Glossary¶

This page explains the SlapOS terms these pages use, in alphabetical order.

Allocation Supply: A record on the master that says which software releases, with which software types, may run on which compute nodes. The master allocates a partition to an instance only if its release is ticked in a validated Allocation Supply of the project. hox setup creates and fills it.
Allocation scope: A setting of a compute node that opens it to new instances. hox setup opens it.
Branch URL: The URL of a software release on a Git branch, https://raw.githubusercontent.com/<repo>/<branch>/<path>. The node rebuilds it in place after each push. See Releases and instances.
Buildout: The tool SlapOS uses to build software releases and deploy instances, from profiles such as software.cfg.
Compute node: A machine that builds software releases and runs instances, each in a partition.
Connection parameters: The values an instance publishes once deployed, such as its addresses. Their names depend on the release: many publish url (the public address, through the frontend) and backend-url (the address on the node). Some hold credentials.
Frontend: The service that publishes an instance at a public HTTPS address. On Rapid.Space, a shared frontend serves every project.
Instance: A running copy of a software release, with a name, in a partition of a compute node.
Master: The central SlapOS server: it records which software releases exist, which nodes can run them, and which instance runs where. Rapid.Space runs one at slap.vifib.com, with a web panel at panel.rapid.space.
Partition: A directory of a compute node where one instance lives, with its processes, ports and data.
Pinned URL: The URL of a software release at a given commit, which never changes. See Releases and instances.
Project: A group of compute nodes, software products and instances on the master, with its members.
Promise: A health check an instance declares, such as "the app answers on its port". The node runs the promises after each deployment and reports those that fail.
re6st: The IPv6 mesh network that connects SlapOS nodes. A node joins it with a token. An instance's backend address is usually reachable only over re6st, which is why hox check runs on the node.
slapgrid: The SlapOS agent on each compute node. Run by cron, slapos node software builds the releases supplied to the node, and slapos node instance deploys the node's instances.
Software Product: A record on the master that groups the software releases of one application, with its software types.
Software release: The description of how to build and run an application: a software.cfg file, identified by its URL.
Software type: The variant of a software release an instance is deployed as. Usually default.
Supply: To ask a compute node to build a software release.