Kubernetes/CKA
Scheduling - Multiple Schedulers
Q) What is the name of the POD that deploys the default kubernetes scheduler in this environment? A) kube-scheduler-controlplanecontrolplane ~ ➜ k get po -ANAMESPACE NAME READY STATUS RESTARTS AGEkube-flannel kube-flannel-ds-wmj7b 1/1 Running 0 10mkube-system coredns-7484cd47db-jkvdl 1/1 Running..
Kubernetes/CKA
Scheduling - Static PODs
Static Pod이란?Static Pod은 Kubernetes API 서버와 상관없이 Kubelet이 직접 관리하는 파드다./etc/kubernetes/manifests/ 경로에서 YAML 파일을 통해 정의됨 Q) How many static pods exist in this cluster in all namespaces?A) 4controlplane ~ ✖ cd /etc/kubernetes/manifests/controlplane /etc/kubernetes/manifests ➜ ls -alttotal 28drwxrwxr-x 1 root root 4096 Mar 17 02:01 .-rw------- 1 root root 2559 Mar 17 02:01 etcd.yaml-rw------- 1 root..
Kubernetes/CKA
Scheduling - DaemonSets
$ k apply -f fluentd.yamlDeamonSet이란?DaemonSet은 각 노드에서 특정 파드가 반드시 실행되도록 보장하는 리소스다. Q) How many DaemonSets are created in the cluster in all namespaces?A) 2$ k get ds -ANAMESPACE NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGEkube-flannel kube-flannel-ds 1 1 1 1 1 7m11skube-..
Kubernetes/CKA
Scheduling - Resource Limits
Q) A pod called rabbit is deployed. Identify the CPU requirements set on the Pod in the current(default) namespaceA) 0.5 (500m)$ k describe po rabbitName: rabbitNamespace: defaultPriority: 0Service Account: defaultNode: controlplane/192.168.193.128Start Time: Sun, 16 Mar 2025 11:59:35 +0000Labels: Annotations: Status: Running..
Kubernetes/CKA
Scheduling - Node Affinity
선호하는 노드를 설정하는 방법으로, nodeSelector 보다 확장된 Label Selector 기능을 지원한다.types - requiredDuringSchedulingIgnoredDuringExecution / preferredDuringSchedulingIgnoredDuringExecutionaffinity > nodeAffinity > ${type} > nodeSelectorTerms > matchExpression > {key/{values}/operator} Q) How many labels exists on node01?$ k describe no node01 | grep -i -A 5 labelLabels: beta.kubernetes.io/arch=amd64 ..
Kubernetes/CKA
Scheduling - Taints and Tolerations
$ k apply -f bee.yaml pod/bee createdtaint : 노드마다 설정가능. 설정한 노드에는 pod이 스케줄되지 않음 (NoSchedule, PreferNoSchedule, NoExecute)key=value:NoSchedule means key=value가 아닌 pod들은 schedule될 수 없음toleration : pod에 설정, key, value, effect, operator을 지정해서 어떤 taint를 무시할 지 정할 수 있음operator이 Equal이면 value설정해야함 (key value 둘 다 matching 필요), Exists면 key만 있으면 됨 $ k get poNAME READY STATUS RESTARTS AGEmosqui..
Kubernetes/CKA
Scheduling - Labels and Selectors
Q) We have deployed a number of PODs. They are labelled with tier, env and bu. How many PODs exist in the dev enviroment (env)? $ k get po --selector='env=dev' -A --no-headers | wc -l7A) 7 Q) How many PODs are in the finance business unit (bu)? $ k get po -A --selector bu=finance --no-headers | wc -l6A) 6 Q) How many objects are on prod environment? (including all kubernetes objects such as repl..
Kubernetes/CKA
Scheduling - Manual Scheduling
Q) A pod definition file nginx.yaml is given. Create a pod using the file.$ k apply -f nginx.yaml Q) Why is the POD in a pending state?yaml 보기Name: nginxNamespace: defaultPriority: 0Service Account: defaultNode: Labels: Annotations: Status: PendingIP: IPs: Containers: nginx: Image: nginx Por..
Kubernetes/CKA
Core Concepts - Imperative Commands
Q) Deploy a pod named nginx-pod using the nginx:alpine image$ k run nginx-pod --image=nginx:alpinepod/nginx-pod created Q) Deploy a redis pod using the redis:alpine image with the labels set to tier=db.$ k run redis --image=redis:alpine \> --labels="tier=db"pod/redis created Q) Create a service redis-service to expose the redis application within the cluster on port 6379.$ k expose po redis --po..
Kubernetes/CKA
Core Concepts - Services
Q) What is the Type of kubernetes Service?$ k get svcNAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGEkubernetes ClusterIP 10.43.0.1 443/TCP 8m11sA) ClusterIPClusterIP: 클러스터 내부에서만 접근 가능한 기본 서비스 (기본값). NodePort: 클러스터 외부에서 각 노드의 고정 포트로 접근 가능. LoadBalancer: 클라우드 제공자의 로드 밸런서를 통해 외부에서 접근 가능. ExternalName: DNS 이름을 클러스터 외부 서비스에 매핑 (외부 서비스와의 연동). Q) What is the targetPor..
