学習内容：Udemy MockExam1,2

メモ：
kubectl expose po (pod名) --type=ClusterIP --port=(ポート番号) --name=(サービス名) でサービスを作る
https://kubernetes.io/ja/docs/tutorials/stateless-application/expose-external-ip-address/
ETCDCTL_API=3によるETCDバックアップ
ETCDCTL_API=3 etcdctl --endpoints=https://127.0.0.1:2379 \
--cacert=<trusted-ca-file> --cert=<cert-file> --key=<key-file> \
snapshot save <backup-file-location>
https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/#backing-up-an-etcd-cluster
CertificateSigningRequestを作成し、kubectl certificate approve <certificate-signing-request-name>にてCertificateSigningRequestsを許可する
https://kubernetes.io/docs/reference/access-authn-authz/certificate-signing-requests/#create-certificatessigningrequest
https://kubernetes.io/docs/reference/access-authn-authz/certificate-signing-requests/#create-certificatessigningrequest

反省：焦りすぎてケアレスミスや間違いが多いので、早く注意深くする