MultiCluster 2019 unconference notes

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+#### Presenter:
+ Vallery Lancey
+
+#### Topic:
+ Unconference: Deploying and Scaling across Multiple Clsuters
+
+#### Date & time:
+ 11/18/2019 9:30am
+
+#### Notes
+
+Getting started: what is multicluster? 
+* Federation / copy across otherwise independent clusters
+* Deployment: rollout changes
+  - Hard w/o big CI/CD changes
+  - Granularity of rollouts is hard, if you have two clusters how do you launch less
+    than 50% at a time
+  - Non-native k8s apps often don’t deal with with partial rollout.
+* Big variety of use cases & solutions, custom implementations everywhere
+
+What is definition of multicluster? (vs just having a bunch of clusters)
+* Deploy same app in multiple clusters
+
+What are reasons to run?
+* Big range, very customer-dependent
+* Range from east-coast/west coast clusters to a cluster in every cell tower
+* Different fault domains
+* Avoid canary deployments
+* Backup environment for rollbacks
+
+Need tools above deployment layer, service meshes require committing to fearsome
+stack (eg Istio)
+* Example: how to generate Flagger to multicluster (Weaveworks incremental rollout
+  tool based on linkerd)
+* Is there load balancing across clusters?
+* Is the system aware of multiple clusters--basic things like how many clusters
+  to adjust rollout #s
+
+Why multi-cluster?
+* Technical reasons (5k node limit, etc) vs customer/user need
+* User needs include
+  - CI/CD
+  - High availability
+  - Blast radius (or is this a technical detail?)
+  - Isolated environments
+  - Data locality/federal regulations
+  - Disaster recovery
+
+Service meshes are an additional step for customers to migrate existing applications
+to, but federation is needed now. This leads to custom solutions.
+
+What are multi-cluster building blocks?
+* Deployment
+* Service  mesh. But this is too big and meshes are too opinionated, should be
+broken into layers
+  - Service discovery
+  - Connectivity
+  - Ingress
+  - Routing
+  - Signals: alerts/health/observability
+
+Fundamental problems that define multicluster:
+* Resource usage / technical limitations of data centers
+* Administrative groups: independently run clusters that use common organizational
+  security policies
+* Coordination across clusters
+* Deployment
+* Rollout new app
+* Cascading triggers (service X launches which unblocks service Y to launch etc)
+
+
+#### Key learnings / takeaways
+
+Multi-cluster is being used today, but in ad-hoc and specific ways. Common usage
+patterns need to be discovered and standardized in order to learn how k8s needs
+to be extended to support multi-cluster well.
+
+
+#### Action items
+* Survey on customer needs
+  - Rather than current usage, as that can be driven by legacy accidents
+* Start defining building block/concepts
+* Actually we also need to survey current solutions in order to identify building blocks
+* Focus on defining minimal set of building blocks to avoid the usual k8s explosion.