This is SQL Server 2014 Enterprise.
This instance has been running for 1 year.
Now I need to install the Full-Text Search feature. (I ran SELECT FULLTEXTSERVICEPROPERTY('IsFullTextInstalled') and it returns 0
After I add that feature, will a restart of the server be required? I need to know if it I need to arrange for an outage.
After re-reading my comments below, I realize they are not very helpful, sohopefully someone else will chime in.
My recollection is that installing FTS does not require a reboot of the windows OS and it does not require a restart of SQL Server. But the last time I did this was about a year ago, and when I have done it, it has always been during maintenance windows when reboot did not matter.
I would recommend testing it in a test environment to make sure that it does not require restart/reboot. Also, watch whether it causes the system to slowdown or queries to be blocked when you do this.