Some additional location types are supported for specialized situations:
The spec host, taking a string argument (the address) or a map (host, user, password, etc.), provides a convenient syntax when specifying a single host. For example:
{% read snippets/_location-special-single.camp.md %}
Or, in brooklyn.properties, set brooklyn.location.named.host1=host:(192.168.0.1).
The spec multi allows multiple locations, specified as targets, to be combined and treated as one location.
In its simplest form, this will use the first target location where possible, and will then switch to the second and subsequent locations when there are no machines available.
In the example below, it provisions the first node to 192.168.0.1, then it provisions into AWS us-east-1 region (because the bring-your-own-nodes region will have run out of nodes).
{% read snippets/_location-special-sequential.camp.md %}
A DynamicCluster can be configured to cycle through its deployment targets round-robin when provided with a location that supports the AvailabilityZoneExtension -- the multi location supports this extension.
The configuration option dynamiccluster.zone.enable on DynamicCluster tells it to query the given location for AvailabilityZoneExtension support. If the location supports it, then the cluster will query for the list of availability zones (which in this case is simply the list of targets) and deploy to them round-robin.
In the example below, the cluster will request VMs round-robin across three different locations (in this case, the locations were already added to the catalog, or defined in brooklyn.properties).
{% read snippets/_location-special-round.camp.md %}
Of course, clusters can also be deployed round-robin to real availability zones offered by cloud providers, as long as their locations support AvailabilityZoneExtension. Currently, only AWS EC2 locations support this feature.
In the example below, the cluster will request VMs round-robin across the availability zones provided by AWS EC2 in the “us-east-1” region.
{% read snippets/_location-special-availability.camp.md %}
For more information about AWS EC2 availability zones, see this guide.
Custom alternatives to round-robin are also possible using the configuration option dynamiccluster.zone.placementStrategy on DynamicCluster.
The {% include java_link.html class_name=“ServerPool” package_path=“org/apache/brooklyn/entity/machine/pool” project_subpath=“software/base” %} entity type allows defining an entity which becomes available as a location.