If you try to use e.g. TEST_SUBJECTS=CentOS-6-x86_64-GenericCloud-1907.qcow2c, the script will appear to hang and you will get errors in the artifacts logs like this:

sign_and_send_pubkey: no mutual signature supported
Permission denied

Jakub Jelen explains the problem here: https://unix.stackexchange.com/questions/630446/ssh-in-fedora-33-error-sign-and-send-pubkey-no-mutual-signature-supported

I have filed an issue: https://pagure.io/standard-test-roles/issue/400

The workaround listed in the issue is to make a copy of /usr/share/ansible/inventory/standard-inventory-qcow2 -> /usr/share/ansible/inventory/standard-inventory-qcow2.sshfix

Edit /usr/share/ansible/inventory/standard-inventory-qcow2.sshfix

around line 485 - where ansible_ssh_common_args is set - add -o PubkeyAcceptedKeyTypes=+ssh-dss like this:

                "ansible_ssh_common_args": "-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o PubkeyAcceptedKeyTypes=+ssh-dss"

Then run sti tests with /usr/share/ansible/inventory/standard-inventory-qcow2.sshfix