On Friday, the singer Adele’s residency at Caesars Palace in Las Vegas was supposed to begin — the key words being “supposed to.”

The shows have been postponed because too many crew members have the coronavirus as well as what Adele called “delivery delays.”

With the omicron variant surging, live performances of all kinds are suffering similar fates.

Adele let her fans know about the postponement on Instagram.

“And I’m gutted, I’m gutted. I’m sorry it’s so last minute,” she said in a video.

Last minute — as in the night before the opening, and she’s getting flack for making such a last-minute decision. But Dayna Frank, CEO of First Avenue, a music venue in Minneapolis, said this is how the business works these days.

“We’ve canceled shows a week before, an hour before, even 10 minutes after doors open. We’re all figuring this out. There are no rules because no one in our industry has ever had to handle this before,” Frank said.

Sometimes it’s the artist’s choice, sometimes it’s the venue’s, she said. Most often it’s a joint decision and a reluctant one. Before a show even begins, the venue’s already spent a quarter of the budget on marketing, equipment rentals and staging, according to Frank.

But sometimes there’s no choice, she said.

“Having too many staff out on quarantine to open the doors or artists themselves getting positive test results, you know, 20 minutes before they’re supposed to go onstage,” she said.

That’s what recently troubled Broadway shows, which have been heavily relying on understudies. Charlotte St. Martin, president of the trade association the Broadway League, said there were times when even backups were out sick.

“If the cast or crew, anybody in the cast or crew is, tests positive and we don’t have a replacement for them, then we do not go on,” St. Martin said.

Some performers have had to scale back production values at their shows.

Dave Pomeroy is a musician and president of the Nashville Musicians Association in Tennessee. He said many artists are keeping sound, lighting and stage crews small.

“The bigger the tour, the more complicated it can be,” he said.

The show must go on, that is, if it can dodge omicron.