OpenShift and Kubernetes

OpenShift is Red Hat’s distribution of Kubernetes, analogous to a Linux distro. This session will look at OpenShift operations through a kubectl lens, detailing the developer features OpenShift provides atop its Kubernetes core, how they map to underlying Kubernetes abstractions, and where the two APIs diverge. Along the way, we’ll enumerate elemental Kubernetes resources to show how this “platform for platforms” is harnessed and extended to solve real-world deployment and lifecycle problems

Transcript

1. bit.ly/kubemaster1 dn.dev/openshift-workshop 1 OpenShift and Kubernetes Today’s slides are here: dn.dev/openshift-workshop Homework dn.dev/openshift-tutorial
2. dn.dev/kubemaster2 Josh Wood Principal Developer Advocate Formerly CoreOS Kubernetes Operators, O’Reilly 2020 OpenShift for Developers, O’Reilly 2021 joshix@redhat.com
3. dn.dev/openshift-workshop Developer Sandbox! Get free access for renewable 30 days to a self-service, cloud-hosted Kubernetes experience with Developer Sandbox for Red Hat OpenShift. https://developers.redhat.com/developer-sandbox
4. dn.dev/openshift-workshop Why developers care about Hybrid Cloud? Applications can easily be made highly scalable and available Platform looks the same wherever it runs - same APIs and rich UI Applications can be developed and deployed in the same way Clusters typically stretch across cloud AZ for data center resilience But what about load balancing and HA across clusters running in different cloud providers? - It would need multiple data centers to fail to halt your application! X X
5. dn.dev/openshift-workshop Why Kubernetes?
6. dn.dev/openshift-workshop Love Thy Mono Old School New School
7. dn.dev/openshift-workshop Container Technology Supporting Modern Apps workloads Cloud Native Portable and interoperable Mature technology
8. dn.dev/openshift-workshop CONTAINERS CLOUD INFRASTRUCTURE LINUX HOST (KERNEL) Container App Container App Container App Container App DEVELOPERS • Cloud-native apps • Simplified packaging • Simplified testing IT OPERATIONS • Consistent app deploys • Automated app deploys • Improved app performance • Multi-cloud consistency BUSINESS LEADER • Enable devops culture • Enable hybrid cloud • Reduce vm licensing costs • Accelerate app-dev cycles
9. dn.dev/openshift-workshop DevOps Challenges - Multiple Containers ▪ How to scale? ▪ How to avoid port conflicts? ▪ How to manage them on multiple hosts? ▪ What happens if a host fails? ▪ How to keep them running continuously? ▪ How to update them? ▪ Rebuild Container Images?
10. dn.dev/openshift-workshop ▪ Greek for “Helmsman” ▪ Container orchestrator ▪ Supports multiple cloud and bare-metal environments ▪ Inspired by Google’s experience with containers ▪ Open source, written in Go ▪ Manage applications, not machines Meet Kubernetes
11. dn.dev/openshift-workshop What is Kubernetes?
12. dn.dev/openshift-workshop ✓ 1+ containers ✓ Single IP address ✓ Shared storage (ephemeral) ✓ Shared resources ✓ Shared lifecycle Kubernetes Terms - Pod
13. dn.dev/openshift-workshop ✓ The Desired State - replicas, pod template: health checks, resources, image Kubernetes Terms - Deployment/ReplicaSet
14. dn.dev/openshift-workshop ✓ Grouping of pods (acting as one) has stable virtual IP and DNS name Kubernetes Terms - Service
15. dn.dev/openshift-workshop ✓ Network available storage ✓ PVs and PVCs Kubernetes Terms - Persistent Volume
16. dn.dev/openshift-workshop ✓ Key/Value pairs associated with Kubernetes objects (env=production) Kubernetes Terms - Labels
17. dn.dev/openshift-workshop Kubernetes terms and concepts Control Plane The control plane implements loop(s), checking that actual state == desired state • Controller - a control plane member implementing state reconciliation • The default control plane schedules pods onto cluster Nodes
18. dn.dev/openshift-workshop Primary Node Node Istio proxy Node Node Node Node Dev Ops api etcd scheduler controllers Kubernetes Cluster - Nodes kubelet kubelet kubelet kubelet kubelet kubelet
19. dn.dev/openshift-workshop Dev Ops Kubernetes Cluster - Declarative
20. dn.dev/openshift-workshop Node Node Istio proxy Node Node Node Node Kubernetes Cluster - 4 Tomcats kubelet kubelet kubelet kubelet kubelet kubelet
21. dn.dev/openshift-workshop Node Node Istio proxy Node Node Node Node Kubernetes Cluster - Pod Fail kubelet kubelet kubelet kubelet kubelet kubelet X
22. dn.dev/openshift-workshop Node Node Istio proxy Node Node Node Node Kubernetes Cluster - Correcting kubelet kubelet kubelet kubelet kubelet kubelet
23. dn.dev/openshift-workshop Node Node Istio proxy Node Node Node Node Kubernetes Cluster - Node Fail kubelet kubelet kubelet kubelet kubelet kubelet X
24. dn.dev/openshift-workshop Node Node Istio proxy Node Node Node kubelet kubelet kubelet kubelet kubelet Kubernetes Cluster - Pods Replaced
25. Access Developer Console and open Web Terminal
26. OpenShift build tools: Pipelines and GitOps Building and deploying app containers on the cluster OpenShift promotes build elements to first-class abstractions on the platform • Integrated container registry • Software catalog • Build configuration builds from source repo • Image stream: Tagged images, source in registry, rollbacks to arbitrary points on that stream, rebuild apps when FROM is updated
27. OpenShift web console and oc Managing apps on the cluster OpenShift promotes some new elements. These tools know about them • Web console built around the Project → App • Graphical tools for native k8s things like volume claims, etc • oc: CLI tool • odo: CLI tool for developers
28. Elements Kubernetes (blue) and OpenShift (red) Abstractions Route Namespace == Project Build Configuration Image Stream Integrated Registry Pod Replica Set Service Ingress Persistent Volume Claim Persistent Volume
29. OpenShift Project Namespace ready for work Projects draw on the Kubernetes namespace, which isolates resources and access • Intelligent RBAC defaults and user role • Project defines and seals an “application” • … in a way flexible enough for various architectures • Projects enable multi-tenant use of an OpenShift cluster with access privileges determined by the identity of the user or the team they belong to
30. OpenShift Route Real world external traffic The OpenShift Route(r) • Routes predate Ingress resource/controllers • And remain considerably easier to think about and use • OpenShift admins define Routers -- effectively, edge routing between the cluster SDN and the real world where your customers live • HAProxy: L7 is in the box • Easy TLS, edge or pass through
31. OpenShift and Kubernetes Conclusions OpenShift makes it easier for devs to get distributed system benefits • Deployment choices reduced: SDN, Ingress controller and LB costs • But what about Layer 4? • What about site specific SDN concerns? • Kubernetes flexibility: • Define alternative implementations • OpenShift Routers: can be replaced, or • Kubernetes Ingress
32. dn.dev/openshift-workshop Additional Resources
33. dn.dev/openshift-workshop Developer Sandbox! Get free access for renewable 30 days to a self-service, cloud-hosted Kubernetes experience with Developer Sandbox for Red Hat OpenShift. https://developers.redhat.com/developer-sandbox
34. dn.dev/openshift-workshop Lab: dn.dev/openshift-tutorial
35. dn.dev/openshift-workshop Want More - Labs! developers.redhat.com • Using OpenShift • Developing on OpenShift • GitOps and Pipelines • Serverless • Operators • Istio • Storage • AI/ML • Quarkus
36. dn.dev/openshift-workshop Download https://red.ht/3IxJCzY
37. dn.dev/openshift-workshop Download https://red.ht/modernize-enterprise-java
38. dn.dev/openshift-workshop Download https://dn.dev/k8s-patterns
39. dn.dev/openshift-workshop Thank You!