Add VirtualBox 5 support

[hheimbuerger]

Some improvements to make boot2docker more compatible with VirtualBox 5.

There's still some issues, e.g. that you have to create the exact expected host-only network yourself to make boot2docker-cli pick it up without issues.
But at least this allowed me to bootstrap a boot2docker VM on Windows 10 with VirtualBox 5 (VBox4 doesn't work very well on Windows 10, specifically no host-only networks).

I don't think this a PR ready for merging right away. I've never wrote any go before and didn't set up a proper dev environment either. I just did the minimum steps to get a boot2docker VM up and running. But I figured I might still submit this, maybe there's something useful for you in here.

PS: I know you consider boot2docker-cli deprecated, but docker-machine has the same issues with VirtualBox 5 and its dev environment requires to have docker already running, which was a hen and egg problem for me.

[hheimbuerger]

Note that the VM this currently creates has 8 CPUs and 2048 MiB base memory, both of which are probably a bit excessive.

It also only allocates 8 MiB of video memory, while VirtualBox complains that it needs at least 12.

For now, I'm just taking care of these issues manually with the VBox GUI.

[jmorganca]

Remove before merging?

[hheimbuerger]

Yeah, probably a good idea.

[jmorganca]

This fixed VBox 5 issues for me. Thanks for this PR!

• See GH comments
• Squash commits and sign it off see this

I've added some notes.

[hheimbuerger]

Did it also create a VM with the maximum available CPUs and huge memory requirements for you?

[hheimbuerger]

Something's not right yet. I regularly have VMs which error out during boot (so I have to recreate them with boot2docker-cli) and right now, I can't manage to have the docker client connect into a fresh VM anymore.

An error occurred trying to connect: Get https://192.168.59.104:2376/v1.19/containers/json: dial tcp 192.168.59.104:2376: ConnectEx tcp: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

[hheimbuerger]

It stopped mounting the user directory as a shared folder (even though there's no error and it's not aborting when running boot2docker-cli). I suspect that's part of the problem. I'm getting lots of errors during boot now, for example:

sysctl: cannot stat /proc/sys/net/ipv6/conf/all/forwarding: No such file or directory
sysctl: setting key "cannot stat %s": No such file or directory
sysctl: "cannot stat %s" is an unknown key
sysctl: setting key "cannot stat %s": No such file or directory
Segmentation fault

and

Calling ioctl() to re-read partition table
partprobe: error while loading shared libraries: libdevmapper.so.1.02: cannot open shared object file: No such file or directory

and

[[1;32mSetting hostname to [[1;35mboot2docker[[0;39m [[1;32mDone.[[0;39m
mv: can't rename '/usr/local/etc/ssh/ssh_config.example': No such file or directory
mv: can't rename '/usr/local/etc/ssh/sshd_config.example': No such file or directory
grep: /usr/local/etc/ssh/sshd_config: No such file or directory

[hheimbuerger]

The cause of my connection problems was local routes and is now fixed.

The above errors (including the segfault) do still occur in the boot2docker VM. Not sure if that's VBox5-specific or if they are normal to occur in 1.7.0 (but segfaulting always feels wrong).

[jmorganca]

I'll give it another go to try - sorry for the delay!

[hheimbuerger]

Now I'm having my shared folders syncing incompletely (symptom: a simple text file opens fine with vi inside the boot2docker VM, but the last 20 characters are missing when reading the same file with cat), so this is definitely not ready for primetime yet.