Hi antony and @quba42
I saw this post when i had this issue aswell, it’s the top result when googling the information message, i found a more proper fix and want to post it here as it’s alot easier then is suggested here.
So in short, create a file with some content in: echo tux > /etc/apt/trusted.gpg.d/client.asc
unregister/clean your subscription-manager vm/host and then re-register it. Now your apt update/upgrade will work withoud those messages!
TLDR on why:
From here Subscription-manager for Ubuntu 24.04 i eventually digged into the source code and found:
subscription-manager/src/rhsm/repofile.py at 3e116be960d8eafc055749d58cd28704add785d6 · ATIX-AG/subscription-manager · GitHub
apt will give you a warning if you name your key .pub, not if you name it .asc.
Adding that file basically turns the check True and adds the missing Signed-By statements in each repo from Foreman on your client. This parameter also seems to go unused, as GPG checking is done differently.
Sorry for reviving an old topic, but i think it’s good to share this info online 