KubeCon-HealthChecks-pdf.pdf

Transcript

1. Your App Is Alive Michelle Noorali Developer at Deis @michellenoorali
2. Helm • Kubernetes Package Manager • Packages = “Charts” • “Homebrew” for Kubernetes • Great way to find, share, and use software built for Kubernetes • Community focused • www.helm.sh
3. Helm Charts Kubernetes 
 manifests + metadata
4. Try it out github.com/helm/charts
5. Health Checks
6. What?
7. a way to monitor your app’s health A Health Check is
8. Is your app… responsive?
9. Is your app… Performant?
10. Is your app… Stable?
11. What does it look like?
12. • /healthcheck or /healthz endpoint • checked by external system at intervals • On success, do nothing • On failure, notify and heal Health checks continued …
13. In Kubernetes Land… • Health checks are built in! • But first…
14. Introducing Puffy • … a simple go web server
15. Pre-requisites • Running Kubernetes cluster on GCE [Google Compute Engine] • Docker Image for app stored on DockerHub • DockerHub = place to store images • Can also use Quay.io or GCR [Google Container Registry]
16. Puffy Repo
17. Dockerfile
18. Makefile
19. Manifest file
20. Life of Puffy: It’s Alive • Create a pod definition in manifest • Create resource in kubernetes from manifest with 
 $ kubectl create -f puffy-pod.yaml • Watch it come to life with $ kubectl get pods -w • Talk to a route • curl pod_ip:port/index on a node • https://asciinema.org/a/7okfmusa0c368obqxba8t9my4
21. Let’s make sure puffy is ok. Here comes the health check part…
22. Two Probes walk into a coffeeshop… • Readiness Probe • Liveness Probe
23. Wait. What is this probe thing? • a probe = a diagnostic periodically performed on a container • Three ways to perform a diagnostic: • Execute a command in a container • Successful if exit status code 0 • Perform tcp check on a container’s IP address on a specific port • Successful if the port is open • Perform an HTTP Get against the container’s IP address on a specific port • Successful if response has status code >= 200 and <400
24. Back to the probes… • Readiness Probe • Is my app ready to serve traffic? • On failure, it stops serving requests • Liveness Probe • Is my app in a good state? • On failure, it restarts the pod
25. Define a Liveness Probe in the Pod Manifest
26. Apply the Changes in the Pod Manifest to the Cluster $ kubectl delete -f puffy-pod.yaml ~ edit puffy-pod.yaml ~ $ kubectl create -f pod-puffy.yaml
27. You’ll see failure
28. Oops • Forgot to add the /healthz endpoint • kubectl delete -f puffy-pod.yaml
29. Add /healthz • Define /healthz in app (common convention) • Re-build/re-tag image • Push image to registry • Edit image declaration in manifest
30. Bring Puffy Back! $ kubectl create -f puffy-pod.yaml 
 or $ helm install puffy $ kubectl get pods $ kubectl describe pod puffy On node, curl ip:port/healthz
31. Let’s add some complexity.
33. Puffy on /play
34. Puffy + Spotify API
35. ReadinessProbe Definition
36. /ready
37. Now we need a redis pod to hang out with
38. Find a redis chart … to borrow some manifests
40. and create our own chart
41. www.github.com/michelleN/helm-charts/many-directions
42. $ helm repo add michelle https://github.com/michelleN/many-directions $ helm repo list $ helm search many-directions $ helm install many-directions
43. Things to watch out for • Try to leave health checks as simple as possible • Don’t get too aggressive • Use the right probe for your situation
44. Summary • Automate monitoring apps with health checks • Use Kubernetes’s built in health check features • readinessProbe • Is your app ready to serve traffic? • livenessProbe • Is your app in a good state?
45. Deployment Manager + Coming together to bring you a simple and powerful way to deploy and manage Kubernetes Charts and is going to CNCF along with the rest of Kubernetes
46. That’s it folks. Thank you. Puffy: www.github.com/michelleN/puffy Many-directions: www.github.com/michelleN/many-directions My charts: www.github.com/michelleN/charts Helm: www.helm.sh Helm charts: www.github.com/helm/charts Look for www.github.com/kubernetes/helm & www.github.com/kubernetes/charts @michellenoorali