Virtualization support in raspberry pi kernel

[hashken]

How much virtualization support is enabled in the kernel by default.

Specifically, I want to run mininet on raspberry pi and mininet.

Mininet's Github page lists this

Mininet creates virtual networks using process-based virtualization and network namespaces - features that are available in recent Linux kernels.

I want to know if the raspberry pi kernel can support this by default.

[popcornmix]

$ zcat /proc/config.gz |grep -i VIRTUALIZATION
# CONFIG_VIRTUALIZATION is not set

So, I'm guessing no. My suspicion is that virtualizion support would add some overhead to the kernel (when not being used), so I'd need some evidence that this option doesn't cause an overhead (in CPU/memory) and is wanted by a number of people.

If you want to play with config options, here would be a good start:
http://elinux.org/RPi_Kernel_Compilation

[Ferroin]

CONFIG_VIRTUALIZATION is a dummy config that activates a submenu for KVM and virtio-net drivers, neither of which should be needed for this.

If unspecified Namespace support is enabled by deefault, including network namespaces. Additionally, 'process based virtualization' is marketing gibberish for process sandboxing, which is done using standard syscalls that are always in the kernel (ie chroot).

[vk5tu]

The usual reason for running Mininet is to build a virtual network of OpenVSwitches, often controlled by an OpenFlow controller.

$ gzip -d -c /proc/config.gz | grep CONFIG_OPENVSWITCH

CONFIG_OPENVSWITCH is not set

[hashken]

Isn't openvswitch inserted as a module when you compile its source. Are you sure that there is a separate config option for that in the Linux kernel?

[vk5tu]

Isn't openvswitch inserted as a module when you compile its source.

http://git.openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=blob_plain;f=FAQ;hb=HEAD
"Q: What virtualization platforms can use Open vSwitch?
A: ... As of Linux 3.3 it is part of the mainline kernel...."

Are you sure that there is a separate config option for that in the Linux kernel?

$ grep Hardware /proc/cpuinfo
Hardware : BCM2708
$ uname -r -v
3.6.11+ #538 PREEMPT Fri Aug 30 20:42:08 BST 2013
$ gzip -d -c /proc/config.gz | grep CONFIG_OPENVSWITCH

CONFIG_OPENVSWITCH is not set

[popcornmix]

Are we happy CONFIG_OPENVSWITCH is all that is needed for mininet?
As it's a module, then no problem in enabling it.

[vk5tu]

Checking the documentation for OpenVSwitch, it looks like it also needs VLANs, and that's configured anyway.

Checking the documentation for Mininet itself:

https://github.com/mininet/mininet/blob/master/INSTALL
"5. Installation on other Linux distributions
In general, you must have:

• A Linux kernel compiled with network namespace support enabled
• ..."

$ gzip -d -c /proc/config.gz | grep CONFIG_NET_NS
CONFIG_NET_NS=y

So that looks good too.

In short, I'm confident but at the same time wouldn't be shocked if some minor option was missing. Is that a high enough bar? And if not then what do you need?

[popcornmix]

Sounds good enough for me. I'll add it with next update.

[vk5tu]

Thanks heaps. Give me a ping when the next update happens and I'll install mininet on the RPi and put the directions on my blog for others. The RPi should be a good platform for messing about with OpenFlow, as controller scaling problems can be made to happen using a average PC rather than needing professional test gear.

[popcornmix]

Please update and test:

pi@raspberrypi:~ $ uname -a
Linux raspberrypi 3.10.12+ #549 Tue Sep 24 00:41:33 BST 2013 armv6l GNU/Linux
pi@raspberrypi:~ $ zcat /proc/config.gz | grep CONFIG_OPENVSWITCH
CONFIG_OPENVSWITCH=m

[vk5tu]

Tested and works. Documented at Installing OpenVSwitch and Mininet on Raspberry Pi