Devoxx PL 2022

Quick & Dirty (&Right)

Tech debt == financial debt; There is this concept of good financial debt
No credit cards == low credit score
Personal note: "A person can quit == get rid of a tech debt. In real life this is not possible"
Deliberate decisions: for example using a credit card. Debt == value sooner
Plan to pay off !!!

https://structurizr.com/
C4 model
Problems: no rules, missing automation
https://structurizr.com/help/lite - as Docker image
Render tool independent!!!
Content != presentation
GitHub will support Mermaid diagrams within Markdown fields and files -> https://github.blog/2022-02-14-include-diagrams-markdown-files-mermaid/

Trust is exploitable
KUMA (by https://konghq.com/) - another service mesh like Istio; Platform agnostic.
https://github.com/kumahq/kuma
mTLS - CP automates it

Envoy proxy (C++): api based
K8S service == SD because it provides you a ClusterIP
DNS == SD; Not because this...DNS can hold multiple records for the same domain name. DNS can return the list of IP addresses for the same domain name.
SD promoted by Consul, Eureka etc is not SD :)
https://en.wikipedia.org/wiki/Service_discovery
Load balancer != SD (this is just half of a K8S Service)
Blue/green deployment != rollout upgrades

Solves problems like: vechile routing, employee rostering, task assignment
https://en.wikipedia.org/wiki/Integer_programming
https://github.com/dupliaka/2022-devoxx-poland-school-timetabling
Score function must be scalable !!!
If we also define constraints; then the score function can be calculated incrementally
Better than OR Tools -> https://developers.google.com/optimization
Do not work well for "percentages"
Question about airplanes routing :)
https://www.optaplanner.org/

From CPU to Network communication
Move communication concerns outside app
Idea K8s plugin :) !
IP tables rules that forwards traffic to proxy == The pod cannot be unintentionally called !!!
Proxy calls directly == not load balancing == that's why it is called mesh