ElementaryOS Basebox

Goal of this project is to create a vagrant basebox with ElementaryOS. This basebox can be used for setting up developer VMs.

Table of Contents

• Status
• Used technology
• Build the basebox
• Test the basebox
• Explanations
  • SSH configuration
  • Guest additions

Status

Because of missing resources the development is currently only done for the windows packer file elementaryos-base-windows.json

The creation of the box fails in 60% of the builds which looks like timing issues because it succeeds in the other 40% without changing anything.

Used technology

We use packer for the creation of the basebox.

Build the basebox

⚠️ The ElementaryOS installer needs a graphical user interface and because of this the creation of the basebox can't be run on headless systems

VirtualBox images can be created from several sources:

• An .iso file
• An OVF/OVA file
• An available virtual box vm

However as we do not have an already available ElementaryOS VM or an ovf/ova file we will use an iso image to create the basebox.

1. Open the file elementaryos-base-windows.json in your prefered editor
2. Locate the entry iso_checksum and provide the checksum for the downloaded iso file. It can be found in the elementary docs at the install section: https://elementary.io/en/docs/installation#verify-your-download
3. Open a terminal and navigate to the folder with the elementaryos-base-windows.json file
4. If packer isn't available via the PATH environment variable add it: set "PATH=%PATH%;C:\Program Files\Packer"
5. Create an environment variable for the path to your ElementaryOS iso file: set "ELEMENTARY_ISO_PATH=C:\\Users\\dwolff\\Setups\\elementaryos-5.1-stable.20200814.iso"
6. Make sure the packer file is valid: packer validate -var "elementaryos_iso_path=%ELEMENTARY_ISO_PATH%" elementaryos-base-windows.json
7. Build the ElementaryOS basebox: packer build -var "elementaryos_iso_path=%ELEMENTARY_ISO_PATH%" -force elementaryos-base-windows.json
   
8. Packer will now start the vm and install the os
   

Test the basebox

1. Remove a maybe already existing basebox: vagrant box remove ElementaryOS

2. Add the created box to vagrant with: vagrant box add ElementaryOS .\ElementaryOS.box
   

3. Create a new vagrant project with the ElementaryOS basebox: vagrant init -m ElementaryOS

4. Open the vagrantfile

5. Add the following:

   config.vm.provider "virtualbox" do |vb|
       # Display the VirtualBox GUI when booting the machine
       vb.gui = true
   end

6. Start the machine: vagrant up

7. You should get a running ElementaryOS

8. With vagrant ssh access enabled

References:

• https://stackoverflow.com/questions/22065698/how-to-add-a-downloaded-box-file-to-vagrant

Explanations

SSH configuration

As stated by the packer documentation the initial ssh setup needs to be done by the boot command.

If you are building from a brand-new and unconfigured operating system image, you will almost always have to perform some extra work to configure SSH on the guest machine. For most operating system distributions, this work will be performed by a boot command that references a file which provides answers to the normally-interactive questions you get asked when installing an operating system.

Unluckily for us ElementaryOS doesn't support a preseed file. Because of this we need to wait until the installation has been done and then we simulate the keys that are needed to login, open a terminal and install the ssh server. This is done the following way:

1. Install the openssh-server and wget which is needed to download the current vagrant key: sudo apt install wget openssh-server -y
2. Create the ssh directory for the vagrant user: mkdir ~/.ssh
3. Set the correct access rights for the ssh directory: sudo chmod 700 ~/.ssh
4. Change to the ssh directory: cd ~/.ssh
5. Add the current vagrant key to the authorized_keys: wget --no-check-certificate 'https://raw.github.com/mitchellh/vagrant/master/keys/vagrant.pub' -O authorized_keys
6. Add the public key of the ephemeral ssh keypair that packer created automatically: echo {{.SSHPublicKey}} >> ~/.ssh/authorized_keys
7. Set the correct access rights for the authorized_keys file: sudo chmod 600 ~/.ssh/authorized_keys
8. Make sure that the ssh file belongs to the vagrant user: chown -R vagrant ~/.ssh
9. Restart the ssh daemon to activate the changes: sudo systemctl restart sshd

You can see that all these steps are done in the boot_command:

"<wait15s>sudo apt install wget openssh-server -y<enter>",
"<wait2m>mkdir ~/.ssh<enter>",
"<wait2s>sudo chmod 700 ~/.ssh<enter>",
"<wait2s>cd ~/.ssh<enter>",
"<wait2s>wget --no-check-certificate 'https://raw.github.com/mitchellh/vagrant/master/keys/vagrant.pub' -O authorized_keys<enter>",
"<wait3s>echo {{.SSHPublicKey}} >> ~/.ssh/authorized_keys<enter>",
"<wait3s>sudo chmod 600 ~/.ssh/authorized_keys<enter>",
"<wait3s>chown -R vagrant ~/.ssh<enter>",
"<wait3s>sudo systemctl restart sshd<enter><wait3s>"

References:

• https://www.packer.io/docs/communicators/ssh
• https://www.packer.io/guides/automatic-operating-system-installs
• https://github.com/hashicorp/vagrant/tree/master/keys
• https://superuser.com/questions/287651/can-i-have-multiple-ssh-keys-in-my-ssh-folder

Guest additions

Install necessary libraries for guest additions and Vagrant NFS Share: sudo apt-get -y -q install linux-headers-$(uname -r) build-essential dkms nfs-common

References:

• https://www.packer.io/docs/provisioners/shell
• https://www.vagrantup.com/docs/providers/virtualbox/boxes