# Distributed 4-node 4-disk e2e

**Use this when:** adding or diagnosing GitHub Actions coverage for a 4-node cluster, or deciding whether a behaviour belongs in `e2e-distributed` versus the single-node `e2e-full` lane, the nightly cluster-fault lane, or the hardware functional chain.
**Source of truth:** `crates/e2e_test/src/distributed/`, `[profile.e2e-distributed]` in `.config/nextest.toml`, `.github/workflows/e2e-distributed.yml`.

## Topology

The in-tree harness runs every node on `127.0.0.1` with a distinct port. That matches `RustFSTestClusterEnvironment` in `crates/e2e_test/src/common.rs`:

| Layout | Constructor | Use |
|---|---|---|
| 4 nodes × 4 drives, one pool | `ClusterTopology::single_pool_multidrive(4, 4)` | S3, object lock, versioning, quota, observability, concurrency, chaos |
| 4 nodes × 1 drive, one pool | `ClusterTopology::single_pool(4)` | Two-site replication (8 processes total); direct/rolling upgrade from the pinned previous release |
| 2 single-node pools × 4 drives | `ClusterTopology::per_node_pools(4, [[0],[1]])` | Harness-only: `append_single_node_pool` unit tests. Live multi-pool expand/restart currently dies with `pool metadata recovery required`; this lane does not change that production gate |

A pool striped across several localhost ports is not expressible (`RUSTFS_VOLUMES` host ellipses would collide on disk paths). Multi-host striped pools remain the hardware functional-chain / backlog #1313 / #1314 lane.

Decommission and rebalance POST on the 4×4 single-pool layout is refused by the current product (`single pool deployments do not support decommission`, NotImplemented, or an opaque admin 5xx when the inner pool-meta fence is wrapped as InternalError). Those cases still assert object bytes and SHA-256; when the API starts they wait for completion and assert post-move integrity. They do not treat a refusal as a successful move. This lane does not change production pool-meta bootstrap, write-fence, or decommission policy; it only observes the current server behavior.

## What this lane covers

`cargo nextest run --profile e2e-distributed -p e2e_test` selects `distributed::*`:

- S3 put / get / head / list / copy / rename / delete / presign / empty object
- Object Lock COMPLIANCE, GOVERNANCE (with bypass), legal hold
- Versioning, version GET, delete marker
- Bucket replication between two 4-node clusters; hard quota
- Health / admin info / storageinfo / audit target list
- Pool restart, decommission/rebalance *attempts*, checksum integrity, S3 during those attempts on 4×4. Live multi-pool expand/restart is a production pool-meta bootstrap limitation and is not patched here; `append_single_node_pool` is covered by harness unit tests
- Site replication object convergence
- High-concurrency PUT/GET; concurrent PUT during decommission
- Node kill/restart, full process restart, drive offline (4×4). Volume-proxy blackhole stays in `cluster_volume_fault_proxy_pass_smoke` (2×2); a 4-node volume proxy cannot format because RPC audience is the listen port
- Multipart, cross-node listing, list-buckets agreement
- Concurrent GET while a peer node is killed
- Direct and rolling upgrade from the pinned previous release: historical objects, versioned history, and IAM user AK/SK still work afterwards

## Existing Actions gaps this lane does not replace

Those suites stay in place; this lane fills the in-tree 4×4 hole they leave.

| Existing lane | Gap |
|---|---|
| `rustfs-*-test.yml` functional chain | Clones private `rustfs/auto-testing`, runs on three shared VMs (`vm000`–`vm002`), `continue-on-error: true`, not a merge signal, not 4 nodes. Hardware `rustfs-upgrade-test.yml` stays there |
| `e2e-upgrade.yml` | Single-node SSE/multipart/delete-marker contracts plus mixed-version listing; does not pin IAM user AK/SK on a 4-node cluster |
| `e2e-smoke` / `e2e-full` | Almost all cases are single-node |
| `e2e-nightly` | 4-node cluster faults and heal, not S3/lock/versioning/quota/decommission matrix |
| `e2e-repl-nightly` | Site and bucket replication on 1–3 *single-node* processes |
| `e2e-s3tests.yml` `multi` | Weekly ceph/s3-tests against Docker 4-node; not lock/WORM, decommission, chaos, or checksum integrity |
| `crates/e2e_test/src/chaos.rs` | Single-node disk faults only |

Hardware power-loss, NIC pull, and real disk replacement still belong on the smoke-testing VMs. This lane simulates those with SIGKILL, directory rename, and `FaultProxy` blackhole.

## Run

```bash
cargo build -p rustfs --bins
# Upgrade cases require the pinned previous binary (CI downloads it).
export RUSTFS_UPGRADE_SOURCE_BINARY=/path/to/rustfs-1.0.0-rc.2
cargo nextest run --profile e2e-distributed -p e2e_test
```

Without `RUSTFS_UPGRADE_SOURCE_BINARY` the two `distributed::upgrade_test::*` cases fail closed. Filter them out for a local run that is not checking upgrade:

```bash
cargo nextest run --profile e2e-distributed -p e2e_test -E 'not test(/^distributed::upgrade_test::/)'
```

The upgrade topology is `ClusterTopology::single_pool(4)` (4 nodes × 1 drive). That matches the proven mixed-version fixture in `upgrade_compatibility_test`; 4×4 localhost drives are rejected by the previous release's same-device disk check.

Membership is pinned by `.config/e2e-distributed-selection.txt`. Update it with `python3 ./scripts/check_test_wiring.py --update-profile e2e-distributed <listing.json> linux` after adding or renaming a case.