Glamorgan 433 and 365 for 3 dec (Cooke 102*, Ingram 101*, Rudolph 69) drew with Gloucestershire 558 (Dent 268, Fuller 73)
By the time the players shook hands on a draw at just before 4.20pm, the visitors had reached 365 for 3 in their second innings and led by 240. Gloucestershire took 13 points, while their opponents claimed 12. Ingram was 101 not out and Cooke unbeaten on 102, with their fourth-wicket partnership worth 180.
Gloucestershire had claimed three wickets in the first session to keep alive hopes of winning after Glamorgan had begun the day on 88 without loss.
Richard Kettleborough was first to go, lbw to left-arm spinner Tom Smith playing across the line for 34 with the total on 99.
David Payne then claimed the prized wicket of Jacques Rudolph, lbw on the back foot to an inswinger having made 69, with 10 fours, to make it 124 for 2.
The third wicket was a gift as Aneurin Donald, on 35, called for a single having played the ball to mid-wicket and was run out by Hamish Marshall's throw after being sent back by Ingram.
Donald had come within two runs of becoming Glamorgan's youngest-ever Championship century-maker in the first innings and again displayed his promise.
From 191 for 3 at lunch, Ingram and Cooke batted without alarms. Even when the second new ball was taken at 266 for 3 it posed few problems.
The final action of the season was played out in bright afternoon sunshine with the only question being whether the two Glamorgan batsmen would reach three figures.
In the event they both timed it perfectly. Cook was first to his hundred, having faced 135 balls and hit 12 fours and two sixes, while Ingram followed in the next over, reaching his century off 220 deliveries, with 11 fours and a six.
It was Ingram's second Championship century of the season and Cooke's first.
By the end the Glamorgan batsmen found themselves facing the less than fearsome part-time bowlers Will Tavaré and Chris Dent, although the hosts had stuck with their main attack for most of the day.
During the tea interval 24-year-old seam bowler Tom Hampton, formerly with Middlesex, was presented with his Gloucestershire county cap.