Configure password policy for users

Ambari administrator can configure password policy for users.

1. On the Ambari Server host, open open /etc/ambari-server/conf/ambari.properties with a text editor.
2. Add security.password.policy.regexp={some regexp} to ambari.properties file. Regular expression should follow the Java regex formathttps://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html
   security.password.policy.regexp=^(?=.*[A-Za-z])(?=.*\\d)[A-Za-z\\d]{8,}$

   	Note
   	‘\’ character should be escaped by ‘\\’.

3. Add property security.password.policy.description={some description} to ambari.properties file.

   	Note
   	The plain text description of password policy will be displayed to end users when they attempt to change the password to insecure value.

   security.password.policy.description=Minimum length=15, Must contain at least three out of the following four character types (numeric character, lower case alphabetic characters, upper case alphabetic characters, punctuation/special symbol)

4. Restart the Ambari Server.