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Change Summary v1.1

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Ranjith R edited this page Aug 2, 2019 · 3 revisions

Status: Completed ( 02-August-2019 )

New Capabilities

Enhancements

Major Bugs Fixed

Backward Incompatibilities

From 1.0.0: None. The upgrade scripts take care of migrating the existing custom resources to the new format. For previous releases, please refer to the respective release notes and upgrade steps.

Note: As part of OpenEBS upgrade or installation, maya-apiserver pod will restart if NDM blockdevice CRDs are not created before the creation of maya-apiserver. https://github.com/openebs/maya/pull/1381

Uninstall

The recommended steps to uninstall are:

  • delete all the OpenEBS PVCs that were created
  • delete all the SPCs (in case of cStor)
  • ensure that no volume or pool pods are pending in terminating state kubectl get pods -n <openebs namespace>
  • ensure that no openebs cStor volume custom resources are present kubectl get cvr -n <openebs namespace>
  • delete all openebs related StorageClasses.
  • delete the openebs either via helm purge or kubectl delete

Uninstalling OpenEBS doesn't automatically delete the CRDs that were created. If you would like to remove CRDs and the associated objects completely, run the following commands:

kubectl delete crd castemplates.openebs.io
kubectl delete crd cstorpools.openebs.io
kubectl delete crd cstorvolumereplicas.openebs.io
kubectl delete crd cstorvolumes.openebs.io
kubectl delete crd runtasks.openebs.io
kubectl delete crd storagepoolclaims.openebs.io
kubectl delete crd storagepools.openebs.io
kubectl delete crd volumesnapshotdatas.volumesnapshot.external-storage.k8s.io
kubectl delete crd volumesnapshots.volumesnapshot.external-storage.k8s.io
kubectl delete crd disks.openebs.io
kubectl delete crd blockdevices.openebs.io
kubectl delete crd blockdeviceclaims.openebs.io
kubectl delete crd cstorbackups.openebs.io
kubectl delete crd cstorrestores.openebs.io
kubectl delete crd cstorcompletedbackups.openebs.io
kubectl delete crd cstorpoolclusters.openebs.io

Note: As part of deleting the Jiva Volumes - OpenEBS launches scrub jobs for clearing data from the nodes. The completed jobs need to be cleared using the following command:

kubectl delete jobs -l openebs.io/cas-type=jiva -n <namespace>

Limitations / Known Issues

  • The current version of OpenEBS volumes are not optimized for performance-sensitive applications.
  • For taking the backup of cStor volume with OpenEBS velero-plugin, openebs must be installed in openebs namespace.
  • If a pending PVC related to openebs-device StorageClass is deleted, there are chances of getting stale BDCs which ends up in consuming BDs. You have to manually delete the BDC to reclaim it.
  • In OpenShift 3.10 or above, NDM daemon set pods and NDM operators will not be upgraded if NDM daemon set's DESIRED count is not equal to the CURRENT count. This may happen if nodeSelectors have been used to deploy OpenEBS related pods OR if master/other nodes have been tainted in the k8s cluster.
  • Jiva Controller and Replica pods are stuck in Terminating state when any instability with the node or network happens and the only way to remove those containers is by using docker rm -f on the node. https://github.com/openebs/openebs/issues/2675
  • cStor Target or Pool pods can at times be stuck in a Terminating state. They will need to be manually cleaned up using kubectl delete with 0 sec grace period. Example: kubectl delete deploy -n openebs --force --grace-period=0
  • cStor pool pods can consume more memory when there is continuous load. This can cross the memory limit and cause pod evictions. It is recommended that you create cStor pools by setting the Memory limits and requests.
  • Jiva Volumes are not recommended if your use case requires snapshots and clone capabilities.
  • Jiva Replicas use sparse file to store the data. When the application causes too many fragments (extents) to be created on the sparse file, the replica restart can cause replica to take longer time to get attached to the target. This issue was seen when there were 31K fragments created.
  • Volume Snapshots are dependent on the functionality provided by Kubernetes. The support is currently alpha. The only operations supported are:
    • Create Snapshot, Delete Snapshot and Clone from a Snapshot. Creation of the Snapshot uses a reconciliation loop, which would mean that a Create Snapshot operation will be retried on failure until the Snapshot has been successfully created. This may not be a desirable option in cases where Point in Time snapshots are expected.
  • If you are using K8s version earlier than 1.12, in certain cases, it will be observed that when the node hosting the target pod is offline, the target pod can take more than 120 seconds to get rescheduled. This is because target pods are configured with Tolerations based on the Node Condition, and TaintNodesByCondition is available only from K8s 1.12. If running an earlier version, you may have to enable the alpha gate for TaintNodesByCondition. If there is an active load on the volume when the target pod goes offline, the volume will be marked as read-only.
  • If you are using K8s version 1.13 or later, that includes the checks on ephemeral storage limits on the Pods, there is a chance that OpenEBS cStor and Jiva pods can get evicted - because there are no ephemeral requests specified. To avoid this issue, you can specify the ephemeral storage requests in the storage class or storage pool claim. (https://github.com/openebs/openebs/issues/2294)
  • When the disks used by a cStor Pool are detached and reattached, the cStor Pool may miss detecting this event in certain scenarios. Manual intervention may be required to bring the cStor Pool online. (https://github.com/openebs/openebs/issues/2363)
  • When the underlying disks used by cStor or Jiva volumes are under disk pressure due to heavy IO load, and if the Replicas take longer than 60 seconds to process the IO, the Volumes will get into Read-Only state. In 0.8.1, logs have been added to the cStor and Jiva replicas to indicate if IO has longer latency. (https://github.com/openebs/openebs/issues/2337)
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