CKA course and practice labs

How the control plane and the nodes of a kubeadm cluster work together, how the API is organised, and the kubectl and exam habits that make every later module faster. Domain: Cluster Architecture, Installation & Configuration.

1. lessonHow a cluster fits together9 min
2. lessonControl plane components up close12 min
3. lessonNode components and the CRI, CNI and CSI interfaces12 min
4. lessonAPI objects, groups and versions10 min
5. lessonkubectl fluency for the exam14 min
6. demoDemo: a guided tour of a kubeadm cluster15 min
7. lessonExam setup, contexts and time strategy10 min

Run applications the way Kubernetes expects: pods and their helper containers, Deployments with safe rollouts and rollbacks, DaemonSets, Jobs, CronJobs and a first look at StatefulSets. Domain: Workloads & Scheduling.

1. lessonPods: the unit Kubernetes runs10 min
2. lessonMulti-container pods: init containers and native sidecars11 min
3. lessonDeployments, rolling updates and rollbacks12 min
4. demoDemo: update, break and roll back a Deployment12 min
5. lessonDaemonSets: one pod per node9 min
6. lessonJobs and CronJobs: work that finishes13 min
7. lessonStatefulSets and PodDisruptionBudgets12 min

Learn how kube-scheduler picks a node and every lever you have over that choice: requests, labels and nodeSelector, node and pod affinity, topology spread, taints and tolerations, priority, and manual placement. Domain: Workloads & Scheduling.

1. lessonHow the scheduler places pods11 min
2. lessonLabels, selectors and nodeSelector9 min
3. lessonNode affinity: required and preferred rules10 min
4. lessonPod affinity, anti-affinity and topology spread12 min
5. lessonTaints and tolerations11 min
6. lessonPod priority and preemption9 min
7. demoDemo: three Pending pods, three different fixes14 min

Configure applications with ConfigMaps and Secrets, size them with requests and limits, keep namespaces in check with LimitRanges and ResourceQuotas, keep them healthy with probes, and scale them automatically. Domain: Workloads & Scheduling.

1. lessonConfigMaps: configuration outside the image11 min
2. lessonSecrets: sensitive configuration11 min
3. demoDemo: change a ConfigMap and watch who notices14 min
4. lessonResource requests, limits and QoS classes12 min
5. lessonLimitRange and ResourceQuota: namespace guard rails11 min
6. lessonLiveness, readiness and startup probes12 min
7. lessonAutoscaling with HPA, and where VPA fits13 min

Give pods a stable address with Services, see how EndpointSlices and kube-proxy turn that address into real pod IPs, and learn how CoreDNS names everything so you can debug a Service or a lookup under exam pressure. Domain: Services & Networking.

1. lessonService types: ClusterIP, NodePort, LoadBalancer and ExternalName10 min
2. lessonEndpoints and EndpointSlices: where Service traffic really goes10 min
3. lessonkube-proxy, traffic policies and session affinity10 min
4. demoDemo: debug a Service from the outside in14 min
5. lessonCoreDNS: names for Services and pods, and the Corefile11 min
6. lessonPod DNS settings: dnsPolicy and dnsConfig9 min
7. demoDemo: when names stop resolving14 min

Route HTTP and HTTPS traffic from outside the cluster to Services: the frozen but still common Ingress API with IngressClasses and TLS, then the Gateway API that replaces it, from Gateways and HTTPRoutes to filters, TLS listeners and cross-namespace references. Domain: Services & Networking.

1. lessonIngress: host and path routing for HTTP10 min
2. lessonIngressClasses, TLS and the default backend10 min
3. lessonThe Gateway API: GatewayClass, Gateway and HTTPRoute11 min
4. lessonHTTPRoute in depth: header matches, traffic splits and filters11 min
5. lessonHTTPS listeners and cross-namespace routing11 min
6. demoDemo: migrate an Ingress to the Gateway API15 min

How every pod gets an IP and reaches every other pod, what the CNI plugin does on each node and how to spot when it breaks, then how to lock traffic down with NetworkPolicies: selectors, default deny, egress with DNS, ipBlocks and named ports. Domain: Services & Networking.

1. lessonThe pod network model: IPs, CIDRs and host networking10 min
2. demoDemo: find the CNI plugin on a node and spot when it breaks14 min
3. lessonNetworkPolicy basics: selecting pods and allowing ingress12 min
4. lessonDefault deny, egress rules, DNS, ipBlocks and named ports12 min
5. demoDemo: debug a namespace full of NetworkPolicies15 min

Give pods data that outlives a container or the pod itself: ephemeral and projected volumes, PersistentVolumes and claims, access modes and reclaim policies, StorageClasses with dynamic provisioning and expansion, StatefulSet claims, and how to debug claims that won't bind or won't go away. Domain: Storage.

1. lessonVolumes: emptyDir, projected, subPath and ephemeral claims12 min
2. lessonPersistentVolumes and claims: how binding works12 min
3. lessonAccess modes, volume modes and reclaim policies11 min
4. lessonStorageClasses and dynamic provisioning12 min
5. lessonGrowing claims, stuck deletions and moving data12 min
6. lessonStatefulSet storage: claim templates and retention11 min
7. demoDemo: a claim that won't bind and one that won't go away14 min

Who may do what in a cluster: authentication with certificates and tokens, RBAC with Roles and ClusterRoles, ServiceAccounts, kubeconfig files and contexts, and the admission step that runs before anything is stored. Domain: Cluster Architecture, Installation & Configuration.

1. lessonAuthentication, authorisation and admission10 min
2. lessonRBAC: Roles and RoleBindings12 min
3. lessonClusterRoles: reuse, built-in roles and aggregation11 min
4. lessonServiceAccounts and their tokens11 min
5. demoDemo: audit who can do what with kubectl auth can-i15 min
6. lessonCertificates and the CertificateSigningRequest API13 min
7. lessonkubeconfig files, users and contexts12 min
8. lessonAdmission control basics13 min

Build a cluster the way the exam expects: prepare the nodes, configure containerd, run kubeadm init and join, manage static pods and certificates, and extend the control plane behind a load balancer. Domain: Cluster Architecture, Installation & Configuration.

1. lessonPrepare the nodes for kubeadm11 min
2. lessonInstall and configure containerd11 min
3. lessonkubeadm init: what it does and how to drive it13 min
4. demoDemo: build a two-node cluster with kubeadm25 min
5. lessonJoining nodes: tokens, discovery and JoinConfiguration12 min
6. lessonStatic pods10 min
7. lessonA highly available control plane15 min
8. lessonCheck and renew kubeadm certificates11 min

Keep a kubeadm cluster healthy over time: upgrade it one minor version at a time, take nodes out for maintenance safely, back up and restore etcd, and renew the certificates kubeadm manages. Domain: Cluster Architecture, Installation & Configuration.

1. lessonHow a kubeadm upgrade works10 min
2. demoDemo: upgrade the control plane node15 min
3. demoDemo: upgrade a worker node12 min
4. lessonNode maintenance: cordon, drain and disruption budgets12 min
5. lessonBack up etcd with a snapshot11 min
6. demoDemo: restore etcd from a snapshot15 min
7. lessonCheck and renew kubeadm certificates12 min

Install and operate cluster components with Helm releases and repositories, and tailor plain manifests per environment with Kustomize bases, overlays, patches and components. Domain: Cluster Architecture, Installation & Configuration.

1. lessonHelm: charts, releases and repositories11 min
2. lessonHelm values: defaults, overrides and what a release really uses10 min
3. demoDemo: install, upgrade and roll back a release12 min
4. lessonHelm when things go wrong: failed releases and leaving Helm11 min
5. lessonKustomize: bases and overlays11 min
6. lessonKustomize: generators, patches and components12 min
7. demoDemo: a staging overlay with images, a generator and a patch12 min

See how Kubernetes plugs in container runtimes, networks and storage through CRI, CNI and CSI, and how CustomResourceDefinitions and operators add new APIs, including the Gateway API. Domain: Cluster Architecture, Installation & Configuration.

1. lessonCRI, CNI and CSI: how Kubernetes plugs things in11 min
2. demoDemo: inspect the runtime with crictl and use a RuntimeClass14 min
3. lessonCNI and CSI on a real node: where to look11 min
4. lessonCustomResourceDefinitions: adding your own API types12 min
5. demoDemo: harden a CRD with validation, columns and a status subresource14 min
6. lessonOperators: install one and use its custom resources12 min
7. demoDemo: install the Gateway API CRDs and create a Gateway13 min

Read what containers print, what the cluster records about them, and how much CPU and memory they use. These are the first three places you look in every troubleshooting task. Domain: Troubleshooting.

1. lessonContainer logs: current, previous and multi-container10 min
2. lessonEvents: the cluster's own diary9 min
3. lessonThe resource metrics pipeline and metrics-server10 min
4. demoDemo: find the heaviest pod and container with kubectl top12 min
5. lessonRequests, limits, QoS and OOMKilled12 min
6. demoDemo: investigate a namespace and write the report14 min

A repeatable method for broken workloads: read the pod status, follow it to the cause, then trace traffic from Service to endpoints to DNS and network policy. Domain: Troubleshooting.

1. lessonA method for broken workloads: let the status lead10 min
2. lessonCrashLoopBackOff, init containers and probes12 min
3. lessonPending pods and image pull failures11 min
4. lessonJobs, CronJobs and DaemonSets that misbehave11 min
5. lessonServices that don't answer: selectors, ports and kube-proxy12 min
6. lessonNames that don't resolve and policies that block13 min
7. demoDemo: from a stuck pod to a working Service15 min

Bring broken nodes back to Ready and a broken control plane back to life: the kubelet, containerd and CNI on the node; static pods, etcd and certificates on the control plane. Domain: Troubleshooting.

1. lessonNode NotReady: start with the kubelet12 min
2. lessonBelow the kubelet: containerd, crictl and CNI13 min
3. demoDemo: bring a NotReady worker back14 min
4. lessonControl-plane components and static pods13 min
5. lessonThe API server and etcd: a pair that fails together13 min
6. lessonCertificates and kubeconfig files13 min
7. demoDemo: kubectl is dead, revive the API server15 min

How the CKA works on the day and how to work fast inside it: hosts and contexts, kubectl shortcuts, the allowed docs, time management, and a guided run through our mock exams. Domain: Troubleshooting.

1. lessonWhat the CKA exam is really like9 min
2. lessonRight host, right context, right namespace9 min
3. lessonkubectl at exam speed12 min
4. lessonFinding answers fast in the allowed docs10 min
5. lessonSpending 120 minutes well9 min
6. demoDemo: sit a mock exam the way you'll sit the real one15 min