App Lifecycle and Management
Updated Dec 29, 2023 ·
Some of the scenario questions here are based on Kodekloud's CKA course labs.
NOTE
CKAD and CKA can have similar scenario questions. It is recommended to go through the CKAD practice tests.
Shortcuts
First run the two commands below for shortcuts.
export do="--dry-run=client -o yaml"
export now="--force --grace-period=0"
Questions
-
Inspect the current deployment and determine the strategy used.
controlplane ~ ➜ k get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 4/4 4 4 84sAnswer
controlplane ~ ➜ k describe deployments.apps frontend | grep -i strategy
StrategyType: RollingUpdate
RollingUpdateStrategy: 25% max unavailable, 25% max surge -
Upgrade the application by setting the image on the deployment to kodekloud/webapp-color:v2. Do not delete and re-create the deployment. Only set the new image name for the existing deployment.
Answer
controlplane ~ ➜ k edit deployments.apps frontend
deployment.apps/frontend editedapiVersion: apps/v1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "1"
creationTimestamp: "2023-12-29T17:01:17Z"
generation: 1
name: frontend
namespace: default
resourceVersion: "855"
uid: 05c0c824-dd8a-4f28-9c88-0f45cfd1702d
spec:
minReadySeconds: 20
progressDeadlineSeconds: 600
replicas: 4
revisionHistoryLimit: 10
selector:
matchLabels:
name: webapp
strategy:
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
type: RollingUpdate
template:
metadata:
creationTimestamp: null
labels:
name: webapp
spec:
containers:
- image: kodekloud/webapp-color:v2controlplane ~ ➜ k get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 5/4 4 3 5m18s -
Up to how many PODs can be down for upgrade at a time. Consider the current strategy settings and number of PODs - 4
controlplane ~ ✦ ➜ k get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 4/4 4 4 6m30sAnswer
controlplane ~ ✦ ➜ k describe deployments.apps frontend | grep -i unavailable
Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable
RollingUpdateStrategy: 25% max unavailable, 25% max surge -
Change the deployment strategy to Recreate. Delete and re-create the deployment if necessary. Only update the strategy type for the existing deployment.
controlplane ~ ✦ ➜ k get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 4/4 4 4 6m30sAnswer
controlplane ~ ✦ ➜ k get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 4/4 4 4 6m30s
controlplane ~ ✦ ➜ k describe deployments.apps frontend | grep -i unavailable
Replicas: 4 desired | 4 updated | 4 total | 4 available | 0 unavailable
RollingUpdateStrategy: 25% max unavailable, 25% max surgecontrolplane ~ ✦ ➜ k edit deployments.apps frontendapiVersion: apps/v1
kind: Deployment
metadata:
annotations:
deployment.kubernetes.io/revision: "2"
creationTimestamp: "2023-12-29T17:01:17Z"
generation: 2
name: frontend
namespace: default
resourceVersion: "1060"
uid: 05c0c824-dd8a-4f28-9c88-0f45cfd1702d
spec:
minReadySeconds: 20
progressDeadlineSeconds: 600
replicas: 4
revisionHistoryLimit: 10
selector:
matchLabels:
name: webapp
strategy:
type: Recreatecontrolplane ~ ✦ ➜ k get deployments.apps
NAME READY UP-TO-DATE AVAILABLE AGE
frontend 4/4 4 4 10m -
In the current pod, what is the command used to run the pod ubuntu-sleeper?
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
ubuntu-sleeper 1/1 Running 0 22sAnswer
controlplane ~ ➜ k get po ubuntu-sleeper -o yaml | grep -i command -A 5
- command:
- sleep
- "4800"
image: ubuntu
imagePullPolicy: Always
name: ubuntu -
Create a pod with the ubuntu image to run a container to sleep for 5000 seconds.
Answer
## ubuntu-sleeper-2.yaml
apiVersion: v1
kind: Pod
metadata:
name: ubuntu-sleeper-2
spec:
containers:
- name: ubuntu
image: ubuntu
command:
- "sleep"
- "5000"controlplane ~ ➜ k apply -f ubuntu-sleeper-2.yaml
pod/ubuntu-sleeper-2 created
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
ubuntu-sleeper 1/1 Running 0 4m5s
ubuntu-sleeper-2 1/1 Running 0 4s -
Create a pod using the file named ubuntu-sleeper-3.yaml. There is something wrong with it. Try to fix it
## ubuntu-sleeper-3.yaml
apiVersion: v1
kind: Pod
metadata:
name: ubuntu-sleeper-3
spec:
containers:
- name: ubuntu
image: ubuntu
command:
- "sleep"
- 1200Answer
Commands should be enclosed in quotes.
## ubuntu-sleeper-3.yaml
apiVersion: v1
kind: Pod
metadata:
name: ubuntu-sleeper-3
spec:
containers:
- name: ubuntu
image: ubuntu
command:
- "sleep"
- "1200"controlplane ~ ✦2 ➜ k apply -f ubuntu-sleeper-3.yaml
pod/ubuntu-sleeper-3 created
controlplane ~ ✦2 ➜ k get po
NAME READY STATUS RESTARTS AGE
ubuntu-sleeper 1/1 Running 0 11m
ubuntu-sleeper-2 1/1 Running 0 3m19s
ubuntu-sleeper-3 1/1 Running 0 25s -
Create a pod with the given specifications. By default it displays a blue background. Set the given command line arguments to change it to green.
- Pod Name: webapp-green
- Image: kodekloud/webapp-color
- Command line arguments: --color=green
Answer
controlplane ~ ✦2 ➜ k run webapp-green --image kodekloud/webapp-color $do -o yaml > green.yml## green.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: webapp-green
name: webapp-green
spec:
containers:
- image: kodekloud/webapp-color
name: webapp-green
resources: {}
args:
- "--color"
- "green"
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
~controlplane ~ ✦2 ➜ k apply -f green.yml
pod/webapp-green created
controlplane ~ ✦2 ➜ k get po
NAME READY STATUS RESTARTS AGE
ubuntu-sleeper 1/1 Running 0 21m
ubuntu-sleeper-2 1/1 Running 0 13m
ubuntu-sleeper-3 1/1 Running 0 8m50s
webapp-green 1/1 Running 0 3s -
What is the environment variable name set on the container in the pod?
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
webapp-color 1/1 Running 0 19sAnswer
controlplane ~ ➜ k describe po webapp-color | grep -i env -A 5
Environment:
APP_COLOR: pink -
Identify the database host from the config map db-config.
controlplane ~ ✦ ➜ k get cm
NAME DATA AGE
kube-root-ca.crt 1 13m
db-config 3 9sAnswer
controlplane ~ ✦ ➜ k describe cm db-config
Name: db-config
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
DB_HOST:
----
SQL01.example.com
DB_NAME:
----
SQL01
DB_PORT:
----
3306
BinaryData
====
Events: <none> -
Create a new ConfigMap for the webapp-color POD. Use the spec given below.
-
ConfigMap Name: webapp-config-map
-
Data: APP_COLOR=darkblue
-
Data: APP_OTHER=disregard
Answer
controlplane ~ ✦ ➜ k create cm webapp-config-map $do > webapp-color.yml## webapp-color.yml
apiVersion: v1
kind: ConfigMap
metadata:
creationTimestamp: null
name: webapp-config-map
data:
APP_COLOR: "darkblue"
APP_OTHER: "disregard"
~controlplane ~ ✦ ➜ k apply -f webapp-color.yml
configmap/webapp-config-map created
controlplane ~ ✦ ➜ k get cm
NAME DATA AGE
kube-root-ca.crt 1 17m
db-config 3 4m56s
webapp-config-map 2 3s
controlplane ~ ✦ ➜ k describe cm webapp-config-map
Name: webapp-config-map
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
APP_OTHER:
----
disregard
APP_COLOR:
----
darkblue
BinaryData
====
Events: <none> -
-
Update the environment variable on the POD to use only the APP_COLOR key from the newly created ConfigMap.
controlplane ~ ✦ ➜ k get po
NAME READY STATUS RESTARTS AGE
webapp-color 1/1 Running 0 8mAnswer
controlplane ~ ✦ ➜ k get cm
NAME DATA AGE
kube-root-ca.crt 1 20m
db-config 3 7m53s
webapp-config-map 2 3m
controlplane ~ ✦ ➜ k create cm webapp-config-map $do > webapp-color.yml
controlplane ~ ✦ ➜ k get po webapp-color -o yaml > color.yml
controlplane ~ ✦ ➜ k delete -f color.yml $now
Warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
pod "webapp-color" force deleted
controlplane ~ ✦ ➜ k get po
No resources found in default namespace.Follow the K8s docs on how to configure pods to use configmaps.
## color.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2023-12-29T17:36:54Z"
labels:
name: webapp-color
name: webapp-color
namespace: default
resourceVersion: "781"
uid: 1e5515fa-9479-4ddd-a463-1df7723c1f8c
spec:
containers:
- env:
- name: APP_COLOR
valueFrom:
configMapKeyRef:
name: webapp-config-map
key: APP_COLORcontrolplane ~ ✦ ➜ k apply -f color.yml
pod/webapp-color created
controlplane ~ ✦ ➜ k get po
NAME READY STATUS RESTARTS AGE
webapp-color 1/1 Running 0 5s -
How many secrets are defined in the dashboard-token secret?
controlplane ~ ➜ k get secrets
NAME TYPE DATA AGE
dashboard-token kubernetes.io/service-account-token 3 40sAnswer
controlplane ~ ➜ k describe secrets dashboard-token
Name: dashboard-token
Namespace: default
Labels: <none>
Annotations: kubernetes.io/service-account.name: dashboard-sa
kubernetes.io/service-account.uid: dec16229-5c52-414f-928d-28380a3fb4b3
Type: kubernetes.io/service-account-token
Data
====
ca.crt: 570 bytes
namespace: 7 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IjlEc25IMUFwZ1pfZlRVcmVla3pvbS0yTXlsa1ZzT1RyZktaWmJCR1dYVHcifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNl -
Create a new secret named db-secret with the data given below.
-
Secret Name: db-secret
-
Secret 1: DB_Host=sql01
-
Secret 2: DB_User=root
-
Secret 3: DB_Password=password123
Answer
controlplane ~ ➜ kubectl create secret generic db-secret \
--from-literal='DB_Host=sql01' \
--from-literal='DB_User=root' \
--from-literal='DB_Password=password123'
secret/db-secret createdcontrolplane ~ ➜ k get secret
NAME TYPE DATA AGE
dashboard-token kubernetes.io/service-account-token 3 8m18s
db-secret Opaque 3 23s
controlplane ~ ➜ k describe secrets db-secret
Name: db-secret
Namespace: default
Labels: <none>
Annotations: <none>
Type: Opaque
Data
====
DB_Host: 5 bytes
DB_Password: 11 bytes
DB_User: 4 bytes -
-
Configure webapp-pod to load environment variables from the newly created secret (from the previous question).
-
Pod name: webapp-pod
-
Image name: kodekloud/simple-webapp-mysql
-
Env From: Secret=db-secret
Answer
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
webapp-pod 1/1 Running 0 6m55s
mysql 1/1 Running 0 6m55s
controlplane ~ ➜ k get po webapp-pod -o yaml > webapp-pod.yml
controlplane ~ ✦2 ➜ k delete -f webapp-pod.yml $now
Warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
pod "webapp-pod" force deleted
controlplane ~ ✦2 ➜ k get po
NAME READY STATUS RESTARTS AGE
mysql 1/1 Running 0 8m1sFollow steps on how to configure all key-value pairs in a Secret as container environment variables from K8S docs.
## webapp-pod.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2023-12-29T17:57:07Z"
labels:
name: webapp-pod
name: webapp-pod
namespace: default
resourceVersion: "802"
uid: b134a439-e86d-45d2-af52-717d17717da1
spec:
containers:
- image: kodekloud/simple-webapp-mysql
imagePullPolicy: Always
name: webapp
envFrom:
- secretRef:
name: db-secretcontrolplane ~ ✦2 ➜ k apply -f webapp-pod.yml
pod/webapp-pod created
controlplane ~ ✦2 ➜ k get po
NAME READY STATUS RESTARTS AGE
mysql 1/1 Running 0 13m
webapp-pod 1/1 Running 0 2s -
-
Identify the name of the containers running in the blue pod.
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
app 1/1 Running 0 36s
blue 0/2 ContainerCreating 0 7s
fluent-ui 1/1 Running 0 37s
red 0/3 ContainerCreating 0 23sAnswer
controlplane ~ ➜ k describe po blue
Name: blue
Namespace: default
Priority: 0
Service Account: default
Node: controlplane/192.36.217.6
Start Time: Fri, 29 Dec 2023 13:12:32 -0500
Labels: <none>
Annotations: <none>
Status: Pending
IP:
IPs: <none>
Containers:
teal:
Container ID:
Image: busybox
Image ID:
Port: <none>
Host Port: <none>
Command:
sleep
4500
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-vrvfc (ro)
navy:
Container ID:
Image: busybox
Image ID:
Port: <none>
Host Port: <none>
Command:
sleep
4500
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-vrvfc (ro) -
Create a multi-container pod with 2 containers. If the pod goes into the crashloopbackoff then add the command sleep 1000 in the lemon container. Use the spec given below:
-
Name: yellow
-
Container 1 Name: lemon
-
Container 1 Image: busybox
-
Container 2 Name: gold
-
Container 2 Image: redis
Answer
ontrolplane ~ ➜ k run yellow --image busybox $do
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: yellow
name: yellow
spec:
containers:
- image: busybox
name: yellow
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
controlplane ~ ➜ k run yellow --image busybox $do > yellow.yml## yellow.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: yellow
name: yellow
spec:
containers:
- image: busybox
name: lemon
resources: {}
- image: redis
name: gold
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}controlplane ~ ➜ k apply -f yellow.yml
pod/yellow created
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
app 1/1 Running 0 8m39s
blue 2/2 Running 0 7m34s
fluent-ui 1/1 Running 0 8m39s
red 3/3 Running 0 8m26s
yellow 1/2 CrashLoopBackOff 1 (4s ago) 7s## yellow.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: yellow
name: yellow
spec:
containers:
- image: busybox
name: lemon
resources: {}
command:
- "sleep"
- "1000"
- image: redis
name: gold
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}controlplane ~ ➜ k delete -f yellow.yml
pod "yellow" deleted
controlplane ~ ➜ k apply -f yellow.yml
pod/yellow created
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
app 1/1 Running 0 9m44s
blue 2/2 Running 0 8m39s
fluent-ui 1/1 Running 0 9m44s
red 3/3 Running 0 9m31s
yellow 2/2 Running 0 3scontrolplane ~ ➜ k describe po yellow
Name: yellow
Namespace: default
Priority: 0
Service Account: default
Node: controlplane/192.11.203.9
Start Time: Sat, 30 Dec 2023 03:10:46 -0500
Labels: run=yellow
Annotations: <none>
Status: Running
IP: 10.244.0.13
IPs:
IP: 10.244.0.13
Containers:
lemon:
Container ID: containerd://eba9ba778ac377f05a4061170c3229c0361103ab3dbad6710d28f32a95fc8f77
Image: busybox
Image ID: docker.io/library/busybox@sha256:ba76950ac9eaa407512c9d859cea48114eeff8a6f12ebaa5d32ce79d4a017dd8
Port: <none>
Host Port: <none>
Command:
sleep
1000
State: Running
Started: Sat, 30 Dec 2023 03:10:48 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-m8gtm (ro)
gold:
Container ID: containerd://f0ab41cb48bb10d4006833ecb452800b58974d578a869cfac5e6e7dbe2052029
Image: redis
Image ID: docker.io/library/redis@sha256:a7cee7c8178ff9b5297cb109e6240f5072cdaaafd775ce6b586c3c704b06458e
Port: <none>
Host Port: <none>
State: Running
Started: Sat, 30 Dec 2023 03:10:48 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-m8gtm (ro) -
-
Inspect the app pod and identify the number of containers in it. It is deployed in the elastic-stack namespace.
Answer
controlplane ~ ➜ k get po -n elastic-stack
NAME READY STATUS RESTARTS AGE
app 1/1 Running 0 13m
elastic-search 1/1 Running 0 13m
kibana 1/1 Running 0 13m
controlplane ~ ➜ k describe po app
Name: app
Namespace: default
Priority: 0
Service Account: default
Node: controlplane/192.11.203.9
Start Time: Sat, 30 Dec 2023 03:01:05 -0500
Labels: name=app
Annotations: <none>
Status: Running
IP: 10.244.0.8
IPs:
IP: 10.244.0.8
Containers:
app:
Container ID: containerd://80c1ffb344a3f209d2014335e046bf7eef23c4d319274f047c7b8972ff578694
Image: kodekloud/event-simulator
Image ID: docker.io/kodekloud/event-simulator@sha256:1e3e9c72136bbc76c96dd98f29c04f298c3ae241c7d44e2bf70bcc209b030bf9
Port: <none>
Host Port: <none>
State: Running
Started: Sat, 30 Dec 2023 03:02:20 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/log from log-volume (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-s4djx (ro) -
The application in the elastic-stack namespace outputs logs to the file /log/app.log. View the logs and try to identify the user having issues with Login.
controlplane ~ ➜ k get po -n elastic-stack
NAMESPACE NAME READY STATUS RESTARTS AGE
elastic-stack app 1/1 Running 0 18m
elastic-stack elastic-search 1/1 Running 0 18m
elastic-stack kibana 1/1 Running 0 18mAnswer
controlplane ~ ➜ k -n elastic-stack exec -it app -- tail -10 /log/app.log
[2023-12-30 08:18:12,459] INFO in event-simulator: USER3 is viewing page3
[2023-12-30 08:18:12,725] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.
[2023-12-30 08:18:12,725] INFO in event-simulator: USER4 is viewing page2
[2023-12-30 08:18:13,460] INFO in event-simulator: USER3 is viewing page3
[2023-12-30 08:18:13,726] INFO in event-simulator: USER3 logged in
[2023-12-30 08:18:14,461] WARNING in event-simulator: USER7 Order failed as the item is OUT OF STOCK.
[2023-12-30 08:18:14,461] INFO in event-simulator: USER1 logged in
[2023-12-30 08:18:14,727] INFO in event-simulator: USER4 logged in
[2023-12-30 08:18:15,462] INFO in event-simulator: USER1 logged in
[2023-12-30 08:18:15,729] INFO in event-simulator: USER3 logged in -
Edit the pod to add a sidecar container to send logs to Elastic Search. Mount the log volume to the sidecar container. Only add a new container. Do not modify anything else. Use the spec provided below.
-
Name: app
-
Container Name: sidecar
-
Container Image: kodekloud/filebeat-configured
-
Volume Mount: log-volume
-
Mount Path: /var/log/event-simulator/
-
Existing Container Name: app
-
Existing Container Image: kodekloud/event-simulator
controlplane ~ ➜ k get po -n elastic-stack
NAMESPACE NAME READY STATUS RESTARTS AGE
elastic-stack app 1/1 Running 0 18m
elastic-stack elastic-search 1/1 Running 0 18m
elastic-stack kibana 1/1 Running 0 18mAnswer
controlplane ~ ➜ k get po app -n elastic-stack -o yaml > elastic-app.ymlAdd a sidecar container to the YAML file. Follow K8S docs for steps.
## elastic-app.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2023-12-30T08:01:04Z"
labels:
name: app
name: app
namespace: elastic-stack
resourceVersion: "1071"
uid: ee0727bd-ef91-4817-b717-1582c890cae7
spec:
containers:
- image: kodekloud/event-simulator
imagePullPolicy: Always
name: app
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /log
name: log-volume
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-78bvz
readOnly: true
- name: sidecar
image: kodekloud/filebeat-configured
volumeMounts:
- name: log-volume
mountPath: /var/log/event-simulator/controlplane ~ ✦ ✖ k delete -f elastic-app.yml $now
Warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
pod "app" force deleted
controlplane ~ ✦ ✖ vi elastic-app.yml
controlplane ~ ✦ ➜ k apply -f elastic-app.yml
pod/app created
controlplane ~ ✦ ➜ k get po -n elastic-stack
NAME READY STATUS RESTARTS AGE
app 2/2 Running 0 21s
elastic-search 1/1 Running 0 43m
kibana 1/1 Running 0 43m -
-
What is the image used by the initContainer in the blue pod? What is its state?
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
red 1/1 Running 0 32s
green 2/2 Running 0 32s
blue 1/1 Running 0 32sAnswer
controlplane ~ ➜ k describe po blue
Name: blue
Namespace: default
Priority: 0
Service Account: default
Node: controlplane/192.12.137.9
Start Time: Sat, 30 Dec 2023 08:47:05 +0000
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.42.0.10
IPs:
IP: 10.42.0.10
Init Containers:
init-myservice:
Container ID: containerd://a2eb2f74006ea5f3645334bdb11b774f1399e440e53a0a3105717eb260554740
Image: busybox
Image ID: docker.io/library/busybox@sha256:ba76950ac9eaa407512c9d859cea48114eeff8a6f12ebaa5d32ce79d4a017dd8
Port: <none>
Host Port: <none>
Command:
sh
-c
sleep 5
State: Terminated
Reason: Completed
Exit Code: 0
Started: Sat, 30 Dec 2023 08:47:08 +0000
Finished: Sat, 30 Dec 2023 08:47:13 +0000
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-7djbh (ro) -
What is the state of the purple POD?
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
red 1/1 Running 0 3m1s
green 2/2 Running 0 3m1s
blue 1/1 Running 0 3m1s
purple 0/1 Init:0/2 0 40sAnswer
controlplane ~ ➜ k describe po purple | grep -i status
Status: Pending
Type Status -
Update the pod red to use an initContainer that uses the busybox image and sleeps for 20 seconds
controlplane ~ ➜ k get po
NAME READY STATUS RESTARTS AGE
red 1/1 Running 0 5m27s
green 2/2 Running 0 5m27s
blue 1/1 Running 0 5m27s
purple 0/1 Init:0/2 0 3m6sAnswer
controlplane ~ ➜ k get po red -o yaml > red.ymlAdd the initContainer in the YAML file. Follow K8s docs for steps.
## red.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2023-12-30T08:47:05Z"
name: red
namespace: default
resourceVersion: "909"
uid: 2a18cd56-4b47-49f5-8a9b-a294020d2773
spec:
initContainers:
- name: initcontainer
image: busybox
command: ['sh', '-c', 'sleep 20']
containers:
- command:
- sh
- -c
- echo The app is running! && sleep 3600
image: busybox:1.28
imagePullPolicy: IfNotPresent
name: red-container
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-r4zhp
readOnly: truecontrolplane ~ ✦ ➜ k delete -f red.yml $now
Warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
pod "red" force deleted
controlplane ~ ✦ ➜ k get po
NAME READY STATUS RESTARTS AGE
green 2/2 Running 0 10m
blue 1/1 Running 0 10m
purple 0/1 Init:0/2 0 7m53s
controlplane ~ ✦ ➜ k apply -f red.yml
pod/red created
controlplane ~ ✦ ➜ k get po
NAME READY STATUS RESTARTS AGE
green 2/2 Running 0 10m
blue 1/1 Running 0 10m
purple 0/1 Init:0/2 0 8m2s
red 0/1 Init:0/1 0 2s
controlplane ~ ✦ ➜ k get po
NAME READY STATUS RESTARTS AGE
green 2/2 Running 0 10m
blue 1/1 Running 0 10m
purple 0/1 Init:0/2 0 8m33s
red 1/1 Running 0 33s -
A new application orange is deployed. There is something wrong with it. Identify and fix the issue.
controlplane ~ ✦ ➜ k get po
NAME READY STATUS RESTARTS AGE
green 2/2 Running 0 11m
blue 1/1 Running 0 11m
purple 0/1 Init:0/2 0 9m31s
red 1/1 Running 0 91s
orange 0/1 Init:Error 1 (6s ago) 7sAnswer
controlplane ~ ✦2 ➜ k logs orange
Defaulted container "orange-container" out of: orange-container, init-myservice (init)
Error from server (BadRequest): container "orange-container" in pod "orange" is waiting to start: PodInitializing
controlplane ~ ✦2 ➜ k get po orange -o yaml > orange.ymlInspect the YAML file. We can see that the command is wrong.
## orange.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2023-12-30T08:58:50Z"
name: orange
namespace: default
resourceVersion: "1228"
uid: 79f7f539-c1e2-4f74-9ebe-cb6065cc49d2
spec:
containers:
- command:
- sh
- -c
- echo The app is running! && sleep 3600
image: busybox:1.28
imagePullPolicy: IfNotPresent
name: orange-container
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-9d8th
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
initContainers:
- command:
- sh
- -c
- sleeeep 2;
image: busybox
imagePullPolicy: Always
name: init-myservice
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-9d8th
readOnly: trueFix the command in initcontainer.
## orange.yml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2023-12-30T08:58:50Z"
name: orange
namespace: default
resourceVersion: "1228"
uid: 79f7f539-c1e2-4f74-9ebe-cb6065cc49d2
spec:
containers:
- command:
- sh
- -c
- echo The app is running! && sleep 3600
image: busybox:1.28
imagePullPolicy: IfNotPresent
name: orange-container
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-9d8th
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
initContainers:
- command:
- sh
- -c
- sleep 2;
image: busybox
imagePullPolicy: Always
name: init-myservice
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: kube-api-access-9d8th
readOnly: truecontrolplane ~ ✦2 ➜ k delete -f orange.yml $now
Warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
pod "orange" force deleted
controlplane ~ ✦2 ➜ k apply -f orange.yml
pod/orange created
controlplane ~ ✦2 ➜ k get po
NAME READY STATUS RESTARTS AGE
green 2/2 Running 0 20m
blue 1/1 Running 0 20m
red 1/1 Running 0 10m
purple 0/1 Init:1/2 0 18m
orange 0/1 Init:0/1 0 2s
controlplane ~ ✦2 ➜ k get po
NAME READY STATUS RESTARTS AGE
green 2/2 Running 0 20m
blue 1/1 Running 0 20m
red 1/1 Running 0 10m
purple 0/1 Init:1/2 0 18m
orange 1/1 Running 0 5s