Dipendenze delle risorse con DependsOn

Quando si scrivono configurazioni, si aggiungono blocchi di risorse per configurare gli aspetti di un nodo di destinazione. Man mano che si aggiungono blocchi di risorse, le configurazioni possono aumentare considerevolmente di dimensione e diventare complesse da gestire. Uno dei problemi è l'ordine di applicazione dei blocchi di risorse. In genere le risorse vengono applicate nell'ordine con che cui vengono definite all'interno della configurazione. Se la configurazione aumenta di dimensione e diventa più complessa, è possibile usare la chiave DependsOn per gestire l'ordine di applicazione delle risorse, specificando che una risorsa dipende da un'altra risorsa.

La chiave DependsOn può essere usata in qualsiasi blocco di risorse. Viene definita con lo stesso meccanismo di chiave/valore di altre chiavi della risorsa. Per la chiave DependsOn è prevista una matrice di stringhe con la sintassi seguente.

DependsOn = '[<Resource Type>]<Resource Name>', '[<Resource Type>]<Resource Name'

L'esempio seguente consente di configurare una regola del firewall dopo aver abilitato e configurato il profilo pubblico.

# Install the NetworkingDSC module to configure firewall rules and profiles.
Install-Module -Name NetworkingDSC

Configuration ConfigureFirewall
{
    Import-DSCResource -Name Firewall, FirewallProfile
    Node localhost
    {
        Firewall Firewall
        {
            Name                  = 'IIS-WebServerRole-HTTP-In-TCP'
            Ensure                = 'Present'
            Enabled               = 'True'
            DependsOn             = '[FirewallProfile]FirewallProfilePublic'
        }

        FirewallProfile FirewallProfilePublic
        {
            Name = 'Public'
            Enabled = 'True'
            DefaultInboundAction = 'Block'
            DefaultOutboundAction = 'Allow'
            AllowInboundRules = 'True'
            AllowLocalFirewallRules = 'False'
            AllowLocalIPsecRules = 'False'
            NotifyOnListen = 'True'
            LogFileName = '%systemroot%\system32\LogFiles\Firewall\pfirewall.log'
            LogMaxSizeKilobytes = 16384
            LogAllowed = 'False'
            LogBlocked = 'True'
            LogIgnored = 'NotConfigured'
        }
    }
}

ConfigureFirewall -OutputPath C:\Temp\

Quando si applica la configurazione, il profilo del firewall verrà configurato sempre per primo indipendentemente dall'ordine con cui vengono definiti i blocchi di risorse. Se si applica la configurazione, prendere nota della configurazione esistente dei nodi di destinazione in modo da poterla ripristinare se necessario.

PS> Start-DSCConfiguration -Verbose -Wait -Path C:\Temp\ -ComputerName localhost

VERBOSE: Perform operation 'Invoke CimMethod' with following parameters, ''methodName' = SendConfigurationApply,'className' = MSFT_DSCLocalConfigurationManager,'namespaceName' = root/Microsoft/Windows/DesiredStateConfiguration'.
VERBOSE: An LCM method call arrived from computer SERVER01 with user sid S-1-5-21-181338-0189125723-1543119021-1282804.
VERBOSE: [SERVER01]: LCM:  [ Start  Set      ]
VERBOSE: [SERVER01]:                            [DSCEngine] Importing the module C:\Program Files\WindowsPowerShell\Modules\NetworkingDsc\6.1.0.0\DscResources\MSFT_Firewall\MSFT_Firewall.psm1 in force mode.
VERBOSE: [SERVER01]:                            [DSCEngine] Importing the module C:\Program Files\WindowsPowerShell\Modules\NetworkingDsc\6.1.0.0\DscResources\MSFT_FirewallProfile\MSFT_FirewallProfile.psm1 in force mode.
VERBOSE: [SERVER01]: LCM:  [ Start  Resource ]  [[FirewallProfile]FirewallProfilePublic]
VERBOSE: [SERVER01]: LCM:  [ Start  Test     ]  [[FirewallProfile]FirewallProfilePublic]
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Importing the module MSFT_FirewallProfile in force mode.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Testing Firewall Public Profile.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Firewall Public Profile "AllowInboundRules" is "NotConfigured" but should be "True". Change required.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Firewall Public Profile "AllowLocalFirewallRules" is "NotConfigured" but should be "False". Change required.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Firewall Public Profile "AllowLocalIPsecRules" is "NotConfigured" but should be "False". Change required.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Firewall Public Profile "DefaultOutboundAction" is "NotConfigured" but should be "Allow". Change required.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Firewall Public Profile "LogBlocked" is "False" but should be "True". Change required.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Test-TargetResource: Firewall Public Profile "LogMaxSizeKilobytes" is "4096" but should be "16384". Change required.
VERBOSE: [SERVER01]: LCM:  [ End    Test     ]  [[FirewallProfile]FirewallProfilePublic]  in 1.6890 seconds.
VERBOSE: [SERVER01]: LCM:  [ Start  Set      ]  [[FirewallProfile]FirewallProfilePublic]
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Importing the module MSFT_FirewallProfile in force mode.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile.
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile parameter AllowInboundRules to "AllowInboundRules".
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile parameter AllowLocalFirewallRules to "AllowLocalFirewallRules".
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile parameter AllowLocalIPsecRules to "AllowLocalIPsecRules".
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile parameter DefaultOutboundAction to "DefaultOutboundAction".
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile parameter LogBlocked to "LogBlocked".
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile parameter LogMaxSizeKilobytes to "LogMaxSizeKilobytes".
VERBOSE: [SERVER01]:                            [[FirewallProfile]FirewallProfilePublic] Set-TargetResource: Setting Firewall Public Profile updated.
VERBOSE: [SERVER01]: LCM:  [ End    Set      ]  [[FirewallProfile]FirewallProfilePublic]  in 10.0360 seconds.
VERBOSE: [SERVER01]: LCM:  [ End    Resource ]  [[FirewallProfile]FirewallProfilePublic]
VERBOSE: [SERVER01]: LCM:  [ Start  Resource ]  [[Firewall]Firewall]
VERBOSE: [SERVER01]: LCM:  [ Start  Test     ]  [[Firewall]Firewall]
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Importing the module MSFT_Firewall in force mode.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Test-TargetResource: Checking settings for firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP'.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Test-TargetResource: Find firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP'.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Get-FirewallRule: No Firewall Rule found with Name 'IIS-WebServerRole-HTTP-In-TCP'.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Test-TargetResource: Firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP' does not exist.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Test-TargetResource: Check Firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP' returning False.
VERBOSE: [SERVER01]: LCM:  [ End    Test     ]  [[Firewall]Firewall]  in 1.1780 seconds.
VERBOSE: [SERVER01]: LCM:  [ Start  Set      ]  [[Firewall]Firewall]
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Importing the module MSFT_Firewall in force mode.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Set-TargetResource: Applying settings for firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP'.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Set-TargetResource: Find firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP'.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Get-FirewallRule: No Firewall Rule found with Name 'IIS-WebServerRole-HTTP-In-TCP'.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Set-TargetResource: We want the firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP' to exist since Ensure is set to Present.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] Set-TargetResource: We want the firewall rule with Name 'IIS-WebServerRole-HTTP-In-TCP' to exist, but it does not.
VERBOSE: [SERVER01]:                            [[Firewall]Firewall] New-NetFirewallRule DisplayName: IIS-WebServerRole-HTTP-In-TCP
VERBOSE: [SERVER01]: LCM:  [ End    Set      ]  [[Firewall]Firewall]  in 1.0850 seconds.
VERBOSE: [SERVER01]: LCM:  [ End    Resource ]  [[Firewall]Firewall]
VERBOSE: [SERVER01]: LCM:  [ End    Set      ]
VERBOSE: [SERVER01]: LCM:  [ End    Set      ]    in  15.2880 seconds.
VERBOSE: Operation 'Invoke CimMethod' complete.
VERBOSE: Time taken for configuration job to complete is 15.385 seconds

In questo modo si garantisce anche che, se per qualsiasi motivo, la risorsa FirewallProfile avesse esito negativo, il blocco Firewall non sarà eseguito nonostante sia stata definito per primo. La chiave DependsOn consente una maggiore flessibilità nel raggruppamento dei blocchi di risorse. Assicura che le dipendenze siano risolte prima dell'esecuzione di una risorsa.

Nelle configurazioni più avanzate è anche possibile usare la dipendenza tra nodi per consentire un controllo ancora più granulare. In questo modo si assicura che un controller di dominio sia configurato prima di aggiungere un client al dominio.

Pulizia

Se è stata applicata la configurazione precedente, è possibile invertire le chiavi per annullare le modifiche. Se nell'esempio precedente si imposta la chiave Enabled su False, la regola e il profilo del firewall saranno disabilitati. Modificare l'esempio ove necessario per trovare corrispondenza con lo stato configurato precedente del nodo di destinazione.

        Firewall Firewall
        {
            Name                  = 'IIS-WebServerRole-HTTP-In-TCP'
            Enabled               = 'False'
            DependsOn             = '[FirewallProfile]FirewallProfilePublic'
        }

        FirewallProfile FirewallProfilePublic
        {
            Name = 'Public'
            Enabled = 'False'
        }

Vedi anche