Comparing RPC, WMI and WinRM for remote server management with PowerShell V2

  • Article

1. Overview

In a recent blog post, I was looking at PowerShell V2 remoting in Windows Server 2008 R2.
If you haven’t seen it, take a look at https://blogs.technet.com/josebda/archive/2010/03/31/experimenting-with-powershell-v2-remoting.aspx.

In that post, I mentioned three different ways to gather information about services on a remove server (throughout this post, I use this task as an example of what I administrator would run remotely):

· Using Get-Service with the –ComputerName parameter (RPC)

· Using Get-WMIObject with a –ComputerName parameter (WMI)

· Using Invoke-Command to execute Get-Service remotely (WinRM)

In this post, I spent more time looking deeper at some the most significant differences between them.

 

2. Commands and Outputs

For starters, here are the three versions of a sample command to query a remote server and the output they produce: the first using Get-Service, the second using Get-WMIObject and the third using Invoke-Command.

From an IT Administrator perspective, the Get-Service form is short and to the point. It is a good example of how PowerShell makes things simple to manage.

The Invoke-Command is not so bad either, with the advantage that IT Administrators don’t have to restrict themselves to cmdlets that have the –ComputerName option.

The Get-WMIObject seems a bit scary for someone without a developer background. You also lose some of the discoverability advantages of PowerShell (you can’t press TAB to complete your query, for instance).

On the other hand, for developers familiar with Win32 APIs and WMI classes, the option to use Get-WMIObject seems very attractive.

 

Get-Service LanManServer -ComputerName josebda-s0

Status Name DisplayName

------ ---- -----------

Running LanManServer Server

Get-WMIObject -ComputerName josebda-s0 -query "Select * from Win32_Service Where Name='LanManServer '" | ft

 

ExitCode Name ProcessId StartMode State Status

-------- ---- --------- --------- ----- ------

       0 LanmanServer 868 Auto Running OK

Invoke-Command josebda-s0 {Get-Service LanManServer}

Status Name DisplayName PSComputerName

------ ---- ----------- --------------

Running LanManServer Server josebda-s0

 

3. Properties and Methods

While the three options look similar, the objects returned are different. The first is of type “System.ServiceProcess.ServiceController”, the second returns the type “System.Management.ManagementObject#rootcimv2Win32_Service” and last one is of type “Deserialized.System.ServiceProcess.ServiceController”. Take a look below at the details on each different type below, obtained using Get-Member. Note that the deserialized version has no methods to perform actions on the service, like stop or start.

 

Get-Service LanManServer -ComputerName josebda-s0 | Get-Member

TypeName: System.ServiceProcess.ServiceController

Name MemberType Definition

---- ---------- ----------

Name AliasProperty Name = ServiceName

RequiredServices AliasProperty RequiredServices = ServicesDependedOn

Disposed Event System.EventHandler Disposed(System.Object, System.EventArgs)

Close Method System.Void Close()

Continue Method System.Void Continue()

CreateObjRef Method System.Runtime.Remoting.ObjRef CreateObjRef(type requestedType)

Dispose Method System.Void Dispose()

Equals Method bool Equals(System.Object obj)

ExecuteCommand Method System.Void ExecuteCommand(int command)

GetHashCode Method int GetHashCode()

GetLifetimeService Method System.Object GetLifetimeService()

GetType Method type GetType()

InitializeLifetimeService Method System.Object InitializeLifetimeService()

Pause Method System.Void Pause()

Refresh Method System.Void Refresh()

Start Method System.Void Start(), System.Void Start(string[] args)

Stop Method System.Void Stop()

ToString Method string ToString()

WaitForStatus Method System.Void WaitForStatus(System.ServiceProcess.ServiceControllerStatus desi...

CanPauseAndContinue Property System.Boolean CanPauseAndContinue {get;}

CanShutdown Property System.Boolean CanShutdown {get;}

CanStop Property System.Boolean CanStop {get;}

Container Property System.ComponentModel.IContainer Container {get;}

DependentServices Property System.ServiceProcess.ServiceController[] DependentServices {get;}

DisplayName Property System.String DisplayName {get;set;}

MachineName Property System.String MachineName {get;set;}

ServiceHandle Property System.Runtime.InteropServices.SafeHandle ServiceHandle {get;}

ServiceName Property System.String ServiceName {get;set;}

ServicesDependedOn Property System.ServiceProcess.ServiceController[] ServicesDependedOn {get;}

ServiceType Property System.ServiceProcess.ServiceType ServiceType {get;}

Site Property System.ComponentModel.ISite Site {get;set;}

Status Property System.ServiceProcess.ServiceControllerStatus Status {get;}

Get-WMIObject -computername josebda-s0 -query "Select * from Win32_Service Where Name='LanManServer'" | Get-Member

TypeName: System.Management.ManagementObject#rootcimv2Win32_Service

Name MemberType Definition

---- ---------- ----------

Change Method System.Management.ManagementBaseObject Change(System.String DisplayName, System...

ChangeStartMode Method System.Management.ManagementBaseObject ChangeStartMode(System.String StartMode)

Delete Method System.Management.ManagementBaseObject Delete()

GetSecurityDescriptor Method System.Management.ManagementBaseObject GetSecurityDescriptor()

InterrogateService Method System.Management.ManagementBaseObject InterrogateService()

PauseService Method System.Management.ManagementBaseObject PauseService()

ResumeService Method System.Management.ManagementBaseObject ResumeService()

SetSecurityDescriptor Method System.Management.ManagementBaseObject SetSecurityDescriptor(System.Management....

StartService Method System.Management.ManagementBaseObject StartService()

StopService Method System.Management.ManagementBaseObject StopService()

UserControlService Method System.Management.ManagementBaseObject UserControlService(System.Byte ControlCode)

AcceptPause Property System.Boolean AcceptPause {get;set;}

AcceptStop Property System.Boolean AcceptStop {get;set;}

Caption Property System.String Caption {get;set;}

CheckPoint Property System.UInt32 CheckPoint {get;set;}

CreationClassName Property System.String CreationClassName {get;set;}

Description Property System.String Description {get;set;}

DesktopInteract Property System.Boolean DesktopInteract {get;set;}

DisplayName Property System.String DisplayName {get;set;}

ErrorControl Property System.String ErrorControl {get;set;}

ExitCode Property System.UInt32 ExitCode {get;set;}

InstallDate Property System.String InstallDate {get;set;}

Name Property System.String Name {get;set;}

PathName Property System.String PathName {get;set;}

ProcessId Property System.UInt32 ProcessId {get;set;}

ServiceSpecificExitCode Property System.UInt32 ServiceSpecificExitCode {get;set;}

ServiceType Property System.String ServiceType {get;set;}

Started Property System.Boolean Started {get;set;}

StartMode Property System.String StartMode {get;set;}

StartName Property System.String StartName {get;set;}

State Property System.String State {get;set;}

Status Property System.String Status {get;set;}

SystemCreationClassName Property System.String SystemCreationClassName {get;set;}

SystemName Property System.String SystemName {get;set;}

TagId Property System.UInt32 TagId {get;set;}

WaitHint Property System.UInt32 WaitHint {get;set;}