Kubernetes Advanced Resource Features - Episode 1

- Overview
　- Introduction
　- Setup
　- Architecture
　- Components
　- Resources
- What Happens When We Type kubectl run
- Namespace
　- Namespace Resource Introduction
　- Working with Namespaces
　- Not All Objects are in a Namespace
- Kubernetes QoS
　- QoS Classes in K8s
　- QoS of Guaranteed
　- QoS of Burstable
　- QoS of BestEffort

#kubernetes

1. Kubernetes Advanced Resource Features - Episode 1 Date: 2018/12/06 Place: ITRI Presenter: Samina (Shan-Jung Fu) Prepare Hands-On Environment: http://bit.ly/2zLHggi All Lab base on K8s@1.11
2. • Overview • What Happens When We Type kubectl run • Namespace • Kubernetes QoS Outline 2
3. • Overview ◦ Introduction ◦ Setup ◦ Architecture ◦ Components ◦ Resources • What Happens When We Type kubectl run • Namespace • Kubernetes QoS Outline 3
4. • Introduction • Setup • Architecture • Components • Resources Kubernetes Introduction • Kubernetes is Greek for captain or pilot • Aka K8s, replace “ubernete” with 8 • Experiences from Google and design by Google • An open-source system • A container management system 4
5. • Introduction • Setup • Architecture • Components • Resources • Local-machine solutions • Hosted solutions • Turnkey cloud solutions • On-premises turnkey cloud solutions • Custom solutions • etc. Kubernetes Setup Solutions 5
6. • Local-machine solutions A local, single-node Kubernetes cluster for development and testing ◦ Minikube ◦ microk8s ◦ etc. • Hosted solutions • Turnkey cloud solutions • On-premises turnkey cloud solutions • Custom solutions Kubernetes Setup Solutions (Cont.) • Introduction • Setup • Architecture • Components • Resources 6
7. • Local-machine solutions • Hosted solutions Maintain more machines and higher availability ◦ OpenShift ◦ VMware Cloud PKS ◦ etc. • Turnkey cloud solutions • On-premises turnkey cloud solutions • Custom solutions • ... Kubernetes Setup Solutions (Cont.) • Introduction • Setup • Architecture • Components • Resources 7
8. Kubernetes Setup Solutions (Cont.) • Local-machine solutions • Hosted solutions • Turnkey cloud solutions Create K8s clusters on a range of Cloud IaaS providers with only a few commands ◦ AWS ◦ Google Compute Engine (GCE) ◦ etc. • On-psremises turnkey cloud solutions • Custom solutions • Introduction • Setup • Architecture • Components • Resources 8
9. • Local-machine solutions • Hosted solutions • Turnkey cloud solutions • On-premises turnkey cloud solutions Create K8s clusters on your internal, secure, cloud network with only a few commands ◦ GKE On-Prem | Google Cloud ◦ SUSE CaaS Platform ◦ etc. • Custom solutions Kubernetes Setup Solutions (Cont.) • Introduction • Setup • Architecture • Components • Resources 9
10. Kubernetes Setup Solutions (Cont.) • Local-machine solutions • Hosted solutions • Turnkey cloud solutions • On-premises turnkey cloud solutions • Custom solutions ◦ kubeadm ◦ Kubespray ◦ Kubernetes The Hard Way ◦ etc. • Introduction • Setup • Architecture • Components • Resources 10
11. Kubernetes Architecture • Introduction • Setup • Architecture • Components • Resources apiserver etcd scheduler controller kubelet kubelet kubelet API CLI UI Users Control plane Nodes 11
12. Node • A worker machine in K8s • Can be a VM or physical machine • also called "minions" • Node components do: ◦ Run on each node ◦ Maintain running pods ◦ Provid K8s runtime ENV Kubernetes Architecture (Cont.) • Introduction • Setup • Architecture • Components • Resources • Components: ◦ Kubelet ◦ Kube-proxy ◦ Container Runtime 12
13. • K8s logic (its "brains") is a collection of services: ◦ API server (our point of entry to everything!) ◦ core services like scheduler & controller manager ◦ etcd (a highly available key/value store; "database" of K8s) • Together, these services form the control plane of our cluster • Also called the "master" Kubernetes Architecture (Cont.) • Introduction • Setup • Architecture • Components • Resources 13
14. Kubernetes Components • Introduction • Setup • Architecture • Components • Resources 14
15. Kubernetes Components (Cont.) • Introduction • Setup • Architecture • Components • Resources 15
16. • The Kubernetes API defines a lot of objects called resources • These resources are organized by type, or Kind (in the API) Kubernetes Resources • Introduction • Setup • Architecture • Components • Resources 16
17. • A few common resource types are: ◦ node (a machine - physical or virtual - in our cluster) ◦ pod (group of containers running together on a node) ◦ service (stable network endpoint to connect to one or multiple containers) ◦ namespace (more-or-less isolated group of things) And much more! Kubernetes Resources (Cont.) • Introduction • Setup • Architecture • Components • Resources 17
18. Kubernetes Resources (Cont.) • Introduction • Setup • Architecture • Components • Resources • We can see the full list by running kubectl api-resources (In Kubernetes 1.10 and prior, the command to list API resources was kubectl get) 18
19. • Overview • What Happens When We Type kubectl run • Namespace • Kubernetes QoS Outline 19
20. What Happens When We Type kubectl run https://github.com/jamiehannaford/what-happens-when-k8s From: https://github.com/kubernetes/website/blob/master/static/images/docs/architecture.png 20
21. • Overview • What Happens When We Type kubectl run • Namespace ◦ Namespace Resource Introduction ◦ Working with Namespaces ◦ Not All Objects are in a Namespace • Kubernetes QoS Outline 21
22. Namespace Introduction • Virtual clusters • Functionalities ◦ Help pod-to-pod communication using the same namespace ◦ Can sit on top of the same physical cluster ◦ Provide logical separation between the teams and their environments 22
23. Create a namespace(ns) $ kubectl create -f ns-file-name.yml Working with Namespace apiVersion: v1 kind: Namespace metadata: name: my-ns 23
24. Working with Namespace (Cont.) Viewing namespaces(ns) $ kubectl get namespaces NAME STATUS AGE default Active 1d kube-system Active 1d kube-public Active 1d 24
25. NAME READY STATUS RESTARTS AGE pod/coredns-78fcdf6894-cp6hs 1/1 Running 0 4m pod/coredns-78fcdf6894-l6sx7 1/1 Running 0 4m pod/etcd-k8slab 1/1 Running 0 3m pod/kube-apiserver-k8slab 1/1 Running 0 3m pod/kube-controller-manager-k8slab 1/1 Running 0 3m pod/kube-flannel-ds-kzt8n 1/1 Running 0 4m pod/kube-proxy-96srn 1/1 Running 0 4m pod/kube-scheduler-k8slab 1/1 Running 0 3m NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP 4m ... Working with Namespace (Cont.) Viewing resources under namespace(ns) $ kubectl get all -n kube-system 25
26. Working with Namespace (Cont.) Using Namespace in pod - Example apiVersion: v1 kind: Pod metadata: name: nginx-demo namespace: my-ns spec: containers: - name: nginx image: nginx:1.7.9 ports: - containerPort: 80 26
27. Not All Objects are in a Namespace # In a namespace $ kubectl api-resources --namespaced=true # Not in a namespace $ kubectl api-resources --namespaced=false 27
28. • Overview • What Happens When We Type kubectl run • Namespace • Kubernetes QoS ◦ QoS Classes in K8s ◦ QoS of Guaranteed ◦ QoS of Burstable ◦ QoS of BestEffort Outline 28
29. QoS Classes in K8s • K8s provides different levels of Quality of Service(QoS) to pods • For each resource, containers specify ◦ Request: system guarantees to the amount of the resource for the container ◦ Limit: system allows the container to use the maximum quantity • Defining resource constraints for pods ◦ CPU ◦ Memory • QoS Classes • Guaranteed • Burstable • BestEffort 29
30. QoS Classes in K8s (Cont.) QoS classes to the Pod: • Guaranteed • Burstable • BestEffort In decreasing order of priority. • QoS Classes • Guaranteed • Burstable • BestEffort 30
31. • Pods are ◦ Considered Top-priority ◦ Guaranteed to not be killed until pods exceed pods limits • Every Container in the Pod have: ◦ The same memory limit & memory request ◦ The same CPU limit & CPU request QoS of Guaranteed • QoS Classes • Guaranteed • Burstable • BestEffort 31
32. kubectl create namespace qos-example kubectl create -f https://k8s.io/examples/pods/qos/qos-p od.yaml --namespace=qos-example kubectl get pod qos-demo --namespace=qos-example --output=yaml ... qosClass: Guaranteed kubectl delete pod qos-demo --namespace=qos-example apiVersion: v1 kind: Pod metadata: name: qos-demo namespace: qos-example spec: containers: - name: qos-demo-ctr image: nginx resources: limits: memory: "200Mi" cpu: "700m" requests: memory: "200Mi" cpu: "700m" QoS of Guaranteed (Cont.) • QoS Classes • Guaranteed • Burstable • BestEffort $ $ $ $ 32
33. QoS of Burstable • Pods have some form of minimal resource guarantee • Can use more resources when available • Pod can be killed once they exceed their requests • A Pod is given a QoS class of Burstable if: ◦ Pod doesn’t meet the criteria for QoS class Guaranteed. ◦ At least one Container in the Pod has a memory or CPU request. • QoS Classes • Guaranteed • Burstable • BestEffort 33
34. kubectl create namespace qos-example kubectl create -f https://k8s.io/examples/pods/qos/qos-p od-2.yaml --namespace=qos-example kubectl get pod qos-demo-2 --namespace=qos-example --output=yaml ... qosClass: Burstable kubectl delete pod qos-demo-2 --namespace=qos-example apiVersion: v1 kind: Pod metadata: name: qos-demo-2 namespace: qos-example spec: containers: - name: qos-demo-2-ctr image: nginx resources: limits: memory: "200Mi" requests: memory: "100Mi" QoS of Burstable (Cont.) • QoS Classes • Guaranteed • Burstable • BestEffort $ $ $ $ 34
35. kubectl create namespace qos-example kubectl create -f https://k8s.io/examples/pods/qos/qos-p od-4.yaml --namespace=qos-example kubectl get pod qos-demo-4 --namespace=qos-example --output=yaml ... qosClass: Burstable kubectl delete pod qos-demo-4 --namespace=qos-example apiVersion: v1 kind: Pod metadata: name: qos-demo-4 namespace: qos-example spec: containers: - name: qos-demo-4-ctr-1 image: nginx resources: requests: memory: "200Mi" - name: qos-demo-4-ctr-2 image: redis QoS of Burstable (Cont.) • QoS Classes • Guaranteed • Burstable • BestEffort $ $ $ $ 35
36. • Pods are ◦ Considered lowest priority ◦ The first to get killed if the system runs out of memory • These containers can use any amount of free memory in the node Pod must NOT have any memory or CPU limits or requests. QoS of BestEffort • QoS Classes • Guaranteed • Burstable • BestEffort 36
37. kubectl create namespace qos-example kubectl create -f https://k8s.io/examples/pods/qos/qos-p od-3.yaml --namespace=qos-example kubectl get pod qos-demo-3 --namespace=qos-example --output=yaml ... qosClass: BestEffort kubectl delete pod qos-demo-3 --namespace=qos-example apiVersion: v1 kind: Pod metadata: name: qos-demo-3 namespace: qos-example spec: containers: - name: qos-demo-3-ctr image: nginx QoS of BestEffort (Cont.) • QoS Classes • Guaranteed • Burstable • BestEffort $ $ $ $ 37
38. Defined in terms of Request and Limit • Guaranteed: highest protection ◦ request > 0 && limit == request • Burstable: medium protection ◦ request > 0 && limit > request • Best Effort: lowest protection ◦ request == 0 QoS Classes in K8s 38
39. References • https://kubernetes.io • https://github.com/jamiehannaford/what-happens-when-k8s • https://qconsf2018.container.training • https://medium.com/google-cloud/quality-of-service-class-qos-in-kubernetes -bb76a89eb2c6 • https://drive.google.com/file/d/1iOsAa4HwXrNMfkkTJFA1mHt6glgpOYbL/vie w • https://kubernetes.io/docs/tasks/configure-pod-container/quality-service-pod /#qos-classes 39
40. Thanks for your attention. Slides: http://bit.ly/k8s1206 GitHub, Telegram: @sufuf3 Twitter: @sufuf3149 40