Reading Time: 3 Minutes ReadThis is the fifth and last article in this series of posts. The first two articles (Article I., Article II.) in the series focused on hardening possibilities on a project level with Google Cloud Platform. The third post highlighted the topic of built-in GCE Security. In the fourth article in the series, we went through several network-level protection tools available for your Google Compute Engine instances. This article is about the possible security-related settings on the instances’ operating systems themselves. This is not closely related to either Google Cloud Platform (GCP) or Google Compute Engine (GCE). Protecting the OS of your instances is also very important. You cannot ignore these security controls if you use GCE. Read this article to learn know more about GCE OS Security. GCE OS Security is a huge topic with many articles, documents, and papers available. My focus will be on Linux instances and will only mention a small subset of OS protection techniques.