docs: add firecracker vmm configuration description

README.md

@@ -60,6 +60,8 @@ thread::spawn(move || {
 });
 ```
 
+Firepilot configure the microVM with a config file. See more documentation [here](./docs/firecracker-vmm-config.md).
+
 ## Developing
 
 ### Build

docs/firecracker-vmm-config.md

@@ -0,0 +1,176 @@
+# Firecracker VMM Configuration
+
+An **working example** can be found [here](https://github.com/firecracker-microvm/firecracker/blob/main/tools/create_snapshot_artifact/complex_vm_config.json).
+
+**More documentation** in firecracker repository: [Firecracker Getting started](https://github.com/firecracker-microvm/firecracker/blob/main/docs/getting-started.md#configuring-the-microvm-without-sending-api-requests)
+
+```rust
+{
+    /// This struct represents the strongly typed equivalent of the json body
+    /// from balloon related requests.
+    "balloon": Option<{
+        /// Target balloon size in MiB.
+        "amount_mib": u32,
+        /// Option to deflate the balloon in case the guest is out of memory.
+        "deflate_on_oom": bool,
+        /// Interval in seconds between refreshing statistics.
+        "stats_polling_interval_s": u16,
+    }>,
+    /// Use this structure to set up the Block Device before booting the kernel.
+    "drives": [
+        {
+            /// Unique identifier of the drive.
+            "drive_id": String,
+            /// Path of the drive.
+            "path_on_host": String,
+            /// If set to true, it makes the current device the root block device.
+            /// Setting this flag to true will mount the block device in the
+            /// guest under /dev/vda unless the partuuid is present.
+            "is_root_device": bool,
+            /// Part-UUID. Represents the unique id of the boot partition of this device. It is
+            /// optional and it will be used only if the `is_root_device` field is true.
+            "partuuid": Option<String>,
+            /// If set to true, the drive is opened in read-only mode. Otherwise, the
+            /// drive is opened as read-write.
+            "is_read_only": bool,
+            /// If set to true, the drive will ignore flush requests coming from
+            /// the guest driver.
+            "cache_type": Unsafe | Writeback,
+            /// Rate Limiter for I/O operations.
+            /// A public-facing, stateless structure, holding all the data we need to create a RateLimiter
+            /// (live) object.
+            "rate_limiter": {
+                /// Data used to initialize the RateLimiter::bandwidth bucket.
+                "bandwidth": Option<{
+                    "size": u64,
+                    "one_time_burst": u64,
+                    "refill_time": u64,
+                }>,
+                /// Data used to initialize the RateLimiter::ops bucket.
+                "ops": Option<{
+                    "size": u64,
+                    "one_time_burst": u64,
+                    "refill_time": u64,
+                }>,
+            },
+            /// The type of IO engine used by the device.
+            "file_engine_type": Async | Sync,
+        }
+    ],
+    /// Strongly typed data structure used to configure the boot source of the
+    /// microvm.
+    "boot-source": {
+        /// Path to the kernel image.
+        "kernel_image_path": String,
+        /// Path to the initrd image.
+        "initrd_path": Option<String>,
+        /// The boot arguments to pass to the kernel. If this field is uninitialized, the default
+        /// kernel command line is used: `reboot=k panic=1 pci=off nomodules 8250.nr_uarts=0`.
+        "boot_args": Option<String>,
+    },
+    /// Strongly typed structure used to describe the logger.
+    "logger": Option<{
+        /// Named pipe where the logger will output the metrics.
+        "log_path": PathBuf,
+        /// The level of the logger
+        "level": Error | Warning | Info | Debug,
+        /// When enabled, the logger will append to the output the severity of the log entry.
+        "show_level": bool,
+        /// When enabled, the logger will append the origin of the log entry.
+        "show_log_origin": bool,
+    }>,
+    /// Strongly typed structure that represents the configuration of the
+    /// microvm.
+    "machine-config": Option<{
+        /// Number of vcpu to start
+        "vcpu_count": u8,
+        /// The memory size in MiB.
+        "mem_size_mib": u32,
+        /// Enables or disabled SMT.
+        "smt": bool,
+        /// A CPU template that it is used to filter the CPU features exposed to the guest.
+        "cpu_template": C3 | T2 | T2S | None | T2CL | T2A,
+        /// Enables or disables dirty page tracking. Enabling allows incremental snapshots.
+        "track_dirty_pages": bool,
+    }>,
+    "metrics": Option<{
+        /// Named pipe or file used as output for metrics.
+        "metrics_path": PathBuf,
+    }>,
+    /// Keeps the MMDS configuration.
+    "mmds-config": Option<{
+        /// MMDS version.
+        "version": V1 | V2,
+        /// Network interfaces that allow forwarding packets to MMDS.
+        "network-interface": [String],
+        /// MMDS IPv4 configured address.
+        "ipv4_address": Option<Ipv4Addr>,
+    }>,
+    /// This struct represents the strongly typed equivalent of the json body from net iface
+    /// related requests.
+    "network-interfaces": Vec<{
+        /// ID of the guest network interface.
+        "iface_id": String,
+        /// Host name of the network interface.
+        "host_dev_name": String,
+        /// Guest MAC address.
+        "guest_mac": Option<MacAddr>,
+        /// Rate Limiter for receiving packages.
+        /// A public-facing, stateless structure, holding all the data we need to create a RateLimiter
+        /// (live) object.
+        "rx_rate_limiter": {
+            /// Data used to initialize the RateLimiter::bandwidth bucket.
+            "bandwidth": Option<{
+                /// See TokenBucket::size.
+                "size": u64,
+                /// See TokenBucket::one_time_burst.
+                "one_time_burst": Option<u64>
+                /// See TokenBucket::refill_time.
+                "refill_time": u64,
+            }>,
+            /// Data used to initialize the RateLimiter::ops bucket.
+            "ops": Option<{
+                /// See TokenBucket::size.
+                "size": u64,
+                /// See TokenBucket::one_time_burst.
+                "one_time_burst": Option<u64>
+                /// See TokenBucket::refill_time.
+                "refill_time": u64,
+            }>,
+        },
+        /// Rate Limiter for transmitted packages.
+        /// A public-facing, stateless structure, holding all the data we need to create a RateLimiter
+        /// (live) object.
+        "tx_rate_limiter": {
+            /// Data used to initialize the RateLimiter::bandwidth bucket.
+            "bandwidth": Option<{
+                /// See TokenBucket::size.
+                "size": u64,
+                /// See TokenBucket::one_time_burst.
+                "one_time_burst": Option<u64>
+                /// See TokenBucket::refill_time.
+                "refill_time": u64,
+            }>,
+            /// Data used to initialize the RateLimiter::ops bucket.
+            "ops": Option<{
+                /// See TokenBucket::size.
+                "size": u64,
+                /// See TokenBucket::one_time_burst.
+                "one_time_burst": Option<u64>
+                /// See TokenBucket::refill_time.
+                "refill_time": u64,
+            }>,
+        }
+    }>,
+    /// This struct represents the strongly typed equivalent of the json body
+    /// from vsock related requests.
+    "vsock": Option<{
+        /// ID of the vsock device.
+        "vsock_id": Option<String>,
+        /// A 32-bit Context Identifier (CID) used to identify the guest.
+        "guest_cid": u32,
+        /// Path to local unix socket.
+        "uds_path": String,
+    }>,
+}
+```