Bug 1421370 - OCP dynamic storage provisioning uses wrong storage backed to allocate PV when PVC is created dynamically on EC2
Summary: OCP dynamic storage provisioning uses wrong storage backed to allocate PV whe...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: OpenShift Container Platform
Classification: Red Hat
Component: Storage
Version: 3.5.0
Hardware: x86_64
OS: Linux
unspecified
medium
Target Milestone: ---
: ---
Assignee: Bradley Childs
QA Contact: Jianwei Hou
URL:
Whiteboard: aos-scalability-35
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-02-11 17:14 UTC by Elvir Kuric
Modified: 2017-02-13 16:08 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
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Clone Of:
Environment:
Last Closed: 2017-02-13 16:08:15 UTC
Target Upstream Version:


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Description Elvir Kuric 2017-02-11 17:14:13 UTC
Description of problem:

dynamic storage provisioning does not respect storage backend defined in storage class when allocating PVC and allocate PVC from different storage backend than one specified in storageclass

Version-Release number of selected component (if applicable):

installed software : 

atomic-openshift-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-dockerregistry-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-clients-redistributable-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-clients-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-utils-3.5.3-1.git.0.80c2436.el7.noarch
tuned-profiles-atomic-2.7.1-3.el7_3.1.noarch
tuned-profiles-atomic-openshift-node-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-sdn-ovs-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-master-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-node-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-tests-3.5.0.17-1.git.0.c55cf2b.el7.x86_64
atomic-openshift-pod-3.5.0.17-1.git.0.c55cf2b.el7.x86_64


How reproducible:

always 

Steps to Reproduce:

1. Install v3.5 on ec2 ( this issue was noticed with above packages ) 
2. Configure OCP to use ec2 as storage backend 

cloud-config:
    - /etc/origin/cloudprovider/aws.conf
    cloud-provider:
    - aws
  controllerArguments: 
    cloud-config:
    - /etc/origin/cloudprovider/aws.conf
    cloud-provider:
    - aws


3. next,configure CNS pods on same OCP installation ( cns-deploy -n <namespace> topology.json > 

4. Create storageclass and point it to use CNS 

apiVersion: storage.k8s.io/v1beta1
kind: StorageClass
metadata:
  name: elclass
provisioner: kubernetes.io/glusterfs
parameters:
  resturl: "http://172.25.108.77:8080"
  restuser: "admin"

---- 

# oc describe storageclass elclass 
Name:		elclass
IsDefaultClass:	No
Annotations:	<none>
Provisioner:	kubernetes.io/glusterfs
Parameters:	resturl=http://172.25.108.77:8080,restuser=admin
No events.
---- 
# curl http://172.25.108.77:8080/hello
Hello from Heketi

# oc get svc
NAME                      CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
deploy-heketi             172.25.108.77    <none>        8080/TCP   1d

5. Create PVC dynamically with PVC claim 

{
  "kind": "PersistentVolumeClaim",
  "apiVersion": "v1",
  "metadata": {
    "name": "pvcpers",
    "annotations": {
      "volume.alpha.kubernetes.io/storage-class": "elclass"
    }
  },
  "spec": {
    "accessModes": [
      "ReadWriteOnce"
    ],
    "resources": {
      "requests": {
        "storage": "5Gi"
      }
    }
  }
}

6. check 

# oc describe pvc < pvc name >
# oc describe pv < pv name > 

Actual results:

PVC will be allocated and it will use EBS storage backend and not CNS / gluster storage backend. In my test case 

# oc describe pvc pvcpers 
Name:		pvcpers
Namespace:	cnselko
StorageClass:	elclass
Status:		Bound
Volume:		pvc-1179c6c9-f066-11e6-a826-027132b7f605
Labels:		<none>
Capacity:	5Gi
Access Modes:	RWO
No events.


root@ip-172-31-4-145: ~ # oc describe pv pvc-1179c6c9-f066-11e6-a826-027132b7f605
Name:		pvc-1179c6c9-f066-11e6-a826-027132b7f605
Labels:		failure-domain.beta.kubernetes.io/region=us-west-2
		failure-domain.beta.kubernetes.io/zone=us-west-2b
StorageClass:	
Status:		Bound
Claim:		cnselko/pvcpers
Reclaim Policy:	Delete
Access Modes:	RWO
Capacity:	5Gi
Message:	
Source:
    Type:	AWSElasticBlockStore (a Persistent Disk resource in AWS)
    VolumeID:	aws://us-west-2b/vol-06b6895a3ebd96591
    FSType:	ext4
    Partition:	0
    ReadOnly:	false
No events.


Expected results:

PVC to be allocated per storage class definition 

Additional info:
if instead 

"volume.alpha.kubernetes.io/storage-class": "elclass"

is used 

      "volume.beta.kubernetes.io/storage-class": "elclass"

allocation works as expected - from CNS

Comment 1 Jianwei Hou 2017-02-13 00:45:29 UTC
With 'alpha' annotation, the PV will be provisioned irrespective of the storageclas. http://blog.kubernetes.io/2016/10/dynamic-provisioning-and-storage-in-kubernetes.html

Comment 2 Hemant Kumar 2017-02-13 16:08:15 UTC
Yeah the alpha annotation is in process of being phased out. It was a stop gap solution that didn't require a storageclass to be defined and hence any value you specify for "volume.alpha.kubernetes.io/storage-class" is immaterial (you can literally put "foobar" there and it will still work).

For creating PVs dynamically from storageclasses, you will have to use the "beta" annotation.


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