docs (day-1): DNS Talk

content/day-1/04_dns-debugging.md

@@ -0,0 +1,53 @@
+---
+title: Understanding and Debugging DNS in Kubernetes Clusters
+weight: 4
+tags:
+ - <tag>
+---
+
+<!-- {{% button href="https://youtu.be/rkteV6Mzjfs" style="warning" icon="video" %}}Watch talk on YouTube{{% /button %}} -->
+{{% button href="https://github.com/mqasimsarfraz/talks/tree/main/CloudNativeRejekts-2025" style="transparent" icon="person-chalkboard" %}}Slides{{% /button %}}
+
+
+
+## Baseline
+
+### DNS Components
+
+```mermaid
+graph LR
+    Application-->NodeLocalDNS-->CoreDNS-->Upstream
+```
+
+### Problems
+
+- Many hidden systems
+- Not easy to trace across clusters
+
+## Tools
+
+> Demo queries are located in the slides and were executed during the stream
+
+### CoreDNS Log Plugin
+
+- Core-Plugin (just needs to be activated)
+- Logs all requests to stdout
+
+### Hubble
+
+- Cilium observability needs cilium l7 proxy, runs as deamonset
+- Needs CiliumNetworkPolicies for AppPod and CoreDNS
+- Metrics, UI and cli with jq (and protocol filter)
+
+### Inspector Gadget
+
+- Toolset for Kubernetes and Linux that can be customized
+- Runns as daemonset or debug pod - gadgets are distributed as containers (via artifactorhub)
+- DNS-Gadget: Trace via ebpf, post process with wasm
+
+
+## Overview
+
+- CoreDNS: Great for initial, nut only CoreDNS
+- Hubble: Compact overview, but cilium needed with special configs
+- Inspector Gadget: Rich DNS traces, limited tcp support

content/day-1/_index.md

@@ -10,4 +10,10 @@ The second and last day of cloud native rejekts and (some might say most importa
 
 - My Talk: [Evaluating Global Load Balancing Options for Kubernetes in Practice](todo:)
 - Service Mesh Intro + Comparison: [The service mesh wars - a new hope for kubernetes](../03_service-mesh)
-- iNTRO TO OPERATORS: [The Hidden Brains of Kubernetes: Meet Controllers Powering the Cloud](../02_controllers)
+- Intro to operators: [The Hidden Brains of Kubernetes: Meet Controllers Powering the Cloud](../02_controllers)
+
+## Other stuff I learned or people i talk to
+
+- Take a deeper look into CoreDNS plugins
+- A bunch of nice people that heard my talk and had questions
+- Someone from Ampere that would like to help me to convince the infra team to get arm nodes