docs(day1); Operator mistakes talk

content/day1/03_operator-mistakes.md

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+---
+title: Title
+weight: 3
+tags:
+ - <tag>
+---
+
+<!-- {{% button href="https://youtu.be/rkteV6Mzjfs" style="warning" icon="video" %}}Watch talk on YouTube{{% /button %}} -->
+<!-- {{% button href="https://docs.google.com/presentation/d/1nEK0CVC_yQgIDqwsdh-PRihB6dc9RyT-" style="tip" icon="person-chalkboard" %}}Slides{{% /button %}} -->
+
+## Common mistake
+
+### Not using a simple client but directly talk to the api server
+
+- Problem: A
+- Problem: Updates send in the whole object -> Noop updates waste apiserver resources
+- Fix: Use a cache client
+- Problem: Caching validation
+
+### Don't use custom caching
+
+- Problem: Good Luck dealing with concurrency
+- Hard: Controllers mus maintain a per kind cache
+- Problem: Eventual consistency makes everything more complicated
+- Fix: Use a framework
+
+### Predecates only apply to the current
+
+- If you have a predecate in the for (predecate) only appy to this call, not to other watchers
+- Also check if you shold be reconciling your low-level object or reconciling the higher level ones that ref to them is better
+
+## Tools
+
+### KRT
+
+> Still under development
+
+- Operatorions in collections (kubernetes objects with state tracking)
+- Fetch function that handels transformation
+
+### StateDB
+
+- In-memory database for go with watch channels
+- You can setup a table that stores all objects of a kind (provided by the client)
+- Triggers hooks when changes happen in the database that you can react to 
+
+### Controller-Runtime
+
+> The kubebuilder one
+
+- Includes a chached client
+- Works on the reconciler pattern -> Makes triggers simpe
+
+## Tips
+
+- Limit the number of api server updates
+    - Check for dif yourself and don't send updates if there is nothing new
+    - Use patch instead of update just with changed fields -> Especially for `.status`
+- Use a framework that handles watching, coalescing and caching (krt, statedb, controller-runtime)
+- Use predecates if you're using controller-runtime, this helps you filter out no-op events by checking them against the cache and filters
+
+## Q&A
+
+- Do you know where your reconciliations are coming from:
+    - Counts: Yes the frameworks provide metrics and you can implement your own
+    - But controller runtime abstracts the patch source so you have to compare before and after state yourself - but you should not do that
+- What about state sharing across multiple threads?
+    - Controller runtime handels each reconcile as idempotent, so you can just multithread
+    - But handling consistency can still be hard

content/day1/_index.md

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 Day 1 of the main KubeCon event startet with a bunch of keynotes from the cncf themselfes (anouncing the next locations for kubecon - amsterdam and barcelona).
 The also announced a new sovereign cloud edge initiative (CNCF/LF meets EU and soem german ministry) called "NeoNephos" with members like SAP, StackIt or T-Systems.
 
+This is also the day the sponsor showcase opened - so expect more talking to people and meetings or demos and less straight up talks
+
 ## Talk recommendations
 
 - Not that much about gpus with good control plane scaling advice: [Scaling GPU Clusters without melting down](../01_scaling-gpu)
@@ -14,4 +16,6 @@ The also announced a new sovereign cloud edge initiative (CNCF/LF meets EU and s
 
 ## Other stuff I learned or people i talk to
 
-- TODO:
+- The crossplane maintainers
+- Anynines
+- Cloudfoundry/Korifi