Sysdig & CoreOS, Part 2: Troubleshooting Flannel Networking & Confd

The blog post, authored by Gianluca Borello, delves into the intricacies of troubleshooting networking issues and configuration management in CoreOS environments using Sysdig. It highlights the challenges associated with flannel networking, which enables direct communication between containers across different hosts by creating a virtual network through UDP tunneling. The article provides an example of how incorrect network configuration can lead to routing issues, using Sysdig to diagnose and resolve these problems. It also covers troubleshooting confd, a daemon that syncs configuration files with values from etcd, demonstrating how Sysdig can monitor real-time file changes and detect configuration errors due to race conditions in fleet unit files. The post underscores the complexity of managing CoreOS and containerized systems and promotes Sysdig as an essential tool for gaining visibility and resolving issues in such environments.