Remove uart1 connection from Vagrant boxes

[John Chittum]

In discussions on lp: 1874453, a user (haggai-eran) ran into an issue with File::NULL being turned into an absolute path on a derivative image rather than staying the Ruby handling of File::NULL.

In comment 54 during verification (https://bugs.launchpad.net/cloud-images/+bug/1874453/comments/54), nginer tried disabling uart1 connection entirely. He noted that previously this did not work on releases, however, in his current setup it did work.

This led to me (jchittum) investigating removing configuring uart1 in CPC's base Vagrantfile (https://git.launchpad.net/livecd-rootfs/tree/live-build/ubuntu-cpc/hooks.d/base/vagrant.binary#n149). An initial test using the ubuntu/master branch of livecd-rootfs successfully booted. I also tested a user's ability to enable and add a serial debugging file and it worked.

I propose the removal of the entire `config.vm.provider "virtualbox" do |vb|` stanza from the base Vagrantfile in Groovy and newer images, with further testing needed for possible SRU.

[John Chittum (jchittum)]

disabling `uart1` leads to `cloud-init` failures when writing keys:

```
2020-10-26 18:37:30,888 - util.py[WARNING]: Running module keys-to-console (<module 'cloudinit.config.cc_keys_to_console' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_keys_to_console.py'>) failed
2020-10-26 18:37:30,889 - util.py[DEBUG]: Running module keys-to-console (<module 'cloudinit.config.cc_keys_to_console' from '/usr/lib/python3/dist-packages/cloudinit/config/cc_keys_to_console.py'>) failed
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 402, in multi_log
    wfh.flush()
OSError: [Errno 5] Input/output error

During handling of the above exception, another exception occurred:

OSError: [Errno 5] Input/output error

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/cloudinit/stages.py", line 848, in _run_modules
    ran, _r = cc.run(run_name, mod.handle, func_args,
  File "/usr/lib/python3/dist-packages/cloudinit/cloud.py", line 54, in run
    return self._runners.run(name, functor, args, freq, clear_on_fail)
  File "/usr/lib/python3/dist-packages/cloudinit/helpers.py", line 185, in run
    results = functor(*args)
  File "/usr/lib/python3/dist-packages/cloudinit/config/cc_keys_to_console.py", line 69, in handle
    util.multi_log("%s\n" % (stdout.strip()),
  File "/usr/lib/python3/dist-packages/cloudinit/util.py", line 402, in multi_log
    wfh.flush()
OSError: [Errno 5] Input/output error

```

We've had discussions regarding default console connections (specifically console=ttyS0) at various points. It appears cloud-init will have this specific issue when no console is connection is available at boot, at least for NoCloud

[John Chittum (jchittum)]

This appears related to : https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1473527

[John Chittum (jchittum)]

2.5 years later, no comments or "also affects me." The workaround in place is sub-optimal, but we're not hearing chatter of wanting something different.

Setting as won't fix for cloud-images, as the workaround seems to be "accepted."