Setup nested ESXi as below:
1. Physical host has 2 sockets, 8 cores/socket for a total of 32 logical processors and 64GB of RAM
2. Physical host runs ESXi 5.5.0.
3. Nested ESXi (as VM) runs ESXi 5.1.0 update 2 [followed the instructions in http://www.virtuallyghetto.com/2012/08/how-to-enable-nested-esxi-other.html ]
4. Nested ESXi is provisioned with 2 sockets, 4 cores/socket and 2 GB of vRAM
5. Created 10 linux VMs on the nested ESXi host (each with 1 vCPU + 48 MB vRAM)
6. When powering-on the 7th VM, below error message is seen
Could not power on VM : @&!*@*@(msg.vmk.status.VMK_VCPU_LIMIT_EXCEEDED)Number of running VCPUs limit exceeded.
Max VMs limit reached: 6 (2048 worlds)
I have looked at below discussions
Former thread suggests increasing vRAM as a solution. Tried doubling the vRAM from 2 GB to 4 GB and the same issue is hit when powering-up the 16th VM
Is 6 VMs (or 15 VMs with 4GB vRAM) the best I can provision in this setup? I need to keep the vRAM at 2GB so as to fit as many nested ESXi hosts on this server.
2Gb is very little for ESX and is probably the reason for you running into this.
I would usually recommend 8GB for ESX.