Adaption of scenario scripts for 1-node clusters

[GeriOnline]

As Microsoft now supports 1-node clusters for AZSHCI and WS2022, I experimented a bit with the cluster scenario scripts for 1-node environments. I got various errors about non-existent host names.

Reason: Most scenario scripts initially define a variable for the names of the cluster nodes and implicitly assume that this results in a PowerShell array (e.g. $servers = "...", "..."). This works if you assign more than one hostname. However, if only 1 hostname is specified, PowerShell only creates a string variable - i.e. no array. If later the script references a single element (e.g. $server[0]), the result is an invalid hostname.

The remedy is simple: The variable for the host names should be set explicitly as an array type (e.g. [array] $servers="...").

However, this would mean that most of the scenario scripts would have to be adjusted and re-released. I would therefore suggest that an appropriate note be included in the MSLab readme page and the adjustments made in the scenario scripts when they are released as such.

[jaromirk]

Okok. It's easy - you just skip smb nics creation. Everything else is same.

[GeriOnline]

I have the impression that we are talking about different things. I mean the array with the server names at the beginning of the different scenario scripts. As an example, let's take a look at the scenario.ps1 script of the AzSHCI deployment scenario:

With line 7: $numberofnodes=4 and line 10: $Servers=1..$numberofnodes | ForEach-Object {"$ServersNamePrefix$"}

$servers results in an array with 4 strings:

$servers.GetType() IsPublic IsSerial Name BaseType
True True Object[] System.Array

$Servers AzSHCI1 AzSHCI2 AzSHCI3 AzSHCI4

Now for 1-node clusters you have to change line 7 to line 7: $numberofnodes=1 and now $servers results in a simple string:

$Servers.GetType() IsPublic IsSerial Name BaseType
True True String System.Object

Later on in the script if $Servers[0] is referenced (e.g. in line 190) only the first char of the server name is retrieved:

$Servers[0] A

which of course leads to various runtime errors.

The correction is very easy: Simply change line 10 to [array]$Servers=1..$numberofnodes | ForEach-Object {"$ServersNamePrefix$"}_

and everything works like it should independent of the value of $numberofnodes in line 7.

I hope with that I have presented my request a little bit better.

[jaromirk]

Ah, got it! With one server you can simply say $servers="AzSHCI1". I kept this array to make things simpler when you deal with 16 node clusters :)

[GeriOnline]

$servers="AzSHCI1" does not solve the problem. You have to write [array] $servers="AzSHCI1" - then it would work. It's a special PowerShell feature that if only one string is assigned only a string var is allocated. So you have always to use strong type definitions for such situations.

[GeriOnline]

Another way with hard coded server names would be to write $servers=,"AzSHCI1" for single nodes (another trick of PowerShell)

[jaromirk]

Ah, you are ofc right. Okok, I'll fix it! I hope you enjoy this stuff. Check out 22H2 scenario (in dev) . It's lot of fun!

[Karl-WE]

@jaromirk friendly reminder, is this code change implemented yet? might get lost. would still affect S2D and Azure Stack HCI as it is a syntax problem, as I understood.