Guests, Hosts and Pools

Owned by Jorge Olmos (Unlicensed)
Last updated: Jul 05, 2017 by Javier Celaya (Unlicensed)
5 min read

This section of the tree view provides access to the guests, hosts and pools of the platform. The root of the tree is the name you entered when you configured the Manager connection parameters. If you unfold it, two elements are revealed: Hosts and Pools.

Host

Here you will see a list of the Hosts controlled by the flexVDI Manager you are connected to.

Each of the Hosts that are running should have green round icon with a white arrow inside, meaning that its status is "Running". If the Host is not active, its icon will show a crossed out red circle. The tree also displays on which Host the flexVDI Manager is running.

When one of the Hosts in the left area is selected, information about it is shown in the right area. This information is divided into four tabs.

Host info tab

This tab displays basic information about the Host, and a summary of its available resources.

The table on the left shows:

  • Current and desired state. If they differ, the Manager will try to bring the Host to the desired state.
  • Name, address and description.
  • VDI address: This is the IP address reported to the VDI clients to connect to. This is required when the Host has a public and a private address.
  • CPU type and Hypervisor version.
  • Message provided by the Host's agent in case of error.

The graphs on the right show a summary of the available resources in this Host. Hosts provide CPU and RAM resources to Guests. The total resources offered by a Host consist of its physical resources adjusted by an overcommit factor. By overcommiting, a Host can offer more resources than actually available. It is safe to overcommit CPU resources, since they are time-shared by the Guests. On the other hand, overcommiting RAM resources is not recommended at all; do it under your own responsibility.

Resources must be first reserved by a Pool, then used by a Guest of a Pool. The bar graphs show how much resources are in use by Guests, how much are free, and how much are not reserved by any Pool. Next to the graphs there is also the same information in numeric form, and a relation of physical and overcommited resources.

Pools tab

This tab displays information about the Host resources assigned to each of the Pools.

A Pool is a set of CPU and RAM resources available to the Guests associated to it. A Pool's resources may come from different Hosts, and each Host may contribute resources to many Pools. The list on the left contains the Pools to which this Host is contributing resources, plus the set of resources not contributed to any Pool. When you select one of the items in the list, the charts on the right reflect how many resources are free and in use in that Pool.

 Guests tab

This tab shows the Guests running on the selected Host and the amount of resources allocated by them.

You can filter the list with the input box in the top right corner, if you are looking for a specific guest. The charts on the right show the same information in a graphical way.

 Network tab

Finally, this tab shows the network interfaces available to the selected Host. They can be configured with the flexVDI Config tool.

  • Physical interfaces.
  • Bridge interfaces.
  • Bonding interfaces.
  • VLAN interfaces.

Pools

This tree branch shows the Pools in the flexVDI platform. The icon of each Pool shows its state: running, disabled or under an error condition.

When one of these Pools is selected, detailed information about it is shown in the right area of the main window. It consists of three tabs:

 Pool info tab

Similarly to the Host info tab, it shows basic information about the Pool and a summary of its resources.

Besides its name, state and the list of Hosts from which it takes its resources, the basic information of a Pool includes these two properties:

Priority: Indicates the preference that a Pool has for acquiring resources when there are not enough to fulfill the needs of every Pool. This happens when some of the Hosts are down, due to a failure or for maintenance. In that situation, when reassigning the remaining resources to Pools, those with higher priority (lower value) come first.

"CPU block size" / "RAM block size": It is the resource reservation unit used by the Pool. Reservation is done in blocks of this size. For instance, the Pool in the image reserves resources from the Hosts in blocks of 1 CPU and 2GB of RAM.  The purpose of these values is to ensure that Pools reserve Host resources for the Guests in an adequate proportion. This will prevent, for instance, that a Pool reserves a large number of CPUs but a small amount of RAM in a Host. The RAM would limit the amount Guests that could run in the Pool, rendering the rest of the reserved CPUs unusable. These resource reservations are made:

  • Initially when the Pool is created or the Manager starts.
  • Automatically when the amount of available resources changes. For instance, on the event of failure or shutdown of one of the Hosts. High priority Pools may receive resources that are removed from Pools with a lower priority.
  • By explicit request of an administrator clicking on "Rebalance resources" from the context menu of a Pool.

The graphs on the right show the used and available resources for creating and executing Guests handled by the Pool:

  • Required: the amount of resources (CPU / RAM) assigned to the Pool.
  • Present: the current amount of resources available to the Pool. It may be less than the Required value, for instance if one of the Host is off for maintenance.  
  • In use / Free shows the amount of resources that Are being used by the Guests in the Pool, and the amount that is still available. The total amount is equal to "Present".

The resources that are assigned to a Pool, can be used by the Guests in that Pool and are not available to Guests in other Pools.

 Guest Resources tab

This tab displays detailed information about the resources used by each Guest running on the Pool.

As with the Guests in a Host, you can filter the list of Guests.

 Host Resources tab

Information about the amount and state of the resources in each Host.

Guests

If you click on any of the Pools that appear in the tree on the left you will see the Guests housed on it.

If the Guest is running, a green circle icon with a white arrow inside is displayed. If the Guest is stopped it will display a red circle with a white box inside. If it is paused, the icon will be a blue circle with two vertical bars.

Clicking on each Guest, information about it is shown in the right area of the main window.

Guest: Guest info tab

Information about Guest resources, status, and virtual devices attached to it.

Guest: Guest storage tab

Information about the virtual storage devices of a Guest. There are three types of storage objects we will see later, shown in the three columns of the image.