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Configuration Reference

Complete configuration reference for tuning SMG behavior.

Configuration Methods

SMG can be configured through:

  1. Command-line arguments (highest priority)
  2. Environment variables
  3. Default values (lowest priority)

Worker Configuration

Host

Network interface to bind to.

Option --host
Environment -
Default 0.0.0.0
Value Description
127.0.0.1 Localhost only
0.0.0.0 All IPv4 interfaces
:: All IPv6 interfaces
::1 IPv6 localhost

Port

Port for the main API server.

Option --port
Environment -
Default 30000

Worker URLs

List of worker URLs to route requests to.

Option --worker-urls
Environment -
Default Empty
Format Space-separated URLs

Examples: 

--worker-urls http://worker1:8000 http://worker2:8000
--worker-urls http://[::1]:8000 http://192.168.1.1:8000  # IPv6 and IPv4
--worker-urls grpc://worker1:50051  # gRPC mode

Routing Policy Configuration

Load Balancing Policy

Controls how requests are distributed across workers.

Option --policy
Environment -
Default cache_aware
Values random, round_robin, cache_aware, power_of_two, prefix_hash, manual

Policy Comparison:

Policy Use Case KV Cache Load Balance
random Simple deployments Poor Fair
round_robin Uniform workloads Poor Good
power_of_two Variable workloads Poor Excellent
cache_aware LLM inference Excellent Good
prefix_hash Consistent routing by prefix Good Good
manual Session affinity Good Manual

Recommendation: Use cache_aware for LLM workloads to maximize KV cache hit rates.

Cache-Aware Policy Options

Option Description Default
--cache-threshold Cache threshold (0.0-1.0) for cache-aware routing 0.3
--balance-abs-threshold Absolute threshold for load balancing trigger 64
--balance-rel-threshold Relative threshold for load balancing trigger 1.5
--eviction-interval Interval in seconds between cache eviction operations 120
--max-tree-size Maximum size of the approximation tree 67108864

Prefix Hash Policy Options

Option Description Default
--prefix-token-count Number of prefix tokens to use for hashing 256
--prefix-hash-load-factor Load factor threshold for rebalancing 1.25

Manual Policy Options

Option Description Default
--max-idle-secs Maximum idle time before eviction 14400 (4 hours)
--assignment-mode Mode for new routing key assignment random

Assignment Modes: - random - Assign to a random worker - min_load - Assign to worker with fewest active requests - min_group - Assign to worker with fewest routing keys

Advanced Routing Options

Option Description Default
--dp-aware Enable data parallelism aware scheduling false
--enable-igw Enable IGW (Inference Gateway) mode for multi-model support false

PD Disaggregation Configuration

Prefill-Decode disaggregated mode separates prefill and decode operations across different workers.

Enable PD Mode

Option --pd-disaggregation
Environment -
Default false

Prefill Servers

Option --prefill
Format URL [BOOTSTRAP_PORT]
Multiple Yes (specify multiple times)

Examples: 

--prefill http://prefill1:30001 9001 \
--prefill http://prefill2:30002 9002 \
--prefill http://prefill3:30003 none  # No bootstrap port

Decode Servers

Option --decode
Format URL
Multiple Yes (specify multiple times)

Example: 

--decode http://decode1:30003 \
--decode http://decode2:30004

PD-Specific Policies

Option Description Default
--prefill-policy Specific policy for prefill nodes Uses main --policy
--decode-policy Specific policy for decode nodes Uses main --policy

Worker Startup Configuration

Option Description Default
--worker-startup-timeout-secs Timeout for worker startup and registration 1800 (30 min)
--worker-startup-check-interval Interval between worker startup checks 30

Service Discovery (Kubernetes)

Enable Service Discovery

Option --service-discovery
Environment -
Default false

Note: Enabling service discovery automatically enables IGW mode.

Label Selector

Option --selector
Format key=value (space-separated for multiple)

Example: 

--selector app=sglang-worker tier=inference

Namespace

Option --service-discovery-namespace
Environment -
Default All namespaces

Worker Port

Option --service-discovery-port
Environment -
Default 80

PD Service Discovery Selectors

Option Description
--prefill-selector Label selector for prefill server pods
--decode-selector Label selector for decode server pods

Tokenizer Configuration

Model Path

Option --model-path
Environment -
Default None
Description HuggingFace model ID or local path for loading tokenizer

Tokenizer Path

Option --tokenizer-path
Environment -
Default None
Description Explicit tokenizer path (overrides model_path tokenizer)

Chat Template

Option --chat-template
Environment -
Default None
Description Path to chat template file

Tokenizer Cache (L0 - Exact Match)

Option Description Default
--tokenizer-cache-enable-l0 Enable L0 exact match cache false
--tokenizer-cache-l0-max-entries Maximum entries in L0 cache 10000

Tokenizer Cache (L1 - Prefix Matching)

Option Description Default
--tokenizer-cache-enable-l1 Enable L1 prefix matching cache false
--tokenizer-cache-l1-max-memory Maximum memory for L1 cache (bytes) 52428800 (50MB)

Parser Configuration

Reasoning Parser

Option --reasoning-parser
Environment -
Default None
Values deepseek-r1, qwen3, etc.
Description Parser for reasoning models with thinking tokens

Tool Call Parser

Option --tool-call-parser
Environment -
Default None
Values json, qwen, etc.
Description Parser for tool-call/function-calling interactions

MCP Configuration

MCP Config Path

Option --mcp-config-path
Environment -
Default None
Description Path to MCP (Model Context Protocol) server configuration file

Backend Configuration

Backend Runtime

Option --backend
Environment -
Default sglang
Values sglang, vllm, trtllm, openai, anthropic

History Backend

Option --history-backend
Environment -
Default memory
Values memory, none, oracle, postgres, redis

Storage Configuration

Oracle Database

Option Environment Description
--oracle-wallet-path ATP_WALLET_PATH Path to Oracle ATP wallet directory
--oracle-tns-alias ATP_TNS_ALIAS Oracle TNS alias from tnsnames.ora
--oracle-dsn ATP_DSN Oracle connection descriptor/DSN
--oracle-user ATP_USER Oracle database username
--oracle-password ATP_PASSWORD Oracle database password
--oracle-pool-min ATP_POOL_MIN Minimum connection pool size (default: 1)
--oracle-pool-max ATP_POOL_MAX Maximum connection pool size (default: 16)
--oracle-pool-timeout-secs ATP_POOL_TIMEOUT_SECS Pool timeout in seconds (default: 30)

PostgreSQL Database

Option Environment Description Default
--postgres-db-url POSTGRES_DB_URL PostgreSQL connection URL -
--postgres-pool-max-size POSTGRES_POOL_MAX Maximum pool size 16

Redis Database

Option Environment Description Default
--redis-url REDIS_URL Redis connection URL -
--redis-pool-max-size REDIS_POOL_MAX Maximum pool size 16
--redis-retention-days REDIS_RETENTION_DAYS Data retention (-1 for persistent) 30

WASM Configuration

Enable WebAssembly

Option --enable-wasm
Environment -
Default false
Description Enable WebAssembly support

Mesh/HA Configuration

High-availability mesh networking for router coordination.

Option Description Default
--enable-mesh Enable mesh server for HA false
--mesh-server-name Unique name for this mesh node Auto-generated
--mesh-host Host address for mesh server 0.0.0.0
--mesh-port Port for mesh server 39527
--mesh-peer-urls URLs of peer mesh nodes Empty

Example: 

smg \
  --enable-mesh \
  --mesh-server-name router-1 \
  --mesh-port 39527 \
  --mesh-peer-urls 192.168.1.10:39527

Request Handling Configuration

Request Timeout

Option --request-timeout-secs
Environment -
Default 1800 (30 minutes)
Description Maximum time for request processing

Shutdown Grace Period

Option --shutdown-grace-period-secs
Environment -
Default 180 (3 minutes)
Description Time to wait for in-flight requests during shutdown

Maximum Payload Size

Option --max-payload-size
Environment -
Default 536870912 (512MB)
Description Maximum request payload size in bytes

CORS Configuration

Option --cors-allowed-origins
Environment -
Default Empty
Format Space-separated URLs

Example: 

--cors-allowed-origins http://localhost:3000 https://example.com

Request ID Headers

Option --request-id-headers
Environment -
Default None (uses common defaults)
Description Custom HTTP headers to check for request IDs

Example: 

--request-id-headers x-request-id x-trace-id x-correlation-id

Rate Limiting Configuration

Concurrent Request Limit

Option --max-concurrent-requests
Environment -
Default -1 (unlimited)
Range -1 or 1+

Sizing Guide:

max_concurrent_requests = num_workers * requests_per_worker_capacity
Worker GPU Memory Suggested per Worker
16GB 4-8
40GB 8-16
80GB 16-32

Queue Configuration

Option Description Default
--queue-size Maximum requests waiting when rate limit reached 100
--queue-timeout-secs Maximum time a request can wait in queue 60

Token Bucket Rate Limiting

Option --rate-limit-tokens-per-second
Environment -
Default Same as max-concurrent-requests
Description Token bucket refill rate

Retry Configuration

Retry Options

Option Description Default
--retry-max-retries Maximum retry attempts 5
--retry-initial-backoff-ms Initial backoff delay (ms) 50
--retry-max-backoff-ms Maximum backoff delay (ms) 30000
--retry-backoff-multiplier Exponential backoff multiplier 1.5
--retry-jitter-factor Jitter factor (0.0-1.0) 0.2
--disable-retries Disable automatic retries false

Backoff Formula: 

delay = min(initial_backoff * multiplier^attempt, max_backoff) * (1 + random(0, jitter_factor))

Circuit Breaker Configuration

Option Description Default
--cb-failure-threshold Failures before circuit opens 10
--cb-success-threshold Successes needed to close in half-open state 3
--cb-timeout-duration-secs Time before attempting recovery 60
--cb-window-duration-secs Sliding window for tracking failures 120
--disable-circuit-breaker Disable circuit breaker false

Circuit Breaker States: - Closed: Normal operation, tracking failures - Open: All requests fail fast, circuit tripped - Half-Open: Testing if service recovered

Health Check Configuration

Option Description Default
--health-failure-threshold Failures before marking unhealthy 3
--health-success-threshold Successes before marking healthy 2
--health-check-timeout-secs Timeout for health check requests 5
--health-check-interval-secs Interval between health checks 60
--health-check-endpoint Health check endpoint path /health
--disable-health-check Disable all health checks false

Prometheus Metrics Configuration

Metrics Server

Option Description Default
--prometheus-port Port for Prometheus metrics endpoint 29000
--prometheus-host Host for Prometheus metrics server 0.0.0.0
--prometheus-duration-buckets Custom histogram buckets Default buckets

Example: 

--prometheus-duration-buckets 0.001 0.005 0.01 0.025 0.05 0.1 0.25 0.5 1.0 2.5 5.0 10.0

OpenTelemetry Configuration

Enable Tracing

Option --enable-trace
Environment -
Default false

OTLP Endpoint

Option --otlp-traces-endpoint
Environment -
Default localhost:4317
Format host:port

Example: 

smg --enable-trace --otlp-traces-endpoint jaeger:4317

TLS/mTLS Security Configuration

Server TLS

For HTTPS on the gateway:

Option Description
--tls-cert-path Path to server certificate (PEM format)
--tls-key-path Path to server private key (PEM format)

Client mTLS

For secure communication to workers (Python bindings):

Option Description
--client-cert-path Path to client certificate
--client-key-path Path to client private key
--ca-cert-paths Path(s) to CA certificate(s)

Control Plane Authentication

API Key (Worker Authorization)

Option --api-key
Environment -
Default None
Description API key for worker authorization (useful with dp-aware scheduling)

Control Plane API Keys

Option --control-plane-api-keys
Environment CONTROL_PLANE_API_KEYS
Format id:name:role:key
Multiple Yes

Example: 

--control-plane-api-keys 'key1:Admin:admin:secret123' 'key2:ReadOnly:user:secret456'

JWT/OIDC Authentication

Option Environment Description
--jwt-issuer JWT_ISSUER OIDC issuer URL
--jwt-audience JWT_AUDIENCE Expected audience claim
--jwt-jwks-uri JWT_JWKS_URI Explicit JWKS URI (auto-discovered if not set)
--jwt-role-claim - JWT claim containing role (default: roles)
--jwt-role-mapping - Role mapping from IDP to gateway role

JWT Role Mapping Example: 

--jwt-role-mapping 'Gateway.Admin=admin' 'Gateway.User=user'

Audit Logging

Option --disable-audit-logging
Environment -
Default false (audit logging enabled)

Logging Configuration

Log Level

Option --log-level
Environment RUST_LOG
Default info
Values debug, info, warn, error

Per-Module Logging:

RUST_LOG=smg=debug,hyper=warn smg ...

Log Directory

Option --log-dir
Environment -
Default None (console only)
Description Directory to store log files

Configuration Examples

Minimal Configuration

smg --worker-urls http://localhost:8000

High-Throughput Configuration

smg \
  --worker-urls http://w1:8000 http://w2:8000 http://w3:8000 http://w4:8000 \
  --policy cache_aware \
  --max-concurrent-requests 200 \
  --queue-size 400 \
  --queue-timeout-secs 60 \
  --retry-max-retries 3

Low-Latency Configuration

smg \
  --worker-urls http://w1:8000 http://w2:8000 \
  --policy power_of_two \
  --max-concurrent-requests 50 \
  --queue-size 25 \
  --queue-timeout-secs 5 \
  --health-check-interval-secs 5 \
  --request-timeout-secs 30

PD Disaggregated Mode

smg \
  --pd-disaggregation \
  --prefill http://prefill1:30001 9001 \
  --prefill http://prefill2:30002 9002 \
  --decode http://decode1:30003 \
  --decode http://decode2:30004 \
  --prefill-policy cache_aware \
  --decode-policy round_robin

Kubernetes Service Discovery

smg \
  --service-discovery \
  --selector app=sglang-worker \
  --service-discovery-namespace inference \
  --service-discovery-port 8000 \
  --policy cache_aware

High-Availability Mesh

# Router 1
smg \
  --enable-mesh \
  --mesh-server-name router-1 \
  --mesh-port 39527 \
  --mesh-peer-urls 192.168.1.11:39527 \
  --worker-urls http://worker1:8000

# Router 2
smg \
  --enable-mesh \
  --mesh-server-name router-2 \
  --mesh-port 39527 \
  --mesh-peer-urls 192.168.1.10:39527 \
  --worker-urls http://worker2:8000

Secure Production Configuration

smg \
  --service-discovery \
  --selector app=sglang-worker \
  --service-discovery-namespace inference \
  --policy cache_aware \
  --max-concurrent-requests 100 \
  --tls-cert-path /etc/certs/server.crt \
  --tls-key-path /etc/certs/server.key \
  --jwt-issuer https://login.microsoftonline.com/tenant/v2.0 \
  --jwt-audience api://smg-gateway \
  --jwt-role-mapping 'Gateway.Admin=admin' 'Gateway.User=user' \
  --enable-trace \
  --otlp-traces-endpoint jaeger:4317 \
  --host 0.0.0.0 \
  --port 443

With Tokenizer and Parsers

smg \
  --worker-urls http://localhost:8000 \
  --model-path meta-llama/Llama-3-8B-Instruct \
  --tokenizer-cache-enable-l0 \
  --tokenizer-cache-l0-max-entries 50000 \
  --reasoning-parser deepseek-r1 \
  --tool-call-parser json

With Database Backend

# PostgreSQL
smg \
  --worker-urls http://localhost:8000 \
  --history-backend postgres \
  --postgres-db-url "postgres://user:pass@localhost:5432/smg" \
  --postgres-pool-max-size 32

# Redis
smg \
  --worker-urls http://localhost:8000 \
  --history-backend redis \
  --redis-url "redis://localhost:6379" \
  --redis-pool-max-size 32 \
  --redis-retention-days 7

Environment Variable Reference

Environment Variable CLI Option Description
RUST_LOG --log-level Log level
ATP_WALLET_PATH --oracle-wallet-path Oracle wallet path
ATP_TNS_ALIAS --oracle-tns-alias Oracle TNS alias
ATP_DSN --oracle-dsn Oracle DSN
ATP_USER --oracle-user Oracle username
ATP_PASSWORD --oracle-password Oracle password
ATP_POOL_MIN --oracle-pool-min Oracle min pool size
ATP_POOL_MAX --oracle-pool-max Oracle max pool size
ATP_POOL_TIMEOUT_SECS --oracle-pool-timeout-secs Oracle pool timeout
POSTGRES_DB_URL --postgres-db-url PostgreSQL URL
POSTGRES_POOL_MAX --postgres-pool-max-size PostgreSQL max pool
REDIS_URL --redis-url Redis URL
REDIS_POOL_MAX --redis-pool-max-size Redis max pool
REDIS_RETENTION_DAYS --redis-retention-days Redis retention
JWT_ISSUER --jwt-issuer JWT issuer URL
JWT_AUDIENCE --jwt-audience JWT audience
JWT_JWKS_URI --jwt-jwks-uri JWKS URI
CONTROL_PLANE_API_KEYS --control-plane-api-keys Control plane API keys