hashicorp/nomad · error

raft_trailing_logs must be non-negative, got %d

Error message

raft_trailing_logs must be non-negative, got %d

What it means

raft_trailing_logs controls how many log entries Raft keeps after a snapshot. convertServerConfig requires the value to be at least 1; a pointer-valued config option of 0 (or negative) is rejected despite the message saying 'non-negative'.

Source

Thrown at command/agent/agent.go:253

		conf.DataDir = agentConfig.Server.DataDir
	}
	if agentConfig.Server.RaftProtocol != 0 {
		conf.RaftConfig.ProtocolVersion = raft.ProtocolVersion(agentConfig.Server.RaftProtocol)
	}
	if v := conf.RaftConfig.ProtocolVersion; v != 3 {
		return nil, fmt.Errorf("raft_protocol must be 3 in Nomad v1.4 and later, got %d", v)
	}
	raftMultiplier := int(DefaultRaftMultiplier)
	if agentConfig.Server.RaftMultiplier != nil && *agentConfig.Server.RaftMultiplier != 0 {
		raftMultiplier = *agentConfig.Server.RaftMultiplier
		if raftMultiplier < 1 || raftMultiplier > MaxRaftMultiplier {
			return nil, fmt.Errorf("raft_multiplier cannot be %d. Must be between 1 and %d", *agentConfig.Server.RaftMultiplier, MaxRaftMultiplier)
		}
	}

	if vPtr := agentConfig.Server.RaftTrailingLogs; vPtr != nil {
		if *vPtr < 1 {
			return nil, fmt.Errorf("raft_trailing_logs must be non-negative, got %d", *vPtr)
		}
		conf.RaftConfig.TrailingLogs = uint64(*vPtr)
	}

	if vPtr := agentConfig.Server.RaftSnapshotInterval; vPtr != nil {
		dur, err := time.ParseDuration(*vPtr)
		if err != nil {
			return nil, err
		}
		if dur < 5*time.Millisecond {
			return nil, fmt.Errorf("raft_snapshot_interval must be greater than 5ms, got %q", *vPtr)
		}
		conf.RaftConfig.SnapshotInterval = dur
	}

	if vPtr := agentConfig.Server.RaftSnapshotThreshold; vPtr != nil {
		if *vPtr < 1 {
			return nil, fmt.Errorf("raft_snapshot_threshold must be non-negative, got %d", *vPtr)

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Set raft_trailing_logs to a positive integer (e.g. 10000, the default).
2. Remove the stanza to use the Raft default.
3. If intent was 'fewer retained logs', tune raft_snapshot_threshold/interval instead.

Example fix

// before
server {
  raft_trailing_logs = 0
}
// after
server {
  raft_trailing_logs = 10000
}

// Go: pre-validate
if v := cfg.Server.RaftTrailingLogs; v != nil && *v < 1 {
    return fmt.Errorf("raft_trailing_logs must be >= 1")
}

conf, err := convertServerConfig(agentCfg)
if err != nil {
    if strings.Contains(err.Error(), "raft_trailing_logs") {
        return fmt.Errorf("set raft_trailing_logs to a positive integer: %w", err)
    }
    return err
}

When it happens

Trigger: Setting server { raft_trailing_logs = 0 } (or a negative number) then starting or reloading the agent.

Common situations: Attempting to disable trailing logs by setting 0; misreading the doc thinking 0 disables the feature; automated config generators emitting 0 for unset values.

Related errors

• raft_protocol must be 3 in Nomad v1.4 and later, got %d
• raft_multiplier cannot be %d. Must be between 1 and %d
• raft_snapshot_interval must be greater than 5ms, got %q
• raft_snapshot_threshold must be non-negative, got %d
• plugin not found

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/360cfa86c19f71a3. Report an issue: GitHub.