Enum ClusterMode 

pub enum ClusterMode {
    SingleNode,
    Raft {
        node_id: u64,
        peers: Vec<RaftPeer>,
    },
    Static {
        node_id: u64,
        peers: Vec<StaticPeer>,
        heartbeat_interval: Duration,
        failure_threshold: Duration,
    },
    WorkerTier {

        role: WorkerTierRole,
        node_id: Option<u64>,
        peers: Vec<RaftPeer>,
        worker_grpc_addr: SocketAddr,
        servers: Vec<String>,
        token_file: Option<String>,
        identity_dir: Option<String>,
        worker_ca_dir: Option<String>,
        heartbeat_min_ttl: Duration,
        heartbeat_max_ttl: Duration,
        heartbeat_grace: Duration,
        max_heartbeats_per_second: u32,
        failover_heartbeat_ttl: Duration,
        labels: HashMap<String, String>,
    
},
}

How the daemon participates in (or doesn’t) cluster membership.

The WorkerTier variant is intentionally large (~285 bytes) because it carries the full server-role + worker-role config inline. ClusterMode is parsed once at daemon startup and lives in an Arc<DaemonConfig> for the process lifetime, so the size delta is irrelevant in practice — and boxing it would force every caller of is_worker_tier_server() / adaptive_ttl_config() through an extra indirection for no win.

Variants

SingleNode

Single-node daemon. No peers, no consensus. is_leader() is always true. Suitable for development and single-host deployments.

Raft

openraft-backed consensus across the configured peers. This is the existing production mode for multi-node deployments.

Fields

node_id: u64

This node’s id (must be unique within the cluster).

peers: Vec<RaftPeer>

Peer addresses (raft RPC ports). The daemon’s own entry must be present.

Static

Static-membership cluster: config-driven peer list, deterministic leader (lowest healthy node id), HTTP heartbeats for liveness. No consensus log — concurrent writers may race; the per-service scale semaphore in ServiceManager is the primary mitigation.

Fields

node_id: u64

This node’s id (must be unique within the cluster).

peers: Vec<StaticPeer>

All cluster peers including self.

heartbeat_interval: Duration

Heartbeat probe interval. Default 5s.

failure_threshold: Duration

Time after which a peer with no heartbeat is Unreachable. Default 15s (3x interval).

WorkerTier

Nomad-style worker tier: 3–7 control-plane nodes run Raft consensus; up to ~10,000 worker nodes join as gRPC clients with adaptive-TTL heartbeats and never enter consensus.

Workers are issued mTLS leaf certs by the cluster’s worker CA during Register. Heartbeat cadence scales with cluster size — every StatusAck carries the next TTL computed from clamp(N_workers / max_heartbeats_per_second, min_ttl, max_ttl).

Fields

role: WorkerTierRole

What role THIS node plays.

node_id: Option<u64>

Server-only: this node’s id within the raft control plane. Required when role == Server; ignored on workers (assigned by leader during Register).

peers: Vec<RaftPeer>

Server-only: the raft control-plane peer list (3-7 nodes). Required when role == Server.

worker_grpc_addr: SocketAddr

Server-only: address to bind the worker-facing gRPC server. Default 0.0.0.0:3670 (the API server uses 3669; gRPC takes 3670).

servers: Vec<String>

Worker-only: control-plane gRPC endpoints to try (round-robin fallback). Required when role == Worker.

token_file: Option<String>

Worker-only: path to the bootstrap token file (single line, URL-safe-base64 of a WorkerBootstrapToken).

identity_dir: Option<String>

Worker-only: directory to persist mTLS identity (cert.pem, key.pem, ca.pem). Defaults to <data_dir>/worker/identity/ set by ZLayerDirs.

worker_ca_dir: Option<String>

Server-only: worker CA storage directory. Defaults to <data_dir>/cluster/ (same as the existing cluster CA + signer).

heartbeat_min_ttl: Duration

Shared: minimum heartbeat TTL (default 10s).

heartbeat_max_ttl: Duration

Shared: maximum heartbeat TTL (default 10min).

heartbeat_grace: Duration

Shared: grace period beyond TTL before a worker’s lease is considered expired. Default 10s.

max_heartbeats_per_second: u32

Server-only: cluster-wide cap on heartbeats/second the leader is willing to absorb. The leader hands every worker a TTL such that total HB rate ≤ this. Default 50 (Nomad’s default).

failover_heartbeat_ttl: Duration

Server-only: TTL applied immediately after a leader election so workers don’t all expire while the new leader is bootstrapping its FSM. Default 5min.

labels: HashMap<String, String>

Free-form node labels (placement, selector matching, etc.).

Implementations

impl ClusterMode

pub fn adaptive_ttl_config(&self) -> Option<AdaptiveTtlConfig>

Extract an AdaptiveTtlConfig from a WorkerTier variant. Returns None for other modes.

pub fn is_worker_tier_server(&self) -> bool

Convenience: is this a worker-tier server-role config?

pub fn is_worker_tier_worker(&self) -> bool

Convenience: is this a worker-tier worker-role config?

Trait Implementations

impl Clone for ClusterMode

fn clone(&self) -> ClusterMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ClusterMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ClusterMode

fn default() -> ClusterMode

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ClusterMode

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for ClusterMode

impl PartialEq for ClusterMode

fn eq(&self, other: &ClusterMode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ClusterMode

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ClusterMode