https://docs.oracle.com/en-us/iaas/Content/Security/Reference/iam_security_topic-iam_mfa_identity_domains_signon_policy.htm#iam_security_topic-iam_mfa_identity_domains_signon_policy 7月17号后会自动激活新的oci登陆策略，规则里面包括对所有用户启动MFA 如果开启两步验证，账号会自动启动mFA Security_iam_policy_rules.png 策略, 甲骨文, 两步
