Tongan tight-head Halanukonuka has become an integral part of Dave Rennie's squad since arriving from Super Rugby last season, with the former Highlanders front-rower having made a significant impact during his time at the club so far.
His sole try in a Warriors shirt to date came in last season's 37-23 victory over the Cheetahs, whilst his scrummaging prowess has seen him make a considerable impact.
The 32-year-old has earned eight caps for his country in his career thus far, including helping Tonga to an historic 19-17 victory over Italy in Padua back in 2016.
Halanukonuka also made an immediate impression in the Highlanders' defeat of the British and Irish Lions in 2017, coming off the bench to win the scrum penalty that ultimately decided the result.
Highland RFC product Kelly, meanwhile, made his debut for Glasgow in November 2016 and has made four appearances for Dave Rennie's side so far this season.
Included in that tally is Kelly's first start for the club, which came in the 43-17 victory over Connacht at Scotstoun at the end of February.
A former recipient of the prestigious MacPhail Scholarship, the 23-year-old previously plied his trade with French outfit Le Parc and English Championship side London Scottish having come through the Fosroc Scottish Rugby Academy.
When not running out for the Warriors this season, Kelly has played an integral role for Ayr RFC as they secured a Tennent's Premiership and Scottish Cup double.
Glasgow Warriors Head Coach Dave Rennie said: "Siua's work at the set-piece is excellent and he helps provide a solid platform for us to play the free-flowing game we enjoy.
"He is an experienced operator who brings real physicality and we're rapt that he's committed for another two years.
"Paddy impressed us when he got an opportunity in a Warriors shirt this season and was excellent for Ayr in the Premiership.
"His diligence and professionalism in helping the team prepare throughout the year has been hugely impressive and he'll be an important player for us next year with so many international absentees."