Demystifying the Nuts & Bolts of Kubernetes Architecture
2 likes415 views
The document summarizes the architecture of Kubernetes. It uses an analogy of cargo ships and control ships to explain the different components. The master node components like the scheduler, ETCD cluster, and controller manager manage and monitor the worker nodes. The worker node components like Kubelet and kube-proxy run on each node and ensure pods and containers are running properly and can communicate. Pods are the basic building blocks that can contain one or more containers.
![23
In nutshell…
$kubectl get componentstatus
[node1 install]$ kubectl get nodes -o wide
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-
RUNTIME
node1 Ready master 92s v1.14.2 192.168.0.18 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6
node2 Ready <none> 57s v1.14.2 192.168.0.17 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6
node3 NotReady <none> 39s v1.14.2 192.168.0.16 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6
node4 NotReady <none> 32s v1.14.2 192.168.0.15 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6
[node1 install]$ kubectl get componentstatus
NAME STATUS MESSAGE ERROR
scheduler Healthy ok
controller-manager Healthy ok
etcd-0 Healthy {"health":"true"}](https://image.slidesharecdn.com/kubernetesintroslides-1-191226101444/85/Demystifying-the-Nuts-Bolts-of-Kubernetes-Architecture-23-320.jpg)
Demystifying the Nuts & Bolts of Kubernetes Architecture
- 1. Demystifying the Nuts & Bolts of Kubernetes Architecture
- 2. 2 Who Am I? • Principal Systems Development Engineer at DellEMC • Worked with VMware & CGI • Docker Captain | Docker Community Leader • Collabnix Slack – 1800+ Members • DockerLabs – 500+ tutorials http://www.collabnix.com
- 3. Let’s start with an analogy..
- 4. A Cargo Ship… Carries containers across the sea
- 5. A Cargo Ship… Host Application as Containers ~ Worker Nodes
- 7. 7 Control Ships.. Managing & Monitoring of the cargo ships
- 8. 8 Control Ships.. Manage, Plan, Schedule, Monitor ~ Master
- 10. Let’s talk about Master Components..
- 11. 11 Ship Cranes Identifies the placement of containers
- 12. 12 Ship Cranes Identifies the right node to place a containers ~ Kube-Scheduler
- 14. 14 Cargo Ship Profiles HA database ~ Which containers on which ships? When was it loaded?
- 15. 15 Cargo Ship Profiles HA database ~ Which containers on which ships? When was it loaded? ~ The ETCD Cluster
- 17. 17 Offices in Dock - Operation Team Office ~ Ship Handling, Control - Cargo Team Office ~ verify if containers are damaged, ensure that new containers are rebuilt - IT & Communication Office – Communication in between various ships
- 18. 18 Controllers - Node Controllers – Takes care of Nodes | Responsible for onboarding new nodes in a cluster | Availability of Nodes - Replicas Controller – Ensures that desired number of containers are running at all times - Controller Manager - Manages all these controllers in place
- 20. 20 How does each of these service communicate with each other?
- 21. 21 Kube API Server API Server - A primary management component of k8s - Responsible for orchestrating all operations within a cluster - Exposes K8s API ,used by external users to perform management operation in the cluster and number of controller to monitor the state of the cluster
- 23. 23 In nutshell… $kubectl get componentstatus [node1 install]$ kubectl get nodes -o wide NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER- RUNTIME node1 Ready master 92s v1.14.2 192.168.0.18 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6 node2 Ready <none> 57s v1.14.2 192.168.0.17 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6 node3 NotReady <none> 39s v1.14.2 192.168.0.16 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6 node4 NotReady <none> 32s v1.14.2 192.168.0.15 <none> CentOS Linux 7 (Core) 4.4.0-141-generic docker://18.9.6 [node1 install]$ kubectl get componentstatus NAME STATUS MESSAGE ERROR scheduler Healthy ok controller-manager Healthy ok etcd-0 Healthy {"health":"true"}
- 24. Let’s talk about Worker Components..
- 25. 25 Overview A Worker Node Master Scheduler ETCD Controller Manager API ServerAPI kubectl UI
- 26. 26 Captain of the Ship - Manages all sort of activity on the ship - Let master ship knows they are interested to join - Sending reports back to master about the status of the ship - Sending reports about the status of the containers
- 27. 27 Captain of the Ship ~ Kubelet Agent which runs on each nodes of the container
- 28. 28 Overview Worker Node-1 Master Scheduler ETCD Controller Manager API Server Kubelet API kubectl UI
- 29. 29 Communication between Cargo Ships How does two cargo ships communicate with each other?
- 30. 30 Kube-proxy Service How will web server running on one worker node reach out to DB server on another worker node? Communication between worker nodes Kube-proxy
- 31. 31 Overview Worker Node-1 Master Scheduler ETCD Controller Manager API Server Kubelet Kube-proxy Internet
- 32. Let’s talk about Pods..
- 33. 33 Overview Worker Node-1 Master Scheduler ETCD Controller Manager API Server Kubelet Kube-proxy Internet Pod
- 34. 34 Overview Worker Node-1 Master Scheduler ETCD Controller Manager API Server Kubelet Kube-proxy Internet Pod Container
- 35. 35 Docker Containers A popular Container Runtime
- 36. 36 Overall Kubernetes Architecture Worker Node Master Scheduler ETCD Controller Manager API Server Kubelet Kube-proxy Internet Pod Container API kubectl UI
- 37. 37 Demo • Setting up 5 Node Kubernetes Cluster on PWK