Is the conclusion that userns-remap does not work with rootless docker?
I tried using rootless docker with both a domain user, and a local user, on Ubuntu 20.04 but only got errors. /etc/subuid and /etc/subgid have the username:startid:idrange entries
Example commands and errors:
$ dockerd-rootless.sh --userns-remap=ljason:ljason
...
INFO[2021-01-22T17:06:09.607299361-08:00] Starting up
WARN[2021-01-22T17:06:09.607732164-08:00] Running in rootless mode. This mode has feature limitations.
INFO[2021-01-22T17:06:09.607939765-08:00] Running with RootlessKit integration
INFO[2021-01-22T17:06:09.608571470-08:00] User namespaces: ID ranges will be mapped to subuid/subgid ranges of: ljason
Cannot create daemon root: /home/ljason/.local/share/docker/305536.305536: chown /home/ljason/.local/share/docker/305536.305536: invalid argument
[rootlesskit:child ] error: command [/home/ljason/bin/dockerd-rootless.sh --userns-remap=ljason:ljason] exited: exit status 1
[rootlesskit:parent] error: child exited: exit status 1
and after modifying docker-rootless.sh to get “jason:domain user” past the argument quoting…
$ dockerd-rootless.sh
...
exec dockerd --userns-remap=jason:domain users
INFO[2021-01-22T17:17:55.673903034-08:00] Starting up
WARN[2021-01-22T17:17:55.674328737-08:00] Running in rootless mode. This mode has feature limitations.
INFO[2021-01-22T17:17:55.674496638-08:00] Running with RootlessKit integration
INFO[2021-01-22T17:17:55.688611729-08:00] User namespaces: ID ranges will be mapped to subuid/subgid ranges of: jason
Cannot create daemon root: /home/jason/.local/share/docker/170000.170000: chown /home/jason/.local/share/docker/170000.170000: invalid argument
[rootlesskit:child ] error: command [/home/jason/bin/dockerd-rootless.sh] exited: exit status 1
[rootlesskit:parent] error: child exited: exit status 1