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Operations

systemd Service​

[Unit]
Description=Hyper-DERP relay server
After=network-online.target
Wants=network-online.target

[Service]
Type=notify
ExecStart=/usr/bin/hyper-derp -c /etc/hyper-derp/config.toml
Restart=on-failure
RestartSec=5

# Security hardening
NoNewPrivileges=yes
ProtectSystem=strict
ProtectHome=yes
PrivateTmp=yes
ReadOnlyPaths=/
ReadWritePaths=/etc/hyper-derp/certs
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

Install and enable:

sudo cp hyper-derp.service \
  /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now hyper-derp

Memory Footprint​

Base memory usage is low. Per-connection cost depends on buffer ring configuration:

WorkersConnectionsApprox RSS
21,00080 MB
45,000200 MB
810,000400 MB

Metrics​

Prometheus-format metrics are exposed on the metrics address (default :9090):

# Throughput
hyper_derp_recv_bytes_total
hyper_derp_send_bytes_total

# Drops and errors
hyper_derp_send_drops_total
hyper_derp_xfer_drops_total
hyper_derp_slab_exhausts_total
hyper_derp_send_errors_total
hyper_derp_recv_enobufs_total

# Allocation
hyper_derp_frame_pool_hits_total
hyper_derp_frame_pool_misses_total

# Gauges
hyper_derp_peers_active
hyper_derp_workers

Kernel Tuning​

Recommended sysctl settings for high-throughput deployments:

# Socket buffers
sysctl -w net.core.rmem_max=4194304
sysctl -w net.core.wmem_max=4194304
sysctl -w net.core.rmem_default=2097152
sysctl -w net.core.wmem_default=2097152

# Connection backlog
sysctl -w net.core.somaxconn=4096
sysctl -w net.ipv4.tcp_max_syn_backlog=4096

# TCP tuning
sysctl -w net.ipv4.tcp_tw_reuse=1
sysctl -w net.ipv4.tcp_fin_timeout=15

# io_uring memlock limit (for provided buffers)
# Set in /etc/security/limits.conf or systemd unit:
# LimitMEMLOCK=infinity

Monitoring​

Pair the metrics endpoint with Prometheus and Grafana. Key dashboards to set up:

  • Throughput: rate(hyper_derp_send_bytes_total[5m])
  • Active peers: hyper_derp_peers_active
  • Send drops: rate(hyper_derp_send_drops_total[5m])
  • Cross-shard drops: rate(hyper_derp_xfer_drops_total[5m])