In this article by Wasim Ahmed, the author of the book Mastering Proxmox - Second Edition, we will see Virtualization as we all know today is a decade old technology that was first implemented in mainframes of the 1960s. Virtualization was a way to logically divide the mainframe's resources for different application processing. With the rise in energy costs, running under-utilized server hardware is no longer a luxury. Virtualization enables us to do more with less thus save energy and money while creating a virtual green data center without geographical boundaries.

(For more resources related to this topic, see here.)

A hypervisor is a piece software, hardware, or firmware that creates and manages virtual machines. It is the underlying platform or foundation that allows a virtual world to be built upon. In a way, it is the very building block of all virtualization. A bare metal hypervisor acts as a bridge between physical hardware and the virtual machines by creating an abstraction layer. Because of this unique feature, an entire virtual machine can be moved over a vast distance over the Internet and be made able to function exactly the same. A virtual machine does not see the hardware directly; instead, it sees the layer of the hypervisor, which is the same no matter on what hardware the hypervisor has been installed.

The Proxmox Virtual Environment (VE) is a cluster-based hypervisor and one of the best kept secrets in the virtualization world. The reason is simple. It allows you to build an enterprise business-class virtual infrastructure at a small business-class price tag without sacrificing stability, performance, and ease of use. Whether it is a massive data center to serve millions of people, or a small educational institution, or a home serving important family members, Proxmox can handle configuration to suit any situation.

If you have picked up this article, no doubt you will be familiar with virtualization and perhaps well versed with other hypervisors, such VMWare, Xen, Hyper-V, and so on. In this article and upcoming articles, we will see the mighty power of Proxmox from inside out. We will examine scenarios and create a complex virtual environment. We will tackle some heavy day-to-day issues and show resolutions, which might just save the day in a production environment. So, strap yourself and let's dive into the virtual world with the mighty hypervisor, Proxmox VE.

Understanding Proxmox features

Before we dive in, it is necessary to understand why one should choose Proxmox over the other main stream hypervisors. Proxmox is not perfect but stands out among other contenders with some hard to beat features. The following are some of the features that makes Proxmox a real game changer.

It is free!

Yes, Proxmox is free! To be more accurate, Proxmox has several subscription levels among which the community edition is completely free. One can simply download Proxmox ISO at no cost and raise a fully functional cluster without missing a single feature and without paying anything. The main difference between the paid and community subscription level is that the paid subscription receives updates, which goes through additional testing and refinement. If you are running a production cluster with real workload, it is highly recommended that you purchase support and licensing from Proxmox or Proxmox resellers.

Built-in firewall

Proxmox VE comes with a robust firewall ready to be configured out of the box. This firewall can be configured to protect the entire Proxmox cluster down to a virtual machine. The Per VM firewall option gives you the ability to configure each VM individually by creating individualized firewall rules, a prominent feature in a multi-tenant virtual environment.

Open vSwitch

Licensed under Apache 2.0 license, Open vSwitch is a virtual switch designed to work in a multi-server virtual environment. All hypervisors need a bridge between VMs and the outside network. Open vSwitch enhances features of the standard Linux bridge in an ever changing virtual environment. Proxmox fully supports Open vSwitch that allows you to create an intricate virtual environment all the while, reducing virtual network management overhead. For details on Open vSwitch, refer to http://openvswitch.org/.

The graphical user interface

Proxmox comes with a fully functional graphical user interface or GUI out of the box. The GUI allows an administrator to manage and configure almost all the aspects of a Proxmox cluster. The GUI has been designed keeping simplicity in mind with functions and features separated into menus for easier navigation. The following screenshot shows an example of the Proxmox GUI dashboard:

KVM virtual machines

KVM or Kernel-based virtual machine is a kernel module that is added to Linux for full virtualization to create isolated fully independent virtual machines. KVM VMs are not dependent on the host operating system in any way, but they do require the virtualization feature in BIOS to be enabled. KVM allows a wide variety of operating systems for virtual machines, such as Linux and Windows. Proxmox provides a very stable environment for KVM-based VMs.

Linux containers or LXC

Introduced recently in Proxmox VE 4.0, Linux containers allow multiple Linux instances on the same Linux host. All the containers are dependent on the host Linux operating system and only Linux flavors can be virtualized as containers. There are no containers for the Windows operating system. LXC replace prior OpenVZ containers, which were the primary containers in the virtualization method in the previous Proxmox versions. If you are not familiar with LXC and for details on LXC, refer to https://linuxcontainers.org/.

Storage plugins

Out of the box, Proxmox VE supports a variety of storage systems to store virtual disk images, ISO templates, backups, and so on. All plug-ins are quite stable and work great with Proxmox. Being able to choose different storage systems gives an administrator the flexibility to leverage the existing storage in the network. As of Proxmox VE 4.0, the following storage plug-ins are supported:

• The local directory mount points
• iSCSI
• LVM Group
• NFS Share
• GlusterFS
• Ceph RBD
• ZFS

Vibrant culture

Proxmox has a growing community of users who are always helping others to learn Proxmox and troubleshoot various issues. With so many active users around the world and through active participation of Proxmox developers, the community has now become a culture of its own. Feature requests are continuously being worked on, and the existing features are being strengthened on a regular basis. With so many users supporting Proxmox, it is sure here to stay.

The basic installation of Proxmox

The installation of a Proxmox node is very straightforward. Simply, accept the default options, select localization, and enter the network information to install Proxmox VE. We can summarize the installation process in the following steps:

1. Download ISO from the official Proxmox site and prepare a disc with the image (http://proxmox.com/en/downloads).
2. Boot the node with the disc and hit enter to start the installation from the installation GUI. We can also install Proxmox from a USB drive.
3. Progress through the prompts to select options or type in information.
4. After the installation is complete, access the Proxmox GUI dashboard using the IP address, as follows:

   https://<proxmox_node_ip:8006

5. In some cases, it may be necessary to open the firewall port to allow access to the GUI over port 8006.

The advanced installation option

Although the basic installation works in all scenarios, there may be times when the advanced installation option may be necessary. Only the advanced installation option provides you the ability to customize the main OS drive.

A common practice for the operating system drive is to use a mirror RAID array using a controller interface. This provides drive redundancy if one of the drives fails. This same level of redundancy can also be achieved using a software-based RAID array, such as ZFS. Proxmox now offers options to select ZFS-based arrays for the operating system drive right at the beginning of the installation. For details on ZFS, if you are not familiar with ZFS, refer to https://en.wikipedia.org/wiki/ZFS.

It is a common question to ask why one should choose ZFS software RAID over tried and tested hardware-based RAID. The simple answer is flexibility. A hardware RAID is locked or fully dependent on the hardware RAID controller interface that created the array, whereas ZFS software-based is not dependent on any hardware, and the array can be easily be ported to different hardware nodes. Should a RAID controller failure occur, the entire array created from that controller is lost unless there is an identical controller interface available for replacement? The ZFS array is only lost when all the drives or maximum tolerable number of drives are lost in the array.

Besides ZFS, we can also select other filesystem types, such as ext3, ext4, or xfs from the same advanced option. We can also set the custom disk or partition sizes through the advanced option. The following screenshot shows the installation interface with the Target Hard disk selection page:

Click on Options, as shown in the preceding screenshot, to open the advanced option for the Hard disk. The following screenshot shows the option window after clicking on the Options button:

In the preceding screenshot, we selected ZFS RAID1 for mirroring and the two drives, Harddisk 0 and Harddisk 1, respectively to install Proxmox. If we pick one of the filesystems such as ext3, ext4, or xfs instead of ZFS, the Hard disk Option dialog box will look like the following screenshot with different set of options:

Selecting a filesystem gives us the following advanced options:

• hdsize: This is the total drive size to be used by the Proxmox installation.
• swapsize: This defines the swap partition size.
• maxroot: This defines the maximum size to be used by the root partition.
• minfree: This defines the minimum free space that should remain after the Proxmox installation.
• maxvz: This defines the maximum size for data partition. This is usually /var/lib/vz.

Debugging the Proxmox installation

Debugging features are part of any good operating system. Proxmox has debugging features that will help you during a failed installation. Some common reasons are unsupported hardware, conflicts between devices, ISO image errors, and so on. Debugging mode logs and displays installation activities in real time. When the standard installation fails, we can start the Proxmox installation in debug mode from the main installation interface, as shown in the following screenshot:

The debug installation mode will drop us in the following prompt. To start the installation, we need to press Ctrl + D. When there is an error during the installation, we can simply press Ctrl + C to get back to this console to continue with our investigation:

From the console, we can check the installation log using the following command:

# cat /tmp/install.log

From the main installation menu, we can also press e to enter edit mode to change the loader information, as shown in the following screenshot:

At times, it may be necessary to edit the loader information when normal booting does not function. This is a common case when Proxmox is unable to show the video output due to UEFI or a nonsupported resolution. In such cases, the booting process may hang. One way to continue with booting is to add the nomodeset argument by editing the loader. The loader will look as follows after editing:

linux/boot/linux26 ro ramdisk_size=16777216 rw quiet nomodeset

Customizing the Proxmox splash screen

When building a custom Proxmox solution, it may be necessary to change the default blue splash screen to something more appealing in order to identify the company or department the server belongs to. In this section, we will see how easily we can integrate any image as the splash screen background.

The splash screen image must be in the .tga format and must have fixed standard sizes, such as 640 x 480, 800 x 600, or 1024 x 768. If you do not have any image software that supports the .tga format, you can easily convert an jpg, gif, or png image to the .tga format using a free online image converter (http://image.online-convert.com/convert-to-tga).

Once the desired image is ready in the .tga format, the following steps will integrate the image as the Proxmox splash screen:

1. Copy the .tga image in the Proxmox node in the /boot/grub directory.
2. Edit the grub file in /etc/default/grub to add the following code, and click on save:

   GRUB_BACKGROUND=/boot/grub/<image_name>.tga

3. Run the following command to update the grub configuration:

   # update-grub

4. Reboot.

The following screenshot shows an example of how the splash screen may look like after we add a custom image to it:

Picture courtesy of www.techcitynews.com

We can also change the font color to make it properly visible, depending on the custom image used. To change the font color, edit the debian theme file in /etc/grub.d/05_debian_theme, and find the following line of code:

set_background_image "${GRUB_BACKGROUND}" || set_default_theme

Edit the line to add the font color, as shown in the following format. In our example, we have changed the font color to black and highlighted the font color to light blue:

set_background_image "${GRUB_BACKGROUND}" "black/black" "light-blue/black" || set_default_theme

After making the necessary changes, update grub, and reboot to see the changes.

Summary

In this article, we looked at why Proxmox is a better option as a hypervisor, what advanced installation options are available during an installation, and why do we choose software RAID for the operating system drive. We also looked at the cost of Proxmox, storage options, and network flexibility using openvswitch. We learned the presence of the debugging features and customization options of the Proxmox splash screen.

In next article, we will take a closer look at the Proxmox GUI and see how easy it is to centrally manage a Proxmox cluster from a web browser.

Resources for Article:

Further resources on this subject:

• Proxmox VE Fundamentals [article]
• Basic Concepts of Proxmox Virtual Environment [article]