Mounting home dir on host into a container has nobody:nogroup ownership even wih /etc/sub{uid, gid} defined


I have lxd 3.10 installed on my Ubuntu 18.10 host. I have configure the subsidiary ids /etc/subuid and /etc/subgid as shown below:


I have launch an unprivileged container (called fred) from an ubuntu:18.04 image and applied the default profile:

config: {}
description: Default LXD profile
    name: eth0
    nictype: bridged
    parent: lxdbr0
    type: nic
    path: /
    pool: default
    type: disk
name: default
- /1.0/containers/fred

I have added a disk device in the container which maps the ${HOME} on the host to ${HOME} for user ubuntu (uid/gid == 1000:1000) in the container. Here is the config of the container:

architecture: x86_64
  image.architecture: amd64
  image.description: ubuntu 18.04 LTS amd64 (release) (20190212.1)
  image.label: release
  image.os: ubuntu
  image.release: bionic
  image.serial: "20190212.1"
  image.version: "18.04"
  volatile.base_image: 35f6bff57c250208c6dc73445eefe8c1020853a1bc8571ebd8bfb1fe3a239504
  volatile.eth0.hwaddr: 00:16:3e:8a:5f:34
  volatile.idmap.base: "0" '[{"Isuid":true,"Isgid":true,"Hostid":1000000,"Nsid":0,"Maprange":1000000000}]'
  volatile.last_state.idmap: '[{"Isuid":true,"Isgid":true,"Hostid":1000000,"Nsid":0,"Maprange":1000000000}]'
  volatile.last_state.power: RUNNING
    path: /home/ubuntu
    recursive: "true"
    source: /home/joe
    type: disk
ephemeral: false
- default
stateful: false
description: ""

When I log into the container as user ubuntu and go to the ${HOME}, all the file contents are mapped to nobody:nogroup (-1:-1). I was hoping that because the user joe on the host and user ubuntu in the container have the same ids (i.e. uid/gid == 1000:1000) and because of the mapping in the sub{uid,gid} of user ‘joe’ to 1001000, the mapping would be complete. However that is not the case. What could be wrong in my approach and understanding here?

I have found the answer to my problem here: Effectively for an unprivileged container a direct mapping approach has to be employed