Architecture
The Basics
- A maelstrom node is a machine running the
maelstromd process
- A maelstrom cluster is a collection of nodes that share a common database.
- Nodes in a cluster should be able to connect to each other on their private port (8374 by default)
- A maelstrom component is a name mapped to configuration that specifies how to start a docker container that
runs a HTTP server. Requests for the component will be reverse proxied to that container on demand.
- Nodes periodically write their current state to the database (default: once per minute)
- All nodes are peers and should be identically configured.
- Nodes acquire locks from the database before performing certain tasks. This ensures that only
one node is performing critical operations such as autoscaling or cron triggering.
maelctl makes JSON-RPC requests to a maelstrom node.
- The
MAELSTROM_PRIVATE_URL env var tells maelctl where to connect. (default=http://127.0.0.1:8374)
- New nodes that join the cluster will be automatically assigned components to run within 90 seconds of joining.
Routing
- All requests and responses in maelstrom are HTTP
- If multiple instances of a component are running, requests are distributed across using round-robin scheduling.
- Each node maintains a routing table and can route requests to its peers if the component is not running locally.
+-----------------+
+------------------+ Load Balancer +-------------------+
| | (optional) | |
| +--------+--------+ |
| | |
| | |
| 80/443 | 80/443 | 80/443
+--------v--------+ +--------v--------+ +---------v-------+
|node-a | |node-b | |node-c |
| +---------+ +---------+ |
|10.0.0.2 | 8374 |10.0.0.3 | 8374 |10.0.0.4 |
+--------+--------+ +--------+--------+ +---------+-------+
| | |
| | |
| | |
| +--------v--------+ |
+----------------->+ MySQL +<------------------+
| or Postgres |
+-----------------+