Hardware

Zone

Zone is the largest resource definition in ZStack, including cluster, L2 network, primary storage, and other resources.

In a data center, a zone corresponds to an equipment room.
A zone defines a visible boundary. Subresources within the same zone can be visible mutually and can form a certain relationship. However, subresources within different zones are invisible mutually and cannot form mutual relationships.
Resources in a zone is organized as follows, as shown in Zone Resource Structure.
Figure 1. Zone Resource Structure

When you organize a zone, note that:

Hosts in the same physical layer 2 broadcast domain must be in the same zone. These hosts can be grouped as one or more clusters.
A physical layer 2 broadcast domain cannot span multiple zones. Instead, it must be mapped as an L2 network in a single zone.
A primary storage cannot span multiple zones. Instead, it should be mapped as the primary storage in a single zone.
A data center can have multiple zones.
A zone can have one or more backup storages attached.
- Resources in a zone, such as a primary storage, can only access the backup storage that is attached to the zone.
- A backup storage can be detached from a zone. After the backup storage is detached, resources in the zone will not see the backup storage any more.
- If a backup storage is no longer accessible to resources of a zone due to network typology changes in a data center, you can detach the backup storage from this zone.
- To better manage the relationship between backup storages and zones, the UI specifies that a backup storage can only be attached to one zone at a time. That is, a backup storage that has been attached to a zone cannot be reattached to the other zone. When you add a backup storage in the UI, the backup storage will be automatically attached to the current zone. When you delete a zone, you will directly delete the backup storage attached to the zone.

When you use a zone, note that:

After you disable a zone, all clusters in the zone and hosts in these clusters will also be disabled. At this time, new resources in all clusters in this zone can no longer be applied for. To apply for new resources, you need to enable the zone again.
After you enable a zone, all clusters in the zone and hosts in these clusters will also be enabled.
After you delete a zone, all resources and subresources in this zone will also be deleted. Resources include clusters, L2 networks, and primary storages. Subresources include hosts, VM instances, volumes, snapshots, L3 networks, and various network services. Please exercise caution. Note that this delete operation only removes information about these resources recorded in ZStack. The actual data will not be deleted.
To help you better manage the relationship between backup storages and zones, the UI specifies that one backup storage corresponds to only one zone. When you delete a zone, you will also delete the backup storage attached to this zone.

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