From 29f07f854497571db570be79c8df878624f5b41c Mon Sep 17 00:00:00 2001 From: Michael Crosby Date: Mon, 18 Nov 2013 17:20:03 -0800 Subject: [PATCH] Add container migration to aufs driver --- graphdriver/aufs/aufs.go | 2 + graphdriver/aufs/migrate.go | 109 +++++++++++++++++++++++++++--------- runtime.go | 2 +- 3 files changed, 85 insertions(+), 28 deletions(-) diff --git a/graphdriver/aufs/aufs.go b/graphdriver/aufs/aufs.go index 9cfaf90996..cf42f363fc 100644 --- a/graphdriver/aufs/aufs.go +++ b/graphdriver/aufs/aufs.go @@ -107,6 +107,8 @@ func (AufsDriver) Status() [][2]string { return nil } +// Exists returns true if the given id is registered with +// this driver func (a AufsDriver) Exists(id string) bool { if _, err := os.Lstat(path.Join(a.rootPath(), "diff", id)); err != nil { return false diff --git a/graphdriver/aufs/migrate.go b/graphdriver/aufs/migrate.go index 4231ac2111..9cdce5faaa 100644 --- a/graphdriver/aufs/migrate.go +++ b/graphdriver/aufs/migrate.go @@ -6,17 +6,14 @@ import ( "io/ioutil" "os" "path" - "time" ) -type imageMetadata struct { - ID string `json:"id"` - ParentID string `json:"parent,omitempty"` - Created time.Time `json:"created"` - DockerVersion string `json:"docker_version,omitempty"` - Architecture string `json:"architecture,omitempty"` +type metadata struct { + ID string `json:"id"` + ParentID string `json:"parent,omitempty"` + Image string `json:"Image,omitempty"` - parent *imageMetadata + parent *metadata } func pathExists(pth string) bool { @@ -27,48 +24,106 @@ func pathExists(pth string) bool { } // Migrate existing images and containers from docker < 0.7.x -func (a *AufsDriver) Migrate(pth string) error { +// +// The format pre 0.7 is for docker to store the metadata and filesystem +// content in the same directory. For the migration to work we need to move Image layer +// data from /var/lib/docker/graph//layers to the diff of the registered id. +// +// Next we need to migrate the container's rw layer to diff of the driver. After the +// contents are migrated we need to register the image and container ids with the +// driver. +// +// For the migration we try to move the folder containing the layer files, if that +// fails because the data is currently mounted we will fallback to creating a +// symlink. +func (a *AufsDriver) Migrate(pth string, setupInit func(p string) error) error { + if pathExists(path.Join(pth, "graph")) { + if err := a.migrateImages(path.Join(pth, "graph")); err != nil { + return err + } + return a.migrateContainers(path.Join(pth, "containers"), setupInit) + } + return nil +} + +func (a *AufsDriver) migrateContainers(pth string, setupInit func(p string) error) error { + fis, err := ioutil.ReadDir(pth) + if err != nil { + return err + } + + for _, fi := range fis { + if id := fi.Name(); fi.IsDir() && pathExists(path.Join(pth, id, "rw")) && !a.Exists(id) { + if err := tryRelocate(path.Join(pth, id, "rw"), path.Join(a.rootPath(), "diff", id)); err != nil { + return err + } + + metadata, err := loadMetadata(path.Join(pth, id, "config.json")) + if err != nil { + return err + } + + initID := fmt.Sprintf("%s-init", id) + if err := a.Create(initID, metadata.Image); err != nil { + return err + } + + initPath, err := a.Get(initID) + if err != nil { + return err + } + // setup init layer + if err := setupInit(initPath); err != nil { + return err + } + + if err := a.Create(id, initID); err != nil { + return err + } + } + } + return nil +} + +func (a *AufsDriver) migrateImages(pth string) error { fis, err := ioutil.ReadDir(pth) if err != nil { return err } var ( - metadata = make(map[string]*imageMetadata) - current *imageMetadata - exists bool + m = make(map[string]*metadata) + current *metadata + exists bool ) - // Load metadata for _, fi := range fis { if id := fi.Name(); fi.IsDir() && pathExists(path.Join(pth, id, "layer")) && !a.Exists(id) { - if current, exists = metadata[id]; !exists { - current, err = loadMetadata(pth, id) + if current, exists = m[id]; !exists { + current, err = loadMetadata(path.Join(pth, id, "json")) if err != nil { return err } - metadata[id] = current + m[id] = current } } } - // Recreate tree - for _, v := range metadata { - v.parent = metadata[v.ParentID] + for _, v := range m { + v.parent = m[v.ParentID] } - // Perform image migration - for _, v := range metadata { - if err := migrateImage(v, a, pth); err != nil { + for _, v := range m { + if err := a.migrateImage(v, pth); err != nil { return err } } return nil } -func migrateImage(m *imageMetadata, a *AufsDriver, pth string) error { +func (a *AufsDriver) migrateImage(m *metadata, pth string) error { if !pathExists(path.Join(a.rootPath(), "diff", m.ID)) { if m.parent != nil { - migrateImage(m.parent, a, pth) + a.migrateImage(m.parent, pth) } if err := tryRelocate(path.Join(pth, m.ID, "layer"), path.Join(a.rootPath(), "diff", m.ID)); err != nil { return err @@ -92,15 +147,15 @@ func tryRelocate(oldPath, newPath string) error { return nil } -func loadMetadata(pth, id string) (*imageMetadata, error) { - f, err := os.Open(path.Join(pth, id, "json")) +func loadMetadata(pth string) (*metadata, error) { + f, err := os.Open(pth) if err != nil { return nil, err } defer f.Close() var ( - out = &imageMetadata{} + out = &metadata{} dec = json.NewDecoder(f) ) diff --git a/runtime.go b/runtime.go index 6eef38c842..1146079070 100644 --- a/runtime.go +++ b/runtime.go @@ -630,7 +630,7 @@ func NewRuntimeFromDirectory(config *DaemonConfig) (*Runtime, error) { } if ad, ok := driver.(*aufs.AufsDriver); ok { - if err := ad.Migrate(path.Join(config.Root, "graph")); err != nil { + if err := ad.Migrate(config.Root, setupInitLayer); err != nil { return nil, err } }