I am planning to use SonarQube Scanner (http://docs.sonarqube.org/display/SCAN/Analyzing+with+SonarQube+Scanner) for doing sonar analysis for my projects.
Please let me know, if I need to install SonarQube-Scanner on every host or can I install on one host and all other can use the scanner from remote location.
Not sure what you meant by every host but all you need to make sure is project files should be accessible from the machine on which you have sonar scanner. Best practice is to have both the scanner and project files on the same machine.
Sonar scanner can be isolated from the web server. once the analysis is done by the scanner it sends the analysis report to the web server queue from where it is picked by compute engine for processing and pushed to database. However this process was different in older versions(below 5.2).
You don't need to have a scanner on every host.
I'd recommend integrating SonarQube scans into a continuous integration process where your CI server pulls the build and then executes a SonarQube scan on the pulled code base.
This allows developers to submit their changes, start a build on the CI server, and have the code scanned all with only having version control on their development machines.
