http://pad.lv/1718287
https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1718287

=== Begin SRU Template ===
[Impact]
cloud-init DatasourceOVF block device mounting races with systemd.fstab
mount.units resulting in some mount points not being mounted.

[Test Case]

1. Launch Ubuntu 16.04 instance in AWS and attach 25 ebs volumes (sdb .. sdz)
2. sudo apt update && sudo apt upgrade
3. cat >setup.sh << EOF
#!/bin/bash

mkdir /media/{b..z}
for i in {b..z}; do
	   mkfs -t ext4 /dev/xvd\$i
	   mount /dev/xvd\$i /media/\$i
	   echo "/dev/xvd\$i /media/\$i ext4 defaults,nofail 0 2" >> /etc/fstab
done
EOF
4. chmod +x setup.sh && sudo bash ./setup.sh
5  grep -c media /etc/fstab  # expect 25
6. sudo rm -rf /var/log/cloud-init* /var/lib/cloud/
7. grep -c media /proc/mounts # expect 25
8. journalctl --utc -o short-precise --no-pager | grep -c Failed.*to.*mount  # expect 0
9. grep -c Failed.*mount.*iso9660 /var/log/cloud-init.log  # expect 0

[Regression Potential]
Systems using DatasourceOVF could fail to find the datasource on block devices
that didn't get probed by OVF to verify the filesystem present on the devices.

[Other Info]
Upstream commit at
  https://git.launchpad.net/cloud-init/commit/?id=da6562e2

=== End SRU Template ===

=== Abridged verification output ===
ubuntu@ip-172-31-32-16:~$ dpkg-query --show cloud-init
cloud-init  0.7.9-233-ge586fe35-0ubuntu1~16.04.2
ubuntu@ip-172-31-32-16:~$ grep CODE /etc/os-release
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial
ubuntu@ip-172-31-32-16:~$ grep -c media /etc/fstab 
0
ubuntu@ip-172-31-32-16:~$ sudo bash setup.sh
....
ubuntu@ip-172-31-32-16:~$ grep -c media /etc/fstab 
25
ubuntu@ip-172-31-32-16:~$ sudo rm -rf /var/log/cloud-init* /var/lib/cloud/
ubuntu@ip-172-31-32-16:~$ sudo reboot
....
ubuntu@ip-172-31-32-16:~$ grep -c media /proc/mounts 
24
ubuntu@ip-172-31-32-16:~$ journalctl --utc -o short-precise --no-pager | grep -c Failed.*to.*mount
1
ubuntu@ip-172-31-32-16:~$ grep -c Failed.*mount.*iso9660 /var/log/cloud-init.log
28
ubuntu@ip-172-31-32-16:~$ sudo apt install cloud-init
ubuntu@ip-172-31-32-16:~$ dpkg-query --show cloud-init
cloud-init  17.1-18-gd4f70470-0ubuntu1~16.04.1
ubuntu@ip-172-31-32-16:~$ sudo rm -rf /var/log/cloud-init* /var/lib/cloud/
ubuntu@ip-172-31-32-16:~$ sudo reboot
....
ubuntu@ip-172-31-32-16:~$ grep -c media /proc/mounts 
25
ubuntu@ip-172-31-32-16:~$ journalctl --utc -o short-precise --no-pager | grep -c Failed.*to.*mount
0
ubuntu@ip-172-31-32-16:~$ grep -c Failed.*mount.*iso9660 /var/log/cloud-init.log
0


---- Now on Zesty ----
Note: On Zesty, cloud-init only runs EC2 Datasource, so the OVF Datasource never runs
This test passes on current and -proposed version of cloud-init.


ubuntu@ip-172-31-38-68:~$ dpkg-query --show cloud-init
cloud-init	0.7.9-233-ge586fe35-0ubuntu1~17.04.2
ubuntu@ip-172-31-38-68:~$ grep CODE /etc/os-release 
VERSION_CODENAME=zesty
UBUNTU_CODENAME=zesty
ubuntu@ip-172-31-38-68:~$ cat /run/cloud-init/cloud.cfg 
datasource_list: [ Ec2, None ]
ubuntu@ip-172-31-38-68:~$ grep -c media /proc/mounts
25
ubuntu@ip-172-31-38-68:~$ journalctl -o short-precise --no-pager | grep -c Failed.*to.*mount
0
ubuntu@ip-172-31-38-68:~$ grep -c Failed.*mount.*iso9660 /var/log/cloud-init.log 
0
ubuntu@ip-172-31-38-68:~$ sudo apt update && sudo apt install cloud-init
....
ubuntu@ip-172-31-38-68:~$ sudo rm -rf /var/log/cloud-init* /var/lib/cloud/
ubuntu@ip-172-31-38-68:~$ sudo reboot
....
ubuntu@ip-172-31-38-68:~$ dpkg-query --show cloud-init
cloud-init	17.1-18-gd4f70470-0ubuntu1~17.04.1
ubuntu@ip-172-31-38-68:~$ ^Cdo reboot
ubuntu@ip-172-31-38-68:~$ grep -c media /proc/mounts
25
ubuntu@ip-172-31-38-68:~$ journalctl -o short-precise --no-pager | grep -c Failed.*to.*mount
0

=== End Abridged verfication output ===