[RFC pve-storage/proxmox-widget-toolkit/pve-manager 00/27] add guided remote storage setup and SAN visibility

[Dietmar Maurer <dietmar@proxmox.com>]

Adding remote storage currently starts with selecting a storage plugin
from the Add menu. The type-specific dialogs then assume that the
administrator already knows the Proxmox VE storage model and how the
selected backend maps to it.

This series adds a question-driven remote storage wizard. It first asks
which kind of storage to add, then separates connection, resource
selection, and common storage settings into focused steps. The existing
type-specific Add entries stay available for administrators who prefer
the direct workflow.

The wizard supports NFS, SMB/CIFS, iSCSI, Fibre Channel shared LVM, and
ZFS over iSCSI. The iSCSI shared LVM flow creates the connection storage
before selecting a logical unit number (LUN) and creating the LVM
storage. The Fibre Channel flow can initialize an unused SAN LUN or
reuse an existing volume group.

A dedicated NVMe over Fabrics wizard flow is not part of this RFC and
will be added in a follow-up. The SAN view already reports existing
NVMe-FC devices and native NVMe multipath state.

Multi-step submissions keep completed steps when a later request fails.
The wizard reports what it already created and how to finish the setup.
It does not try to roll back storage or volume groups automatically,
because doing so after a partial setup can be more destructive than
leaving the completed resource in place.

Device safety
-------------

Generic disk selectors currently also see remotely attached devices.
This makes it too easy to accidentally select a shared LUN for local
storage. The storage API now hides transports that unambiguously denote
remote attachment by default. Specialized callers can request them with
the new include-remote parameter; the widget-toolkit patch exposes the
corresponding includeRemoteDisks option.

This transport check is deliberately a guard, not proof that a device is
local or shared. It can diverge from that property in these cases:

- An exclusively assigned FC, FCoE, iSCSI, or NVMe fabrics LUN is safe
  for local use but is hidden by default. Explicit opt-in handles this
  false positive.
- SAS and missing or unknown transport information cannot distinguish a
  local disk from a shared attachment. They therefore remain visible to
  generic disk callers.
- The Fibre Channel wizard offers only FC and NVMe-FC devices by
  default. Ambiguous SAS devices require enabling the local/unknown
  transport list. FCoE and software-managed initiator transports stay
  excluded.

The SAN scan combines disk usage, multipath maps, LVM volume groups,
configured storage entries, and iSCSI sessions. It rechecks an unused
device under the disk lock before creating a volume group. It scans one
selected node, however, and cannot prove that the same LUN is visible on
every node selected for the shared storage. This is intentional: the
wizard calls out the visibility requirement and leaves its verification
to the administrator, like the existing shared storage workflows.

SAN visibility
--------------

The new node view lists SAN LUNs separately from local disks and shows
transport, usage, storage ownership, and multipath health. It reports
path state from multipathd and native NVMe multipath on a best-effort
basis.

The same view shows the iSCSI targets and sessions known to the node.
It exposes the initiator identity, connection state, negotiated session
parameters, rescan, logout, and stale node-record cleanup. The storage
plugin remains responsible for session login and activation.

Questions for this RFC
----------------------

1. Is a guided workflow next to the existing expert dialogs the right UI
   boundary?
2. Is default filtering with explicit remote-device opt-in an acceptable
   safety model given the transport predicate limitations above?
3. Does the node SAN view provide the right boundary for LUN, multipath,
   and iSCSI initiator observability?

Series order and dependencies
-----------------------------

Patches 01-14 add the pve-storage APIs and disk handling. Patch 15 adds
the widget-toolkit opt-in. Patches 16-27 add the pve-manager wizard and
node views. Apply them in that order.

pve-storage (01-14):

  diskmanage: collect disk transport type from lsblk
  diskmanage: add helper to list multipath devices
  diskmanage: qualify NVMe over fabrics transport
  disks: list: add include-remote parameter
  diskmanage: include iSCSI session devices in disk enumeration
  diskmanage: link multipath member disks to their map device
  iscsi: factor out session device map from device list
  api: scan: add san-luns method listing SAN LUN candidates
  disks: lvm: allow creating volume groups on multipath devices
  diskmanage: add helper querying multipath path state
  diskmanage: add helper querying NVMe native multipath path state
  api: scan: san-luns: report path state
  iscsi plugin: list sessions of all transports and capture transport
  api: add node-level iSCSI initiator target and session API

proxmox-widget-toolkit (15):

  disk selectors: allow opting into remote devices

pve-manager (16-27):

  ui: storage: allow switching the scan node of NFS/CIFS scan combos
  ui: storage: add guided remote storage wizard with NFS support
  ui: storage wizard: add SMB/CIFS support
  ui: storage wizard: add iSCSI support
  ui: storage wizard: add FC-attached SAN (shared LVM) support
  ui: storage wizard: add ZFS over iSCSI support
  ui: dc: storage: add remote storage wizard entry to the add menu
  ui: node: add SAN LUNs panel
  ui: san luns: show multipath path state
  api: nodes: add iSCSI initiator API endpoint
  pvenode: add iscsi commands
  ui: san luns: show iSCSI targets and sessions

Diffstat
--------

pve-storage:
  97 files changed, 2157 insertions(+), 52 deletions(-)

proxmox-widget-toolkit:
  2 files changed, 16 insertions(+)

pve-manager:
  17 files changed, 2447 insertions(+), 1 deletion(-)

-- 
2.47.3