App placement
Settings → App Placement sets rules for every app: which nodes may run them. An app's own placement, in its Availability & Scaling, comes on top.
The rules
| Rule | Keeps apps |
|---|---|
| Exclude Manager Nodes | off the managers, which run HivePaaS itself. On by default. |
| Exclude Build Nodes | off the nodes Settings → Image Build sets to build images. On by default. |
| Require Node Labels | on nodes carrying all of these labels, such as tier=apps. A bare key, such as apps, is apps=true. |
| Exclude Node Labels | off nodes carrying any of these labels. |
On a single node
With one node, the rules are not applied: it is the manager, it builds, and it runs every app. They apply once the cluster has a second node.
When they apply
The rules apply to an app when it is deployed. After adding the first worker, or changing the rules, Re-deploy the apps to move them.
A set of rules no node satisfies would leave apps waiting forever: HivePaaS refuses to save it.