etcd

Service Overview

• System user: etcd
• Default node name: auto-generated etcd-<timestamp>
• Config file: /etc/etcd/etcd.yml
• Data directory: /var/lib/etcd
• Binaries: /usr/local/bin/etcd, /usr/local/bin/etcdctl, and /usr/local/bin/etcdutl
• Log level: debug

Network & Ports

• Client traffic: http://localhost:2379
• Peer traffic: http://localhost:2380
• Local access only by default (binds to localhost)

Systemd Management

systemctl status etcd         # Check status
systemctl restart etcd        # Start service
systemctl stop etcd           # Stop service
systemctl restart etcd        # Restart service

Basic Commands

# Check etcd server version
etcd --version

# Check etcdctl client version
etcdctl version

# Check etcdutl version
etcdutl version

# Set a key
etcdctl put mykey "HelloEtcd"

# Get a key
etcdctl get mykey

# List all keys with values
etcdctl get "" --prefix

# List only key names
etcdctl get "" --prefix --keys-only

# Delete a key
etcdctl del mykey

# Check cluster health
etcdctl endpoint health

# List cluster members
etcdctl --endpoints=http://127.0.0.1:2379 member list

# Show cluster leader
etcdctl endpoint status --write-out=table

# Watch a key for changes
etcdctl watch mykey

Backup and Restore

Backup a snapshot (save the current etcd state to a file):

etcdctl snapshot save /root/etcd-backup.db

Check snapshot status:

etcdutl snapshot status /root/etcd-backup.db -w table

Stop the etcd service to avoid conflicts:

systemctl stop etcd

Remove existing contents of the data directory:

rm -rf /var/lib/etcd/*

Restore the snapshot:

etcdutl snapshot restore /root/etcd-backup.db --data-dir /var/lib/etcd

Make sure permissions are correct:

chown -R etcd:etcd /var/lib/etcd

Start the etcd service again:

systemctl start etcd

Notes

• Single-node cluster by default, suitable for development/testing.
• Configured with debug log-level.
• For production, enable TLS for client and peer communication.
• Consider setting up a multi-node cluster for high availability.
• Restrict ports 2379 (client) and 2380 (peer) to trusted hosts using firewall rules.
• Modify /etc/etcd/etcd.yml for advanced configuration and restart the etcd service to apply changes.
• Always backup data before performing destructive operations (delete/restore/compact).
• Ensure /var/lib/etcd is owned by etcd:etcd; incorrect permissions can prevent etcd from starting after restores or data changes.