Virtually Jason

The scripts that I write occasionally need access to specific user account credentials in order to do their work, so I wanted to write a quick note about how to securely store those credentials for scripts (especially if they're going to be run as a scheduled task)!  It all revolves around the get-credential cmdlet. The get-credential cmdlet is made for this; by default, the object that it creates is encrypted to the account that executed it as a secure powershell object.  This means that you can easily save those credentials to a secure file with these two commands: $creds = get-credential -message "Enter credentials" $creds | export-clixml $credsFile Many PowerShell cmdlets can take credentials in the form of a credentials object (frequently with the "-credential $creds" syntax), but even when you need to supply a username and password, they're really easy to get out of that $creds object: $creds.UserName $creds.GetNetworkCredential().password If some othe...

I often find myself working with large collections of objects, and one challenge that frequently comes up is to distill that collection to a set of unique items.  For example, I'm working on a project that involves analyzing a lot of network flow data that I receive with parameters for Source, Destination, Protocol, and Port.  For a part of this project, I need to create a bunch of computer objects, with parameters for InboundTCPPorts, InboundUDPPorts, InboundOtherPorts, OutboundTCPPorts, OutboundUDPPorts, and OutboundOtherPorts.  To make these computer objects, I need to start by getting all of the unique computers from my input data's Source and Destination fields.  That's pretty simple.  I start by combining the source and destination fields into a single array: $computers = $data.source + $data.destination That gives me a single list of all computers that are involved in these network flows, but that list is going to have a ton of duplication in it (si...

This is a quickie, but I often find myself working with arrays of objects when I'm working on a PowerShell script.  Occasionally, I need to remove the first item from that array, which I've always done by using the array index:  $array = $array[1..($array.count - 1)] .  That certainly works, but it's also kindof ugly. Today, I learned a better way!  PowerShell does a neat trick with commas, the equals sign, and arrays.  If you're assigning an array to a comma delimited list of variables, the array automatically gets split between those variables.  I've used that in the past in situations like this: $IPAddress = "192.168.0.1" $First,$Second,$Third,$Fourth=$IPAddress.split(".") And, as you'd expect, that will split the IP Address into octets, with each one going into its named variable.  That's great, but what happens if you've got this situation? $IPAddress = "192.168.0.1" $First,$Second=$IPAddress.split("....

I've recently had the opportunity to do some work with NSX during some server migrations.  That work has been fairly repetitive for each group of servers that we're migrating so, you guessed it, I looked for an easy scripting/automation solution, and PowerNSX proved to be the right tool for the job! As the name implies, PowerNSX is the NSX portion of PowerCLI.  Installing it is a breeze - just use a relatively up-to-date PowerShell window and fire off install-module PowerNSX .  That'll give you access to a whole set of NSX-oriented PowerShell cmdlets.  It's still in beta, so there's a lot of rough edges, but it's still proven to be an excellent tool for many tasks, including manipulating large numbers of VM Security Group Membership settings and creating Firewall rules. One of those "rough edges" involves cached instances of objects.  For example, if I want to add a bunch of VMs to various security groups based on a CSV input, I'd often write ...

So, I post a lot of scripts here, and I'm sure that you can see the progress that I've made as I've learnt more and more about PowerCLI, PowerShell and scripting in general.  One of the things that I've recently been considering is how to make my scripts run faster.  I've got some scripts that are designed to make lots of changes, like changing the Port Group assignment of every VM in an environment.  And they take a long time to run.  As in, depending on the size of the environment, several hours.  But, they don't necessarily have to take so long to run... I just wasn't clever enough when I wrote them. There are two major techniques that I'm trying to learn that would seriously speed up those scripts.  The first one is parallel execution of For Each loops... I'm still learning about that one, so will write more about it once I've learnt something worth sharing.  The other though, is much easier, and can generally be worked into any script with...