GDG DevFest 2018 - Kubernetes, Your go-to orchestration tool

Transcript

1. Bakare Emmanuel, Interswitch Group @tiemmaBakare Lagos Kubernetes Your go-to orchestration tool bit.ly/devfest-kube-slides @ T i e m m a B a k a r e 1
2. I’m Bakare Emmanuel • Software Developer Intern @Interswitch • Volunteer Bootcamp Facilitator and LCA @Andela • DevOps and Linux Fan Boy • General Weird Guy with some humour • Incapable of understanding when to use upper case and Lower Case • People call me Bakman, so there’s also that! @ T i e m m a B a k a r e 2
3. Here’s something to note You don’t need to know how to code to use Kubernetes Also, ask questions if you don’t get anything, I don’t bite. Also, forget the pho-ne. I’m an Ijebu Yoruba man. @ T i e m m a B a k a r e 3
4. My talk? Still need a hint? This Photo by Unknown Author is licensed under CC BY-SA-NC @ T i e m m a B a k a r e 4
5. Getting Started With Kubernetes
6. What is Kubernetes?
7. Kubernetes! Kubernetes is an open-source container-orchestration system for automating deployment, scaling and management of containerized applications. @ T i e m m a B a k a r e 7
8. To deploy an application to Kubenertes, Just remember two things CLUSTERS PODS Run your application in a POD. Just like a container but this time, it’s in a VM. Create a cluster which is just running a number of VM’s in parallel, all running the same or different pods @ T i e m m a B a k a r e 8
9. Okay, even I didn’t get that at first! @ T i e m m a B a k a r e 9
10. Let’s break down the tech gibberish! @ T i e m m a B a k a r e 10
11. First up is Containers @ T i e m m a B a k a r e 11
12. What are Containers, you ask? @ T i e m m a B a k a r e 12
13. Containers They’re like a Virtual Machine [VM] but instead of your app running in another operating system, they run using your own operating system. @ T i e m m a B a k a r e 13
14. Here’s an example of how a containers architecture is like! @ T i e m m a B a k a r e 14
15. Containers Virtual machines use a thing called a HYPERVISOR which is like a driver used to access other drivers. Containers on the other hand use a thing called CGROUP on Linux. @ T i e m m a B a k a r e 15
16. VM Architecture @ T i e m m a B a k a r e 16
17. Containers CGROUP In essence, most of us would call it a sandbox or honeypot for those who’re into security. Multiple instances of the same process can be running and not see each other. Examples are LXC and libcontainer Lagos @ T i e m m a B a k a r e 17
18. Cgroups Windows Containers Windows Containers run in VMs. CGROUPS ⊄ WINDOWS Windows are only good for ventilation so why run a container on Windows anyway. Lagos NOT A FEATURE IN @ T i e m m a B a k a r e 18
19. Now let’s see them both together! @ T i e m m a B a k a r e 19
20. Notice that the container version (Docker) doesn’t have a guest operating system Container Architecture VM Architecture @ T i e m m a B a k a r e 20
21. Examples you ask?, There’s Docker! @ T i e m m a B a k a r e 21
22. Cgroups can inherit other cgroups to form larger ones. This is what Docker uses to make containers talk to each other @ T i e m m a B a k a r e 22
23. Cgroup Features These are the features that Cgroups in general enforce. @ T i e m m a B a k a r e 23
24. Cgroups with Docker Notice docker can connect to both but the containers are individually separated. A general example of running multiple containers on Docker. @ T i e m m a B a k a r e 24
25. So, Kubernetes? Is it a CONTAINER or VM based application? @ T i e m m a B a k a r e 25
26. Sorry to disappoint! Kubernetes is a VM based application! @ T i e m m a B a k a r e 26
27. @ T i e m m a B a k a r e 27
28. If you remember the first slide! Kubernetes is an open-source container-orchestration system for automating deployment, scaling and management of containerized applications. @ T i e m m a B a k a r e 28
29. So how does Kubernetes work then? @ T i e m m a B a k a r e 29
30. Clusters and Pods @ T i e m m a B a k a r e 30
31. @ T i e m m a B a k a r e 31
32. Cluster A cluster comprises of a master node and other slave nodes which is where our pods are.
33. Clusters Kubernetes runs in clusters. A cluster is basically a server containing one or more Kubernetes nodes. A common Kubernetes cluster for local development is minikube. It just houses the Kubernetes node. @ T i e m m a B a k a r e 33
34. Within the nodes, you have pods @ T i e m m a B a k a r e 34
35. And the pods are then what? Can anyone guess? @ T i e m m a B a k a r e 35
36. Containers @ T i e m m a B a k a r e 36
37. Pods Pods are containers which are running. @ T i e m m a B a k a r e 37
38. Deployments and Services @ T i e m m a B a k a r e 38
39. Deployments and Services In Kubernetes, a deployment represents running instances of your containerized application in Kubernetes. Deployments are not accessible outside the Kubernetes VM that they’re run in. A service is therefore the entry point that defines what ports are accessible and how the port mapping should be set up on the host. @ T i e m m a B a k a r e 39
40. Here are some pictures of the Kubernetes dashboard showing the deployment and services 40 @ T i e m m a B a k a r e
41. Dashboard Example
42. Deployment Example
43. Service Example
44. @ T i e m m a B a k a r e 44
45. We’d start with the deployment @ T i e m m a B a k a r e 45
46. Let’s break down this tech jargon @ T i e m m a B a k a r e 46
47. apiVersion: apps/v1 kind: Deployment metadata: name: random-deployment namespace: random-namespace spec: selector: matchLabels: run: random-deployment replicas: 4 strategy: rollingUpdate: maxSurge: 1 maxUnavailable: 1 type: RollingUpdate Name of the deployment Namespace where we want to put this. Namespaces are basically sandboxes. The labels our service uses to filter and find this deployment Rolling Updates help with making sure we can make changes and set the number of replicas we want to keep available We’d get here soon API version the deployment kind can be found This is a deployment cluster type @ T i e m m a B a k a r e 47
48. Let’s cover the ApiVersion @ T i e m m a B a k a r e 48
49. What’s the Kubernetes ApiVersion? An object definition in Kubernetes requires an apiVersion field. When Kubernetes has a release that updates what is available for you to use —”changes something in its API”— a new apiVersion is created. @ T i e m m a B a k a r e 49
50. Here’s a list of api versions @ T i e m m a B a k a r e apps/v1 50
51. Changes made in the apps/v1 apiVersion @ T i e m m a B a k a r e 51
52. Notice the kind matches Deployment for the extensions/v1beta1 @ T i e m m a B a k a r e apps/v1 52
53. apiVersion: apps/v1 kind: Deployment metadata: name: random-deployment namespace: random-namespace spec: selector: matchLabels: run: random-deployment replicas: 4 strategy: rollingUpdate: maxSurge: 1 maxUnavailable: 1 type: RollingUpdate Name of the deployment Namespace where we want to deploy this. Namespaces are basically sandboxes. The labels our service uses to filter and find this deployment Rolling Updates help with making sure we can make changes and set the number of replicas we want to keep available We’d get here soon API version the deployment kind can be found This is a deployment cluster type @ T i e m m a B a k a r e 53
54. API Version Despite using apps/v1, the apiVersion still reverts to extensions/v1beta1. It’s not important to cram the apiVersion!
55. apiVersion: apps/v1 kind: Deployment metadata: name: random-deployment namespace: random-namespace spec: selector: matchLabels: run: random-deployment replicas: 4 strategy: rollingUpdate: maxSurge: 1 maxUnavailable: 1 type: RollingUpdate Let’s cover what this is now! @ T i e m m a B a k a r e 55
56. Let’s talk about REPLICAS @ T i e m m a B a k a r e 56
57. What are REPLICAS? @ T i e m m a B a k a r e 57
58. Replica Sets Example
59. Replica Sets Controller are attached to pods
60. @ T i e m m a B a k a r e Those are REPLICAS! 60
61. REPLICA SETS in Kubernetes @ T i e m m a B a k a r e Replicas are just PODs started with the same container. In Kubernetes, we call them REPLICA SETS and they are just a group of REPLICAS. 1 Hence, we can run multiple versions of our application knowing that if we ever have downtime, we can easily start another instance(REPLICA) to cater for that one that went down. 2 61
62. template: metadata: labels: run: random-deployment spec: containers: - name: kube-demo image: node-demo imagePullPolicy: IfNotPresent This is where the label is defined The name we give our container The image we want to use in our deployment We only pull the image if we don’t have it @ T i e m m a B a k a r e 62
63. readinessProbe: httpGet: path: /ready port: liveness-port initialDelaySeconds: 5 timeoutSeconds: 1 periodSeconds: 15 This is what Kubernetes uses to check if our container is ready. It uses status headers to check. Anything between 200 – 400 is fine. Anything after 400 is unsuccessful. If this fails, our application will not be available @ T i e m m a B a k a r e 63
64. livenessProbe: tcpSocket: port: liveness-port initialDelaySeconds: 5 timeoutSeconds: 1 periodSeconds: 15 This is the same as that of the readiness probe but this checks if the entire application is running and not just a service. The TCP thing just checks if my entire application’s port is still accessible. @ T i e m m a B a k a r e 64
65. env: - name: KEY valueFrom: configMapKeyRef: name: random-config key: KEY resources: requests: cpu: 100m memory: 100Mi ports: - name: liveness-port containerPort: 3000 This is how we pass environment variable to our application. I’d explain what the config map ref is in the coming slides. We can allocate resources to our application as well. How much CPU and RAM the entire application can use 100m = 0.1CPU Because it’s node: 3000 is the port I’m using in my app @ T i e m m a B a k a r e 65
66. Finally, ConfigMaps @ T i e m m a B a k a r e 66
67. Config Maps These are just ways to define environment variables on a larger scale. @ T i e m m a B a k a r e 67
68. apiVersion: v1 kind: ConfigMap metadata: name: random-config namespace: random-namespace data: KEY: blank @ T i e m m a B a k a r e 68
69. So why not just use an env file as we’ve always done? @ T i e m m a B a k a r e 69
70. Never bake your config into your app! It’s never a wise thing to bake configurable options into your applications container, especially if you’re running it in production. Keep your properties, env or whatever it’s called outside your app. Make it configurable and call it either using an API or otherwise with ConfigMap as seen here. @ T i e m m a B a k a r e 70
71. Deployment Example
72. And a service? @ T i e m m a B a k a r e 72
73. apiVersion: v1 kind: Service metadata: name: random-service namespace: random-namespace spec: selector: run: random-deployment ports: - protocol: TCP port: 80 targetPort: 3000 name: http type: LoadBalancer @ T i e m m a B a k a r e 73 Service types are defined in the v1 API This is a Service cluster type These are details about the service name and where it is Since our deployment enforced we use this label, this is how we bind it to this service. We want to take our node app from port 3000 and expose it on port 80 Finally, this should load balance and spread traffic across multiple pods. This requires an ingress or load balancer setup
74. What’s an Ingress? @ T i e m m a B a k a r e 74
75. Ingresses Ingress is actually NOT a type of service. Instead, it sits in front of multiple services and acts as a “smart router” or entrypoint into your cluster. This routes to different services depending on the domain you plan to expose your service on. They are smart Layer 7 load balancers. Normal load balancers work on Layer 4. @ T i e m m a B a k a r e 75
76. I guess that’s what you’re thinking! What the hell is a LoadBalancer? 76 @ T i e m m a B a k a r e
77. No Load Balancing @ T i e m m a B a k a r e 77 This Photo by Unknown Author is licensed under CC BY-SA-NC
78. This is how we’ve all deployed our production apps in past times HINT: All you cPanel users ☹ @ T i e m m a B a k a r e 78
79. Load Balancing Here, we have an entry load balancer service which then takes the request and passes it to a REPLICA of our application
80. Remember me saying ingresses are smart load balancers?
81. Notice the difference in how they route the requests! Ingress Controller Load Balancer @ T i e m m a B a k a r e 81
82. apiVersion: extensions/v1beta1 kind: Ingress metadata: name: random-ingress namespace: random-namespace annotations: nginx.ingress.kubernetes.io/rewrite-target: / spec: backend: serviceName: default-http-backend servicePort: 80 @ T i e m m a B a k a r e 82 This allows us to direct traffic from the same URL to another service making it easier to manage different deployments. It’s particularly very effective if you’re running microservices.
83. rules: - host: random.demo # URL I plan to expose my service on http: paths: - path: / backend: serviceName: random-service servicePort: 80 - path: /socket.io backend: serviceName: random-service # another-random-service servicePort: 80 @ T i e m m a B a k a r e 83
84. Service Example
85. In summary, here’s what we’ve covered @ T i e m m a B a k a r e 85
86. Now WE DEMO!!!!! @ T i e m m a B a k a r e 86
87. Now WE DEMO!!!!! GITHUB: • http://bit.ly/kube-talk EXTRA CODELAB: • https://codelabs.developers.google.com/codelabs/cloud-hello- kubernetes/ @ T i e m m a B a k a r e 87
88. “If it’s not broken, don’t fix it ” - Some Random Guy Presenting 88
89. “When you break it, better fix it or you might get fired ” - My conscience or a future boss somewhere 89
90. “If a solution already exists, don’t build another one, unless you’re NETFLIX!” - Any body who can use Google / Github and ask Questions? 90
91. Bakare Emmanuel, Interswitch Group @tiemmaBakare Location Thank you!
92. Q&A Ask me anything! For example, what is your favorite food? Or preferably, what is your account number? Location