He has played for Scotland 7s and was involved at the recent Hong Kong 7s in the Sevens World Series.
This season he has played nine times and scored against the Ospreys at the Liberty Stadium in January.
Bulumakau, who signed from the British Army on a one-year deal in August 2015, was born in Fiji and moved to Scotland at the age of ten with his parents.
This season he has played for Scotland in the Wellington leg of the Sevens World Series and featured four times for Glasgow, scoring his maiden try Guinness PRO12 try against Newport Gwent Dragons.
The duo will be staying at Scotstoun until at least May 2017 and Townsend could not be happier.
He told the club's official website: "Rory and Junior have earned their new contracts and it's a boost for the club that they will be with us again next season.
"Rory has really progressed over the last 12 months and his hard-working approach has enabled him to play in a number of important games for the club and win a cap for Scotland.
"There is much more to come from him and we are going to have some excellent competition for places on the wings next season.
"Junior came in earlier this season and made some very good contributions during the Rugby World Cup period, with the Munster game being a particular highlight.
"This was Junior's first season as a full professional and he's learned a lot about what it takes to succeed at this level.
"We're looking forward to him using this experience to improve even further next season."
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