Refactor rhel7_contenthost and rhel8_contenthost fixtures to use rhel_contenthost

[ogajduse]

Background

The current rhel7_contenthost and rhel8_contenthost oracle_host and centos_host fixtures have diverged from the generic rhel_contenthost fixture, leading to maintenance issues and code duplication. The recent PRs #19950 and #19967 have highlighted problems with network type handling and deploy_network_type parameter conflicts.

As noted by @ogajduse in PR #19967, there are reasons for not using settings.content_host.network_type directly, referencing discussion in PR #18469.

Currently, these version-specific fixtures are causing:

1. Parameter conflicts: deploy_network_type is being passed both through host_conf(request) and explicitly in fixture definitions
2. Code duplication: Version-specific fixtures repeat logic that exists in the generic fixture
3. Maintenance overhead: Changes need to be made in multiple places
4. Testing complexity: The fixtures don't properly support IPv4/IPv6 parametrization like other content host tests

Expected Steps:

• Research the original reasons for separate rhel7/rhel8 fixtures and ensure refactoring addresses those concerns
• Review the network type handling discussion from PR Core fixture - Multiple registered contenthosts #18469 to understand constraints
• Analyze current usage patterns of rhel7_contenthost and rhel8_contenthost across the test suite
• Design a unified approach that leverages the parametrized rhel_contenthost fixture
• Remove hardcoded version-specific fixtures in favor of parametrized rhel_contenthost usage
• Update all test files using rhel7_contenthost and rhel8_contenthost to use the generic fixture with proper parametrization
• Ensure IPv4/IPv6 dualstack testing works correctly for all affected tests
• Validate that convert2rhel tests work properly with both IPv4 and IPv6 networks

Definition of Done:

• rhel7_contenthost and rhel8_contenthost fixtures are removed or significantly simplified
• All tests using these fixtures are migrated to use rhel_contenthost with appropriate parametrization
• Network type handling is consistent across all content host fixtures
• No deploy_network_type parameter conflicts exist
• IPv4/IPv6 parametrization works correctly for version-specific content host tests
• All existing functionality is preserved while reducing code duplication
• PRT passes for affected test suites including convert2rhel tests

Related Issues:

• PR Add deploy_network_type to rhel7_contenthost and rhel8_contenthost fixtures #19967: Remove deploy_network_type from oracle_host and centos_host fixture
• PR Enable ipv6 for rhel7_contenthost and rhel8_contenthost #19950: Enable ipv6 for rhel7_contenthost and rhel8_contenthost
• PR Core fixture - Multiple registered contenthosts #18469: Discussion about network_type usage constraints

This refactoring will resolve the current maintenance burden and parameter conflicts while ensuring proper IPv4/IPv6 support across all content host fixtures.

[ogajduse]

Ref: #19967 (comment)