Problem:
From what I can see, the Foreman proxy connects to targets using the /var/lib/foreman-proxy/ssh/id_rsa_foreman_proxy SSH key. This works OK when the smart proxy can connect to the target system directly, but if an SSH proxy jump is required, configuring it (via the ansible_ssh_common_args host variable) is not as straight-forward.
SSH has the -J user@proxy or -o ProxyJump="user@proxy" flags that can be used to define an SSH proxy, but neither allows defining an SSH key for the proxy - the -i path_to_ssh_key argument only defines the SSH key to be used when connecting to the target, but not to the proxy.
Using something like -o ProxyCommand="ssh -i /var/lib/foreman-proxy/ssh/id_rsa_foreman_proxy user@proxy -W %h:%p appears to work as expected, but is more clunky to use, especially if the proxy is also configured using Foreman (in which case the the remote execution user / SSH key can be used implicitly).
Configuring the SSH key (and possibly user) in the SSH config file of foreman-proxy user can simplify the use of SSH proxies. Temporary, per-connection SSH config files may also be used using the SSH -F flag.
Is there a particular reason why SSH configuration files are not used, and arguments are passed manually instead?
Foreman and Proxy versions:
foreman 3.19.1
foreman-proxy 3.19.1
Distribution and version:
AlmaLinux 9.8 (Olive Jaguar)