VLAN is not suitable for large-scale cloud

Although openstack is deployed in VLAN mode, it is not suitable for large-scale clouds. There are at least the following obvious problems:

1. the VLAN is 12 bits, and the VLAN 4096 is the upper limit of isolation. Private cloud should be enough at present, but public cloud will have problems.

2. suppose we have 100 physical nodes, and each physical node virtualizes 50 virtual machines, there will be at least 5 k Virtual Machine MAC (if the virtual machine is multiple NICs, more ), generally, the MAC address table of a vswitch cannot afford this scale. After the MAC address table overflows, a large amount of flooding traffic will be generated. Considering that there may be more physical nodes, scalability is a problem.

3. If we use VLAN, the physical port responsible for computing inter-node communication is implemented as a trunk. In order to facilitate the configuration, it is generally configured with a VLAN segment in advance, such as the vlan1000-2000, such over provision, it will obviously lead to additional broadcast traffic. Flood of broadcast packets such as ARP.

Anything else? How to solve?

To be continue...

VLAN is not suitable for large-scale cloud