Lab
A Cloud Guru

CKAD Practice Exam - Part 2

This lab is designed to help prepare for the kinds of tasks and scenarios encountered during the Certified Kubernetes Application Developer (CKAD) exam. In this lab, we will practice working with multi-container pods by creating a pod that implements an adapter design pattern. We will create a pod that generates some log output and uses an adapter pod to format the output.

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Path Info

Level

Intermediate

Duration

1h 30m

Published

Mar 31, 2019

Challenge

Create a ConfigMap to Store the fluentd Configuration

Switch to root so you can read the config file:
```
sudo -i
```
Get the contents of the config file:
```
cat /usr/ckad/fluent.conf
```

Create a descriptor for the ConfigMap with vi fluentd-config.yml:

apiVersion: v1
kind: ConfigMap
metadata:
  name: fluentd-config
data:
  fluent.conf: |
    <source>
      type tail
      format none
      path /var/log/1.log
      pos_file /var/log/1.log.pos
      tag count.format1
    </source>

    <source>
      type tail
      format none
      path /var/log/2.log
      pos_file /var/log/2.log.pos
      tag count.format2
    </source>

    <match **>
      @type file
      path /var/logout/count
      time_slice_format %Y%m%d%H%M%S
      flush_interval 5s
      log_level trace
    </match>

Create the ConfigMap in the cluster:
```
kubectl apply -f fluentd-config.yml
```

Challenge

Create the Pod Descriptor

Switch to root so you can work with the descriptor file:
```
sudo -i
```

Edit the descriptor file with vi /usr/ckad/adapter-pod.yml:

apiVersion: v1
kind: Pod
metadata:
  name: counter
spec:
  containers:
  - name: count
    image: busybox
    args:
    - /bin/sh
    - -c
    - >
      i=0;
      while true;
      do
        echo "$i: $(date)" >> /var/log/1.log;
        echo "$(date) INFO $i" >> /var/log/2.log;
        i=$((i+1));
        sleep 1;
      done
    volumeMounts:
    - name: varlog
      mountPath: /var/log
  - name: adapter
    image: k8s.gcr.io/fluentd-gcp:1.30
    env:
    - name: FLUENTD_ARGS
      value: -c /fluentd/etc/fluent.conf
    volumeMounts:
    - name: varlog
      mountPath: /var/log
    - name: config-volume
      mountPath: /fluentd/etc
    - name: logout
      mountPath: /var/logout
  volumes:
  - name: varlog
    emptyDir: {}
  - name: config-volume
    configMap:
      name: fluentd-config
  - name: logout
    hostPath:
      path: /usr/ckad/log_output

Challenge

Create the Pod in the Cluster and Make Sure It Is Working
1. Create the pod:
```
kubectl apply -f /usr/ckad/adapter-pod.yml
```
2. Verify that the pod starts up:
```
kubectl get pod counter
```
3. You can also verify that everything is working by checking the output directory on the worker node. Log in to the worker from the master:
```
ssh [email protected]
```
4. Look for the fluentd output files in the output directory:
```
ls /usr/ckad/log_output
```

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

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