W.r.t CKA exam the etcd is installed on the edge node and the question is to take etcd backup and restore on edge node only. Keep in mind when attempting this question.
Some tips to check etcd server on edge node:
Step 1: check the etcd server status:
cloud@edge-node:~$ systemctl status etcd
● etcd.service - etcd
Loaded: loaded (/etc/systemd/system/etcd.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2021-01-29 21:58:40 CST; 2 days ago
Main PID: 1299767 (etcd)
Tasks: 10 (limit: 4615)
└─1299767 /usr/bin/etcd --name master-1 --cert-file=/etc/etcd/etcd.crt --key-file=/etc/etcd/etcd.key --peer-cert-file=/etc/etcd/etcd.cr>
STep 2: cat /etc/systemd/system/etcd.service
Step 3: You will see certificate and data dir paths on edge node. Keep in mind the certificate paths will be provided in question itself.
Step 4: backup and restore commands from the course should work on edge node.
Step 5: When you attempt restore to different --data-dir make sure to change the folder owner permissions:
For example if the new data-dir is /var/lib/etcd-from-back-up issue the below command to change the permissions
chown +R etcd.etcd /var/lib/etcd-from-back-up
Step 6: Fianlly issue “systemctl daemon-reload”, “systemctl retsart etcd” and “systemctl enable etcd”
Hope this helps.