Challenge - Pod YAML
- Docker & Kubernetes course
- Intermediate
- Lesson 78/82
- 5 min
Write a Pod YAML with specific labels.
Challenge: a production-ready pod
A good pod definition is more than just an image. In this challenge you'll combine the intermediate pod best practices in one definition:
- Meaningful labels
- Resource requests and limits
- Readiness and liveness checks
- Settings from a ConfigMap, the password from a Secret
resources:
requests: {cpu: 100m, memory: 128Mi}
limits: {cpu: 500m, memory: 256Mi}
readinessProbe:
httpGet: {path: /saglik, port: 8080}
livenessProbe:
httpGet: {path: /saglik, port: 8080}
initialDelaySeconds: 10Practice The pod's container
Write a pod YAML: name api, label app: api; container named api, image api:1.0; resources.requests cpu: 100m, memory: 128Mi; resources.limits memory: 256Mi.
Starter code
# buraya yazSample solution
apiVersion: v1
kind: Pod
metadata:
name: api
labels:
app: api
spec:
containers:
- name: api
image: api:1.0
resources:
requests:
cpu: 100m
memory: 128Mi
limits:
memory: 256MiExpected output
pod/api created
Practice Health checks
Write the health checks for the same container (starting with readinessProbe:): readinessProbe checks /saglik on port 8080 with httpGet; livenessProbe uses the same path and port with initialDelaySeconds: 10.
Starter code
# buraya yazSample solution
readinessProbe:
httpGet:
path: /saglik
port: 8080
livenessProbe:
httpGet:
path: /saglik
port: 8080
initialDelaySeconds: 10Expected output
pod/api configured NAME READY STATUS RESTARTS AGE api 1/1 Running 0 25s
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 For a pod without requests, what does the scheduler assume?
- Zero resources; the pod may be placed even on a full node Correct answer
- All of the node's resources
- 1 CPU and 1 GiB
- The pod is rejected
Explanation: With no requests (and no LimitRange), there's no resource guarantee either.
2 Specify the guaranteed resources.
resources:
____:
cpu: 100m
memory: 128Miresources:
requests:
cpu: 100m
memory: 128MiExplanation: requests is the guarantee used in scheduling.
3 Match.
| Term | Meaning |
|---|---|
requests |
Scheduling guarantee |
limits |
Ceiling that can't be exceeded |
readinessProbe |
Traffic gate |
livenessProbe |
Catches hangs |