| package cluster // import "github.com/docker/docker/daemon/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 |
| } |