Feat: support configuring the disk storage size

Sources/Containerization/LinuxContainer.swift

@@ -44,6 +44,8 @@ public final class LinuxContainer: Container, Sendable {
         public var cpus: Int = 4
         /// The memory in bytes to give to the container.
         public var memoryInBytes: UInt64 = 1024.mib()
+        /// Requested storage in bytes.
+        public var storageInBytes: UInt64?
         /// The hostname for the container.
         public var hostname: String = ""
         /// The system control options for the container.
@@ -72,6 +74,7 @@ public final class LinuxContainer: Container, Sendable {
             process: LinuxProcessConfiguration,
             cpus: Int = 4,
             memoryInBytes: UInt64 = 1024.mib(),
+            storageInBytes: UInt64? = nil,
             hostname: String = "",
             sysctl: [String: String] = [:],
             interfaces: [any Interface] = [],
@@ -86,6 +89,7 @@ public final class LinuxContainer: Container, Sendable {
             self.process = process
             self.cpus = cpus
             self.memoryInBytes = memoryInBytes
+            self.storageInBytes = storageInBytes
             self.hostname = hostname
             self.sysctl = sysctl
             self.interfaces = interfaces
@@ -397,6 +401,7 @@ extension LinuxContainer {
             let vmConfig = VMConfiguration(
                 cpus: self.cpus,
                 memoryInBytes: self.memoryInBytes,
+                diskStorageBytes: self.config.storageInBytes,  
                 interfaces: self.interfaces,
                 mountsByID: [self.id: [self.rootfs] + self.config.mounts],
                 bootLog: self.config.bootLog,

Sources/Containerization/VMConfiguration.swift

@@ -70,6 +70,8 @@ public struct VMConfiguration: Sendable {
     public var cpus: Int
     /// The memory in bytes to allocate.
     public var memoryInBytes: UInt64
+    /// Storage in bytes to allocate
+    public var diskStorageBytes: UInt64?  
     /// The network interfaces to attach.
     public var interfaces: [any Interface]
     /// Mounts organized by metadata ID (e.g. container ID).
@@ -84,13 +86,15 @@ public struct VMConfiguration: Sendable {
     public init(
         cpus: Int = 4,
         memoryInBytes: UInt64 = 1024 * 1024 * 1024,
+        diskStorageBytes: UInt64? = nil,
         interfaces: [any Interface] = [],
         mountsByID: [String: [Mount]] = [:],
         bootLog: BootLog? = nil,
         nestedVirtualization: Bool = false
     ) {
         self.cpus = cpus
         self.memoryInBytes = memoryInBytes
+        self.diskStorageBytes = diskStorageBytes
         self.interfaces = interfaces
         self.mountsByID = mountsByID
         self.bootLog = bootLog

Sources/Containerization/VZVirtualMachineInstance.swift

@@ -43,6 +43,8 @@ struct VZVirtualMachineInstance: Sendable {
         public var cpus: Int
         /// Amount of memory in bytes allocated.
         public var memoryInBytes: UInt64
+        /// Amount of storage in bytes allocated.
+        public var diskStorageBytes: UInt64?
         /// Toggle rosetta's x86_64 emulation support.
         public var rosetta: Bool
         /// Toggle nested virtualization support.
@@ -61,6 +63,7 @@ struct VZVirtualMachineInstance: Sendable {
         init() {
             self.cpus = 4
             self.memoryInBytes = 1024.mib()
+            self.diskStorageBytes = nil
             self.rosetta = false
             self.nestedVirtualization = false
             self.mountsByID = [:]
@@ -370,6 +373,26 @@ extension VZVirtualMachineInstance.Configuration {
             throw ContainerizationError(.invalidArgument, message: "rootfs cannot be nil")
         }
 
+        if let diskBytes = self.diskStorageBytes, initialFilesystem.isBlock {
+            let fileURL = URL(fileURLWithPath: initialFilesystem.source)
+
+            if !FileManager.default.fileExists(atPath: fileURL.path) {
+                FileManager.default.createFile(atPath: fileURL.path, contents: nil)
+            }
+
+            do {
+                let handle = try FileHandle(forWritingTo: fileURL)
+                defer { try? handle.close() }
+                try handle.truncate(atOffset: diskBytes)
+            } catch {
+                throw ContainerizationError(
+                    .internalError,
+                    message: "failed to resize rootfs to \(diskBytes) bytes",
+                    cause: error
+                )
+            }
+        }
+
         let loader = VZLinuxBootLoader(kernelURL: kernel.path)
         loader.commandLine = kernel.linuxCommandline(initialFilesystem: initialFilesystem)
         config.bootLoader = loader

Sources/Containerization/VZVirtualMachineManager.swift

@@ -58,6 +58,7 @@ public struct VZVirtualMachineManager: VirtualMachineManager {
             with: { instanceConfig in
                 instanceConfig.cpus = vmConfig.cpus
                 instanceConfig.memoryInBytes = vmConfig.memoryInBytes
+                instanceConfig.diskStorageBytes = vmConfig.diskStorageBytes
 
                 instanceConfig.kernel = self.kernel
                 instanceConfig.initialFilesystem = self.initialFilesystem