guest: delete the old layered init and the managed agent's sandbox mode (SL7.8b) by ppenna · Pull Request #1534 · microsoft/nvx

Pedro Henrique Penna (ppenna) · 2026-11-12T12:11:15Z

Leaving code only. This PR changes only code that this effort removes from NVX: the old layered init (guest/common/nvx-init-agent), the Azure Linux one-shot container helpers (nvx-container-launch-azurelinux and nvx-container-enter-azurelinux) and the managed agent's sandbox mode, with the edits that remove references to them. Nothing that stays changes, and no later PR uses what it changes, so the size limits for kept code don't apply.

Part of #1123 (SL7.8b, "The old layered init is gone"). Parent #1087, umbrella #1076.

What and why

Since SL6.3 (#1530), the shell /init execs /sbin/nvx-init for every nvx_sandbox=1 boot, and starts nvx-managed-agent only with its own root, -, for a managed blockless boot. So nothing starts the old layered init, nvx-init-agent, any more, nor the managed agent's sandbox mode, which only that init started, with the container's assembled root as its ROOTFS. The two Azure Linux one-shot container helpers had no caller before either: the Azure Linux initramfs installed them, but not the old init that ran a container launcher. This PR does SL7.8b's Scope in two commits:

abe7a8c4 deletes the old layered init and the Azure Linux helpers, with their build steps: build.py no longer installs nvx-init-agent among the Alpine initramfs's sandbox-control files, and the Dockerfile's Azure Linux stage no longer installs the two helpers. The ShellCheck and shfmt lists of check-quality, and their copies in doc/setup.md, no longer name them.
00341544 deletes the managed agent's sandbox mode: its root entry (sandbox_entry, through guest::entry), each workload's barrier and cgroup placement (the sandbox launch and managed_agent/cgroup.rs), and its return to the init agent (the teardown that unmounted its mappings, and the exit that handed the VM back to the init). The agent now refuses any ROOTFS but - with status 125, as it does a wrong number of arguments, and runs only as the direct agent, whose loop nvx-init's layered roots and Fresh captures share. Its mapping table and its direct, layered and capture modes stay as they are; only the sandbox mode's use of the table goes: TableRoot::Sandbox, HostMappings::new and teardown. With the mode go the seam's spawn, prepare_entry and bind_runtime with their paths, the AgentConfig fields that only it read (rootfs, hostname, direct and entry), LaunchRequest, sandbox_command, null_device, Workload::Sandbox, LaunchFailure::Sandbox, LaunchError::Entry, Event::CgroupKillFailed and diagnostics::unmapping_error.
Crate-private items that the warning-denied builds then flag as unused go too, in the second commit:
- RestoreHandoff::hostname (guest::init::boot), which only the sandbox entry read, through AgentConfig::hostname. With it goes its conversion to a C string, which restore: report the attribution of a restore that fails in its guest (SL5.1d) #1515's 9dece307 (SL5.1d) classed as ACTIVATION_WORKLOAD: it cannot fail, since admission (activation::is_hostname) refuses a hostname with a NUL;
- Execution::has_open_output and Execution::wait (guest::exec), and Child::from_process (guest::process), which only the sandbox mode called. They are in the process modules that SL6.11b deletes, which this PR otherwise leaves alone;
- GuestFeatures::SANDBOX_AGENT leaves the guest feature: only the fake OpenVMM still announces it, so testing alone gates it;
- test helpers: Prepared::simulated in guest::entry's tests, with Simulation::Skip in guest::sys::entry's, which only it used; and PreparedChild's accessors program, arguments, environment, physical_pwd, physical_pwd_index, has_cgroup and barrier_entry_and_session, with the impl that held them, in guest::sys::spawn's tests, which only the sandbox launch tests read;
- AgentConfig::for_test builds only with cli, as the dispatch tests that call it do, and the host CLI's test features_of_a_guest_that_predates_them_are_none only with testing, as the SANDBOX_AGENT that it announces does.
Docs: the agent's rustdoc, and that of guest, guest::mappings, guest::exec, guest::spawn, guest::init, guest::root, protocol::root and protocol::export, no longer describe the sandbox mode, the deleted init's checks, or the agent as a caller of the process modules. Nor do nvx-rs/README.md, doc/project-structure.md, the Azure Linux guest's page, or the Ubuntu guest's, which described the one-shot workloads that the deleted init ran through the Alpine container helpers. nvx-rs/tests/fixtures/root-tokens.json drops shell_error, which only the old init's root-token test read.
The case matrix: guest::exec's two doc-test rows move to lines 79 and 619, below a deleted rustdoc line. No other inventoried test changes. The three rows that name a test that this PR modifies as coverage (a_failed_mapping_keeps_refusing_workloads_through_dispatch, restored_ready_maps_and_first_exec_share_the_existing_start_transition and restored_proxy_defaults_replace_template_values_before_exec_overrides) stay true: those tests change only in the harness's and the config's signatures.

What stays: guest/common/nvx-snapshot, which the blockless snapshot scenarios run, is unchanged, and so are the managed agent's mapping table and its other modes, nvx-init, the process modules but the three dead methods above, BOOT_CONTRACT_VERSION, CONTROL_CONTRACT_REVISION and the public API snapshots: every deleted item was crate-private.

Deliberately left:

guest/alpine/nvx-container-enter and nvx-container-launch, the Alpine one-shot container helpers. The deleted nvx-init-agent was their only caller, so nothing runs them now, but the Scope names only the Azure Linux helpers ("the three deleted programs"). Deleting them empties guest/alpine, which SOURCE-MANIFEST.json, the Alpine image's input hash in build-guest-artifacts, release.py's source-tree check, build.py, check-quality and several docs and tests name, so they are left for a follow-up decision.
The fake OpenVMM, which still announces SANDBOX_AGENT for a layered sandbox and calls it the sandbox agent's: the fake is outside this Scope.
scripts/nvx_tools/kernel_features.py, which still names nvx-init-agent as a consumer: nvx-rs slimming 4.2.4: the exec engine, the process modules and the old layered init are gone #1123's follow-up K1 waits for SL6.11b.
doc/modules, whose diagrams still draw managed_agent::cgroup: CI redraws and commits them (doc/ci.md).
The 4.x design docs, which nvx-rs slimming 5.2.1: the library's guide, its design and the guest-agent guidelines #1130 rewrites.
The managed agent's Workload and LaunchFailure, now of one variant each: folding them would rework a mode that stays.
guest::activation::Applied::hostname, a hidden public method whose last caller in the crate was that conversion: it is public API, which this PR doesn't change.

Size

Measured as #1076 defines them, against feature/nvx-refactor:

	Core lines	Counted files
Estimate (#1123)	0	9
Measured	31	23

Core lines (31), all where the sandbox mode's conditions leave kept code: 15 in managed_agent/exec.rs (the run loop's and the launch's conditions on the mode, folded into the direct agent's, and an import), 7 in managed_agent/mod.rs (the root check, the config and the finish without the mode), 6 in managed_agent/dispatch.rs (the features reply, always DIRECT_AGENT), an import each in managed_agent/launch.rs and managed_agent/mappings.rs, and 1 in docker/Dockerfile (the install list's new last line). The rest are deletions, comments and docs.
Counted files (23): .github/actions/check-quality/action.yml, docker/Dockerfile, scripts/nvx_tools/build.py, and in nvx-rs/src/: bin/nvx-managed-agent.rs, guest/exec.rs, guest/init.rs, guest/init/boot.rs, guest/managed_agent/{diagnostics,dispatch,exec,launch,mappings,mod,seam}.rs, guest/mappings.rs, guest/mappings/table.rs, guest/mod.rs, guest/process.rs, guest/root.rs, guest/spawn.rs, protocol/export.rs, protocol/root.rs and protocol/features.rs, which only narrows a cfg and rewords the two docs that this forces, so it could be left out (22). The deleted nvx-init-agent, the two helpers and managed_agent/cgroup.rs don't count.

Old tests of the area

Retired, with what they tested:
- the old init's share and root-token readers, in scripts/test_nvx_tools.py: SandboxShareAgentTests (21 tests: test_agent_mounts_share_after_lifecycle_checks_for_both_lifecycles, test_managed_lifecycle_gives_back_the_launcher_process, test_agent_teardown_unmounts_share_before_overlay_layers_and_scratch, test_agent_teardown_unmounts_the_tmpfs_upper_last, test_agent_teardown_unmounts_shares_in_reverse_mount_order, test_agent_teardown_reports_share_unmount_failure, test_agent_fatal_unmounts_share_before_power_off, test_agent_skips_share_without_bootstrap_tokens, test_agent_mounts_share_inside_container_rootfs, test_managed_agent_mounts_no_export_without_bootstrap_tokens, test_managed_agent_mounts_the_export_where_only_root_can_enter, test_managed_agent_refuses_share_tokens_and_other_exports, test_managed_agent_refuses_an_export_directory_that_exists, test_agent_binds_every_child_of_an_aggregate, test_agent_binds_children_by_the_names_that_nvx_gives_them, test_agent_binds_a_file_child_at_a_file, test_agent_rejects_repeated_children_and_overlapping_targets, test_agent_parses_every_share_before_mounting_any, test_agent_fatal_unmounts_mounted_shares, test_agent_fails_closed_for_invalid_share_bootstrap and test_agent_rejects_symbolic_link_in_share_target) and SandboxRootTokenAgentTests (8 tests: test_agent_reads_the_boot_tokens_as_nvx_rs_reads_them, test_agent_explains_the_roots_that_it_cannot_assemble, test_agent_refuses_the_settings_with_the_messages_of_nvx_rs, test_agent_requires_one_upper, test_agent_refuses_a_scratch_device_beside_a_ram_upper, test_agent_checks_a_ram_upper_before_it_mounts_anything, test_agent_mounts_the_upper_that_the_tokens_name and test_agent_checks_the_layer_uuid_only_when_the_token_names_one);
- scripts/test_microvm_tests.py::MicrovmTests.test_managed_executions_enter_through_the_agent_not_the_container_helpers, which read the old init;
- the sandbox entry, sandbox_config's three cases in the agent's tests.rs: the_sandbox_entry_takes_an_existing_account_and_one_machine_id_per_boot, a_refused_sandbox_entry_generates_nothing_and_stops_the_agent and a_failed_runtime_bind_stops_the_sandbox_agent_before_its_session;
- the sandbox mode's mappings and launches through dispatch, in managed_agent::dispatch::tests: sandbox_mappings_mount_in_order_beneath_its_root_and_unblock_workloads, sandbox_mappings_refuse_the_targets_of_the_container_runtime, a_failed_sandbox_mapping_keeps_refusing_workloads, a_sandbox_without_mappings_maps_nothing_and_admits_workloads, sandbox_does_not_launch_when_an_environment_export_fails, sandbox_launch_places_its_workload_before_releasing_it, sandbox_launch_reports_unusable_directories_and_programs_as_its_helper_did and sandbox_launch_fails_on_its_entry_and_its_placement_without_running;
- the sandbox launch, in managed_agent::launch::tests: sandbox_launch_runs_the_workload_itself_through_its_entry, sandbox_launch_applies_exact_and_layered_environments_in_order, sandbox_pwd_is_physical_only_for_noncanonical_names_without_an_entry and sandbox_launch_reports_a_simulated_stage_without_privileges;
- the teardown, in managed_agent::mappings::tests: a_sandbox_table_unmounts_in_reverse_order, a_sandbox_table_reports_each_mapping_that_stays_mounted and a_table_without_mappings_has_nothing_to_tear_down;
- CI's ShellCheck and shfmt of the three deleted programs.
Rewritten:
- managed_agent::exec::tests::environment_failures_stop_direct_and_sandbox_launches_before_exec becomes environment_failures_stop_direct_launches_before_exec, with the direct agent's cases alone.
- managed_agent::tests::the_agent_refuses_any_root_but_its_own is new: it starts the agent with a container's root as its ROOTFS, as the deleted init did, and checks that the agent refuses it before it configures its terminal, reports a diagnostic or runs anything. check_test_changes.py pairs it with a_failed_runtime_bind_stops_the_sandbox_agent_before_its_session, whose place it takes.
Moved: test_hostmount_accepts_only_child_names_inside_the_aggregate and test_hostmount_makes_file_mount_points_without_following_links, the two tests of nvx-hostmount in SandboxShareAgentTests, move to a new HostmountShareTests, which names guest/common/nvx-hostmount by its own path rather than beside the deleted init's. They check the same.
Kept: every other test of the managed agent, nvx-init, nvx-snapshot, the shell /init and the guest images; the ones that check_test_changes.py lists below change only to stop naming what left.

Test changes

python scripts/check_test_changes.py --base origin/feature/nvx-refactor lists 159 changes to existing tests, hence tests-modified:

Removed, as retired above: 47 tests (29 in scripts/test_nvx_tools.py, 1 in scripts/test_microvm_tests.py, and 17 Rust tests) and 6 lines of CI test wiring in .github/actions/check-quality/action.yml, the ShellCheck and shfmt entries of the three deleted programs.
Removed helpers (33) that only the retired tests or the deleted mode used: in scripts/test_nvx_tools.py, the class SandboxShareAgentTests with its setUp, _aggregate, _export, _run and _run_teardown, and SandboxRootTokenAgentTests._read; in the agent's tests, sandbox_config, Harness::in_sandbox, Harness::spawn_at, spawn_sandbox and sandbox_system (dispatch), descriptor, request, direct_paths and prepare_sandbox (launch), HostMappings::announced_for, sandbox and map_three (mappings), and the seam's with_container_cgroup, spawn, prepare_entry and bind_runtime (TestSystem); and the dead test helpers named above in guest::entry (Prepared::simulated with its impl) and guest::sys::spawn (PreparedChild's seven accessors with their impl).
Modified helpers (19), which lose the mode's parameter or field: the dispatch Harness's new, with_system and spawn, and running_restored_workload, lost_status_harness and direct_harness; config and validate (exec), config and prepare_direct (launch); the seam's TestSystem, TestSystem::new and TestSystem::with_direct; AgentConfig::for_test (no argument, cli only); Simulation (without Skip); GuestInitRoutingTests.setUp and _run, which no longer stub /sbin/nvx-init-agent; and SandboxRootTokenAgentTests's class and setUp, which check_test_changes.py pairs with the new HostmountShareTests. The imports of three test modules follow.
Modified tests (50):
- 32 change only in those signatures (Harness::new(), Harness::with_system(system, n), AgentConfig::for_test(), HostMappings::announced(n), config() and prepare_direct(config, execution), which no longer takes the deleted paths): 24 in managed_agent::dispatch::tests, the 4 of dispatch::tests::runtime, and launch::tests::restored_proxy_defaults_replace_template_values_before_exec_overrides, privileged_direct_launch_hardens_credentials_and_resets_priority, direct_launch_applies_exact_empty_and_layered_environments_in_order and direct_pwd_is_deferred_only_for_noncanonical_names.
- The rest lose their sandbox cases or their checks of what the mode had: agent_advertises_the_control_features_of_its_mode_and_stops (the sandbox agent's features), the_root_of_the_export_is_refused_though_it_decodes (the sandbox agent's case), prepared_layered_mappings_and_cli_identity_use_the_existing_dispatcher (the entry count), direct_core_applies_inherited_exact_and_layered_environments and direct_launch_uses_the_plain_process_core_without_a_helper_or_cgroup (their check that nothing appears under the deleted cgroup root), a_layered_cold_boot_takes_only_the_clis_workload_identity (the deleted direct and entry fields), the two loopback tests (the deleted AgentConfig fields), guest::exec::tests::a_status_that_another_collector_took_first_is_left_to_it (its case of the deleted Execution::wait), and a_layered_table_that_announces_mappings_needs_its_retained_export, which builds its layered root itself rather than through the sandbox helper.
- The two renamed tests (Rewritten, above), the two moved nvx-hostmount tests (Moved, above), and features_of_a_guest_that_predates_them_are_none, whose cfg narrows to testing.
- In scripts/test_nvx_tools.py: GuestInitRoutingTests.test_blockless_platform_and_snapshot_vms_keep_their_routes and test_missing_helpers_or_selected_init_fail_without_fallback no longer check that the deleted init does not run, and BuildTests.test_azurelinux_initramfs_uses_locked_busybox_applets no longer reads the deleted launcher.
Test data: nvx-rs/tests/fixtures/root-tokens.json drops shell_error from its 27 cases, which only the old init's root-token test read, and its description no longer names that init.

Validation

local_gates.py --files (from dev) selects, for these files, test-changes, markdown-links, test-layout, quality-code, every step of check-nvx-rs and nvx-cli (validate-nvx), on both systems; its runtime-adapter gates no longer exist on this branch. I ran them from this branch's action definitions, and the microVM scenarios on all three backends, on the final head, 00341544, unless a row says otherwise.

The branch was first validated on SL6.3's head, 604d8dac: the same gates passed, and so did the scenarios below on KVM, MSHV and WHP. SL6.3 then merged, and its branch was deleted, so I rebased onto feature/nvx-refactor twice, with rerere off:

onto 671a192d (SL6.3, SL6.6a and SL6.11a). guest/exec.rs, guest/sys/spawn/tests.rs, nvx-rs/README.md and the case matrix conflicted, since SL6.11a had already deleted Execution::output_hung_up, report_writer_copy and the binding's docs. The resolutions keep the base's text without what this PR deletes; PreparedChild's test impl then held nothing and went, and the two guest::exec doc-test rows moved to 79 and 619. The scenarios and every gate passed there too, at bc8fed95.
onto 00c55b96 (SL5.1d, restore: report the attribution of a restore that fails in its guest (SL5.1d) #1515). guest/init.rs's docs and guest/init/boot.rs's handoff conflicted with the new activation-failure classes: the docs keep restore: report the attribution of a restore that fails in its guest (SL5.1d) #1515's text without nvx-init-agent, and the handoff loses hostname, as above.

git range-diff shows no other change.

Windows, this workstation (Rust 1.95.0):

Check	Result
`cargo fmt --all --check`	passed
`cargo clippy --locked` with `-D warnings`: `--all-targets --all-features`, `--lib`, `--lib --no-default-features`, and `serde`, `cli` and `testing` alone	passed
`cargo test --locked --all-features`	passed: lib 1052 passed, 15 ignored, and every integration and doc test
`cargo test --locked`	passed: lib 733 passed, 7 ignored
`cargo build --locked --lib --no-default-features`, `cargo test --locked --lib --no-default-features`	passed: 190
`RUSTDOCFLAGS=-D warnings cargo doc --locked --no-deps --all-features`	passed
`cargo +1.89 check --locked --all-targets --all-features` (MSRV)	passed
`ruff check scripts .github/specula`, `ruff format --check ...`, `compileall .github/specula`, `pyright --pythonplatform Linux`, `--pythonplatform Windows`	passed, 0 errors
`validate-nvx`'s unittest list, `test_adversarial.py`, `test_hosts.py` and `nvx.py`'s `--help` commands	passed: 1803 tests, 73 skipped; `test_adversarial.py` (11 skipped) and `test_hosts.py` pass
`check_test_layout.py`, `check_markdown_links.py`	passed
SL5.2's `check_matrix.py <worktree> 99d2022085f`	passed
`check_test_changes.py --base origin/feature/nvx-refactor`	159 changes, explained above

Linux, nvx-mshv-test (Azure Linux 3, kernel 6.18, MSHV, virtual machine), in a worktree of this branch with its own target directory, every signal at its default disposition:

Check	Result
`cargo test --locked --all-features --no-fail-fast`	passed: lib 1871 passed, 57 ignored, `cli` 120, `guest_tools` 33, `host_modules` 22, the other integration tests, and 24 doc tests
`cargo test --locked`	passed: lib 729 passed, 7 ignored
`cargo build --locked --lib --no-default-features`, `cargo test --locked --lib --no-default-features`	passed: 190
`python3 scripts/nvx.py check-guest-binaries --toolchain 1.95.0`	passed: the musl lint, and 972 tests, 33 ignored, with the guest tools' tests
`validate-nvx`'s unittest list, `test_adversarial.py`, `test_hosts.py` and `nvx.py`'s `--help` commands	passed: 1803 tests, 38 skipped, which runs the shell `/init` routing and `nvx-hostmount` tests that Windows skips; 84; 4

Linux, nvx-kvm-test (Azure Linux 3, kernel 6.6, KVM, virtual machine), likewise:

Check	Result
`cargo fmt`, and every `clippy` of `check-nvx-rs` with `-D warnings`, with `--features guest` alone on the host target too	passed
`RUSTDOCFLAGS=-D warnings cargo doc --locked --no-deps --all-features`, which documents the Linux-only guest modules	passed
MSRV 1.89, and the macOS check (`--target aarch64-apple-darwin`)	passed. The macOS lib-test build warns that `all_processors_online` and `console_listener` are unused, as it does at the base
`python3 scripts/public_api.py`	passed: the snapshots don't change
`python3 scripts/nvx.py check-guest-binaries --toolchain 1.95.0`	the musl lint passes. The musl tests fail 7 `guest::` tests (965 passed), the identical 7 at the base `00c55b96` on this host (974 passed there, with the 9 guest-only tests that this PR retires): `guest::entry::tests::runtime_binds_need_a_mount_root_unless_there_are_none`, `guest::exec::tests::a_start_after_another_collector_took_the_status_ends_nothing_by_id`, `guest::exec::tests::adopting_a_program_whose_status_another_collector_took_ends_nothing_by_id`, and `guest::init::tests::exec::{a_stolen_or_auto_reaped_status_is_reported_once_and_never_reclassified_by_an_ending, host_launch_tests_use_the_syscall_seam_without_mocking_the_execution_core, native_workload_cwd_accepts_procfs_links_but_closes_inherited_descriptors, only_the_collectors_terminal_status_settles_the_owned_leader_and_output}`. MSHV's kernel 6.18 runs all 972
`build-guest-binaries`, `test-guest-binaries`	passed
`check-quality`'s ShellCheck and shfmt commands, with its pinned images	passed, at `bc8fed95`; no file that they check has changed since
`python3 scripts/nvx.py build-initramfs --guest alpine`, `--guest ubuntu` (native) and `--guest azurelinux` (Docker)	built. SHA-256: Alpine `6a3a1818…`, Ubuntu `52ae53c7…`, Azure Linux `ef9a1ac0…`. The Alpine image's `/sbin` holds `nvx-init`, `nvx-managed-agent` and `nvx-snapshot`, and no `nvx-init-agent`; the Azure Linux image holds `nvx-snapshot` and no `nvx-container-*` helper

MicroVM scenarios, with those images, and the kernel, Ubuntu distro layer and OpenVMM (openvmm-linux-gnu, openvmm-windows-msvc) of run 43185976865 at f03c21c3, each checked by SHA-256, since neither the openvmm pin (14dc4116) nor the kernel's inputs have changed since; NVX_AUTO_DOWNLOAD=0:

Guest	Scenarios	KVM	MSHV	WHP (`nvx-whp-test`)
Alpine, 1 vCPU	`guest-boot`, `guest-identity`, `console-exit`, `lifecycle`, `managed-lifecycle`, `workload-identity`, `console-snapshot`, `network-snapshot`, `filesystem-snapshot`	9 passed	9 passed	9 passed
Public sandboxes, over the Ubuntu distro layer	`managed-exec-config`, `sandbox-lifecycle`, `sandbox-proxy-only`, `sandbox-ram-upper`, `sandbox-gpt-layer`, `vm-lifecycle`, `snapshot-core`, `snapshot-tiers`	8 passed	8 passed	8 passed
Ubuntu, 1 vCPU	`guest-boot`, `guest-identity`, `console-exit`, `lifecycle`, `virtio-net`, `filesystem-snapshot` (WHP: `guest-boot`, `lifecycle`, `filesystem-snapshot`)	6 passed	6 passed	3 passed
Azure Linux, 1 vCPU	`guest-boot`, `guest-identity`, `console-exit`, `virtio-net`, `network-snapshot`, `workload-identity`, `managed-lifecycle`	7 passed	7 passed	not run

The Done-when, on real VMs:

A guest image still builds and boots a layered root through nvx-init: the public sandbox scenarios boot layered roots over the Ubuntu distro layer, with nvx_sandbox=1 nvx_mode=managed and nvx_layer=distro,... on the kernel command line, which the shell /init hands to /sbin/nvx-init in the Alpine image that no longer has nvx-init-agent. nvx-init serves the root's executions in-process, through the managed agent's direct loop (AgentConfig::layered), so they run this branch's agent.
nvx-snapshot still builds and serves blockless snapshots: console-snapshot, network-snapshot and filesystem-snapshot call /sbin/nvx-snapshot in blockless Alpine, Ubuntu and Azure Linux guests and restore from what it captured.

Not run, left to CI: build-guest --guest all and verify-guest-determinism. The hosts have no mkfs.erofs, so the Ubuntu distro layer above is CI's: its input digest covers guest/common and the guest binaries' sources, so CI rebuilds it for this PR, while the layered boots above already run nvx-init and its agent from the initramfs that this branch builds. Also left to CI: the benchmarks, OpenVMM's own tests (the pin doesn't move), the debug-kernel runs, and the rest of the default scenario suite and its other vCPU counts.

github-actions · 2026-11-12T12:11:40Z

This pull request changes existing tests

It modifies or removes 159 existing test asset(s), listed below. Review each with care: a change to a test can hide a regression that the test caught. See doc/contribute.md#changes-to-existing-tests.

Test code

... and 102 more, which the job's summary lists.

Test data

Change	What	Before	After
modified file	`nvx-rs/tests/fixtures/root-tokens.json`	`nvx-rs/tests/fixtures/root-tokens.json`	`nvx-rs/tests/fixtures/root-tokens.json`

CI test wiring

Change	What	Before
removed line	`guest/common/nvx-init-agent \`	`.github/actions/check-quality/action.yml:46`
removed line	`guest/common/nvx-container-enter-azurelinux \`	`.github/actions/check-quality/action.yml:47`
removed line	`guest/common/nvx-container-launch-azurelinux \`	`.github/actions/check-quality/action.yml:48`
removed line	`guest/common/nvx-init-agent \`	`.github/actions/check-quality/action.yml:62`
removed line	`guest/common/nvx-container-enter-azurelinux \`	`.github/actions/check-quality/action.yml:63`
removed line	`guest/common/nvx-container-launch-azurelinux \`	`.github/actions/check-quality/action.yml:64`

Relocated unchanged: 0; added: 0. Compared the merge base 9bb42b28fd62 with a8730286a580.

Copilot

🟢 Approval recommended

No active review issues remain for the cleanup of obsolete guest execution paths.

No open issues 🎉

What changed in this PR

Implements SL7.8b of #1123 by removing obsolete guest execution paths after layered boots moved to nvx-init. The retained mapping table, direct agent, layered-root execution, and blockless snapshot handling remain in place.

Changes:

Deletes the old layered init and Azure Linux one-shot container helpers, including build and lint entries.
Removes the managed agent’s sandbox mode and its unused private support code; rejects ROOTFS values other than -.
Retires obsolete tests and updates retained test helpers, fixtures, and documentation.

File	Description
`scripts/test_microvm_tests.py`	Retires the test that reads the deleted init.
`scripts/nvx_tools/build.py`	Stops installing `nvx-init-agent`.
`nvx-rs/tests/fixtures/root-tokens.json`	Removes shell-only expectations; preserves parser cases.
`nvx-rs/src/protocol/root/tests.rs`	Removes the comment about shell replay.
`nvx-rs/src/protocol/root.rs`	Removes obsolete shell-parser documentation.
`nvx-rs/src/protocol/features.rs`	Gates legacy sandbox features on `testing` only.
`nvx-rs/src/protocol/export.rs`	Removes documentation references to the deleted init.
`nvx-rs/src/host/cli/session/tests.rs`	Aligns the legacy-feature test’s conditional compilation.
`nvx-rs/src/guest/sys/spawn/tests.rs`	Deletes sandbox-only test accessors.
`nvx-rs/src/guest/sys/entry/tests.rs`	Removes the unused successful-entry simulation variant.
`nvx-rs/src/guest/spawn.rs`	Removes the managed-agent caller claim from documentation.
`nvx-rs/src/guest/root.rs`	Removes the shell-init comparison from a permission comment.
`nvx-rs/src/guest/process.rs`	Deletes the unused private child constructor.
`nvx-rs/src/guest/mod.rs`	Updates the managed agent’s documented module usage.
`nvx-rs/src/guest/mappings/table.rs`	Removes sandbox-mode usage documentation.
`nvx-rs/src/guest/mappings.rs`	Removes sandbox-root mapping documentation.
`nvx-rs/src/guest/managed_agent/tests/loopback/tests.rs`	Drops deleted configuration fields from loopback tests.
`nvx-rs/src/guest/managed_agent/tests.rs`	Retires sandbox-entry tests and adds root-rejection coverage.
`nvx-rs/src/guest/managed_agent/seam/tests.rs`	Removes sandbox-only system mocks and helpers.
`nvx-rs/src/guest/managed_agent/seam.rs`	Removes sandbox paths and system operations.
`nvx-rs/src/guest/managed_agent/mod.rs`	Removes sandbox setup and teardown; requires `ROOTFS=-`.
`nvx-rs/src/guest/managed_agent/mappings/tests.rs`	Retires sandbox mapping tests and preserves layered coverage.
`nvx-rs/src/guest/managed_agent/mappings.rs`	Removes sandbox table roots and teardown.
`nvx-rs/src/guest/managed_agent/launch/tests.rs`	Retires sandbox launch tests and adjusts direct helpers.
`nvx-rs/src/guest/managed_agent/launch.rs`	Deletes sandbox command construction and its inputs.
`nvx-rs/src/guest/managed_agent/exec/tests.rs`	Keeps environment-failure coverage for direct launches.
`nvx-rs/src/guest/managed_agent/exec.rs`	Removes sandbox execution, placement, and error branches.
`nvx-rs/src/guest/managed_agent/dispatch/tests/runtime.rs`	Updates mapping-table construction in runtime tests.
`nvx-rs/src/guest/managed_agent/dispatch/tests.rs`	Retires sandbox cases and updates retained test signatures.
`nvx-rs/src/guest/managed_agent/dispatch.rs`	Drops sandbox configuration and always advertises direct features.
`nvx-rs/src/guest/managed_agent/diagnostics.rs`	Deletes the unused unmapping diagnostic.
`nvx-rs/src/guest/managed_agent/cgroup.rs`	Deletes sandbox workload placement.
`nvx-rs/src/guest/init/boot.rs`	Removes the unused hostname handoff and conversion.
`nvx-rs/src/guest/init.rs`	Removes old-init references from status documentation.
`nvx-rs/src/guest/exec/tests.rs`	Removes coverage of the deleted private wait method.
`nvx-rs/src/guest/exec.rs`	Deletes two unused private methods and updates caller docs.
`nvx-rs/src/guest/entry/tests.rs`	Deletes the sandbox-only prepared-entry helper.
`nvx-rs/src/bin/nvx-managed-agent.rs`	Documents PID-1 operation without sandbox mode.
`nvx-rs/README.md`	Removes obsolete mode and caller descriptions.
`guest/common/nvx-init-agent`	Deletes the old layered init script.
`guest/common/nvx-container-launch-azurelinux`	Deletes the Azure Linux one-shot launcher.
`guest/common/nvx-container-enter-azurelinux`	Deletes the Azure Linux container-entry helper.
`docker/Dockerfile`	Stops installing the deleted Azure Linux helpers.
`doc/setup.md`	Removes deleted scripts from documented lint commands.
`doc/project-structure.md`	Removes descriptions of deleted guest components.
`doc/guests/ubuntu-guest.md`	Describes layered execution through `nvx-init`.
`doc/guests/azurelinux-guest.md`	Removes the obsolete sandbox-init omission explanation.
`doc/acceptance-case-matrix.md`	Updates two retained doctest line references.
`.github/actions/check-quality/action.yml`	Removes deleted scripts from ShellCheck and shfmt lists.

_{Review effort: Balanced}

Since SL6.3, the shell /init hands every layered root to nvx-init, so nothing starts the old layered init, nvx-init-agent, any more. The Azure Linux one-shot container helpers, nvx-container-launch-azurelinux and nvx-container-enter-azurelinux, had no caller either: the Azure Linux initramfs installed them, but never the old init that ran the container launcher. Delete guest/common/nvx-init-agent and the two helpers, with their build steps: the Alpine initramfs no longer installs nvx-init-agent, and the Azure Linux Docker stage no longer installs the helpers. ShellCheck and shfmt, in check-quality and in the setup guide, no longer name them. Tests: - SandboxShareAgentTests and SandboxRootTokenAgentTests, which ran the old init's share and root-token readers, retire, except the two tests of nvx-hostmount, which move to HostmountShareTests and name nvx-hostmount by its own path rather than beside the deleted init: test_hostmount_accepts_only_child_names_inside_the_aggregate and test_hostmount_makes_file_mount_points_without_following_links. - test_managed_executions_enter_through_the_agent_not_the_container_helpers, which read the old init, retires. - GuestInitRoutingTests no longer stubs /sbin/nvx-init-agent, and its routes no longer check that the deleted init does not run. - test_azurelinux_initramfs_uses_locked_busybox_applets no longer reads the deleted Azure Linux launcher. - root-tokens.json drops shell_error, which only the old init's root-token test read, and its description no longer names the init. Docs: the project structure, the Azure Linux guest, nvx-init's rustdoc and the nvx README no longer name the deleted programs. The rustdoc of protocol::root, protocol::export and guest::root no longer describes the checks with which the deleted init read the root tokens and mounted the export. The Ubuntu guest no longer describes the one-shot workloads that the deleted init ran through the Alpine container helpers. Part of #1123 (SL7.8b). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Only the old layered init started the managed agent with a root other than its own, `-`: the sandbox mode, in which the agent entered each workload into the container's assembled root through guest::entry, held it at a barrier until it had placed it in the container cgroup that the old init prepared, and after STOP unmounted its host mappings and returned to that init. With the old init gone, nothing starts the mode. The agent now refuses any ROOTFS but `-` with status 125, as it does a wrong number of arguments, and runs only as the direct agent, whose loop nvx-init's layered roots and Fresh captures share. Its mapping table and its direct, layered and capture modes stay as they are; only the sandbox mode's use of the table goes, with TableRoot::Sandbox and the teardown that returned to the init. Deleted with the mode: the agent's cgroup module, the sandbox entry, the barrier and cgroup placement of each workload, the sandbox launch command, the seam's spawn, entry preparation and runtime binds and their paths, the AgentConfig fields that only the mode read (rootfs, hostname, direct and entry), and the teardown's diagnostic. So does what the warning-denied builds then find unused: RestoreHandoff::hostname, which only the sandbox entry read, through AgentConfig::hostname; Execution::has_open_output and Execution::wait in guest::exec, and Child::from_process in guest::process, which only the sandbox mode called; and GuestFeatures::SANDBOX_AGENT in the guest feature, since only the fake OpenVMM still announces it, so the testing feature alone gates it. Among the test helpers, so do Prepared::simulated in guest::entry's tests, with Simulation::Skip, which only it used, and PreparedChild's accessors program, arguments, environment, physical_pwd, physical_pwd_index, has_cgroup and barrier_entry_and_session, with the impl that held them, in guest::sys::spawn's tests, which only the sandbox launch tests read. Tests: - The agent's tests.rs retires sandbox_config with its three cases, the_sandbox_entry_takes_an_existing_account_and_one_machine_id_per_boot, a_refused_sandbox_entry_generates_nothing_and_stops_the_agent and a_failed_runtime_bind_stops_the_sandbox_agent_before_its_session, and the_agent_refuses_any_root_but_its_own checks the refusal. - dispatch/tests.rs retires the sandbox mode's mapping and launch tests: sandbox_mappings_mount_in_order_beneath_its_root_and_unblock_workloads, sandbox_mappings_refuse_the_targets_of_the_container_runtime, a_failed_sandbox_mapping_keeps_refusing_workloads, a_sandbox_without_mappings_maps_nothing_and_admits_workloads, sandbox_does_not_launch_when_an_environment_export_fails, sandbox_launch_places_its_workload_before_releasing_it, sandbox_launch_reports_unusable_directories_and_programs_as_its_helper_did and sandbox_launch_fails_on_its_entry_and_its_placement_without_running. - launch/tests.rs retires sandbox_launch_runs_the_workload_itself_through_its_entry, sandbox_launch_applies_exact_and_layered_environments_in_order, sandbox_pwd_is_physical_only_for_noncanonical_names_without_an_entry and sandbox_launch_reports_a_simulated_stage_without_privileges. - mappings/tests.rs retires the teardown's tests, a_sandbox_table_unmounts_in_reverse_order, a_sandbox_table_reports_each_mapping_that_stays_mounted and a_table_without_mappings_has_nothing_to_tear_down. - environment_failures_stop_direct_and_sandbox_launches_before_exec becomes environment_failures_stop_direct_launches_before_exec, with the direct agent's cases alone. - guest::exec's a_status_that_another_collector_took_first_is_left_to_it loses its case of Execution::wait, which goes. - AgentConfig::for_test builds only with the cli feature, as the dispatch tests that call it do, and the host CLI's features_of_a_guest_that_predates_them_are_none only with the testing feature, as the SANDBOX_AGENT that it announces does. - The kept tests lose what only the sandbox mode had: the harness's mode, the sandbox cases of agent_advertises_the_control_features_of_its_mode_and_stops and the_root_of_the_export_is_refused_though_it_decodes, the checks that the direct agent creates nothing under the deleted cgroup root, and the entry count of prepared_layered_mappings_and_cli_identity_use_the_existing_dispatcher. a_layered_table_that_announces_mappings_needs_its_retained_export builds its layered root without the sandbox agent's helper. Docs: the agent's rustdoc, that of guest, guest::mappings, guest::exec and guest::spawn, and the nvx README no longer describe the sandbox mode, or the agent as a caller of the process modules. The case matrix names guest::exec's doc tests by the lines to which they move. Part of #1123 (SL7.8b). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

SL7.8b (#1534) deleted the old layered init, nvx-init-agent, with the managed agent's sandbox mode, and SL7.8c (#1536) deleted the Alpine one-shot container helpers. The build guide still said that the Alpine initramfs includes "the sandbox PID-1 bootstrap and its container namespace scripts", that the kernel checks cover what "the sandbox bootstrap" needs, and that the APK manifest records the tools "used by the bootstrap". The Ubuntu guest still named "the Alpine control initramfs and its init agent" as the boot supervisor of the distro layer, and the cgroups and namespaces "that the sandbox uses". The project structure still credited the common scripts with shutdown and the time ABI, which the Rust guest binaries took over. Say instead what the code does now: - the Alpine initramfs is the one that nvx-rs sandbox boots, and with nvx_sandbox=1 the common /init hands PID 1 to nvx-init (exec /sbin/nvx-init in guest/common/init), which initializes the sandbox's layered root and serves its managed control session; - the APK manifest records every package of the image, among them the five that AlpineBuildConstants.PACKAGES adds to the minirootfs; - nvx-init supervises the Ubuntu distro layer, and the kernel provides the memory and process-count cgroups and the PID, mount, UTS and network namespaces for the guest's programs, without claiming that the sandbox uses them; - the common scripts mount the host share (nvx-hostmount), prepare the guest for a snapshot and repair its restores (nvx-snapshot), and probe for the tests and benchmarks; the Rust binaries provide PID 1, the time ABI's guest side, shutdown and the rest. The kernel inventory and its checks table keep their text: SL6.11b (#1542) rewrites them. Part of #1131 (SL6.10e). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

SL7.8b (#1534) deleted the old layered init, nvx-init-agent, with the managed agent's sandbox mode, and SL7.8c (#1536) deleted the Alpine one-shot container helpers. The build guide still said that the Alpine initramfs includes "the sandbox PID-1 bootstrap and its container namespace scripts", that the kernel checks cover what "the sandbox bootstrap" needs, and that the APK manifest records the tools "used by the bootstrap". The Ubuntu guest still named "the Alpine control initramfs and its init agent" as the boot supervisor of the distro layer, and the cgroups and namespaces "that the sandbox uses". The project structure still credited the common scripts with shutdown and the time ABI, which the Rust guest binaries took over. Say instead what the code does now: - the Alpine initramfs is the one that nvx-rs sandbox boots, and with nvx_sandbox=1 the common /init hands PID 1 to nvx-init (exec /sbin/nvx-init in guest/common/init), which initializes the sandbox's layered root and serves its managed control session; - the APK manifest records every package of the image, among them the five that AlpineBuildConstants.PACKAGES adds to the minirootfs; - nvx-init supervises the Ubuntu distro layer, and the kernel provides the memory and process-count cgroups and the PID, mount, UTS and network namespaces for the guest's programs, without claiming that the sandbox uses them; - the common scripts mount the host share (nvx-hostmount), prepare the guest for a snapshot and repair its restores (nvx-snapshot), and probe for the tests and benchmarks; the Rust binaries provide PID 1, the time ABI's guest side, shutdown and the rest. The kernel inventory and its checks table keep the text that SL6.11b (#1542) gave them. Part of #1131 (SL6.10e). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Pedro Henrique Penna (ppenna) added feat-nvx-refactor tests-modified Changes existing tests, test data, or test wiring labels Nov 12, 2026

Pedro Henrique Penna (ppenna) self-assigned this Nov 12, 2026

Pedro Henrique Penna (ppenna) requested a balanced review from Copilot November 12, 2026 12:11

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nvx-rs slimming 4.2.4: the exec engine, the process modules and the old layered init are gone #1123

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guest: delete the Alpine one-shot container helpers (SL7.8c) #1536

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Pedro Henrique Penna (ppenna) and others added 2 commits November 12, 2026 05:18

Pedro Henrique Penna (ppenna) force-pushed the agents/slim-sl7-8b-old-init branch from 0034154 to a873028 Compare November 12, 2026 13:18

Pedro Henrique Penna (ppenna) marked this pull request as ready for review November 12, 2026 13:19

Pedro Henrique Penna (ppenna) merged commit 2afac62 into feature/nvx-refactor Nov 12, 2026
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Pedro Henrique Penna (ppenna) deleted the agents/slim-sl7-8b-old-init branch November 12, 2026 13:40

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doc: describe the final gates, test owners, packaging and publishing (SL6.10f) #1540

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guest: delete the process modules and cgroups (SL6.11b) #1542

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doc: describe the nvx package's build, release packages and setup (SL6.10e) #1546

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Pedro Henrique Penna (ppenna) mentioned this pull request Nov 12, 2026

nvx-rs: serve NVXC v2 in the guest loop and the fake OpenVMM (SL4.4b) #1531

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guest: delete the old layered init and the managed agent's sandbox mode (SL7.8b) - #1534

guest: delete the old layered init and the managed agent's sandbox mode (SL7.8b)#1534
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