I solved that problem – the issue was indeed that the .ldif file was outside the container, not inside. I resolved that by doing
ps cp odk2_admin.ldif [dockerinstance]:/tmp
and then once the ldif had been copied, I could execute the docker exec command pointing to the local file path. I was also able to execute a ldappasswd command to set the new account’s password, and another .ldif to add it to the site_admin group.
The opendatakit web ui still doesn’t accept those credentials even though I’ve verified that the admin account I created is there and in the appropriate group, but I see there is another long thread about unknown username or password (Problems with login in to ODK-X Server web-ui. Incorrect username or password) so I’ll see if I can get some help there.
Thanks again.