What is the _node and _cluster_setup API used for in CouchDB clustering?

The _node and _cluster_setup APIs are the two primary endpoints for managing a CouchDB cluster's topology. They are distinct in scope: _node operates on individual node configuration, while _cluster_setup orchestrates the multi-step process of forming or extending a cluster.

The _node API (/_node/{node-name}/) provides per-node operations:

• GET /_node/_local/_config — read the running configuration of the local node.
• PUT /_node/_local/_config/{section}/{key} — change a configuration value live without restart.
• GET /_node/_local/_stats — performance counters for the local node.
• GET /_node/_local/_system — Erlang VM stats (memory, processes, ports).

The _cluster_setup API (/_cluster_setup) provides a guided wizard for cluster formation:

# Step 1: Enable cluster mode on node 1
curl -X POST http://admin:pass@node1:5984/_cluster_setup \
  -H "Content-Type: application/json" \
  -d '{"action":"enable_cluster","username":"admin","password":"pass",
       "node_count":3,"bind_address":"0.0.0.0","port":5984}'

# Step 2: Add node 2 to the cluster
curl -X POST http://admin:pass@node1:5984/_cluster_setup \
  -H "Content-Type: application/json" \
  -d '{"action":"add_node","username":"admin","password":"pass",
       "host":"node2","port":5984}'

# Step 3: Finish cluster setup
curl -X POST http://admin:pass@node1:5984/_cluster_setup \
  -d '{"action":"finish_cluster"}'

# Check cluster membership
curl http://admin:pass@localhost:5984/_membership

After cluster formation, GET /_membership returns the list of all nodes in the ring. Nodes are identified by their Erlang node name, typically couchdb@hostname. The _node/_local shortcut always refers to the node receiving the request, which is convenient in scripting.

Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!

Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.

Webull! Receive free stock by signing up using the link: Webull signup.