Josh left the Golden Lions last summer following their relegation from Super Rugby after an impromptu phone call from Gregor Townsend.
And the big South African flanker insists the reason he is enjoying himself so much at Scotstoun is because he feels wanted by the Glasgow head coach.
"Gregor Townsend phoned me out of the blue and I had several extensive talks with him on Skype," Josh told Scotland on Sunday.
"I liked his enthusiasm and his vision for the club and it is always nice to feel wanted and that is what Glasgow did for me.
"Given the circumstances at the Lions after the franchise was relegated out of Super Rugby, it seemed the right thing to do.
"The facilities here are worldclass. The strength and conditioning was exceptional, the medical staff and everyone involved in the club had such high standards.
"As an outsider experiencing my first season here, you can really feel the excitement within the players and fans. There is a real buzz and it's exciting and a big privilege to be part of it."