Firecracker.MmdsConfig (firecracker v0.1.0)

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Configures the Microvm Metadata Service (MMDS) for Firecracker virtual machines.

MMDS provides a way to serve metadata to guest VMs through a standardized HTTP endpoint, similar to EC2 instance metadata service. It allows the guest to retrieve configuration data and credentials without additional network dependencies.

Fields

  • :network_interfaces - Required. List of network interface IDs that can access MMDS
  • :version - Optional. MMDS service version (e.g., "V1", "V2")
  • :ipv4_address - Optional. IPv4 address for MMDS endpoint, defaults to 169.254.169.254
  • :imds_compat - Optional. Enable EC2 IMDS compatibility mode (responds with "text/plain" regardless of Accept header)
  • :applied? - Internal flag indicating whether this configuration has been applied

Post-boot Behavior

No fields can be modified after VM starts

Notes

  • MMDS is accessible from within the guest VM at the specified IPv4 address
  • Only network interfaces listed in :network_interfaces can access MMDS
  • Version "V2" requires authentication tokens for accessing metadata
  • The default IPv4 address (169.254.169.254) matches EC2's metadata service

Summary

Types

t()

Types

t()

@type t() :: %Firecracker.MmdsConfig{
  applied?: boolean(),
  imds_compat: boolean() | nil,
  ipv4_address: String.t() | nil,
  network_interfaces: [String.t()],
  version: String.t() | nil
}