Virtualization

Jun 19, 2019
Sep 26, 2019

edublog

IMAGE GALLERY (1)

Virtualization

ovmf: OVMF “is a project to enable UEFI support for Virtual Machines”; can run wic image
Virtualization: abstraction layer which make a s/w (like OS) installed on shared h/w as if its native and completely isolated from other s/w apps.; Virtualization saved cost and reuse hardware infrastructure.¹

Sharing a common development environment with everyone on your team

Types of virtualization

Server virtualization + total isolation
- Type 1 - Hypervisor runs as native
  - KVM Kernel-Based Virtual Machine
  - VMware ESX,
  - Citrix XenServer
  - Microsoft’s Hyper-V.
- Type 2 - Hypervisor runs on top of OS
  - Oracle virtualbox
  - VMware Workstation
  - SWSoft’s Parallels Desktop.
  - LinuX Containers (LXC)/Docker
  - they dont require a full-fledged guest OS like virtual machines
Network virtualization
Storage virtualization
Service/ Application virtualization

Blacklisting a hypervisor

lsmod | grep -i kvm
echo 'blacklist kvm-intel' >> /etc/modprobe.d/blacklist.conf

# Virtualbox Guest Additions
sudo apt-get install linux-headers-$(uname -r) build-essential dkms

Vagrant

the command line utility for managing the lifecycle of virtual machines.
script the virtual machine configuration as well as the provisioning

Base images like bento are important to have clean slate starting point.

Vagrant File sections and structure


Vagrant.configure("2") do |config|
  config.vm.box = "bento/ubuntu-18.04"
  config.vm.hostname = "myUbuntuBionic"
  config.vm.synced_folder "src/", "/var/www/html"

  config.vm.provider "virtualbox" do |vb|
    vb.name = "myExcalibur"
    vb.memory = "1024"
    vb.cpus = "1"
    vb.gui = false
  end

  config.vm.provision "ansible" do |ansible|
    ansible.extra_vars = {
      variable_host: "all",
      sys_user: "vagrant",
      variable_dotfile: "true"
    }
    # ansible.verbose = "v"
    # ansible.tags=["cleanup", "dotfile"]
    # ansible.tags="cleanup"
    ansible.playbook = "dotfiles.yml"
  end
end

Vagrant base box section
provider virtualbox, Hyper-V, docker (doesnt require config.vm.box section)
Vagrant provision Ansible

Start with uncluttered basebox, install apps on top of and then package it to be reused

# List all intalled vagratn boxes
vagrant box list

FAQ

Is it possible to pass values from command line to Vagrant File?

You cannot pass any parameter to vagrant. The only way is to use environment variables

MY_VAR='my value'
vagrant up

And use ENV['MY_VAR'] in recipe.

What exactly does vagrant snapshot save ?

Vagrant snapshots just call the provider “snapshots” method. So Vagrant snapshot on virtualbox just calls virtualbox snapshot.

Package and reuse your own vagrant box

# BUILD
# 1. Downaload ot init a vagrant basebox or bentobox
# 2. Install required softwares, createa a ansible provision playbook or shellscript
# 3. Package to resue
vagrant package --output mynew.box --base NAME --vagrantfile FILE Vagrantfile to package with the box

Packer

Builder builds an OS image for various environments like
- AWS
- Azure
- DigitalOcean
- Docker
- Hyper-V
- LXC
- OpenStack
- Parallels
- QEMU
- VirtualBox
- VMware
The Template contains instructions in simple JSON format
Packer only builds images. It does not attempt to manage them in any way
The real utility of Packer comes from being able to install and configure software into the images as well, provision step.
shell provisioner to install user apps and packages
cmdline tools fits nicely in continuous delivery pipeline

consistent images for multiple platforms in parallel,

{
"builders": ["..."],
"provisioners": ["..."],
"post-processors": ["vagrant"]
}

Abbr	Expanded
AMI	Amazon Machine Image

Docker

uses kernel cgroup and namespacing via LXC.
Boot2Docker (minimal OS that can run Docker).
Docker is a program (and much more) that runs containers.
Could be automated with docker-compose or ansible

Where are docker images stored?: in your machine’s local Docker image registry.; docker info

Running docker container

docker pull ubuntu
docker run --interactive --tty ubuntu bash

Automating docker containers with Ansible

Questions

Can I build linux from source and run it from virtualbox?
Virtualbox can run ISO images, how to get ISO from compiled linux kernel?

Writing your own virtualization API?

https://docs.rs/virt/0.2.11/virt/

References

yt, diff b/w kvm,virtualization ^[return]