Home » VMware » VCP550D » Which caused this issue?
A number of virtual machines in a vSphere 5.5 DRS cluster are connected to the same virtual switch port group. After several of these VMs are migrated to another host, an administrator notices that they have lost network connectivity. The Events tab in vCenter Server shows this error message:
Failed to initialize ethernet0.
The vmkernel log file on the host running the affected VMs contains this message:
Can’t connect device:’port group name’: Out of resources.
Which caused this issue?
A. Network I/O Control was enabled.
B. The DRS cluster containing the VMs was set to Fully Automated with the Migration Threshold set to Conservative.
C. There were insufficient uplinks configured on the virtual switches.
D. The virtual switch port allocation was changed from the default setting.
Correct Answer: D
Explanation/Reference:
Explanation:
D: A port group is added to a vSphere switch to create a switch network for you virtual machines. Thus if the switch’s port allocation was changed from the default setting it would affect connectivity since the virtual machines in the DRS cluster are connected to the same virtual switch port group initially and afterward some are migrated to another host in the same cluster which means that the virtual machines would still use the same switch port group.
Incorrect Answers:
A: When network I/O control is enabled, distributed switch traffic is divided into predefined network resource pools. This will not cause non-connectivity.
B: These settings are used to regulate the cluster balance with regard to host CPU and memory loads; and not connectivity issues as experienced in this case.
C: Without uplinks a virtual switch cannot provide connectivity for the VMkernel or the VMs. In other words the uplinks provide the external connectivity to the vSwitches.
References:
Lowe, S. & Marshall, N., Mastering VMWare vSphere 5.5, Wiley and Sons, Indianapolis, 2014, pp. 194-196
