Tether

Tether

This is a working document for updates to tether design.

Functional requirements

• launch & monitor processes
• capture and forward process output
  • persistent logging - accessible when powered off
  • timestamps
• inject process input
• dispatch signals to processes
• toolbox commands
  • power/shutdown operations
  • IP address publishing
• network configuration
  • IP address
  • Firewall
• hotadd
  • mem
  • cpu
  • NIC - support docker network connect and similar
• mount configuration
  • switch-root
  • block device mount
  • network share mount
• bidirectional file copy - support docker cp and similar
• vmfork
  • pre/post handling
  • fork trigger
• system limits (e.g. ulimits)
• status reporting/diagnostics
  • system status (includes tether initialization stages)
  • process status (including exit status)

Non-functional requirements

• limited filesystem dependencies
• immutable configuration - accessible when powered off
• publishing of runtime data - e.g. process status, DHCP-assigned address
• idempotent application of configuration
• more portable the better
• no in-guest network dependency
• containerVM and endpointVM enforce mutual authentication