tumult-network — Network Chaos

Script-based plugin for network fault injection. Covers latency, packet loss, corruption, DNS disruption, and host partitioning. Foundation for Kafka and database network chaos.

Prerequisites

• Linux with tc (iproute2) and iptables
• Root/sudo access for tc netem and iptables rules
• Probes (ping, DNS) work on both Linux and macOS

Actions

Action	Description	Key Variables
add-latency	Add network latency (tc netem)	TUMULT_INTERFACE, TUMULT_DELAY_MS, TUMULT_JITTER_MS, TUMULT_TARGET_IP
add-packet-loss	Add packet loss (tc netem)	TUMULT_INTERFACE, TUMULT_LOSS_PCT, TUMULT_CORRELATION
add-corruption	Add packet corruption	TUMULT_INTERFACE, TUMULT_CORRUPTION_PCT
reset-tc	Remove all tc rules (rollback)	TUMULT_INTERFACE
block-dns	Block DNS via iptables	TUMULT_DNS_PORT
partition-host	Network partition via iptables DROP	TUMULT_TARGET_IP (required), TUMULT_DIRECTION

Probes

Probe	Description	Output
ping-latency	Round-trip latency (ms)	Float
dns-resolve	DNS resolution check	IP address or "failed"

Rollback

Always use reset-tc as a rollback action to clean up tc netem rules:

rollbacks[1]:
  - name: cleanup-latency
    activity_type: action
    provider:
      type: process
      path: plugins/tumult-network/actions/reset-tc.sh
      env:
        TUMULT_INTERFACE: eth0

For iptables rules, use rollback scripts that remove rules by comment:

iptables -D OUTPUT -m comment --comment "tumult-partition" -j DROP