Nodes & Domains
On this page 3 sections
A node is one running QSCS process on one host. A domain (also called a cluster) is a named collection of nodes that serve the same set of origins.
This page describes how the two relate and what each one stores.
What a node knows
Each node keeps four small pieces of state on disk:
- Its identity, a UUID, generated on first start, that uniquely identifies this node across all clusters it ever joins.
- Its license, proves to the control plane that this node is allowed to participate.
- Its configuration file,
/etc/qscs/qscs.conf. This is the file QSCS reads at startup; the subscribe command rewrites it. - Its cache, recent response bodies, in memory and (optionally) on disk for warm restarts.
A node can belong to one cluster at a time. To move it, simply re-subscribe.
What a domain is
A domain has:
- A short, human-friendly tag (for example
europe-edge). - A list of member nodes with their public addresses.
- A designated master (one of the members).
- A list of origins, virtual hostnames mapped to backend addresses.
Membership and origins live in the control plane. When a node subscribes to a domain it pulls this information and rewrites its local configuration file.
Lifecycle
| Event | What changes |
|---|---|
| Node starts | Reads qscs.conf, opens cache, binds listening port. |
| License activates | Node UUID is bound to an account in the control plane. |
| Domain subscribed | Config is rewritten with new peers and origins; daemon must restart. |
| Origins added/removed | Re-subscribe and restart to pick them up. |
| Master changed | Each node re-subscribes; new master holds backend addresses; thin clients rewrite to point at new master. |
| Node removed | Remaining members re-subscribe to drop it from their peer list. |
Why re-subscribe instead of hot-reload?
Re-subscribing is cheap (one HTTP call to the control plane, one config rewrite) and the daemon restart takes well under a second. Doing the change as an atomic restart avoids the half-states that creep into long-lived daemons that try to reconfigure themselves on the fly.