines 33 - 38 call the XenDesktop resource and install one of the roles defined.

If the role installation sets that the system requires a reboot, the LCM handles that.  On reboot it processes the configuration again, until the XenDesktop resource returns 'true' for ensure being set to 'present'.

For the Controller this is generally one reboot, for a session host or VDA tis could be two reboots.  The great thing for me is that it is totally hands off.  DevOps in the XenDesktop world.

Personally, I hope that you check this out, and I am looking for feedback on where this needs to go next and if it is useful to you.  So please, speak up in comments, in the forum, or complete the survey.

Next - lets show this all in action in some real use cases.