Availability Zone

Availability zones are a logical subdivision of cloud block storage, compute and network services. They provide a way for cloud operators to logically segment their compute based on arbitrary factors like location (country, datacenter, rack), network layout and/or power source.

For more information, refer to Host aggregates.

Host Aggregate

Host aggregates can be regarded as a mechanism to further partition an availability zone; while availability zones are visible to users, host aggregates are only visible to administrators. Host aggregates provide a mechanism to allow administrators to assign key-value pairs to groups of machines. Each node can have multiple aggregates, each aggregate can have multiple key-value pairs, and the same key-value pair can be assigned to multiple aggregates.

For more information, refer to Host aggregates.