Environment.
CentOS 7
Question.
In use
curl https://192.168.1.8:6443/api/v1/nodes –cert /etc/kubernetes/pki/apiserver-kubelet-client. crt –key /etc/kubernetes/pki/apiserver-kubelet-client. key –cacert /etc/kubernetes/pki/ca. crt -v
Error NSS error -12190 (SSL_ERROR_PROTOCOL_VERSION_ALERT)：
* Connection died, retrying a fresh connect
* Closing connection 0
* Issue another request to this URL: ‘https://192.168.1.8:6443/api/v2/nodes’
* About to connect() to 192.168.1.8 port 6443 (#1)
*   Trying 192.168.231.224…
* Connected to 192.168.1.8 (192.168.1.8) port 6443 (#1)
* TLS disabled due to previous handshake failure
*   CAfile: /etc/kubernetes/pki/ca. crt
CApath: none
* NSS error -12190 (SSL_ERROR_PROTOCOL_VERSION_ALERT)
* Peer reports incompatible or unsupported protocol version.
* Closing connection 1
How to Fix:
(1) yum update nss nss-util nspr(2)yum update curl
Updating only (1) doesn’t work, it should be that (2) this works (not verified).

Reference.
1、https://stackoverflow.com/questions/43975973/how-to-fix-error-failed-to-download-on-rbenv-install
2、https://stackoverflow.com/questions/30678583/centos-6-6-curl-returns-error-when-connecting-to-some-ssl-site