Bond slave interface down
A slave NIC in a bonded interface has MII status down. The bond is running with reduced redundancy; one more failure breaks the bond entirely.
Remediation
When this rule fires on one of your servers, the dashboard alert detail page renders the full remediation guidance: the command to run, what to verify after, and Furnace's annotation for your specific distro + hardware. Sign in at app.glassmkr.com to see the live alert.