Kubernetes Cluster Administration

Kubernetes cluster administration refers to the set of technical skills needed to deploy, configure, maintain, and secure a Kubernetes cluster in production.

If you manage cloud-native infrastructures in 2026, this expertise represents the essential foundation of your path toward CKA (Certified Kubernetes Administrator) certification.

TL;DR: Administering a Kubernetes cluster requires mastery of five key domains: installation and configuration (25%), workloads and scheduling (15%), networking (20%), storage (10%), and troubleshooting (30%). The LFS458 Kubernetes Administration training (4 days, 28h, 18 modules) prepares you for the CKA exam.

Why must you master Kubernetes administration in 2026?

According to the CNCF Annual Survey 2024, 80% of organizations use Kubernetes in production, up from 66% in 2023 (20% growth). This massive adoption creates critical demand for qualified administrators.

The main challenge? Skills. According to a 2025 study on Kubernetes challenges, 51% of organizations cite lack of internal expertise as a major obstacle. IT teams spend an average of 34 working days per year resolving Kubernetes incidents, with over 60% of time on troubleshooting.

Kubernetes cluster administration covers five domains you absolutely must master:

CKA Domain 2025-2026	Key skills	Weight
Troubleshooting	Logs, events, debugging pods, cluster diagnostics	30%
Cluster Architecture, Installation & Configuration	kubeadm, control plane, bootstrap tokens, upgrades	25%
Services & Networking	CNI, Services, NetworkPolicies, Ingress, Gateway API	20%
Workloads & Scheduling	Deployments, scheduling, taints/tolerations, affinity	15%
Storage	PV, PVC, StorageClasses, CSI drivers	10%

Key takeaway: The CKA certification allocates 30% to troubleshooting, the heaviest domain. The 2025 revision condensed the exam from 10 to 5 domains (Linux Foundation).

Consult our Kubernetes Training: Complete Guide to position administration within the overall certification path. For upcoming evolutions, check the Kubernetes Roadmap 2026.

How to install a production-ready Kubernetes cluster?

You have several tools available to deploy your cluster. Our detailed guide kubeadm vs kops vs k3s compares each approach. For manual installation with kubeadm, follow this sequence:

System prerequisites

Before running kubeadm init, verify these prerequisites on each node:

# Check minimum resources (2 CPU, 2GB RAM)
cat /proc/cpuinfo | grep processor | wc -l
free -h

# Disable swap (mandatory)
sudo swapoff -a
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

# Load required kernel modules
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter

# Configure sysctl parameters
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

sudo sysctl --system

Control plane initialization

Execute initialization with a configuration suited to your infrastructure:

# Initialize the control plane
sudo kubeadm init \
--pod-network-cidr=10.244.0.0/16 \
--kubernetes-version=v1.30.0 \
--control-plane-endpoint="k8s-api.example.com:6443"

# Configure kubectl for your user
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Our complete guide to install a multi-node cluster with kubeadm details each step of this procedure.

Key takeaway: Carefully save the kubeadm join command generated after initialization. It contains the token and CA hash needed to join worker nodes.

What are the daily tasks of a Kubernetes administrator?

Troubleshooting represents 30% of the CKA exam, reflecting field reality: diagnosing and resolving incidents is a daily skill. Structure your work around these key activities:

Node lifecycle management

You must regularly add, update, or remove nodes. Use these commands for maintenance without service interruption:

# Mark a node as non-schedulable
kubectl cordon node-03

# Evict pods to other nodes
kubectl drain node-03 --ignore-daemonsets --delete-emptydir-data

# After maintenance, reactivate scheduling
kubectl uncordon node-03

# Check the status of all your nodes
kubectl get nodes -o wide

Our article Kubernetes node management: add, maintenance, drain and autoscaling expands on these operations.

Monitoring and troubleshooting

Quickly identify problems with these essential commands:

# General cluster status
kubectl get --raw='/healthz?verbose'  # Replaces componentstatuses (deprecated)
kubectl cluster-info

# Failed pods across the cluster
kubectl get pods -A --field-selector=status.phase!=Running

# Recent events (valuable diagnostic source)
kubectl get events -A --sort-by='.lastTimestamp' | tail -20

# Logs from a restarting pod
kubectl logs pod-name --previous

Consult our kubectl cheatsheet for all administration commands.

How to effectively secure your Kubernetes cluster?

Security is integrated into several CKA exam domains (RBAC, NetworkPolicies, ServiceAccounts). You must master three levels of protection:

RBAC configuration

RBAC (Role-Based Access Control) controls who can do what on your cluster. Apply the principle of least privilege:

# Example: read-only role on pods in a namespace
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
namespace: production
name: pod-reader
rules:
- apiGroups: [""]
resources: ["pods", "pods/log"]
verbs: ["get", "list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: read-pods
namespace: production
subjects:
- kind: User
name: alice
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: Role
name: pod-reader
apiGroup: rbac.authorization.k8s.io

Our guide RBAC Kubernetes: understand and configure access management details best practices.

Network Policies

Isolate your workloads with strict network rules:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: deny-all-ingress
namespace: production
spec:
podSelector: {}
policyTypes:
- Ingress

For complete network configuration, consult Configure Kubernetes cluster network: CNI, Services and Ingress.

Key takeaway: Deploy a "deny-all" Network Policy by default in each production namespace, then explicitly authorize necessary flows.

Deepen these concepts with our article Secure a Kubernetes cluster: best practices. For complete security expertise, the LFS460 Kubernetes Security training prepares you for CKS certification.

How to ensure high availability and disaster recovery?

Managing etcd, the Kubernetes datastore, is a critical skill. etcd stores the entire cluster state: its corruption or loss results in total environment loss. Google has invested in improving etcd corruption detection following major incidents.

etcd backup

Automate backups with this script:

#!/bin/bash
# Daily etcd backup
ETCDCTL_API=3 etcdctl snapshot save /backup/etcd-$(date +%Y%m%d).db \
--endpoints=https://127.0.0.1:2379 \
--cacert=/etc/kubernetes/pki/etcd/ca.crt \
--cert=/etc/kubernetes/pki/etcd/server.crt \
--key=/etc/kubernetes/pki/etcd/server.key

# Verify integrity
ETCDCTL_API=3 etcdctl snapshot status /backup/etcd-$(date +%Y%m%d).db

Our etcd cheatsheet: backup, restore and maintenance covers all recovery scenarios.

Multi-control-plane cluster

For production, deploy at least three control plane nodes. This architecture guarantees service continuity even if one master node is lost.

How to manage persistent storage on your cluster?

Storage represents 10% of the CKA exam. You must master PersistentVolumes (PV), PersistentVolumeClaims (PVC) and StorageClasses to manage your applications' data.

Kubernetes storage architecture

# StorageClass to automatically provision volumes
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: fast-ssd
provisioner: kubernetes.io/gce-pd  # or aws-ebs, csi.ceph.com, etc.
parameters:
type: pd-ssd
reclaimPolicy: Retain
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer

Create a PersistentVolumeClaim

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: database-storage
namespace: production
spec:
accessModes:
- ReadWriteOnce
storageClassName: fast-ssd
resources:
requests:
storage: 100Gi

# Check PV and PVC
kubectl get pv,pvc -A

# Diagnose a Pending PVC
kubectl describe pvc database-storage -n production

Key takeaway: Use reclaimPolicy: Retain for your critical data. With Delete, the volume is automatically deleted with the PVC.

Managed Kubernetes or self-hosted: how to choose?

In 2026, you have the choice between managed services (EKS, AKS, GKE) and self-hosting. Our detailed comparison Managed Kubernetes vs self-hosted analyzes decision criteria.

Criterion	Managed (EKS/AKS/GKE)	Self-hosted
Initial cost	Low	High (infrastructure + expertise)
Control plane maintenance	Provider	Your team
Customization	Limited	Total
Required skills	CKAD sufficient	CKA mandatory
Strict compliance	Variable by provider	Total control

Key takeaway: Even on a managed cluster, you must master administration to manage worker nodes, networking and application security.

If you're a beginner, our page Kubernetes fundamentals for beginners will guide you through your first steps.

What problems do you encounter most often?

Our article Solve the 10 most common problems on a Kubernetes cluster lists frequent incidents. Here are the three most critical:

CrashLoopBackOff

Diagnose quickly with this sequence:

# Identify the problem
kubectl describe pod <pod-name>
kubectl logs <pod-name> --previous

# Common causes:
# - Image not found or wrong tag
# - Incorrect startup command
# - Missing dependencies (ConfigMap, Secret)
# - Insufficient resources

Pods Pending

A pod stays Pending when the scheduler can't find a suitable node. Check:

# Reason for pending
kubectl describe pod <pod-name> | grep -A 5 Events

# Available resources on nodes
kubectl describe nodes | grep -A 5 "Allocated resources"

Network problems

For application developers, our section Kubernetes Application Development complements this administration knowledge.

Which training to choose for Kubernetes administration?

The CKA (Certified Kubernetes Administrator) certification officially validates your skills. The exam lasts 2 hours and requires a minimum score of 66% to pass (Linux Foundation FAQ). The certification is valid for 2 years.

According to Hydranode, CKA-certified professionals in the United States earn between $90,000 and $130,000 per year, a 15 to 25% increase compared to non-certified professionals.

Recommended path in 2026

Discovery: Kubernetes Fundamentals (1 day)
Administration: LFS458 Kubernetes Administration (4 days, 28h)
Certification: Pass the CKA (valid 2 years)

Training is available in several cities: check our pages Kubernetes Administration Training in Bordeaux or Kubernetes Administration Training in Lille for dates.

Take action: your path to CKA

You now have a complete vision of Kubernetes cluster administration. The skills covered in this article directly correspond to the CKA 2026 exam domains.

To structure your learning:

Beginner: Start with Kubernetes Fundamentals to acquire basics in one day
Administrator: The LFS458 Kubernetes Administration training prepares you for CKA in 4 intensive days with practical labs
Developer: The LFD459 Kubernetes for Developers training targets CKAD certification
Security: The LFS460 Kubernetes Security training prepares for CKS

SFEIR group training organizations (SFEIR SAS, SFEIR-EST) are Qualiopi certified for training actions. Contact your OPCO to explore funding possibilities.