Taihsiang Ho tai271828

Running Ubuntu 16.04.1 armhf on Qemu

This is a writeup about how to install Ubuntu 16.04.1 Xenial Xerus for the 32-bit hard-float ARMv7 (armhf) architecture on a Qemu VM via Ubuntu netboot.

The setup will create a Ubuntu VM with LPAE extensions (generic-lpae) enabled. However, this writeup should also work for non-LPAE (generic) kernels.

The performance of the resulting VM is quite good, and it allows VMs with >1G ram (compared to 256M on versatilepb and 1G on versatile-a9/versatile-a15). It also supports virtio disks whereas versatile-a9/versatile-a15 only support SD cards via the -sd argument.

Get netboot files

Setting up Qemu with a tap interface

There are two parts to networking within QEMU:

The virtual network device that is provided to the guest (e.g. a PCI network card).
The network backend that interacts with the emulated NIC (e.g. puts packets onto the host's network).

Example: User mode network

Memo Date: 2018-07-18 MAAS version: 2.3

Curtin’s assumption is that a fairly rich Linux (Ubuntu) environment is booted.

But if your image is not Linux (Ubuntu) based, you could customize the image via:

Understand curtin stages
http://curtin.readthedocs.io/en/latest/topics/config.html
Stages:

Adding Sections to ELF Binaries

Suppose you need to add a section to an ELF binary to contain information gathered at compile time, but to be used at link time or run time. Here's how to add a section named .okdata and either populate it with data either after or before emitting the ELF binary.

Adding a Section After Emitting

In this case, you'll add file’s contents to an already existing binary. objcopy copies and translates object files, such that adding a new section is a matter of writing that new section’s contents into the ELF file.

(Optional) Create a simple program’s object file.

The Freenode resignation FAQ, or: "what the fuck is going on?"

IMPORTANT NOTE:

It's come to my attention that some people have been spamming issue trackers with a link to this gist. While it's a good idea to inform people of the situation in principle, please do not do this. By all means spread the word in the communities that you are a part of, after verifying that they are not aware yet, but unsolicited spam is not helpful. It will just frustrate people.

Update 3 (May 24, 2021)

A number of things have happened since the last update.

	/// Make CPUs usage as a sin wave

	#include <math.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/time.h>
	#include <unistd.h>

	const float PI = 3.1415926;
	const int TIME_SLICE = 40000; // 40 ms

	# For recent versions of Ubuntu:
	- https://www.pugetsystems.com/labs/hpc/ubuntu-22-04-server-autoinstall-iso/

	# Docs:
	- https://wiki.ubuntu.com/FoundationsTeam/AutomatedServerInstalls
	- https://wiki.ubuntu.com/FoundationsTeam/AutomatedServerInstalls/ConfigReference
	- https://cloudinit.readthedocs.io/en/latest/topics/datasources/nocloud.html
	- https://discourse.ubuntu.com/t/please-test-autoinstalls-for-20-04/15250/53

	# Download ISO Installer: