Undercloud installation fails with TASK of Container image prepare in environment under proxy

Issue

• Failure to obtain container image during container preparation process executed when installing undercloud.
• "Error running container image prepare: check_hostname requires server_hostname" is displayed and fails during undercloud installation.

2022-10-23 23:20:06.830956 | 52540076-3487-4607-a2e7-0000000013f6 |       TASK | Container image prepare
2022-10-23 23:20:08.437900 | 52540076-3487-4607-a2e7-0000000013f6 |      FATAL | Container image prepare | undercloud-0 | error={"changed": false, "error": "check_hostname requires server_hostname", "msg": "Error running container image prepare: check_hostname requires server_hostname", "params": {}, "success": false}

• Undercloud connects to the Internet via proxy, which is configured in /etc/environment as follows.

https_proxy=https://XXX.XXX.XXX.XXX:3128
http_proxy=http://XXX.XXX.XXX.XXX:3128