Both are Red Hat funded managed products. Pacemaker is a generic high availability service that can be used across physical machines or vms to make a cluter of "resources" which can be almost anything if you write a bash script for it. Virtual IPS, filesystem mounts, HA filesystems, systemd services etc.

Podman is a daemonless + rootless docker implementation in pretty much a single binary. It's minimally invasive and straightforward. Doesn't mess up your firewalls (using slirp4net and bridge networks) and can basically be removed simply by stopping all running containers, deleting container storage and removing the package. It doesn't molest your install like docker does. It also integrates well with RedHat linux distros that use SELinux features.

Pacemaker: https://clusterlabs.org/projects/pacemaker/

Podman: https://podman.io/