Needed to establish an SSH connection to poll another server for the current GIT revision of a repo.
This is an non-standard PECL package, you must compile and install it.
SELinux by default prevents Apache from certain network activity, it is very likely that when trying to use any of the SSH2 methods you will see several denials logged in your SElinux Audit logs. To fix this you will need to allow Apache this access:
sudo setsebool -P httpd_can_network_connect=1