Virtualization Functions

From the user's point of view, the comprehensive management framework underpinning Proxmox VE pays off: VMs – whether KVM or container based – can be launched using a standardized REST-like API defined in JSON. Proxmox VE supports different approaches on the network side: Basically, the network concept of the solution is based on network bridges, but you can also integrate software-defined networking (SDN) solutions such as Open vSwitch. IPv4 and IPv6 support for VMs is included.

On the storage side, Proxmox can handle typical cloud solutions. Local storage can be connected by logical volume management (LVM) or the classical Linux filesystems (ext4/XFS, based on LVM), such as ZFS. If you want network storage, instead, you will find many options: Fibre Channel, iSCSI, and NFS are all supported, as are distributed storage solutions, such as Ceph and GlusterFS. (Proxmox can install Ceph, itself, if so desired.)

If you frequently have to juggle your VMs around, you will be happy to hear that live migration in Proxmox VE works. However, the VM should be on redundant storage, preferably on object storage such as Ceph.

If something goes wrong, the Proxmox developers fortunately have prepared for such an event: Backup and restore tools integrated directly into the solution can be used to restore VMs in an emergency, as well as snapshots taken on the fly, and you have the option of creating a completely new backup with point and click in the GUI.

Of Templates and Cloning

Proxmox VE allows you to create and clone VM templates. Both functions are particularly popular in cloud computing: If a VM is based on a template, it can be rolled out far more quickly than would be possible for a manual installation. Essentially, a VM template is a prebuilt and generalized hard disk image that launches as a new VM at the push of a button. Parameters come from outside.

Templates are cloned at rollout; the vendor distinguishes between "linked clones" and "complete clones." For linked clones, the template and clone are mapped, and the clone does not work without the template. Although this restricts flexibility, it also means that the VM does not require much storage space. With a full clone, Proxmox copies the entire template at startup, but the VM then runs without its original template (Figure 3).

Figure 3: Cloning VM templates in Proxmox VE lets you create new VMs, which are then ready to run after a few mouse clicks.

Access Options

I already mentioned the extremely well-designed web GUI that comes with Proxmox VE. It can be reached via the web browser and can run on any host in the cloud, meaning that a separate management server is not needed. In the past few years, Proxmox has successively altered the visual appearance of the graphical interface, without losing sight of user friendliness.

Nor has functionality fallen by the wayside. In the left pane, you find a list of available hosts. If you click on one of these hosts, a list of its properties, including the option to edit them, appears in the right part of the window.

Rudimentary monitoring of system values such as CPU load and RAM utilization is also integrated. If so desired, you can look at the central logfiles (e.g., the Syslog). A virtual console login also supports Proxmox VE in the web GUI, making it a key management tool and in no way inferior to SUSE or Red Hat (Figure 4).

Figure 4: With noVNC, Proxmox 5.0 supports direct access to the command line of the virtualized system.

If you are experienced on the command line (CLI) and can't really come to grips with the web GUI, Proxmox offers a truckload of command-line tools as an alternative. Proxmox VE fully leverages the open and standardized API. The CLI commands ultimately produce the same API calls as the web interface. Maintaining the CLI tools also means less overhead, and Proxmox is obviously keen to keep them to avoid annoying power users.