feat(storage): add Dell PowerFlex backend support

sunbeam-python/sunbeam/storage/backends/dellpowerflex/__init__.py

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+# SPDX-FileCopyrightText: 2026 - Canonical Ltd
+# SPDX-License-Identifier: Apache-2.0
+
+"""Dell PowerFlex backend for Sunbeam storage."""

sunbeam-python/sunbeam/storage/backends/dellpowerflex/backend.py

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+# SPDX-FileCopyrightText: 2025 - Canonical Ltd
+# SPDX-License-Identifier: Apache-2.0
+
+"""Dell PowerFlex backend implementation using base step classes."""
+
+import logging
+from enum import StrEnum
+from typing import Annotated, Literal
+
+from pydantic import Field
+from rich.console import Console
+
+from sunbeam.core.manifest import StorageBackendConfig
+from sunbeam.storage.base import StorageBackendBase
+from sunbeam.storage.models import SecretDictField
+
+LOG = logging.getLogger(__name__)
+console = Console()
+
+
+class Protocol(StrEnum):
+    """Enumeration of valid PowerFlex protocol types."""
+
+    SCALEIO = "scaleio"
+    NVME_TCP = "nvme-tcp"
+
+
+class PowerFlexConfig(StorageBackendConfig):
+    """Configuration model for Dell PowerFlex backend.
+
+    This model includes the essential configuration options for deploying
+    a Dell PowerFlex backend. Additional configuration can be managed dynamically
+    through the charm configuration system.
+    """
+
+    # Mandatory connection parameters
+    san_ip: Annotated[
+        str, Field(description="IP address of the PowerFlex Gateway server")
+    ]
+    san_login: Annotated[
+        str,
+        Field(
+            description="Username for PowerFlex Gateway with administrative privileges"
+        ),
+        SecretDictField(field="san-login"),
+    ]
+    san_password: Annotated[
+        str,
+        Field(description="Password for PowerFlex Gateway authentication"),
+        SecretDictField(field="san-password"),
+    ]
+    powerflex_storage_pools: Annotated[
+        str,
+        Field(
+            description="Comma-separated list of storage pools in format "
+            "protection_domain_name:storage_pool_name"
+        ),
+    ]
+
+    # Protocol selection
+    protocol: Annotated[
+        Literal["scaleio", "nvme-tcp"],
+        Field(
+            description="Dell PowerFlex protocol selector: scaleio (PowerFlexDriver) "
+            "or nvme-tcp (PowerFlexNVMeDriver)"
+        ),
+    ] = "scaleio"
+
+    # PowerFlex Gateway configuration
+    powerflex_rest_server_port: Annotated[
+        int | None,
+        Field(description="Secured port to use when connecting to PowerFlex Manager"),
+    ] = 443
+
+    # Storage management
+    powerflex_max_over_subscription_ratio: Annotated[
+        float | None,
+        Field(description="Maximum oversubscription ratio allowed"),
+    ] = 10.0
+
+    # Volume management
+    powerflex_round_volume_capacity: Annotated[
+        bool | None,
+        Field(
+            description="Round volume sizes up to 8GB boundaries. "
+            "PowerFlex OS requires volumes to be sized in multiples of 8GB"
+        ),
+    ] = True
+
+    # Advanced configuration
+    powerflex_allow_non_padded_volumes: Annotated[
+        bool | None,
+        Field(
+            description="Allow volumes to be created in Storage Pools when zero "
+            "padding is disabled. Should not be enabled if multiple tenants use "
+            "volumes from a shared Storage Pool"
+        ),
+    ] = None
+    powerflex_allow_migration_during_rebuild: Annotated[
+        bool | None,
+        Field(description="Allow volume migration during rebuild operation"),
+    ] = None
+
+    # REST API timeouts
+    rest_api_connect_timeout: Annotated[
+        int | None,
+        Field(description="Connection timeout value (in seconds) for REST calls"),
+    ] = 30
+    rest_api_read_timeout: Annotated[
+        int | None,
+        Field(description="Read timeout value (in seconds) for REST calls"),
+    ] = 30
+
+    # Image cache configuration
+    powerflex_max_image_cache_vtree_size: Annotated[
+        int | None,
+        Field(
+            description="Maximum size of the vTree associated with an entry in the "
+            "image volume cache"
+        ),
+    ] = 0
+
+    # Performance options
+    use_multipath_for_image_xfer: Annotated[
+        bool | None,
+        Field(description="Enable multipathing for image transfer operations"),
+    ] = None
+
+    # Replication configuration
+    replication_device: Annotated[
+        str | None,
+        Field(
+            description="Specific replication configuration settings. Must be set "
+            "under the form of backend_id:powerflex_repl, "
+            "san_ip: <Replication system San ip>, "
+            "san_login: <Replication system San username>, "
+            "san_password: <Replication system San password>"
+        ),
+    ] = None
+
+    # SSL and security
+    driver_ssl_cert: Annotated[
+        str | None,
+        Field(description="PEM-encoded SSL certificate to use for HTTPS connections"),
+    ] = None
+
+    # Standard Cinder options
+    backend_availability_zone: Annotated[
+        str | None,
+        Field(description="Availability zone to associate with this backend"),
+    ] = None
+    volume_backend_name: Annotated[
+        str | None,
+        Field(description="Name that Cinder will report for this backend"),
+    ] = None
+
+
+class PowerFlexBackend(StorageBackendBase):
+    """Dell PowerFlex backend implementation."""
+
+    backend_type = "dellpowerflex"
+    display_name = "Dell PowerFlex"
+    generally_available = True
+
+    @property
+    def charm_name(self) -> str:
+        """Return the charm name for this backend."""
+        return "cinder-volume-dellpowerflex"
+
+    @property
+    def charm_channel(self) -> str:
+        """Return the charm channel for this backend."""
+        return "latest/stable"
+
+    @property
+    def charm_revision(self) -> str | None:
+        """Return the charm revision for this backend."""
+        return None
+
+    @property
+    def charm_base(self) -> str:
+        """Return the charm base for this backend."""
+        return "ubuntu@24.04"
+
+    @property
+    def supports_ha(self) -> bool:
+        """Return whether this backend supports HA deployments."""
+        return True
+
+    def config_type(self) -> type[StorageBackendConfig]:
+        """Return the configuration class for Dell PowerFlex backend."""
+        return PowerFlexConfig