$ cat podman-migrate-from-docker.txt
migrate from docker to podman

rootless containers

"cannot find UID/GID for user xxxxxx: no subuid ranges found for user "xxxxxx" in /etc/subuid - check rootless mode in man pages"

add subgid/subuid for user

cat /etc/subgid
xxxxxx:100000:65536

cat /etc/subuid
xxxxxx:100000:65536

podman system migrate

Error: building at STEP "RUN apt-get -y update": setup network: /usr/bin/slirp4netns failed: "open(\"/dev/net/tun\"): No such device\nWARNING: Support for seccomp is experimental\nWARNING: Support for IPv6 is experimental\nchild failed(1)\nWARNING: Support for seccomp is experimental\nWARNING: Support for IPv6 is experimental\n"

related to upgraded kernel, reboot to move to latet