[exam] CKA 예제 문제 2022 - 1

본 예제 풀이는 v1.20.00에서 진행되었음을 말씀드립니다.

 

문제 1 - Print the state of a pod

Print pod name and start time to "/opt/que1/pod-status" file

 

풀이

root@controlplane ~ ➜  k get po -o jsonpath={.items[*].metadata.name}

root@controlplane ~ ➜  k get po -o jsonpath={.items[*].status.startTime}

root@controlplane ~ ➜  k get po -o custom-columns=NAME:{.metadata.name},START_TIME:{.status.startTime} --no-headers

root@controlplane ~ ➜  k get po -o custom-columns=NAME:{.metadata.name},START_TIME:{.status.startTime} --no-headers > /opt/que1/pod-status

 

전체 풀이

root@controlplane ~ ➜  k get po -o jsonpath={.items[*].metadata.name}
coredns-74ff55c5b-brqqz coredns-74ff55c5b-ts8wz etcd-controlplane kube-apiserver-controlplane kube-controller-manager-controlplane kube-proxy-8pq2h kube-proxy-w7wd6 kube-scheduler-controlplane nginx non-persistent-redis weave-net-n9lk9 weave-net-ss9zq webserver-559b886555-dsrfd webserver-559b886555-vjmhx webserver-559b886555-zzkj2
root@controlplane ~ ➜  k get po -o jsonpath={.items[*].status.startTime}
2022-07-19T00:30:28Z 2022-07-19T00:30:28Z 2022-07-19T00:29:53Z 2022-07-19T00:29:53Z 2022-07-19T00:29:53Z 2022-07-19T00:30:03Z 2022-07-19T00:30:30Z 2022-07-19T00:29:53Z 2022-07-19T00:39:49Z 2022-07-19T00:38:15Z 2022-07-19T00:30:03Z 2022-07-19T00:30:30Z 2022-07-19T00:40:34Z 2022-07-19T00:40:24Z 2022-07-19T00:40:34Z
root@controlplane ~ ➜  k get po -o custom-columns=NAME:{.metadata.name},START_TIME:{.status.startTime} --no-headers
coredns-74ff55c5b-brqqz                2022-07-19T00:30:28Z
coredns-74ff55c5b-ts8wz                2022-07-19T00:30:28Z
etcd-controlplane                      2022-07-19T00:29:53Z
kube-apiserver-controlplane            2022-07-19T00:29:53Z
kube-controller-manager-controlplane   2022-07-19T00:29:53Z
kube-proxy-8pq2h                       2022-07-19T00:30:03Z
kube-proxy-w7wd6                       2022-07-19T00:30:30Z
kube-scheduler-controlplane            2022-07-19T00:29:53Z
nginx                                  2022-07-19T00:39:49Z
non-persistent-redis                   2022-07-19T00:38:15Z
weave-net-n9lk9                        2022-07-19T00:30:03Z
weave-net-ss9zq                        2022-07-19T00:30:30Z
webserver-559b886555-dsrfd             2022-07-19T00:40:34Z
webserver-559b886555-vjmhx             2022-07-19T00:40:24Z
webserver-559b886555-zzkj2             2022-07-19T00:40:34Z
root@controlplane ~ ➜  k get po -o custom-columns=NAME:{.metadata.name},START_TIME:{.status.startTime} --no-headers > /opt/que1/pod-status

 

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문제 2 - ETCD backup and Restore

First, create a snapshot of the existing etcd instance running at https://127.0.0.1:2379, saving the snapshot to /opt/data/etcd-snapshot-2022.db. Next, create a pod nginx image nginx. Next, restore an existing, previous snapshot located at /opt/data/etcd-snapshot-2022.db.

풀이

root@controlplane ~ ➜  k get po etcd-controlplane -n kube-system -o jsonpath={.spec.containers[0].command}

 

root@controlplane ~ ➜  mkdir /opt/data root@controlplane ~ ➜  ETCDCTL_API=3 etcdctl snapshot save /opt/data/etcd-snapshot-2022.db \ > --cacert=/etc/kubernetes/pki/etcd/ca.crt \ > --cert=/etc/kubernetes/pki/etcd/server.crt \ > --key=/etc/kubernetes/pki/etcd/server.key \ > --endpoints=127.0.0.1:2379

root@controlplane ~ ➜  k run nginx --image nginx -n default

root@controlplane ~ ➜  k get po nginx -n default

root@controlplane ~ ➜  ETCDCTL_API=3 etcdctl snapshot restore /opt/data/etcd-snapshot-2022.db \ --data-dir=/var/lib/etcd-snapshot-2022 \ --initial-advertise-peer-urls=https://10.73.68.3:2380 \ --initial-cluster=controlplane=https://10.73.68.3:2380 \ --name=controlplane

root@controlplane ~ ➜  sed -i -e 's/path:\s\/var\/lib\/etcd/path: \/var\/lib\/etcd-snapshot-2022/' /etc/kubernetes/manifests/etcd.yaml

root@controlplane ~ ➜  k get po nginx -n default

 

전체풀이

root@controlplane ~ ➜  k get po etcd-controlplane -n kube-system -o jsonpath={.spec.containers[0].command}
["etcd","--advertise-client-urls=https://10.73.68.3:2379","--cert-file=/etc/kubernetes/pki/etcd/server.crt","--client-cert-auth=true","--data-dir=/var/lib/etcd","--initial-advertise-peer-urls=https://10.73.68.3:2380","--initial-cluster=controlplane=https://10.73.68.3:2380","--key-file=/etc/kubernetes/pki/etcd/server.key","--listen-client-urls=https://127.0.0.1:2379,https://10.73.68.3:2379","--listen-metrics-urls=http://127.0.0.1:2381","--listen-peer-urls=https://10.73.68.3:2380","--name=controlplane","--peer-cert-file=/etc/kubernetes/pki/etcd/peer.crt","--peer-client-cert-auth=true","--peer-key-file=/etc/kubernetes/pki/etcd/peer.key","--peer-trusted-ca-file=/etc/kubernetes/pki/etcd/ca.crt","--snapshot-count=10000","--trusted-ca-file=/etc/kubernetes/pki/etcd/ca.crt"]
root@controlplane ~ ➜  mkdir /opt/data
root@controlplane ~ ➜  ETCDCTL_API=3 etcdctl snapshot save /opt/data/etcd-snapshot-2022.db \
--cacert=/etc/kubernetes/pki/etcd/ca.crt \
--cert=/etc/kubernetes/pki/etcd/server.crt \
--key=/etc/kubernetes/pki/etcd/server.key \
--endpoints=127.0.0.1:2379
Snapshot saved at /opt/data/etcd-snapshot-2022.db

root@controlplane ~ ➜  k run nginx --image nginx -n default
pod/nginx created

root@controlplane ~ ➜  k get po nginx -n default
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          6s

root@controlplane ~ ➜  ETCDCTL_API=3 etcdctl snapshot restore /opt/data/etcd-snapshot-2022.db \
--data-dir=/var/lib/etcd-snapshot-2022 \
--initial-advertise-peer-urls=https://10.73.68.3:2380 \
--initial-cluster=controlplane=https://10.73.68.3:2380 \
--name=controlplane
2022-07-19 01:38:09.979419 I | mvcc: restore compact to 4959
2022-07-19 01:38:09.986899 I | etcdserver/membership: added member 4e00da14c627878 [https://10.73.68.3:2380] to cluster d9d586278a0a5b2c

root@controlplane ~ ➜  sed -i -e 's/path:\s\/var\/lib\/etcd/path: \/var\/lib\/etcd-snapshot-2022/' /etc/kubernetes/manifests/etcd.yaml

root@controlplane ~ ✖ k get po nginx -n default
Error from server (NotFound): pods "nginx" not found

 

문제 3 - Create pod and check ip

Create a pod nginx-dev with image nginx and get IP address of the pod and write the value to /opt/question/nginx-dev-ip.txt

풀이

root@controlplane ~ ➜  k run nginx-dev --image nginx

root@controlplane ~ ➜  k get po nginx-dev -o jsonpath={.status.podIP}

root@controlplane ~ ➜  mkdir /opt/question/ root@controlplane ~ ➜ k get po nginx-dev -o jsonpath={.status.podIP} > /opt/question/nginx-dev-ip.txt root@controlplane ~ ➜ cat /opt/question/nginx-dev-ip.txt

전체풀이

root@controlplane ~ ➜ k run nginx-dev --image nginx
pod/nginx-dev created
root@controlplane ~ ➜ k get po nginx-dev -o jsonpath={.status.podIP}
10.50.192.2
root@controlplane ~ ➜ mkdir /opt/question/
root@controlplane ~ ➜ k get po nginx-dev -o jsonpath={.status.podIP} > /opt/question/nginx-dev-ip.txt

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