The Nodes section of your cluster provides information on each node. A green circle next to a node's name denotes the leader node, while a blue circle indicates a follower node. The leader node can change periodically due to the nature of the Raft algorithm. For technical details on the Leader Election algorithm, please refer to this article.
You can add one or more nodes to your cluster at any time.
The ADDRESS column shows the hostname and port of each node, SQLite Cloud assigns a unique UUID to every node and adds it to our
sqlite.cloud domain name system. To map this name to your domain, add a CNAME entry to your DNS.
The HARDWARE column summarizes the hardware specifications of the node running your SQLite Cloud instance.
The STATUS column provides Raft-specific information and can display the following values:
- Replicate: A follower that eagerly receives log entries to append to its log.
- Probe: A follower whose last index is unknown and is "probed" periodically to narrow down its last index. In the ideal (and common) case, only one round of probing is necessary as the follower will react with a hint. Followers that are probed over extended periods of time are often offline.
- Snapshot: A follower that needs log entries not available from the leader's Raft log and requires a full snapshot to return to Replicate status.
- Unknown: An error condition that should not occur.
The RAFT column displays information on the node's Raft log ID and the leader log ID. A green color indicates that the two values are equal, meaning that the follower node is up to date. An orange color indicates that the follower is about 10% behind the leader Raft Log ID. In case of a read operation, the node will require an update from the leader node, and the client may need to wait a bit before the operation is completed. A red color indicates that the follower node is more than 10% behind the leader Raft Log ID.
The CONNECTIONS column shows the number of currently established connections in the node.
The CPU, RAM, and DISK values display information on the node's hardware resource usage. By clicking on the CPU or RAM values, you can view a more detailed historical graph.
The last option symbol contains links to:
- Logs: Lists all logs related to the node, which can be filtered by type, date, and log level.
- Connections: Displays information on all currently established connections in the node.
- Delete: Used to remove the node. Please note that this action cannot be undone.
Finally, the world map at the bottom of the page visualizes all cluster nodes in their specific geo-locations.