I need to write a python script to install an app/add-on to the remote Splunk search head.
The app file ".spl" and ".tgz" is in the server which hosts my python script.
As far as i understand from all the errors that I got and from documentation, bot services/app/local and services/app/appinstall either searches for a local file or splunkbase but never from a remote server
based on documentation and other answers the local in this content means splunk SH server not the local server where you are running your python script! So you must 1st copy your app to target splunk SH server and then you can use a REST api to install it "locally" on that server. See e.g. https://community.splunk.com/t5/Getting-Data-In/Using-the-REST-API-to-install-an-app-from-a-file/td-...
I think that only way to install into remote server is via GUI. Just login to remote server (SH or HF and if you have individual indexers then also those can use). Then open Apps on top navigation bar and select Manage Apps. Then Install App from File and follow instructions.
If you have CI/CD pipeline or possibility to log on shell level to those server, then you can do a scripted installation.