Kubernetes Fundamentals

Kubernetes. It's so hot right now. But what is it?

This session is designed to show the fundamentals of Kubernetes. It assumes you know what a container is, that Kubernetes does something called "orchestration" with it, but that's it.

We'll cover the following: Container Registry, Pods, Services, Ingress, Scaling, Networking, mounting volumes, package management (Helm) and what's next.

Transcript

4. VM VM VM VM Server Host OS Hypervisor Guest OS Guest OS Guest OS App C App B App A Server Host OS Hypervisor
5. VM VM VM VM Server Host OS Hypervisor Guest OS Guest OS Guest OS App C App B App A Server Host OS Hypervisor
6. VM Container VM VM VM Server Host OS Hypervisor Guest OS Guest OS Guest OS App C App B App A Server Host OS Hypervisor Bins/Libs App A
7. VM Container Container Container VM VM VM Server Host OS Hypervisor Guest OS Guest OS Guest OS App C App B App A Server Host OS Hypervisor Bins/Libs App B App C Bins/Libs App A Bins/Libs
8. VM Container Container Container VM VM VM Server Host OS Hypervisor Guest OS Guest OS Guest OS App C App B App A Server Host OS Hypervisor Bins/Libs App B App C Bins/Libs App A Bins/Libs
10. Image Name Process started in an executing container Initializes a new build stage and sets the base image Execute commands in a new layer on top of the current image and commit results Provide defaults for an executing container Captures the steps to build a container image Version-able asset in your DevOps flows Configuration-as-Code
12. VM Container Container Container Server Host OS Hypervisor Bins/Libs App B App C Bins/Libs App A Bins/Libs Container Image Container Image Container Image Container Image Container Image Container Image
13. VM Container Container Container Server Host OS Hypervisor Bins/Libs App B App C Bins/Libs App A Bins/Libs Container Image Container Image Container Image Container Image Container Image Container Image
15. VM Container Container Container Server Host OS Hypervisor Bins/Libs App B App C Bins/Libs App A Bins/Libs VM Container Container Container Server Host OS Hypervisor Bins/Libs App B App C Bins/Libs App A Bins/Libs
19. Container Orchestrator
20. Container Orchestrator Cluster
21. VM Server Host OS Hypervisor Guest OS Container Orchestrator Cluster
22. VM Server Host OS Hypervisor Guest OS Cluster
23. Kubernetes comes from the Greek word κυβερνήτης:, which means helmsman or ship pilot, ie: the captainer of a container ship. "Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications."
24. VM Server Host OS Hypervisor Guest OS Kubernetes Master Cluster Node Node Node Node Node Node
25. AKS reduces the complexity and operational overhead of managing Kubernetes by offloading much of that responsibility to Azure. You only pay for the worker nodes within your clusters, not for the master nodes
27. Kubernetes Cluster Node Node Node Node Node Node
28. Master Cluster Node api-server etcd controller- manager scheduler
29. Master Cluster Node api-server etcd controller- manager scheduler
30. Container Container Container Bins/Libs App B App C Bins/Libs App A Bins/Libs Where do the Containers go?
31. Container Container Container Bins/Libs App B App C Bins/Libs App A Bins/Libs Introducing…. Pods!
32. Pods Master Cluster Node api-server etcd controller- manager scheduler
33. Pods Master Cluster Node api-server etcd controller- manager scheduler
34. ratings-api Label(s) app=ratings-api Container-image my.azurecr.io/ratings-api Port 3001 (VolumeMount) /mnt/share (Resources) <cpu/memory> ratings-web Label(s) app=ratings-web Container-image my.azurecr.io/ratings-web Port 3000 (VolumeMount) /mnt/share (Resources) <cpu/memory> Pods – What are they? otherApp Label(s) app=otherApp Container-image other.azurecr.io/other App Port 4045 (VolumeMount) /mnt/share Metadata that describes how the containers are configured.
35. Deployments Metadata that describes how to deploy a pod More Metadata ratings-web replicas 2 ratings-web Label(s) app=ratings-web Container- image my.azurecr.io/ ratings-web Port 3000 (Volume) … (Resources) …
36. Cluster Node Node Master
37. Cluster Node Node Master
38. Cluster Node Node Master
39. ratings-web2 Label(s) app=ratings-web Container- image my.azurecr.io/ ratings-web Port 3000 Services Metadata that describes how to reach the pods Yet More Metadata! ratings-web Selector app=ratings-web Port Mapping 8080:3000 Type (Internal or External) LoadBalancer ratings-web1 Label(s) app=ratings-web Container- image my.azurecr.io/ ratings-web Port 3000
40. Services Cluster Node Node Service ratings-web IP Address Master
41. Services Cluster Node Node Service ratings-web IP Address Master
42. Manual via Kubernetes Portal Infra-as-Code a YAML file
44. Scaling Pods ratings-web replicas 3 ratings-web Label(s) app=ratings-web Container- image my.azurecr.io/ ratings-web Port 3000 (Volume) … (Resources) …
45. Scaling Pods ratings-web replicas 6 ratings-web Label(s) app=ratings-web Container- image my.azurecr.io/ ratings-web Port 3000 (Volume) … (Resources) …
46. Node Master Cluster Node Node
47. Node Node Node Master Cluster Node az scale –name –g –node-count
48. Azure Container Instances Node With Azure Container Instances Master Cluster Node az enable-addons –g –name –addons –subnet-name
50. Master Cluster Service ratings-web IP Address Updated App Updated App Updated App
51. Node Node Node Master Cluster Service ratings-web IP Address
52. Node Node Node Master Cluster Service ratings-web IP Address
54. Why do we need volumes ? Volume (state)
56. PV vs PVC Volumes emptyDir hostPath Persistent Volume Claim (PVC) ConfigMap Security …. Persistent Volume (PV)
57. Dynamic Storage in AKS – Azure Disk
59. Inter-Pod Communication
60. Why Services?
61. Why Services?
63. How does ClusterIP Work
64. How does LoadBalancer Work
65. How does NodePort Work
66. How does Ingress Controller Work
68. 1. Kubernetes users communicate with API server and apply desired state 2. Master nodes actively enforce desired state on worker nodes 3. Worker nodes support communication between containers Kubernetes control API server replication, namespace, serviceaccounts, etc. -controller- manager -scheduler etcd Master node Worker node kubelet Service Docker Pods Pods Worker node kubelet Service Docker Pods Pods Internet 4. Worker nodes support communication from the Internet
69. API server Controller Manager Scheduler etcd Store Cloud Controller Self-managed master node(s) • Automated upgrades, patches • High reliability, availability • Easy, secure cluster scaling • Self-healing • API server monitoring • At no charge Customer VMs App/ workload definition User Docker Pods Docker Pods Docker Pods Docker Pods Docker Pods Schedule pods over private tunnel Kubernetes API endpoint Azure managed control plane
70. Task The old way With Azure Create a cluster Provision network and VMs Install dozens of system components including etcd Create and install certificates Register agent nodes with control plane az aks create Upgrade a cluster Upgrade your master nodes Cordon/drain and upgrade worker nodes individually az aks upgrade Scale a cluster Provision new VMs Install system components Register nodes with API server az aks scale
73. Operationalizing Kubernetes
74. Helm Helm Charts helps you define, install, and upgrade even the most complex Kubernetes application pods services Chart.yml db deployments ci …
75. Helm The best way to find, share, and use software built for Kubernetes Manage complexity Charts can describe complex apps; provide repeatable app installs, and serve as a single point of authority Easy updates Take the pain out of updates with in-place upgrades and custom hooks Simple sharing Charts are easy to version, share, and host on public or private servers Rollbacks Use helm rollout to roll back to an older version of a release with ease
76. Many Choices
77. A fully managed service of Red Hat OpenShift on Azure, jointly, engineered, operated and supported by Microsoft and Red Hat
78. https://kubernetes.io/docs/home/ https://aka.ms/learnkubernetes https://aksworkshop.io/ https://helm.sh/blog/helm-3-preview-pt7/ https://docs.microsoft.com/en-us/azure/aks/best-practices