fix(azure): Enable storage account and private endpoint reuse for AzureFileShare on re-runs

[shekharsorot]

fix(azure): Enable storage account and private endpoint reuse for AzureFileShare on re-runs

Problem

When LISA tests are re-run on the same VM (with keep_environment: true), the AzureFileShare feature was:

1. Failing to reuse existing storage accounts - Creating duplicate resources
2. Failing to reuse private endpoints - Causing conflicts and failures
3. Corrupting /etc/fstab - Leaving stale mount entries that caused boot issues
4. Credential file conflicts - Single credential file was overwritten when multiple storage accounts existed

Solution

This PR implements intelligent resource reuse with proper tracking and conditional cleanup.

Important Changes

1. Storage Account Reuse (features.py)

• Added _storage_account_reused: bool tracking flag
• Checks for existing storage accounts with lisasc* prefix before creating new ones
• Replaced @lru_cache with module-level _storage_account_cache dict (fixes unhashable object error)

2. Private Endpoint Reuse (features.py, common.py)

• Added _private_endpoint_created_by_lisa: bool tracking flag
• create_update_private_endpoints() now returns Tuple[str, bool] (name, was_created)
• New _get_private_endpoint_ip() helper with fallback methods for IP retrieval
• Unique PE naming: <storage_account_name>-file-pe, ensures future implementations from other tests are not impacted.

3. Credential File Management (features.py)

• Storage-account-specific credential files: /etc/smbcredentials/<storage_account_name>.cred
• Added credential_file property for external access
• Class constant CREDENTIAL_DIR = "/etc/smbcredentials"

4. Safe Cleanup Logic (features.py)

• Extracted cleanup into focused sub-methods:
  • _delete_file_shares() - Always deletes file shares
  • _cleanup_private_endpoint_resources() - Conditional PE cleanup
  • _cleanup_storage_account() - Conditional storage account cleanup
  • _cleanup_vm_state() - Cleans fstab entries and credentials
• Uses sed for surgical fstab entry removal (not backup restore)

5. Code Quality Improvements

• Added comprehensive class-level docstring for AzureFileShare
• Added class constants: STORAGE_ACCOUNT_PREFIX, PRIVATE_ENDPOINT_SUFFIX, CREDENTIAL_DIR
• Enhanced docstrings with full Args/Returns/Raises documentation
• Fixed type annotations throughout

Cleanup Behavior Matrix

Resource	LISA Created	Pre-existing
File Shares	✅ Delete	✅ Delete
Storage Account	✅ Delete	❌ Keep
Private Endpoint	✅ Delete	❌ Keep
fstab entries	✅ Remove	✅ Remove
Credential files	✅ Remove	✅ Remove

Resource Naming Conventions

Resource	Pattern	Example
Storage Account	lisasc<random10>	lisascab12cd34ef
Private Endpoint	<storage>-file-pe	lisascab12cd34ef-file-pe
Credential File	/etc/smbcredentials/<storage>.cred	/etc/smbcredentials/lisascab12cd34ef.cred

Files Changed

• lisa/sut_orchestrator/azure/features.py - AzureFileShare class enhancements
• lisa/sut_orchestrator/azure/common.py - PE helper functions, cache, list_file_shares
• lisa/microsoft/testsuites/storage/storage.py - Simplified cleanup logic
• lisa/microsoft/testsuites/xfstests/xfstesting.py - Uses credential_file property

Testing

• ✅ All unit tests pass
• ✅ CI pipeline passing
• ✅ Verified re-run scenarios with keep_environment: true
• ✅ Verified clean-run scenarios create resources correctly
• ✅ Verified cleanup properly respects pre-existing resources

Impact

• No breaking changes - Existing test configurations work unchanged
• Improved reliability - Re-runs no longer fail due to resource conflicts
• Cost efficiency - Reuses existing resources instead of creating duplicates
• Safer cleanup - Never deletes resources LISA didn't create

[Copilot]

Pull request overview

This pull request enables resource reuse for AzureFileShare operations when LISA is re-run with preserved resource groups. The changes address issues where storage accounts and private endpoints were being recreated instead of reused, and fixes an IndexError when retrieving IP addresses from existing private endpoints.

Key changes include:

• Storage account reuse logic to scan for existing "lisasc*" accounts before creating new ones
• Private endpoint IP retrieval improvements with fallback methods and existence checking
• Test fix to explicitly pass allow_shared_key_access=True for key-based authentication

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

File	Description
lisa/sut_orchestrator/azure/features.py	Adds storage account reuse logic by scanning existing accounts with "lisasc" prefix; adds get_storage_client import
lisa/sut_orchestrator/azure/common.py	Adds private endpoint existence check and _get_private_endpoint_ip helper with fallback IP retrieval methods (custom_dns_configs and network interface)
lisa/microsoft/testsuites/core/storage.py	Fixes test to pass allow_shared_key_access=True; adds TODO comment noting the test doesn't use private endpoints

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Key Test Cases:
verify_cifs_basic|verify_azure_file_share

Impacted LISA Features:
AzureFileShare, Nfs

Tested Azure Marketplace Images:

• canonical 0001-com-ubuntu-server-jammy 22_04-lts-gen2 latest
• debian debian-12 12-gen2 latest
• redhat rhel 95_gen2 latest