VM Orchestration¶

How to define and launch Virtual Machines

experiment design¶

These are some of the things you'll need to think about before building your environment

Topology - what does the environment look like?
VM images - which OS? Preload software, or push at runtime?
Instrumentation and data capture - how do we measure and collect the data we want?

The answers to these questions impact how you will deploy your VMs. Such as

The image used for the VM
Network configuration
physical charactersitics of the VM
- cpu
- memory
- etc.

Configure, Launch, Start¶

Once you have settled on what the VM properties in your experiment should be, you'll need a way to define those properties and deploy those VMs. minimega provides an easy way to define and deploy your VMs.

There are essentially 3 steps to deploying VMs in minimega:

CONFIGURE VM properties with minimega's 'vm config' API
LAUNCH a number of VMs with the configuration described
Repeat steps 1 and 2 until all VMs in your experiment are launched.
START all the VMs

vm config - the heart of minimega¶

Use 'vm config' to define the properties of the VMs you want to launch such as
- memory
- vcpus
- net
- KVM or Container?
minimega supports a variety of VM images
- disk (qcow, qc2, etc.)
- CD (.iso)
- Kernel/Initrd (kvm)
- Filesystem (container)

For a detailed explanation of Virtual Machine Types, see the Virtual Machine Types article.

Configuring a VM¶

minimega requires very little configuration to launch a VM
only a vm image is required to be set in order to launch
from start to finish there are exactly three steps to launching a VM
- start minimega
- set an image in vm config
- launch and start the vm(s)
We've already covered starting minimega, let's look at the other two

Configuring and Launching VMs¶

Set an image with vm config using one of the below

disk.mm

# uncomment the one you would like to use
#vm config cdrom myOS.iso
#vm config disk diskImage.qc2
#vm config kernel mykernel.kernel
#vm config initrd myInitrd.initrd
#vm config filesystem path/to/myfs/

Download this example

Launch a number of VMs you specify, and minimega will name them automatically.
- Alternatively, you can specify the names, and even the numerical range that is appended:

launch.mm

vm launch kvm 5
vm launch kvm foo
vm launch kvm bar[1-5]

Download this example

¶

or launch containers

launch_c.mm

vm launch container 1
vm launch container footainer
vm launch container bartainer[1-5]

# The VMs will be in the BUILDING state

Download this example

A state of ERROR would mean something failed.
- use 'flush' to clear out VMs in the ERROR or QUIT states

flush.mm

# This will flush any VMs in Error or Quit state
vm flush

Download this example

This lets you adjust your config and correct any issues to try again.

Starting vms¶

We are not running yet! To start the VM use:

start.mm

vm start foo
vm start bar[1-3]
vm start all

Download this example

This puts the VM in the RUNNING state
Use 'vm info' to confirm running state and other details:

vminfo.mm

# For full details run:
vm info
# For select details, run:
.columns name,state,snapshot,cdrom vm info
# Try modifying the above selected columns and run again!

Download this example

Stopping VMs¶

mdk.mm

vm stop foo
vm stop bar[1-3,5]
vm stop all
# 'vm stop' puts the specified VM(s) in the PAUSED state
vm info

vm kill foo
vm kill bar[1-5]
vm kill all
# 'vm kill' puts the specified VM(s) in the QUIT state
vm info

# 'vm flush' will clear all VMs in the QUIT or ERROR state
vm flush

Download this example

VM States¶

A Closer Look at VM CONFIG¶

There are many configuration options available to you, so we will try to focus on the common options first. You can find a comprehensive list at the end of this module.

Memory:           2048
VCPUs:            1
Networks:         []
Snapshot:         true
Tags:             {}

Memory: Configures the amount of physical memory to allocate (in megabytes).
VCPUs: Configures the number of virtual CPUs to allocate for a VM.
Networks: Specify Network(s) by VLAN, MAC address, and network device (e.g. e1000)
Snapshot: default = true. Set false if you want changes made to the VM to be persistent.
Tags: User-specified tags (<key> [value]). Ex. vm config tags router true

KVM configuration:¶

Disk Paths:         []
CDROM Path:
Kernel Path:
Initrd Path:

Disk Paths: Attach one or more disks to a vm. Any supported by QEMU is valid.
CDROM Path: Attach a cdrom to a VM. Will automatically be set as boot device.
Kernel Path: Attach a kernel image to a VM.
Initrd Path: Attach an initrd image to a VM.

Note: One of either Disk, CD, or Kernel+Initrd must be specified to launch a kvm

Container configuration:¶

Filesystem Path:
Hostname:
Init:            [/init]
Pre-init:

Filesystem Path: Configure the filesystem to use for launching a container.
Hostname: Set a hostname for a container before launching the init program.
Init: Set the init program and args to exec into upon container launch.

Note: Filesystem is required to launch a container

Base Directory¶

minimega creates a number of files that describe and allow control of virtual machines. By default, it keeps these files in "/tmp/minimega" unless modified via the -base flag at startup.

Likewise, minimega uses /tmp/minimega/files/ as a default directory for working with files. If you reference files, in vm config for example, it will look for those files relative to this base directory.

If you attempt to run minimega while another instance is already running, it will exit with an error that the base directory is already in use.

The base directory is important when connecting to an already running minimega instance with the attach or e flags, as those modes both look for the minimega command socket in a specified base directory.

A simple example¶

simple.mm

# As an exercise, let's launch a few VMs of various types

# Let's start by setting some properties
vm config vcpu 4
vm config memory 8196 # MB
vm config net 100 # vlan 100
vm config disk foo.qc2 # defaults to /tmp/minimega/files/foo.qc2
vm launch kvm foo[1-5]
# Now to use a different image
clear vm config disk
vm config kernel miniccc.kernel
vm config initrd miniccc.initrd
vm launch kvm foo[6-10]
# Now some containers
vm config memory 4098
vm config tags container=true
vm config filesystem /tmp/minimega/files/minicccfs
# both filesystem and kernel/initrd are set, but that is ok
vm launch container bar[1-5]
vm start all

Download this example

The Results in miniweb:¶

VM Config - the full list¶

host: VM configuration:
Memory:           2048
VCPUs:            1
Networks:         []
Snapshot:         true
UUID:
Schedule host:
Coschedule limit: -1
Colocate:
Backchannel:      true
Tags:             {}

Memory: Configures the amount of physical memory to allocate (in megabytes).
VCPUs: Configures the number of virtual CPUs to allocate for a VM.
Networks: Specify Network(s) by VLAN, MAC address, and network device for qemu to use (e.g. e1000)

¶

Snapshot: true = changes to VM are not persistent.
UUID: Assign a UUID if desired, otherwise a random value is assigned
Schedule host: Set a host where the VM should be scheduled.
Coschedule limit: Specify max # of VMs that can be scheduled on the same host as the VM. -1 = no limit; 0 = vm scheduled by itself
Colocate: Colocate this VM with another VM
Backchannel: Enable/disable serial command and control layer for this VM.
Tags: User-specified tags (<key> [value]). Ex. vm config tags router true

KVM configuration:¶

Migrate Path:
Disk Paths:         []
CDROM Path:
Kernel Path:
Initrd Path:
Kernel Append:      []
QEMU Path:          kvm
QEMU Append:        []
SerialPorts:        0
Virtio-SerialPorts: 0
Machine:
CPU:                host
Cores:              1

Migrate Path: A migration image to boot with that was previously generated with 'vm migrate'
Disk Paths: Attach one or more disks to a vm. Any supported by QEMU is valid.

¶

CDROM Path: Attach a cdrom to a VM. Will automatically be set as boot device.
Kernel Path: Attach a kernel image to a VM.
Initrd Path: Attach an initrd image to a VM.
Kernel Append: Add an append string to a kernel set with vm kernel.
QEMU Path: Set the QEMU binary name to invoke.
QEMU Append: Add additional arguments to be passed to the QEMU instance.
SerialPorts: Specify the serial ports that will be created for the VM to use.
Virtio-SerialPorts: Specify the virtio-serial ports that will be created for the VM to use
Machine: Specify the machine type. See 'qemu -M help' for supported machine types.
CPU: Set the virtual CPU architecture. See 'qemu -cpu help' for supported CPUs.
Cores: Set the number of CPU cores per socket.

Container configuration:¶

Filesystem Path:
Hostname:
Init:            [/init]
Pre-init:
FIFOs:           0
Volumes:

Filesystem Path: Configure the filesystem to use for launching a container.
Hostname: Set a hostname for a container before launching the init program.
Init: Set the init program and args to exec into upon container launch.
Pre-init: allows running processes before isolation mechanisms are enabled.
FIFOs: Set the number of named pipes to include in the container for container-host communication.
Volumes: Attach one or more volumes to a container.

Next Up...¶

Module 04: Experiment Visualization