Xenial is facing same/similar issue for qemu-user-static being installed into LXD aarch64 (possibly for other arches as well). ---- The following NEW packages will be installed: binfmt-support qemu-kvm qemu-user-static 0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded. Need to get 5678 kB of archives. After this operation, 68.4 MB of additional disk space will be used. Get:1 http://ports.ubuntu.com/ubuntu-ports xenial/main arm64 binfmt-support arm64 2.1.6-1 [44.5 kB] Get:2 http://ports.ubuntu.com/ubuntu-ports xenial-updates/main arm64 qemu-kvm arm64 1:2.5+dfsg-5ubuntu10.41 [6484 B] Get:3 http://ports.ubuntu.com/ubuntu-ports xenial-updates/universe arm64 qemu-user-static arm64 1:2.5+dfsg-5ubuntu10.41 [5627 kB] Fetched 5678 kB in 3s (1434 kB/s) Selecting previously unselected package binfmt-support. (Reading database ... 47223 files and directories currently installed.) Preparing to unpack .../binfmt-support_2.1.6-1_arm64.deb ... Unpacking binfmt-support (2.1.6-1) ... Selecting previously unselected package qemu-kvm. Preparing to unpack .../qemu-kvm_1%3a2.5+dfsg-5ubuntu10.41_arm64.deb ... Unpacking qemu-kvm (1:2.5+dfsg-5ubuntu10.41) ... Selecting previously unselected package qemu-user-static. Preparing to unpack .../qemu-user-static_1%3a2.5+dfsg-5ubuntu10.41_arm64.deb ... Unpacking qemu-user-static (1:2.5+dfsg-5ubuntu10.41) ... Processing triggers for man-db (2.7.5-1) ... Processing triggers for ureadahead (0.100.0-19.1) ... Processing triggers for systemd (229-4ubuntu21.22) ... Setting up binfmt-support (2.1.6-1) ... update-binfmts: warning: unable to open /proc/sys/fs/binfmt_misc/status for writing: Permission denied update-binfmts: warning: unable to open /proc/sys/fs/binfmt_misc/register for writing: Permission denied update-binfmts: warning: unable to enable binary format python3.5 Job for binfmt-support.service failed because the control process exited with error code. See "systemctl status binfmt-support.service" and "journalctl -xe" for details. invoke-rc.d: initscript binfmt-support, action "start" failed. ● binfmt-support.service - Enable support for additional executable binary formats Loaded: loaded (/lib/systemd/system/binfmt-support.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Sun 2019-09-29 09:54:54 UTC; 30ms ago Docs: man:update-binfmts(8) Process: 16763 ExecStart=/usr/sbin/update-binfmts --enable (code=exited, status=2) Main PID: 16763 (code=exited, status=2) Sep 29 09:54:54 xenial systemd[1]: Starting Enable support for additional executable binary formats... Sep 29 09:54:54 xenial update-binfmts[16763]: update-binfmts: warning: unable to open /proc/sys/fs/binfmt_misc/status for writing:... denied Sep 29 09:54:54 xenial update-binfmts[16763]: update-binfmts: warning: unable to open /proc/sys/fs/binfmt_misc/status for writing:... denied Sep 29 09:54:54 xenial update-binfmts[16763]: update-binfmts: warning: unable to open /proc/sys/fs/binfmt_misc/register for writin... denied Sep 29 09:54:54 xenial update-binfmts[16763]: update-binfmts: exiting due to previous errors Sep 29 09:54:54 xenial systemd[1]: binfmt-support.service: Main process exited, code=exited, status=2/INVALIDARGUMENT Sep 29 09:54:54 xenial systemd[1]: Failed to start Enable support for additional executable binary formats. Sep 29 09:54:54 xenial systemd[1]: binfmt-support.service: Unit entered failed state. Sep 29 09:54:54 xenial systemd[1]: binfmt-support.service: Failed with result 'exit-code'. ----