Getting started with Kubernetes

Getting started with Kubernetes Kubernetes is a very powerful container orchestration platform that is quickly gaining traction and gives you lots of benefits in deploying, running and scaling your microservice web application. But it has also a steep learning curve. In this talk I will introduce you to Kubernetes, and show you, based on a practical example, how to continuously deploy a web application into it.

Transcript

1. @BastianHofmann Introduction to Kubernetes Bastian Hofmann
3. Container orchestration platform
4. Deploy, run and scale your services in isolated containers
6. Kubernetes helps you running containers
7. Very Powerful
8. Large community
9. Lot’s of large company backers
10. No vendor lock in
11. Runs on
12. AWS
13. Azure
14. Google Cloud Platform
15. Bare metal
16. Your laptop
17. Included in Docker Desktop Clients
18. SysEleven Stack
19. Learning curve
20. This talk is supposed to get you started
21. Let’s define some core concepts first
22. Kubernetes Cluster
23. • A docker image built from a Dockerfile that contains everything a service needs to run Image
24. • A container runs a docker image. • Only 1 process can run inside of a container Container
25. • A group of 1 or more containers • Same port space • Separate FS and process spaces • Ports are not accessible from outside of the pod Pod
26. • Defines and manages how many instances of a pod should run Replica Set
27. • Manages updates and rollbacks of replica sets Deployment
28. • Makes a port of a pod accessible to other pods Service
29. • Makes a service accessible to the outside of Kubernetes Ingress
30. • A physical server • Containers get distributed automatically Node
31. • Configuration that can be mounted inside of a container ConfigMap
32. • Volumes can be mounted into a container to access a ConfigMap, Secret or a folder on the host Volumes
33. • Dedicated environment to deploy services in Namespaces
34. Example
35. PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER PHP Application POD
36. PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER PHP Application POD ReplicaSet: 2 instances PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER PHP Application POD
37. PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER ReplicaSet: 2 instances PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER CONFIG WEB :80 PHP Application POD PHP Application POD
38. PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER ReplicaSet: 2 instances PHP-FPM NGINX LINKERD STATSD MEM CACHED MONGO ROUTER CONFIG WEB :80 https://php-app.k8s.foo.com:443/ PHP Application POD PHP Application POD
39. To interact with Kubernetes
40. Tooling
41. kubectl
42. $ kubectl get pods
43. NAME READY STATUS RESTARTS AGE kubernetes-dashboard-5b5bf59977-t9xb9 1/1 Running 2 9d nginx-ingress-controller-5549f5597c-97kcw 0/1 Running 2 9d nginx-ingress-default-backend-564d9d9477-tmnnr 1/1 Running 4 9d mysql-556c9b5bcb-5jdrt 1/1 Running 1 8d symfony-demo-5b75f5fc6-c7wr9 1/1 Running 0 8d symfony-demo-5b75f5fc6-jg8n4 1/1 Running 23 8d
44. REST API
45. $ kubectl proxy --port=8080 $ curl http://localhost:8080/api/v1/namespaces/default/ pods { "kind": "PodList", "apiVersion": "v1", "metadata": { "selfLink": "/api/v1/namespaces/default/pods", "resourceVersion": "336834" }, "items": [ { "metadata": { "name": "kubernetes-dashboard-5b5bf59977-t9xb9",
46. kubernetes-dashboard
48. Helm The package manager for Kubernetes
49. $ helm install stable/wordpress
50. Practical example
51. Preparations
52. A Kubernetes Cluster
54. Helm
55. Nginx Ingress Controller
56. Cert-Manager
57. Docker Registry
58. Let’s deploy the symfony demo app
59. https:/ /github.com/symfony/demo
60. First the Dockerfile
61. PHP
62. Copy our code
63. Build the project
64. Composer install
65. yarn install
66. yarn run build
67. Build the image
68. docker build -t symfony-demo:2.0.0 .
69. Demo
70. Now we have to tell Kubernetes what to do with the image
71. Resources are defined in YAML or JSON
72. Deployment
73. kind: Deployment apiVersion: extensions/v1beta1 metadata: name: symfony-demo spec: template: metadata: labels: app: symfony-demo spec: containers: - name: symfony-demo image: symfony-demo:1.0.0 ports:
74. containers: - name: symfony-demo image: symfony-demo:1.0.0 ports: - containerPort: 80 livenessProbe: httpGet: path: / port: 80 timeoutSeconds: 1 initialDelaySeconds: 10 readinessProbe: httpGet: path: /
75. Many more options configurable
76. Many more options • Setting environment variables • Mounting volumes • Requesting resources • Defining upgrade strategies • Defining command • Configure networking • Configure the scheduler • Listen on lifecycle events • Configure system capabilities for the container • …
77. Service
78. kind: Service apiVersion: v1 metadata: name: symfony-demo spec: ports: - name: http port: 80 targetPort: 80 protocol: TCP selector: app: symfony-demo
79. Ingress
80. kind: Ingress apiVersion: extensions/v1beta1 metadata: name: symfony-demo spec: rules: - host: symfony-demo.local.k8s http: paths: - path: / backend: serviceName: symfony-demo servicePort: 80
81. Creating everything
82. kubectl apply -f deployment/webapp.yaml
84. Rolling Deployments
85. kind: Deployment apiVersion: extensions/v1beta1 metadata: name: symfony-demo spec: template: spec: containers: - name: symfony-demo image: symfony-demo:1.1.0 ports: - containerPort: 80
86. kubectl apply -f deployment/webapp.yaml
87. Demo
88. What about data?
89. Storage
90. Volumes
91. https:/ /kubernetes.io/docs/concepts/ storage/volumes/
92. apiVersion: v1 kind: Pod metadata: name: test-pd spec: containers: - image: k8s.gcr.io/test-webserver name: test-container volumeMounts: - mountPath: /cache name: cache-volume volumes: - name: cache-volume emptyDir: {}
93. Persistent Storage
94. You define a Persistent Volume or Storage Class, e.g. NFS, S3, OpenStack Cinder, ...
95. Depends on your Kubernetes Setup
96. Specify a Persistent Volume Claim
97. apiVersion: v1 kind: PersistentVolumeClaim metadata: name: postgresql-pv-claim labels: name: postgresql spec: storageClassName: generic accessModes: - ReadWriteOnce resources: requests: storage: 10Gi
98. And then mount the Claim into a Volume in a container
99. apiVersion: extensions/v1beta1 kind: Deployment metadata: name: postgresql spec: template: spec: containers: … volumes: - name: postgresql-data persistentVolumeClaim: claimName: postgresql-pv-claim
100. https:/ /kubernetes.io/docs/concepts/ storage/persistent-volumes/
101. Configuration
102. Should not be included in the docker image
103. ConfigMap
104. Key/Value Store
105. kind: ConfigMap apiVersion: v1 metadata: name: special-config data: special-key: value bool-value: true
106. Can be accessed in a pod through environment variables
107. spec: containers: - name: test-container image: k8s.gcr.io/busybox command: [ "/bin/sh", "-c", "env" ] env: - name: SPECIAL_KEY valueFrom: configMapKeyRef: name: special-config key: special-key
108. spec: containers: - name: test-container image: k8s.gcr.io/busybox command: [ "/bin/sh", "-c", "env" ] envFrom: - configMapRef: name: special-config
109. Can be accessed through volumes
110. spec: containers: - name: test-container image: k8s.gcr.io/busybox command: [ "/bin/sh", "-c", "ls /etc/config/" ] volumeMounts: - name: config-volume mountPath: /etc/config volumes: - name: config-volume configMap: name: special-config
111. https:/ /kubernetes.io/docs/tasks/ configure-pod-container/configure-pod- configmap/
112. Secret
113. Storage for sensitive information
114. https:/ /kubernetes.io/docs/concepts/ configuration/secret
115. Scaling
116. Manual Scaling
117. kubectl scale --replicas=3 deployment/my-app
118. AutoScaling
119. https:/ /kubernetes.io/docs/user-guide/ horizontal-pod-autoscaling/
120. Summary
121. Powerful
122. Helpful
123. Fast paced development
124. There is more
125. Logging
126. Monitoring
127. Service Discovery
128. Service Meshs
129. ...
130. Keep up to date
131. Documentation
132. https:/ /kubernetes.io/docs/
133. KubeCons
134. https:/ /www.youtube.com/channel/ UCvqbFHwN-nwalWPjPUKpvTA
135. ContainerDays
136. Or come and have a chat with us @ booth E7
137. http:/ /speakerdeck.com/ u/bastianhofmann
138. https:/ /github.com/bashofmann/ symfony-demo-kubernetes
139. b.hofmann@syseleven.de https:/ /twitter.com/BastianHofmann We are hiring! Interested? Say "Ahoy" at booth E7! kubernetes@syseleven.de http:/ /speakerdeck.com/u/bastianhofmann