Fix/issue #1001 dead node detection (#1054)

Co-authored-by: weisd <im@weisd.in>
Co-authored-by: Jitterx69 <mohit@example.com>
This commit is contained in:
Jitter
2025-12-08 09:59:46 +05:30
committed by GitHub
parent 834025d9e3
commit 76d25d9a20
9 changed files with 369 additions and 79 deletions

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@@ -5,25 +5,30 @@
**Symptoms**:
- The application became unable to upload files.
- The Console Web UI became unresponsive across the cluster.
- The `rustfsadmin` user was unable to log in after a server power-off.
- The performance page displayed 0 storage, 0 objects, and 0 servers online/offline.
- The system "hung" indefinitely, unlike the immediate recovery observed during a graceful process termination (`kill`).
**Root Cause**:
The standard TCP protocol does not immediately detect a silent peer disappearance (power loss) because no `FIN` or `RST` packets are sent. Without active application-layer heartbeats, the surviving nodes kept connections implementation in an `ESTABLISHED` state, waiting indefinitely for responses that would never arrive.
**Root Cause (Multi-Layered)**:
1. **TCP Connection Issue**: The standard TCP protocol does not immediately detect a silent peer disappearance (power loss) because no `FIN` or `RST` packets are sent.
2. **Stale Connection Cache**: Cached gRPC connections in `GLOBAL_Conn_Map` were reused even when the peer was dead, causing blocking on every RPC call.
3. **Blocking IAM Notifications**: Login operations blocked waiting for ALL peers to acknowledge user/policy changes.
4. **No Per-Peer Timeouts**: Console aggregation calls like `server_info()` and `storage_info()` could hang waiting for dead peers.
---
## 2. Technical Approach
To resolve this, we needed to transform the passive failure detection (waiting for TCP timeout) into an active detection mechanism.
To resolve this, we implemented a comprehensive multi-layered resilience strategy.
### Key Objectives:
1. **Fail Fast**: Detect dead peers in seconds, not minutes.
2. **Accuracy**: Distinguish between network congestion and actual node failure.
3. **Safety**: Ensure no thread or task blocks forever on a remote procedure call (RPC).
2. **Evict Stale Connections**: Automatically remove dead connections from cache to force reconnection.
3. **Non-Blocking Operations**: Auth and IAM operations should not wait for dead peers.
4. **Graceful Degradation**: Console should show partial data from healthy nodes, not hang.
---
## 3. Implemented Solution
We modified the internal gRPC client configuration in `crates/protos/src/lib.rs` to implement a multi-layered health check strategy.
### Solution Overview
The fix implements a multi-layered detection strategy covering both Control Plane (RPC) and Data Plane (Streaming):
@@ -43,23 +48,109 @@ The fix implements a multi-layered detection strategy covering both Control Plan
### Configuration Changes
```rust
let connector = Endpoint::from_shared(addr.to_string())?
.connect_timeout(Duration::from_secs(5))
// 1. App-Layer Heartbeats (Primary Detection)
// Sends a hidden HTTP/2 PING frame every 5 seconds.
.http2_keep_alive_interval(Duration::from_secs(5))
// If PING is not acknowledged within 3 seconds, closes connection.
.keep_alive_timeout(Duration::from_secs(3))
// Ensures PINGs are sent even when no active requests are in flight.
.keep_alive_while_idle(true)
// 2. Transport-Layer Keepalive (OS Backup)
.tcp_keepalive(Some(Duration::from_secs(10)))
// 3. Global Safety Net
// Hard deadline for any RPC operation.
.timeout(Duration::from_secs(60));
pub async fn storage_info<S: StorageAPI>(&self, api: &S) -> rustfs_madmin::StorageInfo {
let peer_timeout = Duration::from_secs(2);
for client in self.peer_clients.iter() {
futures.push(async move {
if let Some(client) = client {
match timeout(peer_timeout, client.local_storage_info()).await {
Ok(Ok(info)) => Some(info),
Ok(Err(_)) | Err(_) => {
// Return offline status for dead peer
Some(rustfs_madmin::StorageInfo {
disks: get_offline_disks(&host, &endpoints),
..Default::default()
})
}
}
}
});
}
// Rest continues even if some peers are down
}
```
### Outcome
- **Detection Time**: Reduced from ~15+ minutes (OS default) to **~8 seconds** (5s interval + 3s timeout).
- **Behavior**: When a node loses power, surviving peers now detect the lost connection almost immediately, throwing a protocol error that triggers standard cluster recovery/failover logic.
- **Result**: The cluster now handles power-offs with the same resilience as graceful shutdowns.
### Fix 4: Enhanced gRPC Client Configuration
**File Modified**: `crates/protos/src/lib.rs`
**Configuration**:
```rust
const CONNECT_TIMEOUT_SECS: u64 = 3; // Reduced from 5s
const TCP_KEEPALIVE_SECS: u64 = 10; // OS-level keepalive
const HTTP2_KEEPALIVE_INTERVAL_SECS: u64 = 5; // HTTP/2 PING interval
const HTTP2_KEEPALIVE_TIMEOUT_SECS: u64 = 3; // PING ACK timeout
const RPC_TIMEOUT_SECS: u64 = 30; // Reduced from 60s
let connector = Endpoint::from_shared(addr.to_string())?
.connect_timeout(Duration::from_secs(CONNECT_TIMEOUT_SECS))
.tcp_keepalive(Some(Duration::from_secs(TCP_KEEPALIVE_SECS)))
.http2_keep_alive_interval(Duration::from_secs(HTTP2_KEEPALIVE_INTERVAL_SECS))
.keep_alive_timeout(Duration::from_secs(HTTP2_KEEPALIVE_TIMEOUT_SECS))
.keep_alive_while_idle(true)
.timeout(Duration::from_secs(RPC_TIMEOUT_SECS));
```
---
## 4. Files Changed Summary
| File | Change |
|------|--------|
| `crates/common/src/globals.rs` | Added `evict_connection()`, `has_cached_connection()`, `clear_all_connections()` |
| `crates/common/Cargo.toml` | Added `tracing` dependency |
| `crates/protos/src/lib.rs` | Refactored to use constants, added `evict_failed_connection()`, improved documentation |
| `crates/protos/Cargo.toml` | Added `tracing` dependency |
| `crates/ecstore/src/rpc/peer_rest_client.rs` | Added auto-eviction on RPC failure for `server_info()` and `local_storage_info()` |
| `crates/ecstore/src/notification_sys.rs` | Added per-peer timeout to `storage_info()` |
| `crates/iam/src/sys.rs` | Made `notify_for_user()`, `notify_for_service_account()`, `notify_for_group()` non-blocking |
---
## 5. Test Results
All 299 tests pass:
```
test result: ok. 299 passed; 0 failed; 0 ignored
```
---
## 6. Expected Behavior After Fix
| Scenario | Before | After |
|----------|--------|-------|
| Node power-off | Cluster hangs indefinitely | Cluster recovers in ~8 seconds |
| Login during node failure | Login hangs | Login succeeds immediately |
| Console during node failure | Shows 0/0/0 | Shows partial data from healthy nodes |
| Upload during node failure | Upload stops | Upload fails fast, can be retried |
| Stale cached connection | Blocks forever | Auto-evicted, fresh connection attempted |
---
## 7. Verification Steps
1. **Start a 3+ node RustFS cluster**
2. **Test Console Recovery**:
- Access console dashboard
- Forcefully kill one node (e.g., `kill -9`)
- Verify dashboard updates within 10 seconds showing offline status
3. **Test Login Recovery**:
- Kill a node while logged out
- Attempt login with `rustfsadmin`
- Verify login succeeds within 5 seconds
4. **Test Upload Recovery**:
- Start a large file upload
- Kill the target node mid-upload
- Verify upload fails fast (not hangs) and can be retried
---
## 8. Related Issues
- Issue #1001: Cluster Recovery from Abrupt Power-Off
- PR #1035: fix(net): resolve 1GB upload hang and macos build
## 9. Contributors
- Initial keepalive fix: Original PR #1035
- Deep-rooted reliability fix: This update