open-nomad/client/allocrunner/migrate_hook.go
2018-12-11 13:12:35 +01:00

57 lines
1.5 KiB
Go

package allocrunner
import (
"context"
"fmt"
log "github.com/hashicorp/go-hclog"
"github.com/hashicorp/nomad/client/allocdir"
"github.com/hashicorp/nomad/client/allocwatcher"
)
// diskMigrationHook migrates ephemeral disk volumes. Depends on alloc dir
// being built but must be run before anything else manipulates the alloc dir.
type diskMigrationHook struct {
allocDir *allocdir.AllocDir
allocWatcher allocwatcher.PrevAllocMigrator
logger log.Logger
}
func newDiskMigrationHook(logger log.Logger, allocWatcher allocwatcher.PrevAllocMigrator, allocDir *allocdir.AllocDir) *diskMigrationHook {
h := &diskMigrationHook{
allocDir: allocDir,
allocWatcher: allocWatcher,
}
h.logger = logger.Named(h.Name())
return h
}
func (h *diskMigrationHook) Name() string {
return "migrate_disk"
}
func (h *diskMigrationHook) Prerun(ctx context.Context) error {
// Wait for a previous alloc - if any - to terminate
if err := h.allocWatcher.Wait(ctx); err != nil {
return err
}
// Wait for data to be migrated from a previous alloc if applicable
if err := h.allocWatcher.Migrate(ctx, h.allocDir); err != nil {
if err == context.Canceled {
return err
}
// Soft-fail on migration errors
h.logger.Warn("error migrating data from previous alloc", "error", err)
// Recreate alloc dir to ensure a clean slate
h.allocDir.Destroy()
if err := h.allocDir.Build(); err != nil {
return fmt.Errorf("failed to clean task directories after failed migration: %v", err)
}
}
return nil
}