Gather network information using qemu-guest-agent

[OpenNebulaProject]

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Author Name: OpenNebula Systems Support Team (OpenNebula Systems Support Team) Original Redmine Issue: 5255, https://dev.opennebula.org/issues/5255 Original Date: 2017-07-19

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Use a system similar to vCenter to gather network information for VMs that do not use IPs generated by OpenNebula.

[rsmontero]

Related to #1529

[vholer]

Example use:

virsh # domifaddr one-291532 --source agent --full
 Name       MAC address          Protocol     Address
-------------------------------------------------------------------------------
 lo         00:00:00:00:00:00    ipv4         127.0.0.1/8
 lo         00:00:00:00:00:00    ipv6         ::1/128
 eth0       02:00:0a:0a:02:01    ipv4         10.10.2.1/8
 eth0       02:00:0a:0a:02:01    ipv6         fe80::aff:fe0a:201/64

[rightkick]

+1 for this. It is convenient to retrieve such IP details in this way. This will cover cases such as having deployed VMs with or without context. At the first case one verifies that contextualization is working while at the later one can access IP details even when no contextualization is configured.