etcdctl

etcdctl is the upstream CLI for interacting with and administering etcd v3 clusters over the network. It covers both application-facing key-value operations and operator tasks such as member management, authentication, health checks, snapshots, and diagnosis.

• Read, write, delete, and transactionally update keys, query ranges and revisions, watch changes, and manage leases from the shell.
• Inspect endpoint health, status, and hash consistency, manage cluster membership, take backend snapshots, and run diagnosis or performance checks.
• Enable authentication, manage users and roles, and use built-in distributed lock or leader-election helpers backed by etcd.

• Most commands are direct subcommands with flags and exit codes against a live cluster, so they fit inspect, change, and verify loops once endpoints and TLS or auth settings are known.
• Machine-readable output is real through global --write-out modes including JSON, fields, protobuf, and table, which makes endpoint, member, and many RPC-backed responses script-friendly.
• Automation fit is mixed by command: many paths are non-interactive, but watches, lease keep-alives, locks, elections, and interactive txn sessions are streaming or session-oriented, and upstream only guarantees compatibility for the default simple output format.

• Useful automation requires a reachable etcd cluster plus the right endpoint, TLS, and authentication configuration.
• JSON output exists, but the v3 README explicitly says backward compatibility is only guaranteed for normal commands in simple format.