Introduction

According to the Linux Foundation's 10th Annual Open Source Jobs Report, 77% of organizations are expanding their use of cloud and container technologies. Furthermore, the Udemy for Business Workspace Learning Trends Report highlighted an 842% surge in Kubernetes demand—a growth rate more than double that of any other IT operational skill over the past five years.

My name is Mumshad Mannambeth, and in this article, I will guide you through your first steps into Kubernetes, the leading platform for hosting production-grade applications. With an increasing demand for Kubernetes-skilled engineers, this is the ideal time to explore the technology.

For many beginners, Kubernetes appears complex due to a lack of foundational knowledge and the absence of a proper learning infrastructure. This guide addresses those challenges by starting with the basics:

We begin by covering container fundamentals before gradually introducing core Kubernetes concepts. Throughout this guide, you will find clear illustrations, engaging analogies, and step-by-step demos designed to simplify complex topics.

Beyond theory, our interactive labs provide live Kubernetes environments directly in your browser. You will complete coding exercises that mirror real-world Kubernetes challenges. For example, you may review detailed pod status outputs like the following:

Initialized              True
Ready                   True
ContainersReady         True
PodScheduled            True
Volumes:
  default-token-f5ntk:
    Type:           Secret (a volume populated by a Secret)
    SecretName:     default-token-f5ntk
    Optional:       false
    QoS Class:      BestEffort
    Node-Selectors: <none>
    Tolerations:    node.kubernetes.io/not-ready:NoExecute for 300s
                    node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason        Age   From                    Message
  ----    ------        ----  ----                    ------
  Normal  Scheduled     46s   default-scheduler       Successfully assigned default/nginx
  Normal  Pulling       45s   kubelet, minikube       Pulling image "nginx"
  Normal  Pulled        44s   kubelet, minikube       Successfully pulled image "nginx"
  Normal  Created       44s   kubelet, minikube       Created container nginx
  Normal  Started       44s   kubelet, minikube       Started container nginx

In another scenario, you might encounter errors that need troubleshooting. Consider this example:

Last State:          Terminated
Reason:              ContainerCannotRun
Message:             OCI runtime create failed: container_linux.go:367: starting container process caused
                     exec: "kube-schedulerrrr": executable file not found in $PATH: unknown
Exit Code:          127
Started:            Fri, 22 Apr 2022 22:17:39 +0000
Finished:           Fri, 22 Apr 2022 22:17:39 +0000
Ready:              False
Restart Count:      6
Requests:
  cpu:             100m
Liveness:          http-get https://127.0.0.1:10259/healthz delay=0s timeout=1s period=10s failure=8
Startup:           http-get https://127.0.0.1:10259/healthz delay=0s timeout=1s period=10s failure=24
Environment:       <none>
Mounts:
  /etc/kubernetes/scheduler.conf from kubeconfig (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             False
  ContainersReady   False
  PodScheduled      True
Volumes:
  kubeconfig:
    Type:          HostPath (bare host directory volume)
    Path:          /etc/kubernetes/scheduler.conf
    HostPathType:  FileOrCreate
QoS Class:         Burstable
Node-Selectors:    <none>
Tolerations:       :NoExecute op=Exists
Events:
  Type    Reason    Age                   From                Message
  Normal  Pulled    5m15s (x5 over 6m47s) kubelet             Container image "kube-scheduler:v1.20.0" already present on machine
  Normal  Created   5m15s (x5 over 6m47s) kubelet             Created container kube-scheduler
  Warning Failed    5m15s (x5 over 6m47s) kubelet             Error: failed to start container "kube-scheduler": E

Each lab is uniquely designed with tools tailored to the lesson at hand. Instead of a generic copy-and-paste environment, every lab is curated to emphasize the topic you have just studied. For example, you might explore deployments using commands like these:

root@controlplane:~# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
app-586dbdbc54-hc779    1/1     Running   0          10m

root@controlplane:~# kubectl describe deploy app
Name:                   app
Namespace:              default
CreationTimestamp:      Fri, 22 Apr 2022 22:11:45 +0000
Labels:                 app=app
Annotations:            deployment.kubernetes.io/revision=1
Selector:               app=app
Replicas:               2 desired | 1 updated | 1 total
StrategyType:          RollingUpdate
MinReadySeconds:       0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=app
  Containers:
   nginx:
    Image:      nginx:alpine
    Port:       <none>
    Host Port:  <none>
    Environment:  <none>
    Mounts:     <none>
  Volumes:    <none>
Conditions:
  Type           Status  Reason
  --------       ------  -------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
New ReplicaSet:  app-586dbdbc54 (1/1 replicas created)
Events:
  Type    Reason              Age   From                       Message
  ----    ------              ----  ----                       -------
  Normal  ScalingReplicaSet   10m   deployment-controller      Scale up replica set app-586dbdbc54 to 1

For a more advanced demonstration, consider the following YAML configuration for creating a Pod that runs the kube-controller-manager:

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-controller-manager
    tier: control-plane
  name: kube-controller-manager
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-controller-manager
    - --allocate-node-cids=true
    - --authentication-kubeconfig=/etc/kubernetes/conf
    - --authorization-kubeconfig=/etc/kubernetes/conf
    - --bind-address=127.0.0.1
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --cluster-cidr=10.244.0.0/16
    - --cluster-name=kubernetes
    - --cluster-signing-cert-file=/etc/kubernetes/pki/ca.crt
    - --cluster-signing-key-file=/etc/kubernetes/pki/ca.key
    - --controllers=*,bootstrapsigner,token cleaner
    - --kubeconfig=/etc/kubernetes/controller-manager.conf
    - --leader-elect=true
    - --port=0
    - --requestheader-client-ca-file=/etc/kubernetes/pki/ca.crt
    - --root-ca-file=/etc/kubernetes/pki/ca.crt
    - --service-account-private-key-file=/etc/kubernetes/pki/sa.key
    - --service-cluster-ip-range=10.96.0.0/12
    - --service-account-credentials=true
    image: k8s.gcr.io/kube-controller-manager:v1.20.0
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 8
      httpGet:
        host: 127.0.0.1
        path: /healthz

Rather than presenting pre-filled environments, each lab challenges you to actively solve problems, analyze logs, and adjust configurations. For instance, you might troubleshoot a CrashLoopBackOff status with the following session:

kube-controller-manager-controlplane   0/1     CrashLoopBackOff   5                  3m31s
kube-flannel-ds-b85q5                   1/1     Running            0                  36m
kube-proxy-pthlt                         1/1     Running            0                  36m
kube-scheduler-controlplane              1/1     Running            0                  11m
root@controlplane:~# k logs kube-controller-manager-controlplane
Flag --port has been deprecated, see --secure-port instead.
10422 22:31:03.31107 1 serving.go:331] Generated plugin "kubelet" unable to load client CA file "/etc/kubernetes/pki/ca.crt"
root@controlplane:~# ls /etc/kubernetes/pki/ca.crt
/etc/kubernetes/pki/ca.crt
root@controlplane:~# cat /etc/kubernetes/pki/ca.crt
-----BEGIN CERTIFICATE-----
MIICtSZCACgGAVABIGABADBgkhkIG9wBAsQFAWNMRWEQYDVQ
cm5ldGxvM2JBdIY0M2dIY0M1XQ0M1OY0M1FJY0M3FJY0M0
AxMkA3V1XZLCZCdVODJYJJo2vHBAEBQDA0wGg0DAI0YQzA0
QxgrxLkGxzNZBzQkMXByKLh1GJ5ZQGUJ1U5AhfdQGmxZ4bYp
jI4CuqmZ5NGrIEZmC5Ykj+n6KwWxeWb0+eySb5BslAw8RzQ0
6c0lctImFg0JDgx4ZcgXeb3W4CAW6ASaYj4sFvkvIjvx5FQV
QyCq8NdD+GuTSNQ2bzUsFZHqjoxK7ej4TLybsTIULVJ1H6XZ
BOSSbmvOQWTDugejWc16bMimc00GAAZREZEMCM+hOHGSi9q
-----END CERTIFICATE-----
root@controlplane:~# vi /etc/kubernetes/mal

You will also be challenged with tasks that require analyzing logs, modifying configurations, and performing other hands-on exercises. If you need assistance, hints and solutions are available, along with access to an exclusive Slack community channel:

[bob@student-node ~]$ ip a | grep eth1
2926: eth1@if2927: <BROADCAST,MULTICAST>
    inet 172.25.0.6/24 brd 172.25.0.255
[bob@student-node ~]$

In addition to our robust lab environments, we are proud to be a CNCF certified Kubernetes training partner. This certification confirms that our training and course content meet industry standards.

We are confident that you will benefit immensely from this course. To ensure your satisfaction, we offer a 30-day money-back guarantee. There is nothing to lose—enroll today and embark on your Kubernetes journey with confidence. I'll see you in class!