Munster drew 24-24 with Ulster, while there were Pro14 wins for the Cheetahs, Scarlets, Ospreys, Connacht, Zebre and Edinburgh.
In the final round of the regular season, hosts Munster came back from a 24-14 half-time deficit, with flyhalf JJ Hanrahan kicking a 68th-minute penalty to level the scores.
Munster scored their first try in the second minute of the match after Ulster conceded possession on their line, which allowed wing Duncan Williams to go over.
The visitors soon levelled the scores as they won a turnover just outside the Munster 22, with centre Stuart McCloskey eventually scoring and flyhalf Johnny McPhillips converting.
McPhillips then kicked a penalty to put his side ahead, but Munster regained the lead after Ulster failed to clear their lines properly as tighthead prop Brian Scott crashed over.
The visitors struck back with two tries from hooker Rory Best to take a 24-14 half-time lead.
Ulster suffered a blow early in the second half when they lost centre Luke Marshall to a yellow card. Munster took immediate advantage as No 8 Robin Copeland, who had been yellow-carded in the first half, made the most of his side’s numbers to go over and cut Ulster’s lead to three.
Hanrahan then kicked a penalty to level the scores and end Ulster’s playoff hopes.
In other results, the Cheetahs secured their place in the playoffs with a 29-20 win against the Kings. The Cheetahs will travel to the Scarlets who, with the help of a brace from flank Tadhg Beirne, beat the Dragons 33-8.
Connacht ended their season with 47-10 victory against a much-changed Leinster side, who were already assured of a home semi-final.
Zebre edged Italian rivals Treviso 22-17, a late rally from the Ospreys gave them a 26-23 win against the Cardiff Blues, and Edinburgh survived a late comeback from Glasgow to win 24-19.
Round 21 results:
Munster 24 Ulster 24
Kings 20 Cheetahs 29
Dragons 8 Scarlets 33
Connacht 47 Leinster 10
Treviso 17 Zebre 22
Cardiff Blues 23 Ospreys 26
Edinburgh 24 Glasgow 19
Saturday, 5 May
Munster vs Edinburgh
Scarlets vs Cheetahs
Friday, 18 May
Glasgow Warriors vs Scarlets/Cheetahs
Saturday, 19 May
Leinster vs Munster/Edinburgh
Photo: Andrew Surma/Getty Images