Prevalidates hardware resources on Linux platforms for Virtualbox and
VMware builders. This is currently only available on Linux, as enabling
for both Darwin and Windows platforms, relies on cgo bindings that would
prevent effective cross-compilation.
Packer will now fail to build and validate templates if the template is
requesting that the VM to be created would allocate more system
resources than the host system has available.
This _however_ doesn't catch parallel builds that overflow the hosts
resources, will probably still need a better error message for VM's
failing to boot in that case.
Example Outputs:
```
$ $GOPATH/bin/packer build -debug ./vmware-iso.json
Debug mode enabled. Builds will not be parallelized.
vmware-iso output will be in this color.
2 error(s) occurred:
* Unavailable Resources: RAM - Requested - 204800000MB - Available 21721MB
* Unavailable Resources: Disk - Requested - 4000000000MB - Available 76701MB
```
```
$ $GOPATH/bin/packer build -debug ./vbox-iso.json
Debug mode enabled. Builds will not be parallelized.
virtualbox-iso output will be in this color.
2 error(s) occurred:
* Unavailable Resources: RAM - Requested - 10240000MB - Available 21721MB
* Unavailable Resources: Disk - Requested - 1000000000MB - Available 76701MB
```
The Vagrant post processor expects the DO artifact ID to look like an
AWS artifact ID (region_id:snapshot_id). This commit makes the DO
artifact Id() function output this format.
* I suspect the logic written for checking if the vm has been destroyed is incorrect. The test will come back from the esx server indicating that the vm is gone as it should, but the logic I believe is reversed so we never hit the break in the if statement
* Feedback is MORE than welcome
https://ext4.wiki.kernel.org/index.php/Ext4_VM_Images does not
recommends to dd zero file and deletes it, but in case of enabling
discards and qcow2 image we can recreate qcow2 file with less used
space.
Also qemu-img able to enable compression for qcow2 files, that
sometimes may be useful because it natively supported by qemu.
Signed-off-by: Vasiliy Tolstov <v.tolstov@selfip.ru>
