How to backup etcd on a Kubernetes cluster created with kubeadm - rpc error: code = 13

I managed to make it work adding the certificates info to the command:

ETCDCTL_API=3 etcdctl --endpoints https://127.0.0.1:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key /etc/kubernetes/pki/etcd/healthcheck-client.key snapshot save ./snapshot.db

You can also check the Etcd configuration file in the following line on a node that Etcd is running.

/etc/kubernetes/manifests/etcd.yaml

After getting the command in the command section of the Etcd configuration,

ETCDCTL_API=3 etcdctl --endpoints https://127.0.0.1:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key /etc/kubernetes/pki/etcd/healthcheck-client.key

you can run Etcd commands like below commands.

ETCDCTL_API=3 etcdctl --endpoints https://127.0.0.1:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key /etc/kubernetes/pki/etcd/healthcheck-client.key member listETCDCTL_API=3 etcdctl --endpoints https://127.0.0.1:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key /etc/kubernetes/pki/etcd/healthcheck-client.key snapshot save ./snapshot.db  ETCDCTL_API=3 etcdctl --endpoints https://127.0.0.1:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/healthcheck-client.crt --key /etc/kubernetes/pki/etcd/healthcheck-client.key snapshot status ./snapshot.db