Christos Polydorou

Hello and welcome to an article on how to create your own Powershell DSC Pull Service. This is the fifth article of the series and things are starting to build our own DSC infrastructure.  To configure the DSC Pull Service we are going to need a windows server machine running at least Powershell v5 and a certifite. For the purpose of this post, I've created a dedicated machine and the certificate that I'm going to use is issued by my Active Directory Certificate Services. What would be the easiest way to create a Pull Service? DSC of course. We are going to push a DSC configuration to our machine that is going to convert it to a DSC Pull Service! First off, we're going to need that certificate installed in the Personal container of the machine. I prefer using my CA to issue certificates since it is trusted by all the domain member machines and for this one I've enrolled for a certificate based on the Web Server template: You can use any web server certificate as long as...

Welcome to the fourth article of the Desired Configuration series! Today we're going to discuss more on the ways you can apply configurations to virtual machines and how to examine the LCM verbose output. Without further ado, let me present the two ways you can apply configurations: Push and Pull. Push The push method is the simplest, we just send the configuration to the node and from then on the node has to act accordingly. We just sit and watch. Let's go through the process of pushing a configuration to a node. I'm going to be using my domain controller machine as the management host to avoid touching the node at all. First we have to put together the configuration itself. Here we are going to use a configuration from one of the previous posts that installs the Web-Server role and copies a web page file. We'll confirm that the Web-Server role is not installed on the node using the Get-WindowsFeature cmdlet: Great, IIS is not installed. Now, the default LCM configura...

Following my previous post on how to configure the LCM, we are now going to deep dive into configurations and how to author them. We'll start with a very simple configuration and work our way to a more complicated one. In the first article of the series we configured a server with the Web-Server windows feature using the below configuration: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Configuration WebApp001 { # Import the module that contains the resources we're using. Import-DscResource -ModuleName PsDesiredStateConfiguration # The Node statement specifies which targets this configuration will be applied to. Node 'localhost' { # The first resource block ensures that the Web-Server (IIS) feature is enabled. WindowsFeature WebServer { Ensure = "Present" Name = "Web-Server" } # The second resource block ensures that the website conten...

In the previous post of the series (available here ) we went through an introduction of Powershell DSC and how it can help with configuring virtual machines. This post is going to be about the Local Configuration Manager, also known as LCM, the engine that is the heart of DSC. When a configuration file is pushed to a node, the LCM is the component that is responsible for performing all the operations in order to bring the system to the desired state. Apart from that, LCM can also monitor the system for configuration drift and take actions in order to remedy it. LCM works with files in the C:\Windows\System32\Configuration directory and there are three of them in particular that you should be aware of: Current.mof . This is the file that contains the current configuration. Previous.mof . This file contains the previous configuration that was applied to the system. Usefull for reverting to a previous state. The following screenshot shows the above files: Pending.mof.  When a configu...

With the ever evolving world of cloud, organizations need to deploy and configure resources faster and in a more controlled manner. Although Azure ARM and other tools like Terraform provide the ability to manage all the resources as code and just submit deployment jobs, we sometimes need a bit more, especially when it comes to virtual machines. Microsoft Desired State Configuration is a technology that helps to approach the guest operating system of virtual machines is a similar manner. So, what is DSC exactly? As per Microsoft Docs,  DSC is a management platform in PowerShell that enables you to manage your IT and development infrastructure with configuration as code. But what does that mean to the everyday consultant or administrator? With DSC, you are able to describe the configuration to be applied to a virtual machine and then the engine will take any steps necessary in order for the machine to reach that state. DSC can also manage configuration drift and not only apply config...

In most cases, the scripts, functions and cmdlets we develop have to save events to a log file to make troubleshooting easier. With PowerShell, the easiest thing would be to write an event to the event log or a file. When it comes to centralized log management, most organizations have based their strategy on the syslog server and protocol. There may be agents on the windows server machines that your code is running on to collect the messsages but that's not always the case. So how can we send messages to a syslog server directly using PowerShell? Although that's not that hard, I've put together a cmdlet to do just that! My General PowerShell module that is published on the Gallery  contains the   Send-SyslogMessage cmdlet from version 2.12.0 onwards. A call to the Send-SyslogMessage would be pretty much like the following: Send - SyslogMessage - Server syslog . lab . local ` - Severity Error ` - Facility Local0 ` ...

In the era of the cloud, service releases and changes are nearly constant. Microsoft Office 365 could not be an exception, especially with the large and increasing number of services and millions of users. But some of those changes and releases sometimes cause issues with on-premises infrastructure that is not property configured. Today I am going to focus on the networking side of things and talk about allowing access to Office 365 services from firewall and proxy servers. The first thing you'll need to permit access to Office 365 services from your on-premises machines is to know the service endpoints and by endpoints I mean IP addresses and URLs. Fortunatelly, this information is available from Microsoft in this   article so the only thing you'll have to do is read through it, get the information for the services you're using and configure your proxy server and firewall. That's easy, what happens though when that information is updated? This is where the problems sta...