How to Activate nested virtualization on a VM in ESXi

I am consolidating here a couple of instructions (here and here, and here for the ESXi shell activation part) I found to activate nested virtualization on a VM in an ESXi server without access to the server vmware part. You need to:

  1. Check that the ESXi will support it (BIOS, hypervisor…). Look for nestedHVSupported in the output of https://[your-esxi-host-ip-address]/mob/?moid=ha-host&doPath=capability after authenticating.
  2. Enable the ESXi shell (you need this so that you can edit the VM definition later):
    1. Use the vSphere Client to enable local and remote access to the ESXi Shell:
    2. Log in to a vCenter Server system using the vSphere Client.
    3. Select the host in the Inventory panel.
    4. Click the Configuration tab and click Security Profile.
    5. In the Services section, click Properties.
    6. Select ESXi Shell from this list:
    7. Click Options and select Start and stop manually. Note: When you select Start and stop manually, the service does not start when you reboot the host. If you want the service to start when you reboot the host, select Start and stop with host.
    8. Click Start to enable the service.
    9. Click OK.
  3. Log in to the shell with credentials and Alt-F1
  4. Add the vhv.enable = “TRUE” at the end of the .vmx file corresponding to the VM that you want to activate the nested virtualization on…
  5. Identify the  hypervisor vm ID and reload it’s configuration with the vim-cmd esxi command:

    ~ # vim-cmd vmsvc/getallvms | grep -i ubun 44 VM6-Ubuntu-KVM [datastore1] VM6-Ubuntu-KVM/VM6-Ubuntu-KVM.vmx ubuntu64Guest vmx-08

    ~ # vim-cmd vmsvc/reload 44

  6. Check within the VM as root that it sees the “hardware virtualization” with:

    egrep -c ‘(vmx|svm)’ /proc/cpuinfo

OpenStack nova network multihost with external gateway. Solving a metadata issue in Kilo. The power of ebtables.

In a recent project we found the issue that the metadata service running on the compute node was not reachable by the VMs running on it.

In the project we use Ubuntu 14.04.3 and vanilla OpenStack (kilo). The implementation uses nova network (with VLANs) in multihost mode with an external gateway for each VLAN. The latter can be achieved by:

  • configuring nova in /etc/nova/nova.conf with the option:


  • and by supplying a file /etc/dnsmasq-nova.conf where you give the external gateway configuration for the different networks (demo-net, in the following example):


In our configuration the VMs are not able to reach the metadata service when being provisioned. In other words is not properly DNATed to hypervisor_IP:8775 for the VM.

The underlying reason is that since the VM has a different gateway (the external gateway) than the hypervisors VLAN IP, there will be no IP routing (it is only a L2 not an L3) so the  PREROUTING chain in table NAT will not be traversed by these packets.

To solve this issue we force these packets to traverse the IP routing with an ebtables rule like:

ebtables -t nat -I PREROUTING -p ipv4  –ip-dst –ip-protocol 6 –ip-dport 80 -j redirect –redirect-target ACCEPT

Enjoy the ebtables! Find more examples and documentation in here.

Exposing Infiniband (or any PCI device) to the VMs on an OpenStack Cloud

For a recent project we (me and Wuming) had to provide an OpenStack cloud in which the raw infiniband protocol would be available to the VMs running on the cloud.

The installation was done on Ubuntu 14.04.3 with vanilla OpenStack. Exposing infiniband requires quite a few steps and reading/googling quite a bit so I will document it here in case somebody needs to do the same.

To expose the native hardware interfaces to the VM:

  • The BIOS of the computer has to support it (you may need to activate Intel VT-d (or AMD I/O Virtualization Technology), as with virtualization extensions, it may be off by default). Explore the BIOS of your servers to activate it if necessary;
  • The Infiniband cards themselves have to support it. Look for SR-IOV in an “lspci -v” output as below:

$ sudo lspci -v |grep -A40 Mellanox
04:00.0 Network controller: Mellanox Technologies MT27520 Family [ConnectX-3 Pro]
Subsystem: Hewlett-Packard Company Device 22f5
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at 96000000 (64-bit, non-prefetchable) [size=1M]
Memory at 94000000 (64-bit, prefetchable) [size=32M]
Capabilities: [40] Power Management version 3
Capabilities: [48] Vital Product Data
Capabilities: [9c] MSI-X: Enable+ Count=128 Masked-
Capabilities: [60] Express Endpoint, MSI 00
Capabilities: [100] Alternative Routing-ID Interpretation (ARI)
Capabilities: [148] Device Serial Number 24-be-05-ff-ff-b6-e3-40
Capabilities: [108] Single Root I/O Virtualization (SR-IOV)
Capabilities: [154] Advanced Error Reporting
Capabilities: [18c] #19
Kernel driver in use: mlx4_core


  • The kernel in linux needs to be configured by passing the option intel_iommu=on. You can do it by editing the file /etc/default/grub so that it contains the option GRUB_CMDLINE_LINUX_DEFAULT=”intel_iommu=on” and running update-grub;
  • The Infiniband cards need to be configured to expose the VFs. Edit the file /etc/modprobe.d/mlx4_core.conf to contain options like: options mlx4_core num_vfs=16 (or as high as your card supports. One VM will take one VF so this could be the limiting factor as of how many VMs can be deployed per compute node). You can find more documentation for the mellanox cards in the Mellanox Linux User Manual Mellanox_OFED_Linux_User_Manual_v3.10 or here since you may need to enable this option (in our case it was enabled already);
  • Nova has to be configured to allow pci passthrough. Follow the documentation in here on “How to prepare the environment”
    • Configure the nova (find the Virtualized Interfaces vendor_id and product_id for your case by running an lspci -vn)
    • Create a flavor that automatically adds the interface to the VM

And now… Just launch a VM and log in! You should see the Infiniband card!

5 TED talks to inspire and get you out searching for more

Here you have 5 TED talks that will inspire you and will make you move and search for more!

Manu Prakash: A 50-cent microscope that folds like origami

Steve Jobs: How to live before you die

Elon Musk: The mind behind Tesla, SpaceX, SolarCity …

Simon Sinek: How great leaders inspire action

Jack Andraka: A promising test for pancreatic cancer … from a teenager

If privacy is important for you, open a protonmail account

If privacy is important for you, you will wish to have a protomail account. They provide a very good privacy in hosted email, if you of course believe their claims, which I have no reason not to.

To celebrate the 1st year anniversary, protonmail has created a special link that allows instant account creation:

This will only last for a limited amount of time.

Happy private e-mailing.

A very nice overview talk on OpenStack HA

This talk: “Deep Dive Into a Highly Available OpenStack Architecture“, given at the recent OpenStack Summit in Vancouver, provides an unusual nice balance between overview and details!

It will provide you with a sound understanding of the architecture and services of OpenStack, specially the later, and how to make the OpenStack services Highly available.

It does not cover Heat or Ceilometer but once you understand the other services it is not complicated to use the same architectural concepts.

I highly recommend watching it!

How to fix an installation issue with the Openstack command line tools in OS X 10.9.5 and 10.9.4

If you follow the Openstack  command line client tools installation guide you will have an issue. For example to install the keystone tools (Mind root access, add sudo when needed):

#easy_install pip

#pip install python-keystoneclient

This will result in the error when trying to execute the tools (with nova you would get the same error!):

$ keystone –list

Traceback (most recent call last):

File “/usr/local/bin/keystone”, line 7, in <module>

from import main

File “/Library/Python/2.7/site-packages/keystoneclient/”, line 37, in <module>

__version__ = pbr.version.VersionInfo(‘python-keystoneclient’).version_string()

File “/Library/Python/2.7/site-packages/pbr/”, line 78, in version_string

for part in self.release_string().split(‘.’):

File “/Library/Python/2.7/site-packages/pbr/”, line 70, in release_string

self.release = self._get_version_from_pkg_resources()

File “/Library/Python/2.7/site-packages/pbr/”, line 62, in _get_version_from_pkg_resources

return packaging.get_version(self.package)

File “/Library/Python/2.7/site-packages/pbr/”, line 870, in get_version

raise Exception(“Versioning for this project requires either an sdist”

Exception: Versioning for this project requires either an sdist tarball, or access to an upstream git repository. Are you sure that git is installed?

The solution: install also the distribute package:

 pip install –upgrade distribute



Cloudlynx. A Highly Compliant and Secure Swiss Cloud

As the website for this new company Cloudlynx states. They are a Highly Compliant Swiss Cloud. They will go to an encrypted experience of the Cloud.

They will not have the problem with data being hosted in the US and thus being subject to the patriot act. For many European this should be attractive.

Also the privacy rules that characterise Switzerland should be very appealing.