What is the command to determine if OpenSSL and mod_ssl are installed on apache2?

To check apache modules installed on your system:

apache2ctl -M or apachectl -M

To check if OpenSSL is installed in your system:

For GNU/Linux distros that use rpm packages:

rpm -qa | grep -i openssl

For GNU/Linux distros that use deb packages:

dpkg -l | grep -i openssl

With apache2 in a Debian environment:

sudo apache2ctl -t -D DUMP_MODULES

or

sudo apache2ctl -S

This will show all the modules that are currently loaded into Apache, you may have other installed, but not loaded. To find that out the simplest way I know of is to look in the /etc/apache2/mods-available directory.

If it is not loaded, and you think it is installed, you can always use the load module directive to try to load it and see if it errors out (if you can have a little downtime that is)