Comment 1 for bug 2074309

OK, found a workaround. From the 24.04 system, make sure to

systemctl stop rabbitmq-server.service
systemctl stop epmd.service

make a safety copy/backup of /var/lib/rabbitmq

Repeat the following two podman commands for 3.9 , 3.10, and 3.11:

In one shell run (replace 127 and 138 with uid and gid of rabbitmq on your system and make sure that $HOST is set to your hostname, must be the same as your host for things to work, the -p ports are not needed, but a way to make sure no other daemon is running)

podman run -it --rm -v /var/lib/rabbitmq:/var/lib/rabbitmq --uidmap=0:0 --uidmap=u999:127 --gidmap=0:0 --gidmap=g999:138 -p 5672:5672 -p 15672:15672 --name $HOST -h $HOST docker.io/library/rabbitmq:3.9

wait for it to come up and run from a second shell

podman exec -it -u rabbitmq $HOST rabbitmqctl enable_feature_flag all

(or run /bin/bash and check with
rabbitmqctl list_feature_flags
rabbitmqctl enable_feature_flag all
rabbitmqctl list_feature_flags
)

after doing this three times with 3.9 3.10 and 3.11

restart services epmd and then rabbitmq-server , and things should work now. Once happy, you can remove the podman images.