open-nomad/client/csi_endpoint.go
Tim Gross 7d53ed88d6
csi: client RPCs should return wrapped errors for checking (#8605)
When the client-side actions of a CSI client RPC succeed but we get
disconnected during the RPC or we fail to checkpoint the claim state, we want
to be able to retry the client RPC without getting blocked by the client-side
state (ex. mount points) already having been cleaned up in previous calls.
2020-08-07 11:01:36 -04:00

237 lines
8.2 KiB
Go

package client
import (
"context"
"errors"
"fmt"
"time"
metrics "github.com/armon/go-metrics"
grpc_retry "github.com/grpc-ecosystem/go-grpc-middleware/retry"
"github.com/hashicorp/nomad/client/dynamicplugins"
"github.com/hashicorp/nomad/client/pluginmanager/csimanager"
"github.com/hashicorp/nomad/client/structs"
nstructs "github.com/hashicorp/nomad/nomad/structs"
"github.com/hashicorp/nomad/plugins/csi"
)
// CSI endpoint is used for interacting with CSI plugins on a client.
// TODO: Submit metrics with labels to allow debugging per plugin perf problems.
type CSI struct {
c *Client
}
const (
// CSIPluginRequestTimeout is the timeout that should be used when making reqs
// against CSI Plugins. It is copied from Kubernetes as an initial seed value.
// https://github.com/kubernetes/kubernetes/blob/e680ad7156f263a6d8129cc0117fda58602e50ad/pkg/volume/csi/csi_plugin.go#L52
CSIPluginRequestTimeout = 2 * time.Minute
)
var (
ErrPluginTypeError = errors.New("CSI Plugin loaded incorrectly")
)
// ControllerValidateVolume is used during volume registration to validate
// that a volume exists and that the capabilities it was registered with are
// supported by the CSI Plugin and external volume configuration.
func (c *CSI) ControllerValidateVolume(req *structs.ClientCSIControllerValidateVolumeRequest, resp *structs.ClientCSIControllerValidateVolumeResponse) error {
defer metrics.MeasureSince([]string{"client", "csi_controller", "validate_volume"}, time.Now())
if req.VolumeID == "" {
return errors.New("VolumeID is required")
}
if req.PluginID == "" {
return errors.New("PluginID is required")
}
plugin, err := c.findControllerPlugin(req.PluginID)
if err != nil {
// the server's view of the plugin health is stale, so let it know it
// should retry with another controller instance
return fmt.Errorf("%w: %v", nstructs.ErrCSIClientRPCRetryable, err)
}
defer plugin.Close()
csiReq, err := req.ToCSIRequest()
if err != nil {
return err
}
ctx, cancelFn := c.requestContext()
defer cancelFn()
// CSI ValidateVolumeCapabilities errors for timeout, codes.Unavailable and
// codes.ResourceExhausted are retried; all other errors are fatal.
return plugin.ControllerValidateCapabilities(ctx, csiReq,
grpc_retry.WithPerRetryTimeout(CSIPluginRequestTimeout),
grpc_retry.WithMax(3),
grpc_retry.WithBackoff(grpc_retry.BackoffExponential(100*time.Millisecond)))
}
// ControllerAttachVolume is used to attach a volume from a CSI Cluster to
// the storage node provided in the request.
//
// The controller attachment flow currently works as follows:
// 1. Validate the volume request
// 2. Call ControllerPublishVolume on the CSI Plugin to trigger a remote attachment
//
// In the future this may be expanded to request dynamic secrets for attachment.
func (c *CSI) ControllerAttachVolume(req *structs.ClientCSIControllerAttachVolumeRequest, resp *structs.ClientCSIControllerAttachVolumeResponse) error {
defer metrics.MeasureSince([]string{"client", "csi_controller", "publish_volume"}, time.Now())
plugin, err := c.findControllerPlugin(req.PluginID)
if err != nil {
// the server's view of the plugin health is stale, so let it know it
// should retry with another controller instance
return fmt.Errorf("%w: %v", nstructs.ErrCSIClientRPCRetryable, err)
}
defer plugin.Close()
// The following block of validation checks should not be reached on a
// real Nomad cluster as all of this data should be validated when registering
// volumes with the cluster. They serve as a defensive check before forwarding
// requests to plugins, and to aid with development.
if req.VolumeID == "" {
return errors.New("VolumeID is required")
}
if req.ClientCSINodeID == "" {
return errors.New("ClientCSINodeID is required")
}
csiReq, err := req.ToCSIRequest()
if err != nil {
return err
}
// Submit the request for a volume to the CSI Plugin.
ctx, cancelFn := c.requestContext()
defer cancelFn()
// CSI ControllerPublishVolume errors for timeout, codes.Unavailable and
// codes.ResourceExhausted are retried; all other errors are fatal.
cresp, err := plugin.ControllerPublishVolume(ctx, csiReq,
grpc_retry.WithPerRetryTimeout(CSIPluginRequestTimeout),
grpc_retry.WithMax(3),
grpc_retry.WithBackoff(grpc_retry.BackoffExponential(100*time.Millisecond)))
if err != nil {
return err
}
resp.PublishContext = cresp.PublishContext
return nil
}
// ControllerDetachVolume is used to detach a volume from a CSI Cluster from
// the storage node provided in the request.
func (c *CSI) ControllerDetachVolume(req *structs.ClientCSIControllerDetachVolumeRequest, resp *structs.ClientCSIControllerDetachVolumeResponse) error {
defer metrics.MeasureSince([]string{"client", "csi_controller", "unpublish_volume"}, time.Now())
plugin, err := c.findControllerPlugin(req.PluginID)
if err != nil {
// the server's view of the plugin health is stale, so let it know it
// should retry with another controller instance
return fmt.Errorf("%w: %v", nstructs.ErrCSIClientRPCRetryable, err)
}
defer plugin.Close()
// The following block of validation checks should not be reached on a
// real Nomad cluster as all of this data should be validated when registering
// volumes with the cluster. They serve as a defensive check before forwarding
// requests to plugins, and to aid with development.
if req.VolumeID == "" {
return errors.New("VolumeID is required")
}
if req.ClientCSINodeID == "" {
return errors.New("ClientCSINodeID is required")
}
csiReq := req.ToCSIRequest()
// Submit the request for a volume to the CSI Plugin.
ctx, cancelFn := c.requestContext()
defer cancelFn()
// CSI ControllerUnpublishVolume errors for timeout, codes.Unavailable and
// codes.ResourceExhausted are retried; all other errors are fatal.
_, err = plugin.ControllerUnpublishVolume(ctx, csiReq,
grpc_retry.WithPerRetryTimeout(CSIPluginRequestTimeout),
grpc_retry.WithMax(3),
grpc_retry.WithBackoff(grpc_retry.BackoffExponential(100*time.Millisecond)))
if err != nil {
if errors.Is(err, nstructs.ErrCSIClientRPCIgnorable) {
// if the controller detach previously happened but the server failed to
// checkpoint, we'll get an error from the plugin but can safely ignore it.
c.c.logger.Debug("could not unpublish volume: %v", err)
return nil
}
return err
}
return nil
}
// NodeDetachVolume is used to detach a volume from a CSI Cluster from
// the storage node provided in the request.
func (c *CSI) NodeDetachVolume(req *structs.ClientCSINodeDetachVolumeRequest, resp *structs.ClientCSINodeDetachVolumeResponse) error {
defer metrics.MeasureSince([]string{"client", "csi_node", "detach_volume"}, time.Now())
// The following block of validation checks should not be reached on a
// real Nomad cluster. They serve as a defensive check before forwarding
// requests to plugins, and to aid with development.
if req.PluginID == "" {
return errors.New("PluginID is required")
}
if req.VolumeID == "" {
return errors.New("VolumeID is required")
}
if req.AllocID == "" {
return errors.New("AllocID is required")
}
ctx, cancelFn := c.requestContext()
defer cancelFn()
mounter, err := c.c.csimanager.MounterForPlugin(ctx, req.PluginID)
if err != nil {
return err
}
usageOpts := &csimanager.UsageOptions{
ReadOnly: req.ReadOnly,
AttachmentMode: string(req.AttachmentMode),
AccessMode: string(req.AccessMode),
}
err = mounter.UnmountVolume(ctx, req.VolumeID, req.ExternalID, req.AllocID, usageOpts)
if err != nil && !errors.Is(err, nstructs.ErrCSIClientRPCIgnorable) {
// if the unmounting previously happened but the server failed to
// checkpoint, we'll get an error from Unmount but can safely
// ignore it.
return err
}
return nil
}
func (c *CSI) findControllerPlugin(name string) (csi.CSIPlugin, error) {
return c.findPlugin(dynamicplugins.PluginTypeCSIController, name)
}
func (c *CSI) findPlugin(ptype, name string) (csi.CSIPlugin, error) {
pIface, err := c.c.dynamicRegistry.DispensePlugin(ptype, name)
if err != nil {
return nil, err
}
plugin, ok := pIface.(csi.CSIPlugin)
if !ok {
return nil, ErrPluginTypeError
}
return plugin, nil
}
func (c *CSI) requestContext() (context.Context, context.CancelFunc) {
return context.WithTimeout(context.Background(), CSIPluginRequestTimeout)
}