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Linux network corruption

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Linux network corruption is a chaos fault that flips bits in NETWORK_PACKET_CORRUPTION_PERCENTAGE percent of egress packets on NETWORK_INTERFACES of the target Linux machine for DURATION, then restores normal connectivity. Corruption is restricted to traffic destined for DESTINATION_HOSTS/DESTINATION_IPS and the configured port filters; SSH ports stay reachable when WHITELIST_SSH is true. The fault runs through the Linux Chaos Infrastructure (LCI) systemd service installed on the target VM.

Use this fault to test how a workload behaves when packet payloads are damaged in transit: whether TCP retransmits keep the connection alive, whether UDP-based protocols recover, whether application checksum/verification layers reject the corrupt data, and whether monitoring detects the degradation within the alerting SLA.

Run your first experiment

If you have not installed the Linux Chaos Infrastructure yet, go to Linux Chaos Infrastructure to install the agent and connect the VM to the control plane.

Use cases​

Run this fault when you want to answer concrete questions like:

  • TCP recovery: When NETWORK_PACKET_CORRUPTION_PERCENTAGE of egress packets are corrupted, does the application stay inside its latency SLA via TCP retransmits?
  • UDP behavior: Do UDP-based protocols (DNS, syslog, application metrics) drop the corrupt packets or surface bad data?
  • Application validation: Does the application reject malformed payloads cleanly when corruption sneaks past TCP?
  • Monitoring fidelity: Do alerts on retransmits and connection errors fire within the alerting SLA?

Prerequisites​

  • Linux Chaos Infrastructure installed: The linux-chaos-infrastructure systemd service is active on the target VM and the infrastructure is in CONNECTED state. Go to Linux Chaos Infrastructure to install it.
  • Target interface exists: Each entry in NETWORK_INTERFACES exists on the target VM. Confirm with ip -br link.
  • tc available: The fault uses Linux Traffic Control (tc) with the netem qdisc. Provided by iproute2.

Supported environments​

The fault has been tested on the following Linux distributions. Go to Linux fault requirements to see the full compatibility matrix.

PlatformSupport status
Ubuntu 16+, Debian 10+Supported
CentOS 7+, RHEL 7+, Fedora 30+Supported
openSUSE LEAP 15.4+ / SUSE Linux Enterprise 15+Supported

Permissions required​

This fault is classified as an Advanced Linux fault. It requires the Linux Chaos Infrastructure systemd service to run with the root user and root user group on the target VM so it can manage the tc qdisc. No cloud credentials are needed.

Fault tunables​

Configure the following fault parameters when you add Linux network corruption to an experiment in Chaos Studio. Defaults are shown for reference.

Chaos parameters

TunableDescriptionDefault
DURATIONTotal duration of the fault. Accepts [hours]h[minutes]m[seconds]s format.30s
NETWORK_PACKET_CORRUPTION_PERCENTAGEPercentage of packets to corrupt (0 to 100).100
NETWORK_INTERFACESComma-separated network interfaces to apply chaos on.eth0
RAMP_TIMEWait period in seconds before and after the fault. Go to ramp time to read how it is applied.0

Target filters (provide at least one host or IP to limit blast radius)

TunableDescriptionDefault
DESTINATION_HOSTSComma-separated destination host names to target.""
DESTINATION_IPSComma-separated destination IPs to target. Per-IP ports can be specified using the ip|port format.""
SOURCE_PORTSComma-separated source ports to target. Prefix with ! to whitelist.""
DESTINATION_PORTSComma-separated destination ports to target. Prefix with ! to whitelist.""
WHITELIST_SSHKeep SSH ports (22,2222) excluded from chaos.true

When neither DESTINATION_HOSTS nor DESTINATION_IPS is set, the fault applies to all destinations on the interface.

Tunables that apply to every fault are documented in common tunables for all faults.

Fault execution in brief​

Adds a netem qdisc on NETWORK_INTERFACES that corrupts NETWORK_PACKET_CORRUPTION_PERCENTAGE percent of egress packets matching the configured filters for DURATION, then removes the qdisc.

Expected behavior during fault execution​

  • The configured percentage of egress packets to matched destinations is bit-flipped.
  • TCP detects the corruption via checksum and retransmits; throughput drops and retransmits rise sharply.
  • UDP-based protocols may receive bad data (depending on whether the application validates payloads).
  • After the duration ends, the qdisc is removed and packet integrity returns to baseline.
When the fault ends

The chaos pod removes the netem qdisc. Packets flow normally on the next send; TCP recovers quickly via standard retransmission.

Signals to watch​

Attach resilience probes to assert each layer:

  • TCP retransmits: Use a Prometheus probe on node_netstat_TcpExt_TCPLostRetransmit.
  • Application errors: Use a Prometheus probe on application checksum or decode error counters.
  • End-to-end availability: Use an HTTP probe on a user-visible endpoint.

Verify the fault execution effect​

  1. Inspect the active qdisc.

    tc -s qdisc show dev <interface>

  2. Run TCP throughput against a matched destination.

    iperf3 -c <target> -t 30

    Throughput drops sharply during the chaos window and returns to baseline afterwards.

  3. Inspect Linux Chaos Infrastructure logs.

    sudo journalctl -u linux-chaos-infrastructure -n 100 --no-pager

Recovery and cleanup​

  • End of duration: The chaos pod removes the netem qdisc when DURATION elapses.
  • Abort the experiment: Stopping the experiment from Chaos Studio also removes the qdisc.
  • Manual recovery: If the qdisc survives an abort, remove it with sudo tc qdisc del dev <interface> root.

Limitations​

  • Egress only: The fault corrupts packets leaving the VM on the configured interfaces.
  • Single VM scope: Each fault run targets one VM.
  • Corruption is random: Bit-flips happen at random positions; payloads are usually rejected by TCP checksum, occasionally accepted as bad UDP data.
  • SSH whitelisting: When WHITELIST_SSH is false, your SSH session may break.

Troubleshooting​

Linux network corruption fault shows no measurable retransmits in Harness Chaos Engineering

Confirm the destination filter matches your test traffic. Run tc -s qdisc show dev <interface> to verify the netem qdisc is installed and check ss -ti for retransmit counts.

SSH session became unresponsive during the experiment

WHITELIST_SSH defaults to true to exclude ports 22 and 2222. If your SSH session broke, your SSH may be on a different port; add it with the ! prefix in SOURCE_PORTS to whitelist it.

Corruption persists after the experiment ends

If the netem qdisc was not removed, remove it manually with sudo tc qdisc del dev <interface> root.