add a new cobalt learning path to link to from the .NET path, and add LD path info to the .NET path

Author: JoeStech

content/learning-paths/servers-and-cloud-computing/cobalt/1-create-cobalt-vm.md

@@ -0,0 +1,25 @@
+---
+title: Create the Cobalt 100 virtual machine
+weight: 2
+
+### FIXED, DO NOT MODIFY
+layout: learningpathall
+---
+
+## Use the Azure Portal to deploy a Cobalt 100 VM
+
+Azure Cobalt 100 VMs are a part of the ['D' family of Azure VMs](https://learn.microsoft.com/en-us/azure/virtual-machines/sizes/general-purpose/d-family). To deploy one, follow these steps:
+
+1. Sign in to the [Azure Portal](https://portal.azure.com/).
+2. Select **Create a resource → Compute → Virtual machine**.
+3. Complete the *Basics* tab:
+   ![Azure Portal – Basics tab for the VM wizard#center](images/create-cobalt-vm.png)
+   The Dpsv6-series are powered by Cobalt 100. Selecting Standard_D4ps_v6 will give you a Cobalt VM with 4 physical cores. you can change the 4 to another value if you want a different number of cores.
+4. Upload your public SSH key or generate a new one in the wizard.
+5. Disallow public inbound ports for now.
+5. Accept the defaults on the *Disks* tab.
+6. On the *Networking* tab ensure that a **Public IP** is selected. You will need it to connect later. Leave the NSG settings as *Basic* for now. 
+
+Click **Review + create** followed by **Create**. Azure now deploys the VM and the automatically-generated Network Security Group (NSG). Provisioning takes ~2 minutes.
+
+Navigate to the **Deployment in progress** pane or open the **Notifications** panel to track progress. When the deployment succeeds proceed to the next step to expose an inbound port.

content/learning-paths/servers-and-cloud-computing/cobalt/2-open-port.md

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+---
+title: Open an inbound port in the Network Security Group
+weight: 3
+
+### FIXED, DO NOT MODIFY
+layout: learningpathall
+---
+
+## Allow external traffic to TCP ports 22 (SSH) and 8080
+
+Every new virtual machine created through the Azure wizard is associated with a **Network Security Group (NSG)**. An NSG acts like a stateful firewall – if no rule explicitly allows traffic, Azure blocks it.
+
+In this step you will open port 22 for SSH, as well as port 8080 so that a web application running on the VM is reachable from your IP for testing. Substitute a different port if required by your workload, or a different IP range if you'd like broader accessibility.
+
+1. In the Azure Portal open the newly created VM resource and click **Networking → Network settings** in the left nav.
+2. Select the **Network security group**.
+3. In the left nav click **Settings → Inbound security rules**
+4. Click **Add** at the top of the screen.
+5. Fill in the form, specifying **My IP address** as the source and 22 as the destination port:
+   ![Add inbound security rule with source of my IP and destination port 22#center](images/create-nsg-rule.png)
+
+To open port 8080, follow steps 4 and 5 again, but instead choose port 8080 for the destination port.
+
+You have now opened ports 22 and 8080 to your IP. In the next step you will verify connectivity.

content/learning-paths/servers-and-cloud-computing/cobalt/3-verify-connectivity.md

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+---
+title: Verify connectivity to the Cobalt 100 VM
+weight: 4
+
+### FIXED, DO NOT MODIFY
+layout: learningpathall
+---
+
+## Connect over SSH and test the open port
+
+1. On the **Overview** page for the VM copy the **Public IP address**.
+2. Open a terminal on your local machine and SSH to the VM (replace *azureuser* if you chose a different admin username):
+
+```bash
+ssh -i [path to your pem file] azureuser@[public IP]
+```
+
+Where `[public IP]` is your public IP and `[path to your pem file]` is the path to your SSH key file.
+
+Accept the prompt to add the host to *known_hosts* the first time you connect.
+
+### Start a simple HTTP server
+
+If you do not already have an application listening on TCP 8080 you can start one temporarily:
+
+```bash
+sudo apt update -y && sudo apt install -y python3
+python3 -m http.server 8080
+```
+
+Leave this terminal open – the server runs in the foreground.
+
+### Test from your local machine
+
+In a second local terminal run `curl` to confirm you can reach the server through the NSG rule you created:
+
+```bash
+curl http://[public IP]:8080
+```
+
+Where `[public IP]` is your public IP.
+
+You should see an HTML directory listing (or your application response). Receiving a response verifies that TCP 8080 is open and the VM is reachable from the public internet.
+
+Terminate the Python server when you are finished testing (press `Ctrl + C`).
+
+You now have an Arm-based Cobalt 100 VM with an exposed port 8080 that you can use to run any test server. To learn about optimizing .NET workloads on Cobalt, check out [Migrating a .NET application to Azure Cobalt](../../dotnet-migration/).

content/learning-paths/servers-and-cloud-computing/cobalt/_index.md

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+---
+title: Create an Azure Cobalt 100 VM
+
+minutes_to_complete: 10
+
+who_is_this_for: Developers and DevOps engineers who need an Arm-based virtual machine on Azure and want to expose an application port to the internet.
+
+learning_objectives:
+    - Deploy an Arm-based Cobalt 100 virtual machine (VM) on Microsoft Azure.
+    - Connect to the Cobalt 100 VM using SSH.
+    - Open an inbound TCP port in the associated Network Security Group (NSG).
+    - Verify external connectivity to the newly opened port.
+
+prerequisites:
+    - A Microsoft Azure subscription with permission to create resources
+    - Basic familiarity with SSH
+
+author: Joe Stech
+
+### Tags
+# Tagging metadata, see the Learning Path guide for the allowed values
+skilllevels: Introductory
+subjects: Containers and Virtualization
+arm_ips:
+    - Neoverse
+tools_software_languages:
+    - Azure Portal
+    - Azure CLI
+operatingsystems:
+    - Linux
+
+
+further_reading:
+    - resource:
+        title: Azure Cobalt 100 VM documentation
+        link: https://learn.microsoft.com/azure/virtual-machines/cobalt-100
+        type: Documentation
+    - resource:
+        title: Azure Virtual Machines overview
+        link: https://learn.microsoft.com/azure/virtual-machines/
+        type: Documentation
+    - resource:
+        title: Configure Azure network security group rules
+        link: https://learn.microsoft.com/azure/virtual-network/security-overview
+        type: Documentation
+
+
+
+### FIXED, DO NOT MODIFY
+# ================================================================================
+weight: 1                       # _index.md always has weight of 1 to order correctly
+layout: "learningpathall"       # All files under learning paths have this same wrapper
+learning_path_main_page: "yes"  # This should be surfaced when looking for related content. Only set for _index.md of learning path content.
+---

content/learning-paths/servers-and-cloud-computing/cobalt/_next-steps.md

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+---
+# ================================================================================
+#       FIXED, DO NOT MODIFY THIS FILE
+# ================================================================================
+weight: 21                  # Set to always be larger than the content in this path to be at the end of the navigation.
+title: "Next Steps"         # Always the same, html page title.
+layout: "learningpathall"   # All files under learning paths have this same wrapper for Hugo processing.
+---

content/learning-paths/servers-and-cloud-computing/cobalt/images/create-cobalt-vm.png

@@ -8,11 +8,11 @@ layout: learningpathall
 
 # Create a basic OrchardCore application
 
-In this section, you will learn how to create and compile a basic OrchardCore CMS application. OrchardCore is a modular and multi-tenant application framework built with ASP.NET Core, which can be used to create content-driven websites.
+In this section, you will learn how to create and compile a basic [OrchardCore](https://github.com/OrchardCMS/OrchardCore) CMS application, as an example of a popular Linux-based .NET workload. OrchardCore is a modular and multi-tenant application framework built with ASP.NET Core, which can be used to create content-driven websites.
 
 ## Step 1: Set up your development environment
 
-1. Launch an Azure Cobalt instance running Ubuntu 24.04, and open port 8080 to the internet (link to instructions here)
+1. Launch an Azure Cobalt instance running Ubuntu 24.04, and open port 8080 to the internet. For instructions on how to do this, see the [Create an Azure Cobalt 100 VM](../../cobalt) Learning Path.
 
 2. **Install .NET SDK**: Follow the instructions on the [.NET download page](https://dotnet.microsoft.com/download) to install the SDK for your operating system.
 
@@ -23,8 +23,6 @@ In this section, you will learn how to create and compile a basic OrchardCore CM
    node --version
    ```
 
-
-
 ## Step 2: Install the OrchardCore Templates
 
 To start building an OrchardCore application, you need to install the OrchardCore templates. Open your terminal and run the following command:

content/learning-paths/servers-and-cloud-computing/cobalt/images/create-nsg-rule.png

@@ -91,6 +91,7 @@ Now that you have a shared library, you can use it in your .NET application.
 3. Ensure that dotnet can find your shared library:
 
 ```bash
+export LD_LIBRARY_PATH=$(pwd):$LD_LIBRARY_PATH
 ```
 
 ## Step 3: Run your application

content/learning-paths/servers-and-cloud-computing/dotnet-migration/1-create-orchardcore-app.md

@@ -48,4 +48,4 @@ By configuring your application to be architecture agnostic, you gain several be
 - **Efficiency**: Reduce the need for maintaining separate builds for different architectures.
 - **Scalability**: Easily scale your application across different hardware platforms.
 
-This approach ensures that your OrchardCore application can run seamlessly on both Arm and x86 architectures, as well as 64 bit or 32 bit processors.
+This approach ensures that your OrchardCore application can run seamlessly on both Arm and x86 architectures.