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Created March 11, 2022 19:10
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cka-practice-questions
Q: Create a job that calculates pi to 2000 decimal points using the container with the image named perl
and the following commands issued to the container: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
Once the job has completed, check the logs to and export the result to pi-result.txt.
Solution:
kc -o yaml job name --image=perl > perl.yml
### edit the file, edit the name, remove any ID references and include the command argument under container spec.
command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
apiVersion: batch/v1
kind: Job
metadata:
creationTimestamp: 2019-03-02T17:34:12Z
labels:
job-name: pi2000
name: pi2000
namespace: default
resourceVersion: "5161"
spec:
backoffLimit: 6
completions: 1
parallelism: 1
selector:
matchLabels:
template:
metadata:
creationTimestamp: null
labels:
job-name: pi2000
spec:
containers:
- image: perl
command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
imagePullPolicy: Always
name: pi2000
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
dnsPolicy: ClusterFirst
restartPolicy: Never
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
status: {}
### Delete the running job, then recreate the job using the edited yaml file we will call pi2000.yaml:
sudo kubectl delete job perl
kc -f pi2000.yaml
### get the output from the logs and export them to text file
gl pi2000-xvrpt > pi-result.txt
Q. Create a yaml file called nginx-deploy.yaml for a deployment of three replicas of nginx, listening on the container's port 80.
They should have the labels role=webserver and app=nginx. The deployment should be named nginx-deploy.
Expose the deployment with a load balancer and use a curl statement on the IP address of the load balancer
to export the output to a file titled output.txt.
Solution:
sudo kubectl run nginx-deploy --labels="role=webserver,app=nginx" --image=nginx --replicas=3 --port=80 -o yaml > nginx-deployment.yaml
### expose the deployment with a loadbalancer type, call it nginx-service
kubectl expose deployment nginx-deploy --type=LoadBalancer --name=nginx-service
### use a curl statement that connects to the IP endpoint of the nginx-service and save the output to a file called output.txt
curl IP > output.txt
### leave this deployment running
Q. Scale the deployment you just made down to 2 replicas
Solution:
sudo kubectl scale deployment nginx-deploy --replicas=2
Q. Create a pod called "with-files" with an nginx image listening on port 80. The pod should attach to emptyDir storage, mounted to /tmp in the container. Connect to the pod and create a file with zero bytes in the /tmp directory called linuxacademy.txt. Do not delete this pod. If you create other artifacts in the course working on this, you may delete them from your home directory or create a directory called extras in your home directory and move the files there.
Solution:
sudo kubectl exec -it with-files-85b755877f-cbmwh /bin/bash
Q. Label the worker node of your cluster with rack=qa.
Solution:
sudo kubectl label node texasdave2c.mylabserver.com rack=qa
Q. Create a file called counter.yaml in your home directory and paste the following yaml into it:
Solution:
apiVersion: v1
kind: Pod
metadata:
name: counter
spec:
containers:
- name: count
image: busybox
args: [/bin/sh, -c, 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done']
Start this pod.
Once its logs exceed a count of 20 (no need to be precise — any time after it has reached 20 is fine),
save the logs into a file in your home directory called count.result.txt.
Q.
Create a new namespace called "cloud9". Create a pod running k8s.gcr.io/liveness with a liveliness probe that uses httpGet to probe an endpoint path located at /cloud-health on port 8080. The httpHeaders are name=Custom-Header and value=Awesome. The initial delay is 3 seconds and the period is 3.
Q. Create a deployment with two replicas of nginx:1.7.9.
The container listens on port 80. It should be named "web-dep" and be labeled
with tier=frontend with an annotation of AppVersion=3.4.
The containers must be running with the UID of 1000.
Solution:
kubectl run web-dep --labels="tier=frontend" --image=nginx --replicas=2 --port=80 -o yaml > web-dep.yaml
### edit the page to add the annotation in the metadata section:
apiVersion: apps/v1beta1
kind: Deployment
metadata:
annotations:
AppVersion: "3.4"
creationTimestamp: 2019-03-02T18:17:19Z
generation: 1
labels:
tier: frontend
### output the description of the deployment to the file web-dep-description.txt
sudo kubectl describe deploy/web-dep > web-dep-description.txt
Q. Upgrade the image in use by the web-dep deployment to nginx:1.9.
Solution:
kubectl --record deployment/web-dep set image deployment/web-dep nginx=nginx:1.9.1
Q. Roll the image in use by the web-dep deployment to the previous version.
Do not set the version number of the image explicitly for this command.
kubectl rollout history deployment/web-dep
kubectl rollout undo deployment/web-dep
Q. Expose the web-dep deployment as a service using a NodePort.
Solution:
kubectl expose deployment/web-dep --type=NodePort
Q. Configure a DaemonSet to run the image k8s.gcr.io/pause:2.0 in the cluster.
Solution:
kubectl run testds --image=k8s.gcr.io/pause:2.0 -o yaml > testds.yaml
then edited it as Daemonset to get it running, you don't do replicas in a daemonset, it runs on all nodes
Q. Configure the cluster to use 8.8.8.8 and 8.8.4.4 as upstream DNS servers.
Solution:
The answer can be found at: https://kubernetes.io/docs/tasks/administer-cluster/dns-custom-nameservers/
apiVersion: v1
kind: ConfigMap
metadata:
name: kube-dns
namespace: kube-system
data:
stubDomains: |
{"acme.local": ["1.2.3.4"]}
upstreamNameservers: |
["8.8.8.8", "8.8.4.4"]
Q. An app inside a container needs the IP address of the web-dep endpoint to be passed to it as an
environment variable called "ULTIMA". Save the yaml as env-ultima.yaml
Solution:
### get the IP address of the web-dep service
sudo kubectl get svc
apiVersion: apps/v1beta2
kind: Deployment
metadata:
name: ultima-dep
namespace: default
spec:
selector:
matchLabels:
app: ultima-app
template:
metadata:
labels:
app: ultima-app
spec:
containers:
- name: pause-pod
image: k8s.gcr.io/pause:2.0
env:
- name: ULTIMA
value: 55.55.58.23
kc -f env-ultima.yaml
Q. Figure out a way to create a pod with 3 replicas using the the nginx container that can have pods deployed
on a worker node and the master node if needed.
Solution:
sudo kubectl get nodes
sudo kubectl describe node MASTERNODE
### notice the taint on the master node:
Taints: node-role.kubernetes.io/master:NoSchedule
### add the toleration to the yaml file
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
tolerations:
- key: "node-role.kubernetes.io/master"
operator: "Equal"
effect: "NoSchedule"
Q. Copy all Kubernetes scheduler logs into a logs directory in your home directory.
Solution:
gp --namespace=kube-system
gl --namespace=kube-system kube-scheduler-ubuntu.local > test-log.txt
Q. Run the pod below until the counter in exceeds 30, export the log file into a file called counter-log.txt.
Solution:
apiVersion: v1
kind: Pod
metadata:
name: counter
spec:
containers:
- name: count
image: busybox
args: [/bin/sh, -c, 'i=0; while true; do echo "$i: $(date)"; echo "$(date) - File - $i" >> /var/www/countlog; i=$((i+1)); sleep 3; done']
gl POD > counter-log.txt
Q. Create a yaml file called db-secret.yaml for a secret called db-user-pass.
The secret should have two fields: a username and password.
The username should be "superadmin" and the password should be "imamazing".
Solution:
echo -n 'superadmin' > ./username.txt
echo -n 'imamazing' > ./password.txt
kc secret generic db-user-pass --from-file=./username.txt --from-file=./password.txt -o yaml > db-secret.yaml
apiVersion: v1
data:
password.txt: aWhlYXJ0a2l0dGVucw==
username.txt: YWRtaW4=
kind: Secret
metadata:
creationTimestamp: 2019-03-03T00:21:16Z
name: db-user-pass
namespace: default
resourceVersion: "30182"
selfLink: /api/v1/namespaces/default/secrets/db-user-pass
uid: 42b979da-3d4a-11e9-8f41-06f514f6b3f0
type: Opaque
Q.
Create a ConfigMap called web-config that contains the following two entries:
'web_port' set to 'localhost:8080'
'external_url' set to 'reddit.com'
Run a pod called web-config-pod running nginx, expose the configmap settings as environment variables inside the nginx container.
### this has to be done in several steps, first create configmap from literals on command line
sudo kubectl create configmap test-cm --from-literal=web_port='localhost:8080' --from-literal=external_url='reddit.com'
### double check the configmap
sudo kubectl describe cm test-cm
Name: test-cm
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
external_url:
----
reddit.com
web_port:
----
localhost:8080
Events: <none>
### create the pod deployment yaml and then edit the file
sudo kubectl run web-config-pod --image=nginx -o yaml > web-config-pod.yaml
## edit the file:
spec:
containers:
- image: nginx
env:
- name: WEB_PORT
valueFrom:
configMapKeyRef:
name: test-cm
key: web_port
- name: EXTERNAL_URL
valueFrom:
configMapKeyRef:
name: test-cm
key: external_url
imagePullPolicy: Always
name: web-config-pod
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
## delete the UID references in the file
## delete and then reinstall deployment
vi web-config-pod.yaml
sudo kubectl delete deploy/web-config-pod
sudo kubectl create -f web-config-pod.yaml
## get env vars from nginx pod:
sudo kubectl exec nginx-deploy-868c8d4b79-czc2j env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=nginx-deploy-868c8d4b79-czc2j
EXTERNAL_URL=reddit.com
WEB_PORT=localhost:8080
KUBERNETES_PORT_443_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1
KUBERNETES_SERVICE_HOST=10.96.0.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
KUBERNETES_PORT=tcp://10.96.0.1:443
KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
NGINX_VERSION=1.15.9-1~stretch
NJS_VERSION=1.15.9.0.2.8-1~stretch
HOME=/root
Q. Create a namespace called awsdb in your cluster.
Create a pod called db-pod that has one container running mysql image, and one container running nginx:1.7.9
In the same namespace create a pod called plex-pod with a single container running the image plexinc/pms-docker.
Export the output of kubectl get pods for the awsdb namespace into a file called "pod-list.txt"
Q.
Create a new namespace called "cloud9". Create a pod running k8s.gcr.io/liveness with a liveliness probe that uses httpGet to probe an endpoint path located at /cloud-health on port 8080. The httpHeaders are name=Custom-Header and value=Awesome. The initial delay is 3 seconds and the period is 3.
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