Struct Cluster 

pub struct Cluster {

    pub cluster_id: String,
    pub sticky_session: bool,
    pub https_redirect: bool,
    pub proxy_protocol: Option<i32>,
    pub load_balancing: i32,
    pub answer_503: Option<String>,
    pub load_metric: Option<i32>,
    pub http2: Option<bool>,
    pub answers: BTreeMap<String, String>,
    pub https_redirect_port: Option<u32>,
    pub authorized_hashes: Vec<String>,
    pub www_authenticate: Option<String>,
    pub max_connections_per_ip: Option<u64>,
    pub retry_after: Option<u32>,
    pub health_check: Option<HealthCheckConfig>,
    pub udp: Option<UdpClusterConfig>,
    pub max_connections_per_subnet: Option<u64>,
    pub affinity_header: Option<String>,
    pub affinity_cookie: Option<String>,
    pub shard_percent: Option<u32>,
    pub shard_min_backends: Option<u32>,
    pub shard_mode: Option<i32>,
    pub max_connection_attempts: Option<u32>,
}

A cluster is what binds a frontend to backends with routing rules

Fields

cluster_id: String

sticky_session: bool

wether a connection from a client shall be always redirected to the same backend

https_redirect: bool

proxy_protocol: Option<i32>

load_balancing: i32

answer_503: Option<String>

load_metric: Option<i32>

http2: Option<bool>

Backend-capability hint: set to true when THE BACKEND speaks HTTP/2 (h2c or h2+TLS). This does NOT gate H2 acceptance at the frontend — frontend H2 is negotiated via TLS ALPN independently of per-cluster configuration (see alpn_protocols on the listener).

answers: BTreeMap<String, String>

Per-cluster HTTP answer template overrides keyed by HTTP status code (e.g. “503”). Override a listener-level answer for this cluster only.

https_redirect_port: Option<u32>

Optional explicit port to use when building the Location header for an https_redirect. When unset, the listener’s effective HTTPS port is used. Lets operators front a non-standard HTTPS port (e.g. 8443) on the redirect target while keeping https_redirect = true.

authorized_hashes: Vec<String>

Authorized credentials for HTTP basic authentication. Each entry is formatted as username:hex(sha256(password)) (lower-case hex). The mux compares the supplied Authorization: Basic header in constant-time against the full list. Empty list disables auth even when a frontend sets required_auth = true — those requests are rejected with a 401.

www_authenticate: Option<String>

Realm string emitted in WWW-Authenticate: Basic realm="…" when an unauthenticated request is rejected. Treated as an opaque value (no template substitution). Defaults to a generic realm if unset.

max_connections_per_ip: Option<u64>

Per-cluster override for the global max_connections_per_ip. None (field absent) inherits the global default. Some(0) is explicit “unlimited for this cluster”. Some(n > 0) overrides with the cluster-specific limit. Counts are kept per (cluster_id, source_ip) pair, so two clusters never share a counter even from the same IP. On a UDP cluster it limits concurrent flows per datagram source address, per listener; UDP never inherits the global default.

retry_after: Option<u32>

Per-cluster override for the global retry_after header value (seconds, HTTP 429 only). None inherits the global default. Some(0) omits the header.

health_check: Option<HealthCheckConfig>

Optional HTTP health check configuration for backends in this cluster. Tag 8 in this message is the http2 backend-capability hint and tags 9-14 cover answers/redirect/auth/limits, so health-check configuration occupies tag 15.

udp: Option<UdpClusterConfig>

Optional UDP-specific cluster configuration. Present only for clusters that front UDP backends; absent for HTTP/HTTPS/TCP clusters.

max_connections_per_subnet: Option<u64>

Per-cluster override for the global max_connections_per_subnet. Same three-state semantics as max_connections_per_ip above: None (field absent) inherits the global default, Some(0) is explicit “unlimited for this cluster”, Some(n > 0) overrides. This is an INDEPENDENT counter from tag 13, not a replacement: a connection must satisfy BOTH the per-IP and the per-subnet cap to be admitted, which is what lets an operator express “10 per IP AND 100 per /64”. Counts are kept per (cluster_id, masked_ip), so two clusters never share a counter. The mask itself comes from the boot-time ServerConfig.subnet_ipv4_prefix / subnet_ipv6_prefix and is NOT overridable per cluster. A UDP listener counts flows, as for tag 13.

affinity_header: Option<String>

Client affinity key of an HTTP/HTTPS cluster whose load_balancing is HRW or MAGLEV: the value of this request header, matched case-insensitively, first occurrence. A request that does not carry it is keyed on its source IP (the PROXY-protocol source when the listener expects one). Ignored by every other policy and by TCP clusters, which always key on the source IP: the main state refuses a cluster that names a key and serves a TCP frontend. Host and Cookie are refused (never kept as headers). Mutually exclusive with affinity_cookie. The key is read only when a new backend connection is dialled; a request reusing one follows it.

affinity_cookie: Option<String>

Same as affinity_header, keyed on the raw value of this request cookie, matched case-sensitively. Mutually exclusive with affinity_header.

shard_percent: Option<u32>

Shuffle sharding (sozu-proxy/sozu#524): restrict each client’s selection to a shard of k backends, the top k of the rendezvous (HRW) ranking of its affinity key over the cluster’s primary backends, where k = max(2, ceil(shard_percent * N / 100)), capped at N. Off when unset. 1..=100. The cluster’s load_balancing policy picks inside the shard.

shard_min_backends: Option<u32>

Sharding applies only while the cluster has at least this many primary backends; below it the cluster selects over all of them. At least 2; defaults to 8. Requires shard_percent.

shard_mode: Option<i32>

What happens when no backend of a client’s shard can take a connection. Requires shard_percent.

max_connection_attempts: Option<u32>

Per-cluster override for the global max_connection_attempts: how many backend connections a request routed to this cluster may try, the first included, before it is answered 503 (HTTP) or closed (TCP). Every failed connection counts: refused, timed out on connect_timeout, or reporting a socket error. Between 1 and 255. None (field absent) inherits the global value.

Implementations

impl Cluster

pub fn proxy_protocol(&self) -> ProxyProtocolConfig

Returns the enum value of proxy_protocol, or the default if the field is unset or set to an invalid enum value.

pub fn set_proxy_protocol(&mut self, value: ProxyProtocolConfig)

Sets proxy_protocol to the provided enum value.

pub fn load_balancing(&self) -> LoadBalancingAlgorithms

Returns the enum value of load_balancing, or the default if the field is set to an invalid enum value.

pub fn set_load_balancing(&mut self, value: LoadBalancingAlgorithms)

Sets load_balancing to the provided enum value.

pub fn answer_503(&self) -> &str

Returns the value of answer_503, or the default value if answer_503 is unset.

pub fn load_metric(&self) -> LoadMetric

Returns the enum value of load_metric, or the default if the field is unset or set to an invalid enum value.

pub fn set_load_metric(&mut self, value: LoadMetric)

Sets load_metric to the provided enum value.

pub fn http2(&self) -> bool

Returns the value of http2, or the default value if http2 is unset.

pub fn https_redirect_port(&self) -> u32

Returns the value of https_redirect_port, or the default value if https_redirect_port is unset.

pub fn www_authenticate(&self) -> &str

Returns the value of www_authenticate, or the default value if www_authenticate is unset.

pub fn max_connections_per_ip(&self) -> u64

Returns the value of max_connections_per_ip, or the default value if max_connections_per_ip is unset.

pub fn retry_after(&self) -> u32

Returns the value of retry_after, or the default value if retry_after is unset.

pub fn max_connections_per_subnet(&self) -> u64

Returns the value of max_connections_per_subnet, or the default value if max_connections_per_subnet is unset.

pub fn affinity_header(&self) -> &str

Returns the value of affinity_header, or the default value if affinity_header is unset.

pub fn affinity_cookie(&self) -> &str

Returns the value of affinity_cookie, or the default value if affinity_cookie is unset.

pub fn shard_percent(&self) -> u32

Returns the value of shard_percent, or the default value if shard_percent is unset.

pub fn shard_min_backends(&self) -> u32

Returns the value of shard_min_backends, or the default value if shard_min_backends is unset.

pub fn shard_mode(&self) -> ShardMode

Returns the enum value of shard_mode, or the default if the field is unset or set to an invalid enum value.

pub fn set_shard_mode(&mut self, value: ShardMode)

Sets shard_mode to the provided enum value.

pub fn max_connection_attempts(&self) -> u32

Returns the value of max_connection_attempts, or the default value if max_connection_attempts is unset.

Trait Implementations

impl Clone for Cluster

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Cluster

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

Formats the value using the given formatter.

impl Default for Cluster

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Cluster

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for Cluster

impl Hash for Cluster

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for Cluster

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode(&self, buf: &mut impl BufMut) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message to a buffer.

fn encode_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message to a newly allocated buffer.

fn encode_length_delimited( &self, buf: &mut impl BufMut, ) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message with a length-delimiter to a buffer.

fn encode_length_delimited_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message with a length-delimiter to a newly allocated buffer.

fn decode(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes an instance of the message from a buffer.

fn decode_length_delimited(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes a length-delimited instance of the message from the buffer.

fn merge(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl Ord for Cluster

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for Cluster

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Cluster

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for Cluster

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 Cluster