Automatically generate cloud disk image when updating domains configuration

virtweb_backend/src/actors/libvirt_actor.rs

@@ -182,6 +182,13 @@ impl Handler<DeleteDomainReq> for LibVirtActor {
             false => sys::VIR_DOMAIN_UNDEFINE_NVRAM,
         })?;
 
+        // Delete associated cloud init disk
+        let cloud_init_disk = AppConfig::get().cloud_init_disk_path_for_vm(&domain_name);
+        if cloud_init_disk.exists() {
+            std::fs::remove_file(cloud_init_disk)?;
+        }
+
+        // If requested, delete block storage associated with the VM
         if !msg.keep_files {
             log::info!("Delete storage associated with the domain");
             let path = AppConfig::get().vm_storage_path(msg.id);

virtweb_backend/src/app_config.rs

@@ -250,6 +250,19 @@ impl AppConfig {
         self.storage_path().join("iso")
     }
 
+    /// Get the path where generated cloud init disk image are stored
+    pub fn cloud_init_disk_storage_path(&self) -> PathBuf {
+        self.storage_path().join("cloud_init_disks")
+    }
+
+    /// Get the path where the disk image of a VM is stored
+    pub fn cloud_init_disk_path_for_vm(&self, name: &str) -> PathBuf {
+        self.cloud_init_disk_storage_path().join(format!(
+            "{}-{name}.iso",
+            constants::CLOUD_INIT_IMAGE_PREFIX_NAME
+        ))
+    }
+
     /// Get disk images storage directory
     pub fn disk_images_storage_path(&self) -> PathBuf {
         self.storage_path().join("disk_images")

virtweb_backend/src/constants.rs

@@ -57,6 +57,9 @@ pub const DISK_SIZE_MIN: FileSize = FileSize::from_mb(50);
 /// Disk size max (B)
 pub const DISK_SIZE_MAX: FileSize = FileSize::from_gb(20000);
 
+/// Cloud init generated disk image prefix
+pub const CLOUD_INIT_IMAGE_PREFIX_NAME: &str = "virtweb-cloudinit-autogen-image";
+
 /// Net nat entry comment max size
 pub const NET_NAT_COMMENT_MAX_SIZE: usize = 250;
 

virtweb_backend/src/libvirt_rest_structures/vm.rs

@@ -142,9 +142,22 @@ impl VMInfo {
             return Err(StructureExtraction("Invalid number of vCPU specified!").into());
         }
 
-        let mut disks = vec![];
+        let mut iso_absolute_files = vec![];
 
-        // Add ISO files
+        // Process cloud init image
+        if self.cloud_init.attach_config {
+            let cloud_init_disk_path = AppConfig::get().cloud_init_disk_path_for_vm(&self.name);
+
+            // Apply latest cloud init configuration
+            std::fs::write(
+                &cloud_init_disk_path,
+                self.cloud_init.generate_nocloud_disk()?,
+            )?;
+
+            iso_absolute_files.push(cloud_init_disk_path);
+        }
+
+        // Process uploaded ISO files
         for iso_file in &self.iso_files {
             if !files_utils::check_file_name(iso_file) {
                 return Err(StructureExtraction("ISO filename is invalid!").into());
@@ -156,6 +169,13 @@ impl VMInfo {
                 return Err(StructureExtraction("Specified ISO file does not exists!").into());
             }
 
+            iso_absolute_files.push(path);
+        }
+
+        let mut disks = vec![];
+
+        // Add ISO disk files
+        for iso_path in iso_absolute_files {
             disks.push(DiskXML {
                 r#type: "file".to_string(),
                 device: "cdrom".to_string(),
@@ -165,7 +185,7 @@ impl VMInfo {
                     cache: "none".to_string(),
                 },
                 source: DiskSourceXML {
-                    file: path.to_string_lossy().to_string(),
+                    file: iso_path.to_string_lossy().to_string(),
                 },
                 target: DiskTargetXML {
                     dev: format!(
@@ -182,6 +202,7 @@ impl VMInfo {
             })
         }
 
+        // Configure VNC access, if requested
         let (vnc_graphics, vnc_video) = match self.vnc_access {
             true => (
                 Some(GraphicsXML {
@@ -495,6 +516,7 @@ impl VMInfo {
                 .iter()
                 .filter(|d| d.device == "cdrom")
                 .map(|d| d.source.file.rsplit_once('/').unwrap().1.to_string())
+                .filter(|d| !d.starts_with(constants::CLOUD_INIT_IMAGE_PREFIX_NAME))
                 .collect(),
 
             file_disks: domain

virtweb_backend/src/main.rs

@@ -61,6 +61,8 @@ async fn main() -> std::io::Result<()> {
 
     log::debug!("Create required directory, if missing");
     files_utils::create_directory_if_missing(AppConfig::get().iso_storage_path()).unwrap();
+    files_utils::create_directory_if_missing(AppConfig::get().cloud_init_disk_storage_path())
+        .unwrap();
     files_utils::create_directory_if_missing(AppConfig::get().disk_images_storage_path()).unwrap();
     files_utils::create_directory_if_missing(AppConfig::get().vnc_sockets_path()).unwrap();
     files_utils::set_file_permission(AppConfig::get().vnc_sockets_path(), 0o777).unwrap();

virtweb_backend/src/utils/cloud_init_utils.rs

@@ -8,18 +8,18 @@ use std::process::Command;
 /// cloud-localds source code: https://github.com/canonical/cloud-utils/blob/main/bin/cloud-localds
 #[derive(Clone, Debug, serde::Serialize, serde::Deserialize, Default)]
 pub struct CloudInitConfig {
-    attach_config: bool,
+    pub attach_config: bool,
     /// Main user data
-    user_data: String,
+    pub user_data: String,
     /// Instance ID, set in metadata file
     #[serde(skip_serializing_if = "Option::is_none")]
-    instance_id: Option<String>,
+    pub instance_id: Option<String>,
     /// Local hostname, set in metadata file
     #[serde(skip_serializing_if = "Option::is_none")]
-    local_hostname: Option<String>,
+    pub local_hostname: Option<String>,
     /// Network configuration
     #[serde(skip_serializing_if = "Option::is_none")]
-    network_configuration: Option<String>,
+    pub network_configuration: Option<String>,
 }
 
 impl CloudInitConfig {