Test SSH under Apache role
If you need PHP to process bash script, and it need SSH to another server process something else. Example PHP snippet: $bash = shell_exec('bash ./example.sh');.
Because PHP running under Apache, so Apache needs SSH to correct server. However, Ubuntu prevent su apache for obvious security reason, but you still able to change it.1sudo vim /etc/passwd
After find role Apache, change /sbin/nologin to /bin/login. Now you can do su apache.
Under Apache role, test your SSH host, you need add host to your trust list for first time. You probably want create ssh_config file under /var/www/.
Don’t forget update Apache to /sbin/nologin after it.