feat: Add Kraftfile schema v0.7 support

Makefile

@@ -250,7 +250,7 @@ tidy: ## Tidy import Go modules.
 
 .PHONY: fmt
 fmt: ## Format all files according to linting preferences.
-	$(GOCILINT) format
+	$(GOCILINT) fmt
 
 .PHONY: lint
 lint: ## Lint all files according to linting preferences.

go.mod

@@ -109,10 +109,12 @@ require (
 	github.com/anchore/go-logger v0.0.0-20220728155337-03b66a5207d8 // indirect
 	github.com/atotto/clipboard v0.1.4 // indirect
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/bahlo/generic-list-go v0.2.0 // indirect
 	github.com/becheran/wildmatch-go v1.0.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/blang/semver/v4 v4.0.0 // indirect
 	github.com/bmatcuk/doublestar/v4 v4.10.0 // indirect
+	github.com/buger/jsonparser v1.1.1 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/cespare/xxhash v1.1.0 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
@@ -203,13 +205,15 @@ require (
 	github.com/in-toto/attestation v1.1.2 // indirect
 	github.com/in-toto/in-toto-golang v0.10.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/invopop/jsonschema v0.13.0 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/kevinburke/ssh_config v1.2.0 // indirect
 	github.com/klauspost/compress v1.18.5 // indirect
 	github.com/lucasb-eyer/go-colorful v1.3.0 // indirect
 	github.com/lufia/plan9stats v0.0.0-20230110061619-bbe2e5e100de // indirect
 	github.com/magiconair/properties v1.8.10 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-localereader v0.0.1 // indirect
 	github.com/mattn/go-runewidth v0.0.21 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
@@ -246,6 +250,7 @@ require (
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/rootless-containers/rootlesskit/v2 v2.3.6 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
+	github.com/santhosh-tekuri/jsonschema/v5 v5.3.1 // indirect
 	github.com/santhosh-tekuri/jsonschema/v6 v6.0.2 // indirect
 	github.com/sasha-s/go-deadlock v0.3.5 // indirect
 	github.com/scylladb/go-set v1.0.3-0.20200225121959-cc7b2070d91e // indirect
@@ -270,6 +275,7 @@ require (
 	github.com/vishvananda/netns v0.0.5 // indirect
 	github.com/wagoodman/go-partybus v0.0.0-20200526224238-eb215533f07d // indirect
 	github.com/wagoodman/go-progress v0.0.0-20260303201901-10176f79b2c0 // indirect
+	github.com/wk8/go-ordered-map/v2 v2.1.8 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
@@ -306,8 +312,10 @@ require (
 	k8s.io/klog/v2 v2.130.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20250910181357-589584f1c912 // indirect
 	k8s.io/utils v0.0.0-20251002143259-bc988d571ff4 // indirect
+	mvdan.cc/sh/v3 v3.12.0 // indirect
 	sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730 // indirect
 	sigs.k8s.io/randfill v1.0.0 // indirect
 	sigs.k8s.io/structured-merge-diff/v6 v6.3.0 // indirect
 	sigs.k8s.io/yaml v1.6.0 // indirect
+	unikraft.com/x/kraftfile v0.0.0-20260427093726-3fccc9bca88d // indirect
 )

go.sum

@@ -130,6 +130,8 @@ github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiE
 github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
 github.com/aymanbagabas/go-udiff v0.4.1 h1:OEIrQ8maEeDBXQDoGCbbTTXYJMYRCRO1fnodZ12Gv5o=
 github.com/aymanbagabas/go-udiff v0.4.1/go.mod h1:0L9PGwj20lrtmEMeyw4WKJ/TMyDtvAoK9bf2u/mNo3w=
+github.com/bahlo/generic-list-go v0.2.0 h1:5sz/EEAK+ls5wF+NeqDpk5+iNdMDXrh3z3nPnH1Wvgk=
+github.com/bahlo/generic-list-go v0.2.0/go.mod h1:2KvAjgMlE5NNynlg/5iLrrCCZ2+5xWbdbCW3pNTGyYg=
 github.com/becheran/wildmatch-go v1.0.0 h1:mE3dGGkTmpKtT4Z+88t8RStG40yN9T+kFEGj2PZFSzA=
 github.com/becheran/wildmatch-go v1.0.0/go.mod h1:gbMvj0NtVdJ15Mg/mH9uxk2R1QCistMyU7d9KFzroX4=
 github.com/beorn7/perks v0.0.0-20160804104726-4c0e84591b9a/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
@@ -150,6 +152,7 @@ github.com/briandowns/spinner v1.23.2 h1:Zc6ecUnI+YzLmJniCfDNaMbW0Wid1d5+qcTq4L2
 github.com/briandowns/spinner v1.23.2/go.mod h1:LaZeM4wm2Ywy6vO571mvhQNRcWfRUnXOs0RcKV0wYKM=
 github.com/bshuster-repo/logrus-logstash-hook v0.4.1/go.mod h1:zsTqEiSzDgAa/8GZR7E1qaXrhYNDKBYy5/dWPTIflbk=
 github.com/buger/jsonparser v0.0.0-20180808090653-f4dd9f5a6b44/go.mod h1:bbYlZJ7hK1yFx9hf58LP0zeX7UjIGs20ufpu3evjr+s=
+github.com/buger/jsonparser v1.1.1 h1:2PnMjfWD7wBILjqQbt530v576A/cAbQvEW9gGIpYMUs=
 github.com/buger/jsonparser v1.1.1/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
 github.com/bugsnag/bugsnag-go v0.0.0-20141110184014-b1d153021fcd/go.mod h1:2oa8nejYd4cQ/b0hMIopN0lCRxU0bueqREvZLWFrtK8=
 github.com/bugsnag/osext v0.0.0-20130617224835-0dd3f918b21b/go.mod h1:obH5gd0BsqsP2LwDJ9aOkm/6J86V6lyAXCoQWGw3K50=
@@ -774,6 +777,8 @@ github.com/in-toto/in-toto-golang v0.10.0/go.mod h1:wjT4RiyFlLWCmLUJjwB8oZcjaq7H
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/invopop/jsonschema v0.13.0 h1:KvpoAJWEjR3uD9Kbm2HWJmqsEaHt8lBUpd0qHcIi21E=
+github.com/invopop/jsonschema v0.13.0/go.mod h1:ffZ5Km5SWWRAIN6wbDXItl95euhFz2uON45H2qjYt+0=
 github.com/j-keck/arping v0.0.0-20160618110441-2cf9dc699c56/go.mod h1:ymszkNOg6tORTn+6F6j+Jc8TOr5osrynvN6ivFWZ2GA=
 github.com/j-keck/arping v1.0.2/go.mod h1:aJbELhR92bSk7tp79AWM/ftfc90EfEi2bQJrbBFOsPw=
 github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 h1:BQSFePA1RWJOlocH6Fxy8MmwDt+yVQYULKfN0RoTN8A=
@@ -840,6 +845,7 @@ github.com/mailru/easyjson v0.0.0-20190614124828-94de47d64c63/go.mod h1:C1wdFJiN
 github.com/mailru/easyjson v0.0.0-20190626092158-b2ccc519800e/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
 github.com/mailru/easyjson v0.7.0/go.mod h1:KAzv3t3aY1NaHWoQz1+4F1ccyAH66Jk7yos7ldAVICs=
 github.com/mailru/easyjson v0.7.6/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
+github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/markbates/oncer v0.0.0-20181203154359-bf2de49a0be2/go.mod h1:Ld9puTsIW75CHf65OeIOkyKbteujpZVXDpWK6YGZbxE=
 github.com/markbates/safe v1.0.1/go.mod h1:nAqgmRi7cY2nqMc92/bSEeQA+R4OheNU2T1kNSCBdG0=
@@ -1093,6 +1099,8 @@ github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/safchain/ethtool v0.0.0-20190326074333-42ed695e3de8/go.mod h1:Z0q5wiBQGYcxhMZ6gUqHn6pYNLypFAvaL3UvgZLR0U4=
 github.com/safchain/ethtool v0.0.0-20210803160452-9aa261dae9b1/go.mod h1:Z0q5wiBQGYcxhMZ6gUqHn6pYNLypFAvaL3UvgZLR0U4=
+github.com/santhosh-tekuri/jsonschema/v5 v5.3.1 h1:lZUw3E0/J3roVtGQ+SCrUrg3ON6NgVqpn3+iol9aGu4=
+github.com/santhosh-tekuri/jsonschema/v5 v5.3.1/go.mod h1:uToXkOrWAZ6/Oc07xWQrPOhJotwFIyu2bBVN41fcDUY=
 github.com/santhosh-tekuri/jsonschema/v6 v6.0.2 h1:KRzFb2m7YtdldCEkzs6KqmJw4nqEVZGK7IN2kJkjTuQ=
 github.com/santhosh-tekuri/jsonschema/v6 v6.0.2/go.mod h1:JXeL+ps8p7/KNMjDQk3TCwPpBy0wYklyWTfbkIzdIFU=
 github.com/sasha-s/go-deadlock v0.3.5 h1:tNCOEEDG6tBqrNDOX35j/7hL5FcFViG6awUGROb2NsU=
@@ -1257,6 +1265,8 @@ github.com/wagoodman/go-progress v0.0.0-20260303201901-10176f79b2c0 h1:EHsPe0Q0A
 github.com/wagoodman/go-progress v0.0.0-20260303201901-10176f79b2c0/go.mod h1:g/D9uEUFp5YLyciwCpVsSOZOm56hfv4rzGJod6MlqIM=
 github.com/willf/bitset v1.1.11-0.20200630133818-d5bec3311243/go.mod h1:RjeCKbqT1RxIR/KWY6phxZiaY1IyutSBfGjNPySAYV4=
 github.com/willf/bitset v1.1.11/go.mod h1:83CECat5yLh5zVOf4P1ErAgKA5UDvKtgyUABdr3+MjI=
+github.com/wk8/go-ordered-map/v2 v2.1.8 h1:5h/BUHu93oj4gIdvHHHGsScSTMijfx5PeYkE/fJgbpc=
+github.com/wk8/go-ordered-map/v2 v2.1.8/go.mod h1:5nJHM5DyteebpVlHnWMV0rPz6Zp7+xBAnxjb1X5vnTw=
 github.com/x448/float16 v0.8.4 h1:qLwI1I70+NjRFUR3zs1JPUCgaCXSh3SW62uAKT1mSBM=
 github.com/x448/float16 v0.8.4/go.mod h1:14CWIYCyZA/cWjXOioeEpHeN/83MdbZDRQHoFcYsOfg=
 github.com/xanzy/ssh-agent v0.3.3 h1:+/15pJfg/RsTxqYcX6fHqOXZwwMP+2VyYWJeWM2qQFM=
@@ -1784,6 +1794,8 @@ k8s.io/kubernetes v1.13.0/go.mod h1:ocZa8+6APFNC2tX1DZASIbocyYT5jHzqFVsY5aoB7Jk=
 k8s.io/utils v0.0.0-20201110183641-67b214c5f920/go.mod h1:jPW/WVKK9YHAvNhRxK0md/EJ228hCsBRufyofKtW8HA=
 k8s.io/utils v0.0.0-20251002143259-bc988d571ff4 h1:SjGebBtkBqHFOli+05xYbK8YF1Dzkbzn+gDM4X9T4Ck=
 k8s.io/utils v0.0.0-20251002143259-bc988d571ff4/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
+mvdan.cc/sh/v3 v3.12.0 h1:ejKUR7ONP5bb+UGHGEG/k9V5+pRVIyD+LsZz7o8KHrI=
+mvdan.cc/sh/v3 v3.12.0/go.mod h1:Se6Cj17eYSn+sNooLZiEUnNNmNxg0imoYlTu4CyaGyg=
 oras.land/oras-go/v2 v2.6.0 h1:X4ELRsiGkrbeox69+9tzTu492FMUu7zJQW6eJU+I2oc=
 oras.land/oras-go/v2 v2.6.0/go.mod h1:magiQDfG6H1O9APp+rOsvCPcW1GD2MM7vgnKY0Y+u1o=
 pgregory.net/rapid v1.2.0 h1:keKAYRcjm+e1F0oAuU5F5+YPAWcyxNNRK2wud503Gnk=
@@ -1811,5 +1823,7 @@ sigs.k8s.io/yaml v1.6.0 h1:G8fkbMSAFqgEFgh4b1wmtzDnioxFCUgTZhlbj5P9QYs=
 sigs.k8s.io/yaml v1.6.0/go.mod h1:796bPqUfzR/0jLAl6XjHl3Ck7MiyVv8dbTdyT3/pMf4=
 unikraft.com/cloud/sdk v0.0.0-20260409121557-1159639ea4e0 h1:ubn0DJHMIEStyubwa1Pi5r6kgQ8lSCtSPyU7kom2bEY=
 unikraft.com/cloud/sdk v0.0.0-20260409121557-1159639ea4e0/go.mod h1:k4SxfgQFvFmUrBPVIMlU1eYPId9lCkO9/6J9o1sL08s=
+unikraft.com/x/kraftfile v0.0.0-20260427093726-3fccc9bca88d h1:btmDzQqVgwN4lHyK4JjJkKxh5Nse9WaL5dUJ/Dl6NgQ=
+unikraft.com/x/kraftfile v0.0.0-20260427093726-3fccc9bca88d/go.mod h1:OYaIMOzV1IpbZCe2J3SuC5jvT4tAfR0XG9uOPPD+p50=
 xenbits.xenproject.org/git-http/xen.git/tools/golang/xenlight v0.0.0-20240729172045-026c9fa29716 h1:y52AcO4BZop/FrR523z47VCLFViGmMJqY21uL+FxXXI=
 xenbits.xenproject.org/git-http/xen.git/tools/golang/xenlight v0.0.0-20240729172045-026c9fa29716/go.mod h1:tbZ4iMnk8RWkXPxTiCGdAw3hCOa3feShlf3sBh50uIc=

initrd/file.go

@@ -13,6 +13,8 @@ import (
 	"kraftkit.sh/fs/cpio"
 	"kraftkit.sh/fs/erofs"
 	"kraftkit.sh/fsutils"
+
+	kraftfilev07 "unikraft.com/x/kraftfile"
 )
 
 type file struct {
@@ -96,7 +98,7 @@ reevaluateFsType:
 
 // detectFsType attempts to convert from the 'unknown' filesystem type to one
 // of the known types like 'cpio'/'erofs'/'file'.
-func detectFsType(source string) FsType {
+func detectFsType(source string) kraftfilev07.FsType {
 	switch {
 	case fsutils.IsErofsFile(source):
 		return FsTypeErofs

initrd/options.go

@@ -7,6 +7,8 @@ package initrd
 import (
 	"fmt"
 
+	kraftfilev07 "unikraft.com/x/kraftfile"
+
 	"kraftkit.sh/config"
 )
 
@@ -24,7 +26,7 @@ type InitrdOptions struct {
 	buildSecrets map[string]InitrdBuildSecret
 	cacheDir     string
 	compress     bool
-	fsType       FsType
+	fsType       kraftfilev07.FsType
 	keepOwners   bool
 	output       string
 	rootfsPath   string
@@ -126,7 +128,7 @@ func WithOutput(output string) InitrdOption {
 }
 
 // WithOutputType sets the output type of the resulting root filesystem.
-func WithOutputType(fsType FsType) InitrdOption {
+func WithOutputType(fsType kraftfilev07.FsType) InitrdOption {
 	return func(opts *InitrdOptions) error {
 		if fsType == "" {
 			return nil
@@ -194,25 +196,18 @@ func WithAuths(auths map[string]config.AuthConfig) InitrdOption {
 	}
 }
 
-type FsType string
-
+// extended types on the top of kraftfilev07 defined FsTypes
 const (
-	FsTypeCpio    = FsType("cpio")
-	FsTypeErofs   = FsType("erofs")
-	FsTypeFile    = FsType("file")
-	FsTypeUnknown = FsType("unknown")
-)
+	FsTypeFile    = kraftfilev07.FsType("file")
+	FsTypeUnknown = kraftfilev07.FsType("unknown")
 
-var _ fmt.Stringer = (*FsType)(nil)
-
-// String implements fmt.Stringer
-func (fsType FsType) String() string {
-	return string(fsType)
-}
+	FsTypeCpio  = kraftfilev07.FsTypeCpio
+	FsTypeErofs = kraftfilev07.FsTypeErofs
+)
 
 // FsTypes returns the list of possible fsTypes.
-func FsTypes() []FsType {
-	return []FsType{
+func FsTypes() []kraftfilev07.FsType {
+	return []kraftfilev07.FsType{
 		FsTypeCpio,
 		FsTypeErofs,
 		FsTypeFile,

initrd/rootfs.go

@@ -12,6 +12,8 @@ import (
 	"path/filepath"
 	"strings"
 
+	kraftfilev07 "unikraft.com/x/kraftfile"
+
 	"kraftkit.sh/config"
 	"kraftkit.sh/log"
 	"kraftkit.sh/tui/processtree"
@@ -82,39 +84,49 @@ func BuildRootfs(ctx context.Context, opts ...InitrdOption) (Initrd, []string, [
 	return ramfs, cmds, envs, nil
 }
 
-// BuildRoms generates ROM filesystems based on the provided ROM paths.
-func BuildRoms(ctx context.Context, workdir string, roms []string, compress, keepOwners bool, arch string, fsType FsType) ([]string, error) {
-	if len(roms) == 0 || fsType == "" {
-		return roms, nil
+// BuildRoms generates ROM filesystems based on the provided ROM FS (kraftfilev07.FS).
+func BuildRoms(ctx context.Context, workdir string, roms []kraftfilev07.FS, compress, keepOwners bool, arch string, defaultFsType kraftfilev07.FsType) ([]kraftfilev07.FS, error) {
+	if len(roms) == 0 {
+		return nil, nil
 	}
 
 	var processes []*processtree.ProcessTreeItem
-	builtRoms := make([]string, len(roms))
+	builtRoms := make([]kraftfilev07.FS, len(roms))
 	for i, rom := range roms {
+		fsType := rom.Format
+		if fsType == "" {
+			fsType = defaultFsType
+		}
+
+		if fsType == "" {
+			builtRoms[i] = rom
+			continue
+		}
+
 		// Check if the ROM is a directory; if it's a file, skip building and use as-is
-		romPath := rom
-		if !filepath.IsAbs(rom) {
-			romPath = filepath.Join(workdir, rom)
+		romPath := rom.Source
+		if !filepath.IsAbs(rom.Source) {
+			romPath = filepath.Join(workdir, rom.Source)
 		}
 
 		info, err := os.Stat(romPath)
 		if err != nil {
-			return nil, fmt.Errorf("could not stat ROM path '%s': %w", rom, err)
+			return nil, fmt.Errorf("could not stat ROM path '%s': %w", rom.Source, err)
 		}
 
 		// If it's a regular file, don't try to build it as a filesystem
 		if !info.IsDir() && !strings.Contains(strings.ToLower(info.Name()), "dockerfile") {
 			// File ROMs must be aligned to page size
 			const pageSize = 4096
 			if info.Size()%pageSize != 0 {
-				return nil, fmt.Errorf("ROM file '%s' size (%d bytes) is not aligned to page size (%d bytes)", rom, info.Size(), pageSize)
+				return nil, fmt.Errorf("ROM file '%s' size (%d bytes) is not aligned to page size (%d bytes)", rom.Source, info.Size(), pageSize)
 			}
 			builtRoms[i] = rom
 			continue
 		}
 
 		ramfs, err := New(ctx,
-			rom,
+			rom.Source,
 			WithWorkdir(workdir),
 			WithOutput(filepath.Join(
 				workdir,
@@ -132,7 +144,7 @@ func BuildRoms(ctx context.Context, workdir string, roms []string, compress, kee
 			WithOutputType(fsType),
 		)
 		if err != nil {
-			return nil, fmt.Errorf("could not initialize ROM builder for '%s': %w", rom, err)
+			return nil, fmt.Errorf("could not initialize ROM builder for '%s': %w", rom.Source, err)
 		}
 
 		processes = append(processes,
@@ -145,7 +157,10 @@ func BuildRoms(ctx context.Context, workdir string, roms []string, compress, kee
 						return err
 					}
 
-					builtRoms[i] = builtRom
+					builtRoms[i] = kraftfilev07.FS{
+						Source: builtRom,
+						Format: fsType,
+					}
 					return nil
 				},
 			),

internal/cli/kraft/build/build.go

@@ -30,6 +30,8 @@ import (
 	"kraftkit.sh/unikraft"
 	"kraftkit.sh/unikraft/app"
 	"kraftkit.sh/unikraft/target"
+
+	kraftfilev07 "unikraft.com/x/kraftfile"
 )
 
 var ErrContextNotBuildable = fmt.Errorf("could not determine what or how to build from the given context")
@@ -57,7 +59,7 @@ type BuildOptions struct {
 	PrintStats     bool                  `long:"print-stats" usage:"Print build statistics"`
 	Project        app.Application       `noattribute:"true"`
 	Rootfs         string                `long:"rootfs" usage:"Specify a path to use as root file system (can be volume or initramfs)"`
-	RootfsType     initrd.FsType         `noattribute:"true"`
+	RootfsType     kraftfilev07.FsType   `noattribute:"true"`
 	KeepFileOwners bool                  `local:"true" long:"keep-file-owners" usage:"Keep file owners (user:group) in the rootfs (false sets 'root:root')"`
 	SaveBuildLog   string                `long:"build-log" usage:"Use the specified file to save the output from the build"`
 	Target         *target.Target        `noattribute:"true"`
@@ -128,8 +130,7 @@ func Build(ctx context.Context, opts *BuildOptions, args ...string) error {
 			initrd.WithWorkdir(opts.Workdir),
 			initrd.WithKeepOwners(opts.KeepFileOwners),
 			initrd.WithOutput(filepath.Join(
-				opts.Workdir,
-				unikraft.BuildDir,
+				buildOutputDir(opts.Project, opts.Workdir),
 				fmt.Sprintf(initrd.DefaultInitramfsArchFileName, (*opts.Target).Architecture(), opts.RootfsType),
 			)),
 			initrd.WithOutputType(opts.RootfsType),
@@ -205,7 +206,7 @@ func NewCmd() *cobra.Command {
 	}
 
 	cmd.Flags().Var(
-		cmdfactory.NewEnumFlag[initrd.FsType](
+		cmdfactory.NewEnumFlag[kraftfilev07.FsType](
 			initrd.FsTypes(),
 			initrd.FsTypeCpio,
 		),
@@ -225,7 +226,7 @@ func (opts *BuildOptions) Pre(cmd *cobra.Command, args []string) error {
 	cmd.SetContext(ctx)
 
 	if cmd.Flag("rootfs-type").Changed && cmd.Flag("rootfs-type").Value.String() != "" {
-		opts.RootfsType = initrd.FsType(cmd.Flag("rootfs-type").Value.String())
+		opts.RootfsType = kraftfilev07.FsType(cmd.Flag("rootfs-type").Value.String())
 	}
 
 	if opts.Rootfs != "" && !filepath.IsAbs(opts.Rootfs) && !strings.Contains(opts.Rootfs, "://") {
@@ -263,7 +264,7 @@ func (opts *BuildOptions) Run(ctx context.Context, args []string) error {
 		if ok {
 			standardName, err := target.KernelName(*tc)
 			if err == nil {
-				standardPath := filepath.Join(opts.Workdir, unikraft.BuildDir, standardName)
+				standardPath := filepath.Join(buildOutputDir(opts.Project, opts.Workdir), standardName)
 				desiredPath := t.Kernel()
 
 				// If they are different, it means either --kernel was used or 'output'
@@ -360,6 +361,14 @@ func (opts *BuildOptions) Run(ctx context.Context, args []string) error {
 	return nil
 }
 
+func buildOutputDir(project app.Application, workdir string) string {
+	if project != nil && project.OutDir() != "" {
+		return project.OutDir()
+	}
+
+	return filepath.Join(workdir, unikraft.BuildDir)
+}
+
 func moveFile(src, dst string) error {
 	// Ensure the destination directory exists.
 	if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {