ubuntu_lxc test causing filesystem "too many open files" failure

[Sean Feole]

This appears to be limited to Oracle the following flavors and only occured on Xenial.

x-l-oracle-oracle-4-15-0-vm-denseio1-8-lxc
and
x-l-oracle-oracle-4-15-0-vm-standard2-24-lxc

Unrelated in hardware type,

161950K .......... .......... .......... .......... .......... 99% 301M 0s
162000K .......... .......... .......... .. 100% 278M=10s

2019-01-24 08:56:35 (15.3 MB/s) - ‘ubuntu-16.04-server-cloudimg-amd64.squashfs’ saved [165920768/165920768]

Extracting container rootfs
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/importer.py, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/log.py, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/__init__.py, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/__pycache__/__init__.cpython-35.pyc, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/__pycache__/m_dict.cpython-35.pyc, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/__pycache__/m_list.cpython-35.pyc, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/__pycache__/m_str.cpython-35.pyc, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/m_dict.py, because Too many open files
write_file: failed to create file /var/lib/lxc/37c34f8e-bd75-4a7f-b810-325492924c4d/rootfs/usr/lib/python3/dist-packages/cloudinit/mergers/m_list.py, because Too many open files
Parallel unsquashfs: Using 16 processors
28871 inodes (31754 blocks) to write

created 24380 files
created 2924 directories
created 4396 symlinks
created 79 devices
created 0 fifos

Current default time zone: 'Etc/UTC'
Local time is now: Thu Jan 24 08:56:37 UTC 2019.
Universal Time is now: Thu Jan 24 08:56:37 UTC 2019.

Container 37c34f8e-bd75-4a7f-b810-325492924c4d created.
Failed to start networking in ubuntu-cloud container
---
PASS: lxc-tests: /usr/bin/lxc-test-unpriv
PASS: lxc-tests: /usr/bin/lxc-test-usernic
PASS: lxc-tests: /usr/bin/lxc-test-utils
PASS: python3: API

SUMMARY: pass=33, fail=1, ignored=0
01/24 08:58:00 ERROR| parallel:0033| child process failed