HTTP Request Returned 409 Conflict: Client already exists

The Chef server maintains the list of registered nodes and clients in its database.  When you launch a new instance with Chef you may encounter the following error message: *** Input CHEF_CLIENT_NODE_NAME is undefined, using: IP-0AFE6965 … *** Starting chef-client *** Finished chef-client Printing Log … […] INFO: Client key C:\chef\client.pem is not present – …

How to edit the GitHub README.md file

The GitHub repositories usually contain a README.md file to describe how to use the project. The GitHub web site has a simple editor, but it has a few limitations If you accidentally refresh the page, you lose your changes, The preview pane is wider than the page that will display your file, so the formatting can be …

An error occurred while signing

When you deploy and application in Microsoft Visual Studio with ClickOnce, you need to sign the installer with a key. To sign the project Visual Studio needs to use the signtool. If the ClickOnce feature is not enabled in Visual studio, it displays the following error message: An error occurred while signing: SignTool.exe was not found …

No mapping specified for instances of the EntitySet and AssociationSet in the EntityContainer

When you move your Visual Studio solution to another workstation you may encounter the following error message: System.Data.Entity.Core.MappingException was unhandled by user code HResult=-2146232032 Message=Schema specified is not valid. Errors: : error 2062: No mapping specified for instances of the EntitySet and AssociationSet in the EntityContainer … Source=EntityFramework   In this case it may help if …

Save the key file password in Visual Studio

When you have already set up the project signing of the C# application for ClickOnce deployment, and move the solution to another workstation you may get the following error message when you build the solution: Severity Code Description Project File Line Suppression State Error Cannot import the following key file: …..pfx. The key file may …

How to rename a TeamCity agent

It is important to keep the TeamCity agent names unique. If you launch a TeamCity agent with a name that is already used by another agent that is connected to the TeamCity server, the new agent will not show up in the Unauthorized agent list. To change the name of an agent, change the “name” value …

DevOps Engineering part 7. – Launching production instances in the cloud

In the previous parts of this tutorial we have launched instances (servers) in the cloud, but those were created by Test Kitchen, running on our workstation. Those instances are as good as they can be, but the cookbook did not reside on the Chef server. To launch pre-production and production instances in the cloud, first …

DevOps Engineering part 6. – Infrastructure as code

Terraform If you use Terraform in the corporate environment your company most likely has multiple AWS accounts. One for pre-production, one for production. To be able to work in multiple AWS accounts, add those keys to the credentials file at C:\Users\YOUR_USERNAME\.aws [aws01] aws_access_key_id = MY_ACCESS_KEY_FOR_AWS01 aws_secret_access_key = MY_SECRET_KEY_FOR_AWS01 [aws02] aws_access_key_id = MY_ACCESS_KEY_FOR_AWS02 aws_secret_access_key = MY_SECRET_KEY_FOR_AWS02 [default] …