Kubernetes CSI - in-tree plugin Attacher/Detacher API #55809
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| /* | ||
| Copyright 2014 The Kubernetes Authors. | ||
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| Licensed under the Apache License, Version 2.0 (the "License"); | ||
| you may not use this file except in compliance with the License. | ||
| You may obtain a copy of the License at | ||
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| http://www.apache.org/licenses/LICENSE-2.0 | ||
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| Unless required by applicable law or agreed to in writing, software | ||
| distributed under the License is distributed on an "AS IS" BASIS, | ||
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| See the License for the specific language governing permissions and | ||
| limitations under the License. | ||
| */ | ||
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| package csi | ||
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| import ( | ||
| "crypto/sha256" | ||
| "errors" | ||
| "fmt" | ||
| "time" | ||
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| "github.com/golang/glog" | ||
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| "k8s.io/api/core/v1" | ||
| storage "k8s.io/api/storage/v1alpha1" | ||
| meta "k8s.io/apimachinery/pkg/apis/meta/v1" | ||
| "k8s.io/apimachinery/pkg/types" | ||
| "k8s.io/client-go/kubernetes" | ||
| "k8s.io/kubernetes/pkg/volume" | ||
| ) | ||
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| type csiAttacher struct { | ||
| plugin *csiPlugin | ||
| k8s kubernetes.Interface | ||
| waitSleepTime time.Duration | ||
| } | ||
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| // volume.Attacher methods | ||
| var _ volume.Attacher = &csiAttacher{} | ||
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| func (c *csiAttacher) Attach(spec *volume.Spec, nodeName types.NodeName) (string, error) { | ||
| if spec == nil { | ||
| return "", errors.New("missing spec") | ||
| } | ||
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| if spec.PersistentVolume == nil { | ||
| return "", errors.New("missing persistent volume") | ||
| } | ||
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| // namespace := spec.PersistentVolume.GetObjectMeta().GetNamespace() | ||
| pvName := spec.PersistentVolume.GetName() | ||
| attachID := fmt.Sprintf("pv-%s", hashAttachmentName(pvName, string(nodeName))) | ||
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| attachment := &storage.VolumeAttachment{ | ||
| ObjectMeta: meta.ObjectMeta{ | ||
| Name: attachID, | ||
| // Namespace: namespace, TODO should VolumeAttachment namespaced ? | ||
| }, | ||
| Spec: storage.VolumeAttachmentSpec{ | ||
| NodeName: string(nodeName), | ||
| Attacher: csiPluginName, | ||
| Source: storage.VolumeAttachmentSource{ | ||
| PersistentVolumeName: &pvName, | ||
| }, | ||
| }, | ||
| } | ||
| attach, err := c.k8s.StorageV1alpha1().VolumeAttachments().Create(attachment) | ||
| if err != nil { | ||
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There was a problem hiding this comment. You should ignore AlreadyExists error here - Attach will be called periodically, but VolumeAttachment will be already there. There is There was a problem hiding this comment. ah ok, thanks will look into this - TODO P1 |
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| glog.Error(log("attacher.Attach failed: %v", err)) | ||
| return "", err | ||
| } | ||
| glog.V(4).Info(log("volume attachment sent: [%v]", attach.GetName())) | ||
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| return attach.GetName(), nil | ||
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There was a problem hiding this comment. You should wait for a while until There was a problem hiding this comment. Question: Probably not actually do a wait loop here, but instead act on the event state change as a next step, right? There was a problem hiding this comment. @jsafrane I thought the Attacher.WaitForAttach() method is where that is done ? But will look into AWS/GCE for clues. TODO P1. |
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| } | ||
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| func (c *csiAttacher) WaitForAttach(spec *volume.Spec, attachID string, pod *v1.Pod, timeout time.Duration) (string, error) { | ||
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There was a problem hiding this comment.
There was a problem hiding this comment. @jsafrane ok I see your point. I can move the wait logic from |
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| glog.V(4).Info(log("waiting for attachment update from CSI driver [attachment.ID=%v]", attachID)) | ||
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| source, err := getCSISourceFromSpec(spec) | ||
| if err != nil { | ||
| glog.Error(log("attach.WaitForAttach failed to get volume source: %v", err)) | ||
| return "", err | ||
| } | ||
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| ticker := time.NewTicker(c.waitSleepTime) | ||
| defer ticker.Stop() | ||
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| timer := time.NewTimer(timeout) | ||
| defer timer.Stop() | ||
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| for { | ||
| select { | ||
| case <-ticker.C: | ||
| glog.V(4).Info(log("probing VolumeAttachment [id=%v]", attachID)) | ||
| attach, err := c.k8s.StorageV1alpha1().VolumeAttachments().Get(attachID, meta.GetOptions{}) | ||
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There was a problem hiding this comment. Add a TODO to revisit this and replace it with a watch instead of poll. There was a problem hiding this comment. Ok will do. TODO P2 |
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| if err != nil { | ||
| // log error, but continue to check again | ||
| glog.Error(log("attacher.WaitForAttach failed (will continue to try): %v", err)) | ||
| } | ||
| // attachment OK | ||
| if attach.Status.Attached { | ||
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There was a problem hiding this comment. If There was a problem hiding this comment. Ok, good catch, will add a |
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| return attachID, nil | ||
| } | ||
| // driver reports attach error | ||
| attachErr := attach.Status.AttachError | ||
| if attachErr != nil { | ||
| glog.Error(log("attachment for %v failed: %v", source.VolumeHandle, attachErr.Message)) | ||
| return "", errors.New(attachErr.Message) | ||
| } | ||
| case <-timer.C: | ||
| glog.Error(log("attacher.WaitForAttach timeout after %v [volume=%v; attachment.ID=%v]", timeout, source.VolumeHandle, attachID)) | ||
| return "", fmt.Errorf("attachment timeout for volume %v", source.VolumeHandle) | ||
| } | ||
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| } | ||
| } | ||
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| func (c *csiAttacher) VolumesAreAttached(specs []*volume.Spec, nodeName types.NodeName) (map[*volume.Spec]bool, error) { | ||
| return nil, errors.New("unimplemented") | ||
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There was a problem hiding this comment. This must be implemented. At least you should check that There was a problem hiding this comment. Ok, will implement |
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| } | ||
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| func (c *csiAttacher) GetDeviceMountPath(spec *volume.Spec) (string, error) { | ||
| return "", errors.New("unimplemented") | ||
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There was a problem hiding this comment. This must be implemented and it should be the same as GetPath() There was a problem hiding this comment. Probably we don't need to implement this as we don't implement MountDevice. There was a problem hiding this comment. Ok got it. |
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| } | ||
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| func (c *csiAttacher) MountDevice(spec *volume.Spec, devicePath string, deviceMountPath string) error { | ||
| return errors.New("unimplemented") | ||
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There was a problem hiding this comment. This must be implemented. It should be the same as SetUp. DevicePath is probably empty. There was a problem hiding this comment. Probably we don't need to implement this, kubelet should use SetupAt. But it should not return an error though. There was a problem hiding this comment. @jsafrane the last sentence |
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| } | ||
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| var _ volume.Detacher = &csiAttacher{} | ||
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| func (c *csiAttacher) Detach(deviceName string, nodeName types.NodeName) error { | ||
| return errors.New("unimplemented") | ||
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There was a problem hiding this comment. Delete There was a problem hiding this comment. Ok, got it. Implement |
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| } | ||
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| func (c *csiAttacher) UnmountDevice(deviceMountPath string) error { | ||
| return errors.New("unimplemented") | ||
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There was a problem hiding this comment. This must be implemented and should follow the same pattern as There was a problem hiding this comment. Probably we don't need to implement this, kubelet should use TearDown. But it should not return an error though. There was a problem hiding this comment. @jsafrane ok will need to understand why not returning error. There was a problem hiding this comment. Got it. |
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| } | ||
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| func hashAttachmentName(pvName, nodeName string) string { | ||
| result := sha256.Sum256([]byte(fmt.Sprintf("%s%s", pvName, nodeName))) | ||
| return fmt.Sprintf("%x", result) | ||
| } | ||
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Nope,
VolumeAttachment, likePersistentVolumeis non-namespaced because it is a cluster resource.There was a problem hiding this comment.
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Ok, got it.