Thanks!
I tried the steps, but I’m still stucked…
% % cat /etc/apparmor.d/tunables/home.d/ubuntu
# This file is auto-generated. It is recommended you update it using:
# $ sudo dpkg-reconfigure apparmor
#
# The following is a space-separated list of where additional user home
# directories are stored, each must have a trailing '/'. Directories added
# here are appended to @{HOMEDIRS}. See tunables/home for details.
@{HOMEDIRS}+=/data1/home/
% cat /var/lib/snapd/apparmor/snap-confine/my-homes
mount options=(rw rbind) /data1/home/ -> /tmp/snap.rootfs_*/home/,
% snap remove hello
hello removed
% snap install hello
hello 2.10 from 'canonical' installed
% snap run hello
cannot create user data directory: /data1/home/hideo-t/snap/hello/20: Read-only file system
Since you mentioned “with a recent stable core image” I checked the snap version that gets installed by ubuntu 16.04. It says:
% apt-cache show snapd
Package: snapd
Architecture: amd64
Version: 2.29.4.2
Is this recent enough?