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Availability Sets and Zones

Terminology

  • Availability Zone is a common cloud concept that refers to the logical grouping of resources. Each cloud can have one or more availability zones.
  • Availability Set is a CloudCenter-specific concept to denote a group or list of availability zones.

    Cloud Nuances

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    Be aware of the following nuances when configuring Availability Sets using the CCM UI or the CloudCenter REST APIS:

    Supported CloudCloud ReferenceCloudCenter Concept
    AzureConcept of Availability Set
    (does not include Availability Zones)

    The CloudCenter platform provides this input as a boolean value to enable/disable Azure's Availability Set concept.

    AWSConcept of Availability Zone 
    (includes Availability Sets)
    The CloudCenter platform provides this input via the VPC NIC(s) field.
    OpenStackConcept of Availability Zone
    (includes Availability Sets)
    The CloudCenter platform provides this input via the Availability Zone(s) field.

    This feature is currently supported for these three clouds.

Clustered VMs in an Application Tier

When an application tier is in a clustered environment (with more than one VM), then all the VMs in the cluster may need to be launched into the same availability zone. An availability set refers to a group or list of availability zones and ensures that the cluster VMs are evenly distributed across the specified zones using a Round-Robin implementation. Consequently, even during scaling operations (up or down), the VMs continue to be scaled across the zones. This feature is specific to each tier within an application.

For example, if a tier is a cluster of 3 VMs (being the minimum) and you have the availability set as zone1 and zone2, then when the job is launched the first node is launched into zone1, the second node into zone2, and the third node again into the zone1. After a successful job deployment, if you scale up the tier, then a new node is launched to zone2.

Configuration Details

This section provides the related images if configuring using the UI.

  • See Deployment Environments > Adding a Deployment Environment > Cloud and Network Settings section to deploy to each supported cloud.
  • See Deployment Environment Defaults > Configure Default Settings > Cloud and Network Settings section to set defaults for each supported cloud.

See the following section for cloud-specific configuration details:

CloudUI ImageAPI Details when configuring cloudProperties
OpenStackSee OpenStack Configurations > Availability Zones and Sets
AWS

See AWS ConfigurationsAvailability Zones and Sets

AzureSee Azure Configurations > Availability Zones and Sets