open-nomad/client/allocrunner/taskrunner/volume_hook.go

128 lines
3.9 KiB
Go

package taskrunner
import (
"context"
"fmt"
log "github.com/hashicorp/go-hclog"
multierror "github.com/hashicorp/go-multierror"
"github.com/hashicorp/nomad/client/allocrunner/interfaces"
"github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/plugins/drivers"
)
type volumeHook struct {
alloc *structs.Allocation
runner *TaskRunner
logger log.Logger
}
func newVolumeHook(runner *TaskRunner, logger log.Logger) *volumeHook {
h := &volumeHook{
alloc: runner.Alloc(),
runner: runner,
}
h.logger = logger.Named(h.Name())
return h
}
func (*volumeHook) Name() string {
return "volumes"
}
func validateHostVolumes(requestedByAlias map[string]*structs.VolumeRequest, clientVolumesByName map[string]*structs.ClientHostVolumeConfig) error {
var result error
for n, req := range requestedByAlias {
if req.Type != structs.VolumeTypeHost {
continue
}
cfg, err := structs.ParseHostVolumeConfig(req.Config)
if err != nil {
result = multierror.Append(result, fmt.Errorf("failed to parse config for %s: %v", n, err))
continue
}
_, ok := clientVolumesByName[cfg.Source]
if !ok {
result = multierror.Append(result, fmt.Errorf("missing %s", cfg.Source))
}
}
return result
}
// hostVolumeMountConfigurations takes the users requested volume mounts,
// volumes, and the client host volume configuration and converts them into a
// format that can be used by drivers.
func (h *volumeHook) hostVolumeMountConfigurations(taskMounts []*structs.VolumeMount, taskVolumesByAlias map[string]*structs.VolumeRequest, clientVolumesByName map[string]*structs.ClientHostVolumeConfig) ([]*drivers.MountConfig, error) {
var mounts []*drivers.MountConfig
for _, m := range taskMounts {
req, ok := taskVolumesByAlias[m.Volume]
if !ok {
// Should never happen unless we misvalidated on job submission
return nil, fmt.Errorf("No group volume declaration found named: %s", m.Volume)
}
cfg, err := structs.ParseHostVolumeConfig(req.Config)
if err != nil {
return nil, fmt.Errorf("failed to parse config for %s: %v", m.Volume, err)
}
hostVolume, ok := clientVolumesByName[cfg.Source]
if !ok {
// Should never happen, but unless the client volumes were mutated during
// the execution of this hook.
return nil, fmt.Errorf("No host volume named: %s", cfg.Source)
}
mcfg := &drivers.MountConfig{
HostPath: hostVolume.Path,
TaskPath: m.Destination,
Readonly: hostVolume.ReadOnly || req.ReadOnly || m.ReadOnly,
}
mounts = append(mounts, mcfg)
}
return mounts, nil
}
func (h *volumeHook) Prestart(ctx context.Context, req *interfaces.TaskPrestartRequest, resp *interfaces.TaskPrestartResponse) error {
volumes := h.alloc.Job.LookupTaskGroup(h.alloc.TaskGroup).Volumes
mounts := h.runner.hookResources.getMounts()
hostVolumes := h.runner.clientConfig.Node.HostVolumes
// Always validate volumes to ensure that we do not allow volumes to be used
// if a host is restarted and loses the host volume configuration.
if err := validateHostVolumes(volumes, hostVolumes); err != nil {
h.logger.Error("Requested Host Volume does not exist", "existing", hostVolumes, "requested", volumes)
return fmt.Errorf("host volume validation error: %v", err)
}
requestedMounts, err := h.hostVolumeMountConfigurations(req.Task.VolumeMounts, volumes, hostVolumes)
if err != nil {
h.logger.Error("Failed to generate volume mounts", "error", err)
return err
}
// Because this hook is also ran on restores, we only add mounts that do not
// already exist. Although this loop is somewhat expensive, there are only
// a small number of mounts that exist within most individual tasks. We may
// want to revisit this using a `hookdata` param to be "mount only once"
REQUESTED:
for _, m := range requestedMounts {
for _, em := range mounts {
if em.IsEqual(m) {
continue REQUESTED
}
}
mounts = append(mounts, m)
}
h.runner.hookResources.setMounts(mounts)
return nil
}