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Vagrant

Vagrant is a must have CLI tool to manage local virtual machines using VirtualBox (or VMware Fusion or [they-name-it|(https://www.vagrantup.com/docs/providers)). You can script every aspect of creating, provisioning, saving and destroying VMs. This makes this tool perfect for DevOps testing locally on your machine or even out in a cloud.

See the Vagrant Documentation for a primer.

Installation

The installation process is well outlined at the Download Vagrant page.

For macOS users the simplest is to use brew as Vagrant is a cask and there's bash completion formula. Just run:

brew install vagrant vagrant-completion

VM config examples

@TODO

Tips & Tricks / How to...

Change names (VM name, hostname, ...)

There are at least the following levels of naming a virtual server depending on the context:

  • Machine Name: The name of the virtual server when running vagrant status or that you see when starting the VM: Bringing machine 'label' up with 'virtualbox' provider....
  • VM Name: The name of the underlying VirtualBox Machine that you see in the Virtualbx GUI Client and that is used as the name for its subdir in your VirtualBox VMs directory or that you see when running VBoxManage list vms
  • Hostname: The hostname that is set within the virtual machine AKA the running guest OS

The question inherently arises: How are these set by default and how can I customize them?
Well the documentation is not that clear about all this but fear not, you're covered with systematic examples below.

All these examples are run in a project directory named "myproject" using Vagrant-2.2.18 on VirtualBox-6.1.26r145957.

Example 1: All defaults, e.g. only specifying the base box to use

Vagrant.configure("2") do |config|
  config.vm.box = "geerlingguy/rockylinux8"
end

Result:

Machine Name VM Name Guest OS Nostname $(hostname -f)
default myproject_default_1632646458961_81073 localhost

Discussion: Vagrant chooses as the default name of the machine. The name on Virtualbox side is generated (see generating code) as <DIRECTORY>_<MACHINE_NAME>_<TIMESTAMP>_<RANDOM_NUMBER> unless explicitly set, see next examples. The hostname seems to be unchanged, e.g. the hostname of the basebox, localhost in the example.


Example 2: Explicitly define a VM and set a machine name

Vagrant.configure("2") do |config|
  config.vm.box = "geerlingguy/rockylinux8"

  # Explicitly define a vm; first argument is the machine name
  config.vm.define "webserver"
end

Result:

Machine Name VM Name Guest OS Nostname $(hostname -f)
webserver myproject_webserver_1632646458961_81073 localhost

Discussion: Now the default machine name has been overwritten with webserver. This also opens the door to mult-machine setups. As you can see the new machine name is also found in the generated vm name that is visible when running VBoxManage list vms or in the VirtualBox GUI client.


Example 3: Set the hostname of the Guest OS

Vagrant.configure("2") do |config|
  config.vm.box = "geerlingguy/rockylinux8"

  # Explicitly define a vm; first argument is the machine name
  config.vm.define "webserver"
  config.vm.hostname = "web01.test.com"
end

Result:

Machine Name VM Name Guest OS Nostname $(hostname -f)
webserver myproject_webserver_1632646458961_81073 web01.test.com

Discussion: Vagrant now sets the hostname within the guest OS to the specified value:

[vagrant@web01 ~]$ hostname -s
web01
[vagrant@web01 ~]$ hostname -f
web01.test.com


Example 4: Set the hostname of the Guest OS

Vagrant.configure("2") do |config|
  config.vm.box = "geerlingguy/rockylinux8"

  # Explicitly define a vm; first argument is the machine name
  config.vm.define "webserver"
  config.vm.hostname = "web01.test.com"
  config.vm.provider :virtualbox do |vb|
    vb.name = "webserver01"
  end
end

Result:

Machine Name VM Name Guest OS Nostname $(hostname -f)
webserver webserver01 web01.test.com

Discussion: This example, in addition, is setting the name on the virtualbox provider object, which results in a renamed VM. The VM no longer has its name generated as described in example 1, but the name is now set explicitly, see GUI client or VBoxManage list vms.

But wait... there's one more! Instead of setting name on the provider object, it's possible to have Vagrant call VBoxManage and have it set the name. This overrides all of the previous methods:

  config.vm.provider :virtualbox do |vb|
    vb.name = "webserver01"
    vb.customize ["modifyvm", :id, "--name", "web01"]
  end
In the above example, the final name of the VM will be web01.

Conclusion

It makes sense to use of these powerful possibilities of naming things. Especially it is useful to use them to namespace the virtual machines because when approaching the setup from the VM perspective you can map the VM instance to a project and the servers there in. Therefore if you set it to an absolute name using VBoxManage, I'd suggest to namespace it to the project it belongs to, something like "myproject_webserver01" or something like that.

Change machine settings like RAM, network cards, ...

These configuration options are provider-specific. For VirtualBox have a look on the respective page in the documentation. Summarized with two examples, it's possible to set almost everything by calling VBoxManage from within the Vagrantfile. The vb.customize directive calls VBoxManage and the contents of the array specified as its argument are passed straight to it. See VBoxManage --help for all the possible targets - there a lot!

Example modifying apects of a virtualbox machine

config.vm.provider "virtualbox" do |vb|
  vb.customize ["modifyvm", :id, "--cpuexecutioncap", "50"]
  vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
  vb.customize ["modifyvm", :id, "--memory", "384"]
  vb.customize ["modifyvm", :id, "--nic3", "intnet"]
  vb.customize ["modifyvm", :id, "--nic4", "intnet"]
end

# There are some convenience shortcuts for memory and CPU settings:
config.vm.provider "virtualbox" do |vb|
  vb.memory = 1024
  vb.cpus = 2
end

Setting a fixed port for SSH forwwards

Normally the ssh from the guest is automatically forwarded to port 2222 on the host. When port the latter port is already in use for another running VM, the next free post >2222 is choesen. This makes the port dependent of the order you start the VMs. While most of the time this is not a problem, you sometimes still want a fixed set of IPs for a project. Add this to your Vagrantfile for each machine you like to fix the forwarded SSH port:

  config.vm.network "forwarded_port", guest: 22, host: 12345, id: "ssh"

Source was this ticket and this blog entry.


Last update: 2022-09-26