Brewing 1 gallon beer in a 5 gallon kettle?

I’ve been brewing 5 gallon batches of beer for about a year and I thought I might try a small 1 gallon batch so I could have more variety. But I have all the equipment for a 5 gallon. I got a 1 gallon carboy and I’m ready on that end, but it occurs to me I only have a 5 gallon kettle. Is that too big? What problems might arise from using a bigger kettle like this? Thanks!

The only problem may be a higher boil off rate with the larger diameter of the kettle for the volume of wort. This would be easy to compensate for though. Not a big problem.

I have used a 5 gallon carboy to make large starters before without any problem. Certainly no need for a blow off hose.

Are the 1 gallon a true gallon? If so the five gallon would yield a true gallon (or more). Losing a bottle or two becomes more of an issue with small batch size.