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Logging and Monitoring

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​

  1. Deploy metrics-server to monitor the PODs and Nodes.

    Answer 
    controlplane ~ ➜  k get po
    NAME       READY   STATUS    RESTARTS   AGE
    elephant   1/1     Running   0          10s
    lion       1/1     Running   0          10s
    rabbit     1/1     Running   0          10s

    controlplane ~ ➜  git clone https://github.com/kodekloudhub/kubernetes-metrics-server.git
    Cloning into 'kubernetes-metrics-server'...
    remote: Enumerating objects: 31, done.
    remote: Counting objects: 100% (19/19), done.
    remote: Compressing objects: 100% (19/19), done.
    remote: Total 31 (delta 8), reused 0 (delta 0), pack-reused 12
    Unpacking objects: 100% (31/31), 8.06 KiB | 1.34 MiB/s, done.

    controlplane ~ ➜  ls -l
    total 4
    drwxr-xr-x 3 root root 4096 Dec 29 03:44 kubernetes-metrics-server
    -rw-rw-rw- 1 root root    0 Dec 13 05:39 sample.yaml

    controlplane ~ ✖ k apply -f kubernetes-metrics-server/
    clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
    clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
    rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
    apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created
    serviceaccount/metrics-server created
    deployment.apps/metrics-server created
    service/metrics-server created
    clusterrole.rbac.authorization.k8s.io/system:metrics-server created
    clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created

    Start monitoring the nodes.

    controlplane ~ ➜  k top node
    NAME           CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%   
    controlplane   241m         0%     1159Mi          0%        
    node01         24m          0%     300Mi           0%

  2. Identify the POD that consumes the most Memory(bytes) in default namespace.

    Answer 
    controlplane ~ ➜  k get po
    NAME       READY   STATUS    RESTARTS   AGE
    elephant   1/1     Running   0          4m33s
    lion       1/1     Running   0          4m33s
    rabbit     1/1     Running   0          4m33s

    controlplane ~ ➜  k top pod
    NAME       CPU(cores)   MEMORY(bytes)   
    elephant   15m          31Mi            
    lion       1m           18Mi            
    rabbit     107m         252Mi

  3. A user - USER5 - has expressed concerns accessing the application. Identify the cause of the issue.

    controlplane ~ ➜  k get po
    NAME       READY   STATUS    RESTARTS   AGE
    webapp-1   1/1     Running   0          108s
    Answer 
    controlplane ~ ✖ k logs webapp-1 | grep WARNING
    [2023-12-29 08:49:33,717] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.
    [2023-12-29 08:49:36,719] WARNING in event-simulator: USER7 Order failed as the item is OUT OF STOCK.
    [2023-12-29 08:49:38,722] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.
    [2023-12-29 08:49:43,728] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.

  4. A user is reporting issues while trying to purchase an item. Identify the user and the cause of the issue. Inspect the logs of the webapp-2 in the POD

    controlplane ~ ➜  k get po 
    NAME       READY   STATUS    RESTARTS   AGE
    webapp-1   1/1     Running   0          2m53s
    webapp-2   2/2     Running   0          17s
    Answer 
    controlplane ~ ➜  k logs webapp-2 | grep WARNING
    Defaulted container "simple-webapp" out of: simple-webapp, db
    [2023-12-29 08:52:05,219] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.
    [2023-12-29 08:52:08,221] WARNING in event-simulator: USER30 Order failed as the item is OUT OF STOCK.
    [2023-12-29 08:52:10,224] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.
    [2023-12-29 08:52:15,228] WARNING in event-simulator: USER5 Failed to Login as the account is locked due to MANY FAILED ATTEMPTS.
    [2023-12-29 08:52:16,229] WARNING in event-simulator: USER30 Order failed as the item is OUT OF STOCK.