CKAD Prep

Concepts on the Exam

• Core Concepts - 13%
  • API Primitives
  • Create and Configure Basic Pods
• Configuration - 18%
  • Understand ConfigMaps
  • Understand SecurityContexts
  • Define App Resource Requirements
  • Create and Consume Secrets
  • Understand Service Accounts
• Multi-Container Pods - 10%
  • Design Patterns: Ambassador, Adapter, Sidecar
    • - Sidecar Pattern
    • - Init Containers
• Pod Design - 20%
  • Using Labels, Selectors, and Annotations
  • Understand Deployments and Rolling Updates
  • Understand Deployment Rollbacks
  • Understand Jobs and CronJobs
• - State Persistence - 8%
  • - Understand PVCs for Storage
• Observability - 18%
  • Liveness and Readiness Probes
  • Understand Container Logging
  • Understand Monitoring Application in Kubernetes
  • Understand Debugging in Kubernetes
• Services and Networking - 13%
  • Understand Services
  • Basic Network Policies

Exam Tips from Daniel

• 19 questions
• Questions are weighted differently
• Be strategic about which questions you answer
• The terminal is kinda crappy
• use set-context
• investigate crashing pods
• pipe text and logs to a specific file path
• Copy and paste the file paths that you are asked to send a file to
• Side car with a shared value
• Use the --dry-run
• kubectl run nginx --image-nginx
• --restart=Never makes a pod
• ^^ without that makes a deployment

Exam Feburary 2019, first attempt

• Figure out how to use edit
  • It wouldn't work with vim's :wq
• Memorize multi-container pods with logging
• Memorize env variable syntax
• Volume mounts

Run

The kubectl run command lets you quickly create a K8s deployment,pod, job or cronjob.

$ kubectl run hazelcast --image=hazelcast => deployment
$ kubectl run hazelcast --image=hazelcast --restart=Never => pod
$ kubectl run busybox --image=busybox --restart=OnFailure => job 
$ kubectl run busybox --image=busybox --schedule="* * * * *" --restart=OnFailure => cronJob

kubectl create vs. apply

1. Create a basic bod and service
2. Create a multi-continaer pod
3. Create a simple deployment
4. Deploy a simple python app
5. Increase the number of replicas to 6

Basic Pod and NodePort Service

kind: Pod
metadata:
  name: basicpod
  labels:
    type: webserver
spec:
  containers:
  - name: webcont
    image: nginx
    ports:
    - containerPort: 80```

```apiVersion: v1
kind: Service
metadata:
  name: basicservice
spec:
  selector:
    type: webserver
  type: NodePort
  ports:
  - protocol: TCP
    port: 80```

### Basic Pod with Fluentd Sidecar 
```apiVersion: v1
kind: Pod
metadata:
  name: basicpod
  labels:
    type: webserver
spec:
  containers:
  - name: webcont
    image: nginx
    ports:
    - containerPort: 80
  - name: fdlogger
    image: k8s.gcr.io/fluentd-gcp:1.30```