vSphere Nodes

vSphere Nodes

Inside a DSC Configuration vSphereNode is a special dynamic keyword that represents a connection to a VIServer. Each vSphereNode can contain DSC Resources from the module VMware.vSphereDSC. Currently vSphere Nodes only work on PowerShell 7.

With standard DSC we need to supply each resource with a Server and Credential parameter so that they can establish a connection the specified VIServer because the LCM runs the resources in different runspaces and a common connection cannot be reused.

The vSphere Nodes along with the new execution engine allow the user to bundle resources and specify a common VIServer connection which gets reused.

DSC Configurations with a Single Node Examples

Regular DSC Configuration

Configuration Test {
    Import-DscResource -ModuleName 'VMware.vSphereDSC'

    Node 'localhost' {
        DatacenterFolder "MyDatacentersFolder" {
            Server = '<server here>'
            Credential = '<credentials object here>'
            Name = 'MyDatacentersFolder'
            Location = ''
            Ensure = 'Present'
        }

        Datacenter "MyDatacenter" {
            Server = '<server here>'
            Credential = '<credentials object here>'
            Name = 'MyDatacenter'
            Location = 'MyDatacentersFolder'
            Ensure = 'Present'
            DependsOn = "[DatacenterFolder]MyDatacentersFolder"
        }
    }
}

Test

DSC Configuration with vSphere Nodes

Configuration Test {
    Import-DscResource -ModuleName 'VMware.vSphereDSC'

    vSphereNode '<server name goes here>' {
        DatacenterFolder "MyDatacentersFolder" {
            Name = 'MyDatacentersFolder'
            Location = ''
            Ensure = 'Present'
        }

        Datacenter "MyDatacenter" {
            Name = 'MyDatacenter'
            Location = 'MyDatacentersFolder'
            Ensure = 'Present'
            DependsOn = "[DatacenterFolder]MyDatacentersFolder"
        }
    }
}

$splat = @{
    ConfigName = 'Test'
}

$dscConfig = New-VmwDscConfiguration @splat

Here each VMware.vSphere DSC Resource loses the previously mandatory Server and Credentials Parameters and instead the connection is retrieved from the vSphereNode Name. Note that the vSphereNode keyword opening bracket '{' must be placed on the same row as the keyword or else a parsing error is triggered.

DSC Configuration with multiple Nodes Example

Configuration Test {
    Import-DscResource -ModuleName 'VMware.vSphereDSC'

    # $AllNodes gets supplied via ConfigurationData parameter
    vSphereNode $AllNodes.NodeName {
        DatacenterFolder "MyDatacentersFolder" {
            Name = 'MyDatacentersFolder'
            Location = ''
            Ensure = 'Present'
        }

        Datacenter "MyDatacenter" {
            Name = 'MyDatacenter'
            Location = 'MyDatacentersFolder'
            Ensure = 'Present'
            DependsOn = "[DatacenterFolder]MyDatacentersFolder"
        }
    }
}

$splat = @{
    ConfigName = 'Test'
    ConfigurationData = @{
        AllNodes = @(
            @{
                NodeName = '<Connection>' # Example: 10.10.10.10
            },
            @{
                NodeName = '<Connection>'
            }
        )
    }
}

$dscConfig = New-VmwDscConfiguration @splat

Here $AllNodes can contain multiple ViServer connections that can be specified via the NodeName property and a separate node object will be generated for each connection.

Common properties for all nodes can be specified with a $AllNodes entry that has a Nodename property that equals '*'. This value will be applied to all other Nodes. Nodes with duplicate NodeName properties will result in a exception.

ConfigurationData = @{
        AllNodes = @(
            @{
                NodeName = '<Connection>' # Example: 10.10.10.10
            },
            @{
                NodeName = '<Connection>'
            },
            @{
                NodeName = '*'
                MyProp = 'common'
            }
        )
    }

---

After the configuration is compiled the user needs to establish a connection to the VIServers specified in the vSphereNodes before executing the configuration. This can be done using the PowerCLI cmdlet Connect-VIServer. This gives more freedom in terms of ways to connect to a server instead of only supporting connectons via username and password.

Example connection before Invoke

$connection = Connect-ViServer -User '<Username here>' -Password '<Password here>' -Server '<vSphereNode server name here>'

$dscConfig | Start-VmwDscConfiguration

When invoking a DSC configuration object that contains vSphereNodes but connections to those nodes are not established then a warning is printed to the console and those nodes get skipped during execution.