If I have 2 VMs (web server + db server) on same physical host, how can they communicate? Being on the same host what speed can expect? Its CentOS KVM. What is the situation with SmartOS Zones where one VM can not see other VM, how do they communicate?
1 Answer
I believe it depends what mode the virtual machine adapters are in. If they are in NAT mode they probably won't have a connection between each other. Bridge mode will have a interconnection as both virtual machines will get an IP on the LAN.
During intercommunication, a half-round trip of the TCP/IP stack takes place using special network drivers installed by the VM software. The packets would never go out on the wire and probably won't even get an Ethernet frame put around them. The communication takes place solely in software but changes are it's speed is capped to the rate of the physical network card.
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Thanks for the reply micwallace. I believe then communication can stay inside onboard lan (2-port) and should keep latency minimal, correct? Any info about SmartOS VM Zones (Solaris), should there be the same logic?– GoranMar 19, 2014 at 12:41