Overview¶

The documentation in this section illustrates officially HPE supported procedures to perform maintenance tasks on the CSI driver outside the scope of deploying and uninstalling the driver.

Migrate Encrypted Volumes¶

Persistent volumes created with v2.1.1 or below using volume encryption, the CSI driver use LUKS2 (WikiPedia: Linux Unified Key Setup) and can't expand the PersistentVolumeClaim. With v2.2.0 and above, LUKS1 is used and the CSI driver is capable of expanding the PVC.

This procedure migrate (copy) data from LUKS2 to LUKS1 PVCs to allow expansion of the volume.

Assumptions¶

These are the assumptions made throughout this procedure.

• Data to be migrated has a good backup to restore to, not just a snapshot.
• HPE CSI Driver for Kubernetes v2.3.0 or later installed.
• Worker nodes with access to the Quay registry and SCOD.
• Access to the commands kubectl, curl, jq and yq.
• Cluster privileges to manipulate PersistentVolumes.
• None of the commands executed should return errors or have non-zero exit codes.
• Only ReadWriteOnce PVCs are covered.
• No custom PVC annotations.

Prepare the Workload and Persistent Volume Claims¶

First, identify the PersistentVolume to migrate from and set shell variables.

export OLD_SRC_PVC=<insert your existing PVC name here>
export OLD_SRC_PV=$(kubectl get pvc -o json | \
       jq -r ".items[] | \
        select(.metadata.name | \
        test(\"${OLD_SRC_PVC}\"))".spec.volumeName)

In order to copy data out of a PVC, the running workload needs to be disassociated with the PVC. It's not possible to scale the replicas to zero, the exception being ReadWriteMany PVCs which could lead to data inconsistency problems. These procedures assumes application consistency by having the workload shut down.

It's out of scope for this procedure to demonstrate how to shut down a particular workload. Ensure there are no volumeattachments associated with the PersistentVolume.

kubectl get volumeattachment -o json | \
 jq -r ".items[] | \
  select(.spec.source.persistentVolumeName | \
  test(\"${OLD_SRC_PV}\"))".spec.source

Create a new Persistent Volume Claim and Update Retain Policies¶

Create a new PVC named "new-pvc" with enough space to host the data from the old source PVC.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: new-pvc
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 32Gi
  volumeMode: Filesystem

Edit and set the shell variables for the newly created PVC.

export NEW_DST_PVC_SIZE=32Gi
export NEW_DST_PVC_VOLMODE=Filesystem
export NEW_DST_PVC=new-pvc
export NEW_DST_PV=$(kubectl get pvc -o json | \
       jq -r ".items[] | \
       select(.metadata.name | \
       test(\"${NEW_DST_PVC}\"))".spec.volumeName)

Important Validation Steps¶

At this point, there should be six shell variables declared. Example:

$ env | grep _PV
NEW_DST_PVC_SIZE=32Gi
NEW_DST_PVC=new-pvc
OLD_SRC_PVC=old-pvc <-- This should be the original name of the PVC
NEW_DST_PVC_VOLMODE=Filesystem
NEW_DST_PV=pvc-ad7a05a9-c410-4c63-b997-51fb9fc473bf
OLD_SRC_PV=pvc-ca7c2f64-641d-4265-90f8-4aed888bd2c5

Regardless of the retainPolicy set in the StorageClass, ensure the persistentVolumeReclaimPolicy is set to "Retain" for both PVs.

kubectl patch pv/${OLD_SRC_PV} pv/${NEW_DST_PV} \
 -p '{"spec":{"persistentVolumeReclaimPolicy":"Retain"}}'

Validate the "persistentVolumeReclaimPolicy".

kubectl get pv/${OLD_SRC_PV} pv/${NEW_DST_PV} -o json | \
 jq -r ".items[] | \
  select(.metadata.name)".spec.persistentVolumeReclaimPolicy

Copy Persistent Volume Claim and Reset¶

In this phase, the data will be copied from the original PVC to the new PVC with a Job submitted to the cluster. Different tools are being used to perform the copy operation, ensure to pick the correct volumeMode.

PVCs with volumeMode: Filesystem¶

curl -s https://scod.hpedev.io/csi_driver/examples/operations/pvc-copy-file.yaml | \
  yq "( select(.spec.template.spec.volumes[] | \
    select(.name == \"src-pv\") | \
    .persistentVolumeClaim.claimName = \"${OLD_SRC_PVC}\")
    " | kubectl apply -f-

Wait for the Job to complete.

kubectl get job.batch/pvc-copy-file -w

Once the Job has completed, validate exit status and log files.

kubectl get job.batch/pvc-copy-file -o jsonpath='{.status.succeeded}'
kubectl logs job.batch/pvc-copy-file

Delete the Job from the cluster.

kubectl delete job.batch/pvc-copy-file

Proceed to restart the workload.

PVCs with volumeMode: Block¶

curl -s https://scod.hpedev.io/csi_driver/examples/operations/pvc-copy-block.yaml | \
  yq "( select(.spec.template.spec.volumes[] | \
    select(.name == \"src-pv\") | \
    .persistentVolumeClaim.claimName = \"${OLD_SRC_PVC}\")
    " | kubectl apply -f-

Wait for the Job to complete.

kubectl get job.batch/pvc-copy-block -w

Once the Job has completed, validate exit status and log files.

kubectl get job.batch/pvc-copy-block -o jsonpath='{.status.succeeded}'
kubectl logs job.batch/pvc-copy-block

Delete the Job from the cluster.

kubectl delete job.batch/pvc-copy-block

Proceed to restart the workload.

Restart the Workload¶

This step requires both the old source PVC and the new destination PVC to be deleted. Once again, ensure the correct persistentVolumeReclaimPolicy is set on the PVs.

kubectl get pv/${OLD_SRC_PV} pv/${NEW_DST_PV} -o json | \
 jq -r ".items[] | \
  select(.metadata.name)".spec.persistentVolumeReclaimPolicy

Delete the PVCs.

kubectl delete pvc/${OLD_SRC_PVC} pvc/${NEW_DST_PVC}

Next, allow the new PV to be reclaimed.

kubectl patch pv ${NEW_DST_PV} -p '{"spec":{"claimRef": null }}'

Next, create a PVC with the old source name and ensure it matches the size of the new destination PVC.

curl -s https://scod.hpedev.io/csi_driver/examples/operations/pvc-copy.yaml | \
  yq ".spec.volumeName = \"${NEW_DST_PV}\" | \
    .metadata.name = \"${OLD_SRC_PVC}\" | \
    .spec.volumeMode = \"${NEW_DST_PVC_VOLMODE}\" | \
    .spec.resources.requests.storage = \"${NEW_DST_PVC_SIZE}\" \
    " | kubectl apply -f-

Verify the new PVC is "Bound" to the correct PV.

kubectl get pvc/${OLD_SRC_PVC} -o json | \
  jq -r ". | \
    select(.spec.volumeName == \"${NEW_DST_PV}\").metadata.name"

If the command is successful, it should output your original PVC name.

At this point the original workload should be deployed, verified and resumed.

Optionally, the old source PV may be removed.

kubectl delete pv/${OLD_SRC_PV}

Optional Workflow with Filesystem Persistent Volume Claims¶

If there's a lot of content (millions of files, terabytes of data) that needs to be transferred in a volumeMode: Filesystem PVC it's recommended to transfer content incrementally. This is achieved by substituting the "old-pvc" with a dataSource clone of the running workload and perform the copy from the clone onto the "new-pvc".

After the first transfer completes, the copy job may be recreated as many times as needed with a fresh clone of "old-pvc" until the downtime window has shrunk to an acceptable duration. For the final transfer, the actual source PVC will be used instead of the clone.

This is an example PVC.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: clone-of-pvc
spec:
  dataSource:
    name: this-is-the-current-prod-pvc
    kind: PersistentVolumeClaim
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 32Gi

Enabling and setting up the CSI snapshotter and related CRDs is not necessary but it's recommended to be familiar with using CSI snapshots.

Upgrade NFS Servers¶

In the event the CSI driver contains updates to the NFS Server Provisioner, any running NFS server needs to be updated manually.

Upgrade to v2.4.2¶

No changes to NFS Server Provisioner image between v2.4.1 and v2.4.2.

Upgrade to v2.4.1¶

Any prior deployed NFS servers may be upgraded to v2.4.1.

Assumptions¶

• HPE CSI Driver or Operator v2.4.1 installed.
• All running NFS servers are running in the "hpe-nfs" Namespace.
• Worker nodes with access to the Quay registry and SCOD.
• Access to the commands kubectl, yq and curl.
• Cluster privileges to manipulate resources in the "hpe-nfs" Namespace.
• None of the commands executed should return errors or have non-zero exit codes.

Patch Running NFS Servers¶

When patching the NFS Deployments, the Pods will restart and cause a pause in I/O for the NFS clients with active mounts. The clients will recover gracefully once the NFS Pod is running again.

Patch all NFS Deployments with the following.

curl -s https://scod.hpedev.io/csi_driver/examples/operations/patch-nfs-server-2.4.1.yaml | \
  kubectl patch -n hpe-nfs \
  $(kubectl get deploy -n hpe-nfs -o name) \
  --patch-file=/dev/stdin

Validation¶

This command will list all "hpe-nfs" Deployments across the entire cluster. Each Deployment should be using v3.0.3 of the "nfs-provisioner" image after the uprade is complete.

kubectl get deploy -A -o yaml | \
  yq -r '.items[] | [] + { "Namespace": select(.spec.template.spec.containers[].name == "hpe-nfs").metadata.namespace, "Deployment": select(.spec.template.spec.containers[].name == "hpe-nfs").metadata.name, "Image": select(.spec.template.spec.containers[].name == "hpe-nfs").spec.template.spec.containers[].image }'

Manual Node Configuration¶

With the release of HPE CSI Driver v2.4.0 it's possible to completely disable the node conformance and node configuration performed by the CSI node driver at startup. This transfers the responsibilty from the HPE CSI Driver to the Kubernetes cluster administrator to ensure worker nodes boot with a supported configuration.

Stages of Initialization¶

There are two stages of initialization the administrator can control through parameters in the Helm chart.

disableNodeConformance¶

The node conformance runs with the entrypoint of the node driver container. The conformance inserts and runs a systemd service on the node that installs all required packages on the node to allow nodes to attach block storage devices and mount NFS exports. It starts all the required services and configure an important udev rule on the worker node.

This flag was intended to allow administrators to run the CSI driver on nodes with an unsupported or unconfigured package manager.

If node conformance needs to be disabled for any reason, these packages and services needs to be installed and running prior to installing the HPE CSI Driver:

• iSCSI (not necessary when using FC)
• Multipath
• XFS programs/utilities
• NFSv4 client

Package names and services vary greatly between different Linux distributions and it's the system administrator's duty to ensure these are available to the HPE CSI Driver.

disableNodeConfiguration¶

When disabling node configuration the CSI node driver will not touch the node at all. Besides indirectly disabling node conformance, all attempts to write configuration files or manipulate services during runtime are disabled.

Mandatory Configuration¶

These steps are REQUIRED for disabling either node configuration or conformance.

On each current and future worker node in the cluster:

# Don't let udev automatically scan targets(all luns) on Unit Attention.
# This will prevent udev scanning devices which we are attempting to remove.

if [ -f /lib/udev/rules.d/90-scsi-ua.rules ]; then
    sed -i 's/^[^#]*scan-scsi-target/#&/' /lib/udev/rules.d/90-scsi-ua.rules
    udevadm control --reload-rules
fi

iSCSI Configuration¶

Skip this step if only Fibre Channel is being used. This step is only required when node configuration is disabled.

iscsid.conf¶

This example is taken from a Rocky Linux 9.2 node with the HPE parameters applied. Certain parameters may differ for other distributions of either iSCSI or the host OS.

Ensure iscsid is stopped.

systemctl stop iscsid

Download: /etc/iscsi/iscsid.conf

iscsid.startup = /bin/systemctl start iscsid.socket iscsiuio.socket
node.startup = manual
node.leading_login = No
node.session.timeo.replacement_timeout = 10
node.conn[0].timeo.login_timeout = 15
node.conn[0].timeo.logout_timeout = 15
node.conn[0].timeo.noop_out_interval = 5
node.conn[0].timeo.noop_out_timeout = 10
node.session.err_timeo.abort_timeout = 15
node.session.err_timeo.lu_reset_timeout = 30
node.session.err_timeo.tgt_reset_timeout = 30
node.session.initial_login_retry_max = 8
node.session.cmds_max = 512
node.session.queue_depth = 256
node.session.xmit_thread_priority = -20
node.session.iscsi.InitialR2T = No
node.session.iscsi.ImmediateData = Yes
node.session.iscsi.FirstBurstLength = 262144
node.session.iscsi.MaxBurstLength = 16776192
node.conn[0].iscsi.MaxRecvDataSegmentLength = 262144
node.conn[0].iscsi.MaxXmitDataSegmentLength = 0
discovery.sendtargets.iscsi.MaxRecvDataSegmentLength = 32768
node.conn[0].iscsi.HeaderDigest = None
node.session.nr_sessions = 1
node.session.reopen_max = 0
node.session.iscsi.FastAbort = Yes
node.session.scan = auto

Ensure iscsid is running and enabled:

systemctl enable --now iscsid

Multipath Configuration¶

This step is only required when node configuration is disabled.

multipath.conf¶

The defaults section of the configuration file is merely a preference, make sure to leave the device and blacklist stanzas intact when potentially adding more entries from foreign devices.

Ensure multipathd is stopped.

systemctl stop multipathd

Download: /etc/multipath.conf

defaults {
    user_friendly_names yes
    find_multipaths     no
    uxsock_timeout      10000
}
blacklist {
    devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
    devnode "^hd[a-z]"
    device {
        product ".*"
        vendor  ".*"
    }
}
blacklist_exceptions {
    property "(ID_WWN|SCSI_IDENT_.*|ID_SERIAL)"
    device {
        vendor  "Nimble"
        product "Server"
    }
    device {
        product "VV"
        vendor  "3PARdata"
    }
    device {
        vendor  "TrueNAS"
        product "iSCSI Disk"
    }
    device {
        vendor  "FreeNAS"
        product "iSCSI Disk"
    }
}
devices {
    device {
        product              "Server"
        rr_min_io_rq         1
        dev_loss_tmo         infinity
        path_checker         tur
        rr_weight            uniform
        no_path_retry        30
        path_selector        "service-time 0"
        failback             immediate
        fast_io_fail_tmo     5
        vendor               "Nimble"
        hardware_handler     "1 alua"
        path_grouping_policy group_by_prio
        prio                 alua
    }
    device {
        path_grouping_policy group_by_prio
        path_checker         tur
        rr_weight            "uniform"
        prio                 alua
        failback             immediate
        hardware_handler     "1 alua"
        no_path_retry        18
        fast_io_fail_tmo     10
        path_selector        "round-robin 0"
        vendor               "3PARdata"
        dev_loss_tmo         infinity
        detect_prio          yes
        features             "0"
        rr_min_io_rq         1
        product              "VV"
    }
    device {
        path_selector        "queue-length 0"
        rr_weight            priorities
        uid_attribute        ID_SERIAL
        vendor               "TrueNAS"
        product              "iSCSI Disk"
        path_grouping_policy group_by_prio
    }
    device {
        path_selector        "queue-length 0"
        hardware_handler     "1 alua"
        rr_weight            priorities
        uid_attribute        ID_SERIAL
        vendor               "FreeNAS"
        product              "iSCSI Disk"
        path_grouping_policy group_by_prio
    }
}

Ensure multipathd is running and enabled:

systemctl enable --now multipathd

Important Considerations¶

While both disabling conformance and configuration parameters lends itself to a more predictable behaviour when deploying nodes from templates with less runtime configuration, it's still not a complete solution for having immutable nodes. The CSI node driver creates a unique identity for the node and stores it in /etc/hpe-storage/node.gob. This file must persist across reboots and redeployments of the node OS image. Immutable Linux distributions such as CoreOS persist the /etc directory, some don't.