Expand Disk LXD VM

Existing size is about 10G on Centos host called nas

lxc config device set nas root size=100GiB
lxc shell nas

Add tools and expand (you can use fdisk/parted but this is easer)

lsblk
df -h

yum install e2fsprogs cloud-utils-growpart gdisk
growpart /dev/sda 2
resize2fs /dev/sda2

lsblk
df -h

Ubuntu

Ubuntu Script example (replace overide with set for existing)

set -e

readonly VM="myhost"
readonly CPU="8"
readonly MEM="4GB"
readonly DSK="60GB"

lxc init images:ubuntu/focal ${VM} -p default -p vm --vm
lxc config set ${VM} limits.cpu ${CPU}
lxc config set ${VM} limits.memory ${MEM}
lxc config device override ${VM} root size=${DISK}
lxc start ${VM}

sleep 10  # `lxc start` needs a `--wait`.

lxc exec ${VM} -- apt update
lxc exec ${VM} -- apt install cloud-initramfs-growroot -y
lxc exec ${VM} -- growpart /dev/sda 2
lxc exec ${VM} -- resize2fs /dev/sda2