make life easier for lxd users - based on https://gist.github.com/bloodearnest/ebf044476e70c4baee59c5000a10f4c8

lxd-user-profile.sh

#! /bin/bash

# to launch a container using this profile:
# lxc launch <container> -p default -p $USER

set -eu
#UID=$(id -u)
GID=$(id -g)
SUBUID=root:$UID:1
SUBGID=root:$GID:1

# give lxd permission to map your user/group id through
grep $SUBUID /etc/subuid -qs || sudo usermod --add-subuids ${UID}-${UID} --add-subgids ${GID}-${GID} root
UID_OFFSET=$(grep 'root:.*:65536' /etc/subuid | head -1 | awk -F: '{ print $2 }')
GID_OFFSET=$(grep 'root:.*:65536' /etc/subgid | head -1 | awk -F: '{ print $2 }')

# set up a separate key to make sure we can log in automatically via ssh
# with $HOME mounted
KEY=$HOME/.ssh/id_lxd_$USER
PUBKEY=$KEY.pub
AUTHORIZED_KEYS=$HOME/.ssh/authorized_keys
[ -f $PUBKEY ] || ssh-keygen -f $KEY -N '' -C "ssh key for lxd containers"
grep "$(cat $PUBKEY)" $AUTHORIZED_KEYS -qs || cat $PUBKEY >> $AUTHORIZED_KEYS

# create a profile to control this, name it after $USER
lxc profile create $USER &> /dev/null || true

# configure profile
# this will rewrite the whole profile
cat << EOF | lxc profile edit $USER
name: $USER
description: allow home dir mounting for $USER
config:
  # map the special uid/gid in the container to the correct host uid/gid
  raw.lxc: |
    lxc.id_map =
    lxc.id_map = u 0 $UID_OFFSET $(($UID - 1))
    lxc.id_map = g 0 $GID_OFFSET $(($GID - 1))
    lxc.id_map = u $UID 1000 1
    lxc.id_map = g $GID 1000 1
    lxc.id_map = u $(($UID + 1)) $(($UID_OFFSET + $UID + 1)) $((65536 - $UID - 1))
    lxc.id_map = g $(($GID + 1)) $(($GID_OFFSET + $GID + 1)) $((65536 - $GID - 1))
  user.vendor-data: |
    # give sudo rights to the user
    users:
      - name: $USER
        groups: sudo
        shell: $SHELL
        sudo: ['ALL=(ALL) NOPASSWD:ALL']
    # ensure users shell is installed
    packages:
      - $(dpkg -S $(readlink -m $SHELL) | cut -d: -f1)
# mount the \$HOME directory into the container
devices:
  home:
    type: disk
    source: $HOME
    path: $HOME
EOF