进入docker容器，然后 >
$ cd /usr/share/elasticsearch
$ ./bin/elasticsearch-keystore list
keystore.seed
xpack.security.http.ssl.keystore.secure_password
xpack.security.transport.ssl.keystore.secure_password
xpack.security.transport.ssl.truststore.secure_password
$ ./bin/elasticsearch-keystore show xpack.security.http.ssl.keystore.secure_password
F5tj__WeSyqCCTb19jdUaw
F5tj__WeSyqCCTb19jdUaw 就是http.p12 这个文件的密码了，http_ca.crt不需要密码就可以访问
(我最终还是使用了http_ca.crt, http.p12没有验过，^.^)