check-ethlink

Overview

Validates Ethernet interface configuration and operational status against a node manifest. Ensures network interfaces are properly configured, operationally up, and running at expected speeds.

Expects a file with hardware information, like DGX_A100.json

Health Check: Ethernet Link Validation

Manifest File Format

The manifest file defines expected network interface configuration:

{
  "eth": {
    "device_name": {
      "netdev": "eth0",
      "phys": true,
      "flags": ["UP", "LOWER_UP"],
      "speed": 25000,
      "mtu": 9000
    }
  }
}

Manifest Fields

Field	Type	Required	Description
netdev	String	Yes	Network interface name (e.g., "eth0", "bond0")
phys	Boolean	No	If true, check MAC address against ifcfg file
flags	List[String]	Yes	Expected interface flags
speed	Integer	No	Expected link speed in Mbps
mtu	Integer	Yes	Expected MTU size in bytes

Validation Logic

The check performs three sequential validations, stopping at first failure:

1. MAC Address Validation (check_cfg_macaddr)

For interfaces with phys: true:

1. Read configuration from /etc/sysconfig/network-scripts/ifcfg-{netdev}
2. Query physical MAC address via ethtool -P {netdev}
3. Compare HWADDR from config (lowercase) with actual MAC address
4. Exit CRITICAL if:
   • Configuration file missing
   • MAC addresses don't match

2. Link State Validation (check_link_state)

For all interfaces:

1. Query interface state via ip -j addr
2. Check operstate field is "UP"
3. Verify all expected flags are present
4. Validate MTU matches expected value
5. Exit CRITICAL if:
   • Interface operstate is not "UP"
   • Any expected flags are missing
6. Exit WARN if:
   • MTU doesn't match expected (and no other CRITICAL conditions)

3. Link Speed Validation (check_link_speed)

For interfaces with speed defined:

1. Read link speed from /sys/class/net/{netdev}/speed
2. Compare actual speed with expected speed (in Mbps)
3. Exit WARN if speed is lower than expected

Exit Conditions

Exit Code	Condition
OK (0)	Feature flag disabled (killswitch active)
OK (0)	All checks passed
OK (0)	No ethernet interfaces in manifest
WARN (1)	Link speed lower than expected
WARN (1)	MTU mismatch (without other critical issues)
WARN (1)	Exception during check execution
CRITICAL (2)	Configuration file missing for physical interface
CRITICAL (2)	MAC address mismatch
CRITICAL (2)	Interface operstate is DOWN
CRITICAL (2)	Expected interface flags missing

Dependencies

System Requirements

• /usr/sbin/ip command (iproute2 package)
• /usr/sbin/ethtool command (ethtool package)
• /etc/sysconfig/network-scripts/ifcfg-* configuration files (RHEL/CentOS)
• /sys/class/net/ sysfs interface

Command-Line Options

Option	Type	Default	Description
--manifest_file	String	/etc/manifest.json	Path to node manifest file
--timeout	Integer	300	Command execution timeout in seconds
--sink	String	do_nothing	Telemetry sink destination
--sink-opts	Multiple	-	Sink-specific configuration
--verbose-out	Flag	False	Display detailed output
--log-level	Choice	INFO	DEBUG, INFO, WARNING, ERROR, CRITICAL
--log-folder	String	/var/log/fb-monitoring	Log directory
--heterogeneous-cluster-v1	Flag	False	Enable heterogeneous cluster support

Usage Examples

Basic Check (Default Manifest)

health_checks check-ethlink [CLUSTER] app

Custom Manifest Location

health_checks check-ethlink --type monitor --manifest_file /opt/config/network_manifest.json [CLUSTER] app

With Telemetry

health_checks check-ethlink \
  --sink otel \
  --sink-opts "log_resource_attributes={'attr_1': 'value1'}" \
  [CLUSTER]
  app