Kubernetes for Developers

An average developer thinks Kubernetes is just a buzz word that makes a DevOps engineer on his/her team sound smart. That's not totally true. The purpose of this talk is to break down into details the fundamentals of Kubernetes and make developers comfortable enough to deploy simple applications on Kubernetes and to hold conversations about it.

Transcript

1. KUBERNETES FOR (JS) DEVELOPERS Kubernetes 101
2. Hello! I am Idowu Emehinola DevOps Engineer at Deimos Co-organiser at DevOps Nigeria Certified Kubernetes Application Developer @_hydeenoble www.deimos.io
3. What is Kubernetes? Kubernetes (K8s) is an open-source container orchestration system for automating deployment, scaling, and management of containerized applications. @_hydeenoble
4. Okay? What does that even mean?
5. Let’s take a few step backwards.
6. CONTAINERS
7. Why do you need a container? Infrastructure (hardware) Operating System Libraries Depencies
8. Why do you need a container? Infrastructure (hardware) Operating System Libraries Depencies Hardware Compatibility
9. Why do you need a container? Infrastructure (hardware) Operating System Libraries Depencies OS Compatibility + Hardware Compatibility
10. Why do you need a container? Infrastructure (hardware) Operating System Libraries Depencies Libs and Deps Compatibility + OS Compatibility + Hardware Compatibility
11. Why do you need a container? Infrastructure (hardware) Operating System Libraries Depencies Compatibility Hell
12. Why do you need a container? Infrastructure (hardware) Operating System Docker Libs Deps Libs Deps Libs Deps Libs Deps Containers
13. Containers A Container can be said to be a Virtual Machine (VM) but instead of running in a predefined operating system, they run using your defined operating System. © Deimos Cloud (Pty) Ltd
14. Containers VS Virtual Machines Infrastructure (hardware) Operating System Hypervisor OS Libs Deps Application OS Libs Deps Application Virtual Machine Virtual Machine Infrastructure (hardware) Operating System Docker Libs Deps Application Libs Deps Application Container Container CPU Utilization Disk Space Boot up time CPU Utilization Disk Space Boot up time
15. What Next? How do we run it in production? What if our container depends on other containers? How do we manage that? When number of user increase, how do we scale up (or down)? When a container crashes, how do we spin up a new one IMMEDIATELY?
16. CONTAINER ORCHESTRATION
17. Kubernetes Kubernetes (K8s) is an open-source container orchestration system for automating deployment, scaling, and management of containerized applications.
18. Basic Concept - Node A Node is a machine (physical or virtual) which several kubernetes components are installed. It is a worker machine where containers launched by kubernetes would be running in. © Deimos Cloud (Pty) Ltd Node
19. © Deimos Cloud (Pty) Ltd Node Node What if your node fails? Some weird reasons
20. Basic Concept - Cluster Node Node Node
21. Basic Concept - Master Node Master Node Node Node
22. POD A POD is a single instance of an application. A POD is the smallest object, that can created in kubernetes. © Deimos Cloud (Pty) Ltd Node POD
23. © Deimos Cloud (Pty) Ltd API version a "Pod" can be found. Object type to deploy Labels are used to "Identify" pods in the kubernetes cluster Name of the Pod Name of the Container running in the Pod Docker Image to run in the container
24. © Deimos Cloud (Pty) Ltd POD POD What if your pod fails? Some weird reasons
25. ReplicaSet A ReplicaSet’s purpose is to maintain a stable set of replica Pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods. © Deimos Cloud (Pty) Ltd Node POD POD replicaSet
26. © Deimos Cloud (Pty) Ltd API version for ReplicaSet Labels the ReplicaSet uses to filter and find it's Pods Labels are used to "Identify" this replicaSet in the kubernetes cluster Name of ReplicaSet Everything here is similar to the configuration of a pod except the "name" attribute. How many pods to run - how many instance of this application should be running at any given time
27. POD POD POD POD POD POD POD POD REPLICA SET v1 v2 UPGRADE ROLLING UPDATES ROLLBACK
28. www.deimos.io POD POD POD POD POD POD POD POD REPLICA SET v1 v2 UPGRADE ROLLING UPDATES ROLLBACK DEPLOYMENT
29. Deployment Deployment which is a kubernetes object that comes higher in the hierarchy (relative to pod and replicaset). A deployment provides us with capabilities to upgrade the underlying application instances seamlessly.
30. © Deimos Cloud (Pty) Ltd Name of deployment Label to identify Deployment resource in the cluster Defines the strategy used to replace old Pods by new ones Labels used to filter and identify pods. Labels used to target this pod Name of the container running in the pod. Docker Image Environment variable to use in the application e.g: PORT => 8000 PORT application is runs on. How many pods to run - how many instance of this application should be running at any given time
31. © Deimos Cloud (Pty) Ltd Communication between pods?
32. © Deimos Cloud (Pty) Ltd Interaction between pods / external users SERVICE SERVICE
33. Service A Service is a kubernetes object that enables communication between various deployment within the cluster and It can also enable users to communicate with applications running on kubernetes.
34. © Deimos Cloud (Pty) Ltd
35. Ingress An Ingress is an API object that manages external access to the services in a cluster, typically HTTP. It may provide load balancing, SSL termination and name-based virtual hosting. It acts like a "smart router" that routes to different service depending on the domain configure. It can be considered as a smart Loadbalancer.
36. What are Loadbalancers?
37. Loadbalancer A Loadbalancer helps to efficiently distribute incoming network traffic across a multiple instances of an application (or servers).
38. © Deimos Cloud (Pty) Ltd Without LoadBalancers Internet APP (web server) User
39. © Deimos Cloud (Pty) Ltd LoadBalancers Internet APP 1 APP 1 User Load Balancer APP 1
40. Ingress vs Loadbalancers Service test.example.com example.com/api example.com/videos another-domain.com INGRESS Service Service Service Service LoadBalancer Traffic Traffic
41. © Deimos Cloud (Pty) Ltd
42. ConfigMaps ConfigMaps are used to pass configuration data in the form of key value pairs in Kubernetes.
43. © Deimos Cloud (Pty) Ltd
44. Secrets Secrets are used to store sensitive information, like passwords or keys. They are similar to configMaps, except that they are stored in an encoded or hashed format.
45. © Deimos Cloud (Pty) Ltd
46. DEMO: Let’s see some YAMLs https://bit.ly/2SI3WaL
47. Here is what we have covered so far.
48. Summary - Compatibility Hell - Containers - Containers vs VMs - Container Orchestration - Node / Master Node - Cluster - Kubernetes - Pod - ReplicaSet - Deployment - Service - Ingress - ConfigMaps - Secrets
49. Thank you for Listening. Questions? Idowu Emehinola @_hydeenoble www.deimos.io