package cluster import ( "encoding/json" "io/ioutil" "os" "path/filepath" "github.com/docker/docker/pkg/ioutils" ) func loadPersistentState(root string) (*nodeStartConfig, error) { dt, err := ioutil.ReadFile(filepath.Join(root, stateFile)) if err != nil { return nil, err } // missing certificate means no actual state to restore from if _, err := os.Stat(filepath.Join(root, "certificates/swarm-node.crt")); err != nil { if os.IsNotExist(err) { clearPersistentState(root) } return nil, err } var st nodeStartConfig if err := json.Unmarshal(dt, &st); err != nil { return nil, err } return &st, nil } func savePersistentState(root string, config nodeStartConfig) error { dt, err := json.Marshal(config) if err != nil { return err } return ioutils.AtomicWriteFile(filepath.Join(root, stateFile), dt, 0600) } func clearPersistentState(root string) error { // todo: backup this data instead of removing? // rather than delete the entire swarm directory, delete the contents in order to preserve the inode // (for example, allowing it to be bind-mounted) files, err := ioutil.ReadDir(root) if err != nil { return err } for _, f := range files { if err := os.RemoveAll(filepath.Join(root, f.Name())); err != nil { return err } } return nil } func removingManagerCausesLossOfQuorum(reachable, unreachable int) bool { return reachable-2 <= unreachable } func isLastManager(reachable, unreachable int) bool { return reachable == 1 && unreachable == 0 }