This quiz is part of the DevOpsTheHardWay course.

Please answer the quiz and click the "Test" button at the bottom right.

Kubernetes - Pods design - multichoice questions

Given a cluster composed by 3 nodes, as follows: 

$ kubectl describe nodes node1
Name:               node1
[ ... lines removed for clarity ...]
  Resource           Requests      Limits
  --------           --------      ------
  cpu                1820m (91%)   2925m (146%)

$ kubectl describe nodes node2
Name:               node1
[ ... lines removed for clarity ...]
  Resource           Requests      Limits
  --------           --------      ------
  cpu                1620m (40.5%)   6925m (346%)

$ kubectl describe nodes node3
Name:               node1
[ ... lines removed for clarity ...]
  Resource           Requests      Limits
  --------           --------      ------
  cpu                2506m (84%)   3925m (213%)

Answer the below 3 questions.

Question 1

You apply the following Pod: 

apiVersion: v1
kind: Pod
metadata:
  name: myapp
spec:
  containers:
  - name: server
    image: alpine:latest
    command: ["/bin/sh", "-c", "sleep 3600"]
    resources:
      requests:
        cpu: "1000m"
      limits:
        cpu: "1000m"

Which Node the Pod would be scheduled on?

Question 2

You get the following FailedScheduling error when tried to deploy some Pod:

0/3 nodes are available: 1 Insufficient cpu.

Choose the correct sentence:

Question 3

You are now told that every node in the cluster has the following taint: app=contoso:NoSchedule.

You apply the following Pod: 

apiVersion: v1
kind: Pod
metadata:
  name: myapp
spec:
  containers:
  - name: server
    image: alpine:latest
    command: ["/bin/sh", "-c", "sleep 3600"]

Which error could you get?

Question 4

If the node where a Pod is running has enough of a resource available, it's possible (and allowed) for a container to use more resource than its request for that resource specifies.

Question 5

Given the following Pod:

apiVersion: v1
kind: Pod
metadata:
  name: multi-container-pod
spec:
  containers:
  - name: container-1
    image: nginx:latest
    resources:
      requests:
        memory: "256Mi"
        cpu: "100m"
      limits:
        memory: "512Mi"
        cpu: "200m"

  - name: container-2
    image: busybox:latest
    command: ["/bin/sh", "-c", "sleep 3600"]
    resources:
      requests:
        memory: "128Mi"
        cpu: "50m"
      limits:
        memory: "256Mi"
        cpu: "100m"

  - name: container-3
    image: alpine:latest
    command: ["/bin/sh", "-c", "sleep 3600"]
    resources:
      requests:
        memory: "64Mi"
        cpu: "25m"
      limits:
        memory: "128Mi"
        cpu: "50m"

Choose the correct sentence(s):

Question 6

Given the following snippet from kubectl describe pod command:

Events:
  Type     Reason            Age   From               Message
  ----     ------            ----  ----               -------
  Warning  FailedScheduling  23s   default-scheduler  0/42 nodes available: insufficient cpu

What can you do (choose all possible answers)?

Question 7

Given the below command and the output:

$ kubectl describe pod test-pod-123
Name:                           test-pod-123
Namespace:                      default
Image(s):                       alpine
Node:                           kubernetes-node-tf0f/10.240.216.66
Labels:                         name=test-pod-123
Status:                         Running
Reason:
Message:
IP:                             10.244.2.75
Containers:
  alpine:
    Image:  alpine:latest
    Limits:
      cpu:          100m
      memory:       50Mi
    State:          Running
      Started:      Tue, 07 Jul 2019 12:54:41 -0700
    Last State:     Terminated
      Reason:       OOMKilled
      Exit Code:    137
      Started:      Fri, 07 Jul 2019 12:54:30 -0700
      Finished:     Fri, 07 Jul 2019 12:54:33 -0700
    Ready:          False
    Restart Count:  5
Conditions:
  Type      Status
  Ready     False
Events:
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Scheduled  42s   default-scheduler  Successfully assigned test-pod-123 to kubernetes-node-tf0f
  Normal  Pulled     41s   kubelet            Container image "alpine:latest" already present on machine
  Normal  Created    41s   kubelet            Created container alpine
  Normal  Started    40s   kubelet            Started container alpine
  Normal  Killing    32s   kubelet            Killing container with id ead3fb35-5cf5-44ed-9ae1-488115be66c6: Need to kill Pod

Choose the correct sentence:

Question 8

Given: 

$ kubectl describe service myservice
Name:              myservice
Namespace:         default
Labels:            <none>
Annotations:       <none>
Selector:          app=myapp
Type:              ClusterIP
IP Family Policy:  SingleStack
IP Families:       IPv4
IP:                10.97.201.254
IPs:               10.97.201.254
Port:              grpc  9555/TCP
TargetPort:        9555/TCP
Endpoints:         10.244.0.46:9555,10.244.0.15:9555
Session Affinity:  None
Events:            <none>

Resolving myservice from one of the cluster's Pod returns:

Question 9

What happened if resources requests and limit are not specified?

Question 10

Given the below Pod:

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
  - name: container
    image: nginx:latest
    resources:
      limits:
        memory: "64Mi"

What would be the Memory resources request?

Question 11

Choose the correct sentence(s) regarding container resources request and limit:

Question 12

From official k8s HPA docs:

Since the resource usages of all the containers are summed up the total pod utilization may not accurately represent the individual container resource usage. This could lead to situations where a single container might be running with high usage and the HPA will not scale out because the overall pod usage is still within acceptable limits.

How could that issue be addressed efficiently?

Question 13

Given the below Deployment: 

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: nginx:latest

You are told that there is an HPA configured for this Deployment. What is the potential issue when changing the image tag and applying again the Deployment?

Question 14

Given the below Deployment: 

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: nginx:latest
        ports:
        - containerPort: 80
        readinessProbe:
          httpGet:
            path: /index.html
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 10
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 3

In the event of unavailability, how long does it take for kube-proxy to stop routing traffic to a Pod (the time denoted by x)?

Question 15

You deploy an application by applying some Deployment object. You notice that Pods are in CrashLoopBack mode.

Which of the below step(s) can help?

Question 16

Given a node with a taint group=blue, and a Pod with toleration for group=blue.

Question 17

Given the below Pod: 

apiVersion: v1
kind: Pod
metadata:
  name: multi-container-pod
spec:
  containers:
  - name: container1
    image: alpine
    command: ["/bin/sh", "-c", "sleep 5"]

You apply the Pod in your cluster. What is the Pod status after 1 minute?

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