rustfs/crates/config

RustFS Config - Configuration Management

Configuration management and validation module for RustFS distributed object storage

📖 Documentation · 🐛 Bug Reports · 💬 Discussions

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📖 Overview

RustFS Config provides configuration management and validation capabilities for the RustFS distributed object storage system. For the complete RustFS experience, please visit the main RustFS repository.

✨ Features

• Multi-format configuration support (TOML, YAML, JSON, ENV)
• Environment variable integration and override
• Configuration validation and type safety
• Hot-reload capabilities for dynamic updates
• Default value management and fallbacks
• Secure credential handling and encryption

📚 Documentation

For comprehensive documentation, examples, and usage guides, please visit the main RustFS repository.

Environment Variable Naming Conventions

RustFS uses a flat naming style for top-level configuration: environment variables are RUSTFS_* without nested module segments.

Examples:

• RUSTFS_REGION
• RUSTFS_ADDRESS
• RUSTFS_VOLUMES
• RUSTFS_LICENSE
• RUSTFS_LICENSE_PUBLIC_KEY

Current guidance:

• Prefer module-specific names only when they are not top-level product configuration.
• Renamed variables must keep backward-compatible aliases until before beta.
• Alias usage must emit deprecation warnings and be treated as transitional only.
• Deprecated example:
  • RUSTFS_ENABLE_SCANNER -> RUSTFS_SCANNER_ENABLED
  • RUSTFS_ENABLE_HEAL -> RUSTFS_HEAL_ENABLED
  • RUSTFS_DATA_SCANNER_START_DELAY_SECS -> RUSTFS_SCANNER_START_DELAY_SECS

License environment variables

• RUSTFS_LICENSE contains the signed license token.
• RUSTFS_LICENSE_PUBLIC_KEY contains the RSA public key used to verify signed license tokens.

CORS environment variables

• RUSTFS_CORS_ALLOWED_ORIGINS defaults to empty, so the S3 endpoint emits no generic CORS headers unless configured. Set * for wildcard origins without credentials, or a comma-separated allow-list for credentialed explicit origins.
• RUSTFS_CONSOLE_CORS_ALLOWED_ORIGINS defaults to * for the console service.

Console URL prefix

RUSTFS_CONSOLE_PREFIX changes the embedded console URL prefix. The default is /rustfs/console. For example, RUSTFS_CONSOLE_PREFIX=/console serves the UI at http://localhost:9001/console/. Nested prefixes such as /management/console are supported; one trailing slash is removed. Restart the server after changing it.

The prefix must be a non-root absolute path of at most 256 bytes, with nonempty segments containing only ASCII letters, digits, -, _, ., or ~. Dot segments, encoded characters, and overlaps with reserved admin, RPC, health, profiling, browser entry, and icon routes are rejected at startup. / is not supported. Choose a prefix that does not collide with S3 bucket paths.

The console routes, embedded frontend asset URLs, browser redirects, and OIDC console redirects use this prefix. Admin API paths and the identity provider's /rustfs/admin/v3/oidc/callback/... URL remain unchanged. RUSTFS_CONSOLE_ADDRESS continues to control only the listening address and port. The server adapts bundled console asset references from their build-time base path to the runtime prefix.

OEM builds can set RUSTFS_CONSOLE_BASE_PATH when compiling RustFS to embed a different default, such as /nuofans/console. Build the bundled console with the same NEXT_PUBLIC_BASE_PATH. An unset or empty build variable retains /rustfs/console. The build path must satisfy the validation rules above and must not have a trailing slash.

At startup, RUSTFS_CONSOLE_PREFIX takes precedence over the compiled default. Changing RUSTFS_CONSOLE_BASE_PATH when starting an existing binary has no effect; rebuild both components to change the embedded default. If a runtime prefix is configured, asset adaptation uses the compiled base path as its source, including when restoring /rustfs/console for a custom OEM build.

Browser redirect environment variables

• RUSTFS_BROWSER_REDIRECT_URL sets the externally reachable browser origin used for OIDC callback, console success redirect, and logout fallback URLs. Configure it to the public scheme and authority without a path, for example https://console.example.com. In load-balancer deployments, keep OIDC authorize and callback requests on the same backend node because the in-flight OIDC state is local to the RustFS node.

S3 API environment variables

• RUSTFS_API_OBJECT_MAX_VERSIONS caps the number of retained versions for a single object. It defaults to 9223372036854775807, matching MinIO's practical-unlimited default. Set a positive integer to enforce a lower per-object metadata bound.
• MINIO_API_OBJECT_MAX_VERSIONS is accepted as a compatibility alias when the canonical RustFS variable is not set.

Distributed endpoint locality

• RUSTFS_LOCAL_ENDPOINT_HOST identifies this server's host in a distributed RUSTFS_VOLUMES topology without resolving every peer during startup. Set it to exactly one host, without a scheme, port, or path. It is accepted only for orchestrated URL topologies and must match at least one endpoint on the RustFS server port; invalid or unmatched values fail startup. Leave it unset to retain DNS-based locality discovery.

Scanner environment aliases

• RUSTFS_SCANNER_SPEED (canonical, also accepts MINIO_SCANNER_SPEED)
• RUSTFS_SCANNER_DELAY (canonical)
• RUSTFS_SCANNER_MAX_WAIT_SECS (canonical)
• RUSTFS_SCANNER_CYCLE (canonical, also accepts MINIO_SCANNER_CYCLE)
• RUSTFS_SCANNER_START_DELAY_SECS (canonical)
• RUSTFS_DATA_SCANNER_START_DELAY_SECS (deprecated alias for compatibility)
• RUSTFS_SCANNER_IDLE_MODE (canonical)
• RUSTFS_SCANNER_CACHE_SAVE_TIMEOUT_SECS (canonical)
• RUSTFS_SCANNER_CYCLE_MAX_DURATION_SECS (canonical)
• RUSTFS_SCANNER_CYCLE_MAX_OBJECTS (canonical)
• RUSTFS_SCANNER_CYCLE_MAX_DIRECTORIES (canonical)

Scanner cycle budget controls:

• When RUSTFS_SCANNER_CYCLE_MAX_DURATION_SECS is unset, the finite default is 1800 seconds (30 minutes), matching the scanner benchmark guidance.
• An explicit 0 preserves the compatibility behavior of an unbounded runtime budget. Object and directory budgets likewise remain unbounded when explicitly set to 0.
• A timed-out cycle cancels cooperative scanner work, then fences its leader epoch before releasing the lease. An uncooperative I/O operation is dropped after the bounded shutdown window; its cursor is not claimed to be durable and the scanner reports recovery-required when the worker cannot stop cooperatively, the cycle state was not confirmed durable, or epoch fencing cannot be persisted.

Mmap read environment aliases

• RUSTFS_OBJECT_MMAP_READ_ENABLE (canonical)
• RUSTFS_OBJECT_ZERO_COPY_ENABLE (deprecated alias for compatibility)

Health compatibility switches

• RUSTFS_HEALTH_ENDPOINT_ENABLE
  • controls canonical /health, /health/live, and /health/ready endpoint exposure.
• RUSTFS_HEALTH_MINIMAL_RESPONSE_ENABLE
  • enables minimal payload mode for GET health responses (status, ready only).
• RUSTFS_HEALTH_READINESS_CACHE_TTL_MS
  • TTL for readiness cache evaluation.
• RUSTFS_HEALTH_OBJECT_PROGRESS_ENABLE
  • withdraws readiness when bounded object read/write stages stop completing while requests remain active.
  • default is true.
• RUSTFS_HEALTH_OBJECT_PROGRESS_TIMEOUT_MS
  • maximum time without completion in a bounded object stage before readiness is withdrawn.
  • default is 30000; 0 uses the default.
  • the effective value is at least 5 seconds longer than RUSTFS_OBJECT_LOCK_ACQUIRE_TIMEOUT.
  • this readiness SLO is independent of disk read/write failure deadlines and may withdraw traffic before those deadlines expire.
• RUSTFS_HEALTH_COMPAT_BUSY_CHECK_ENABLE
  • enables busy protection behavior for health probes.
  • default is false.
• RUSTFS_HEALTH_COMPAT_BUSY_MAX_ACTIVE_REQUESTS
  • max active HTTP requests; health probes return 429 when active requests reach or exceed this value.
  • 0 disables thresholding even if busy protection is enabled.
• RUSTFS_HEALTH_COMPAT_KMS_READY_CHECK_ENABLE
  • enables KMS readiness enforcement for /health/ready.
  • default is false.

Object lock admission environment variables

• RUSTFS_PUT_COMMIT_NAMESPACE_LOCK_ACQUIRE_TIMEOUT_MS
  • experimental same-object PUT commit namespace-lock admission budget.
  • default is 0, which disables this override and keeps RUSTFS_OBJECT_LOCK_ACQUIRE_TIMEOUT behavior.
  • when set, only put_object_commit write-lock acquisition is bounded by this millisecond budget; other namespace lock users keep the global object-lock timeout.
  • timeout returns S3 SlowDown, so clients should use normal SDK retry handling.
  • this is not a fdatasync or group-commit switch. Track fdatasync batching separately with rustfs_s3_put_object_rename_fdatasync_batch_files.

Foreground write admission environment variables

Large direct PutObject requests, multipart UploadPart requests, and server-side multipart UploadPartCopy requests share one per-process permit pool that bounds concurrent body ingest and storage writes. Small direct PUTs stay on the legacy path.

• RUSTFS_PUT_LARGE_FOREGROUND_ADMISSION_ENABLE
  • enables the default-on pool; false keeps only the soft request counter.
  • default is true.
• RUSTFS_PUT_LARGE_FOREGROUND_ADMISSION_LIMIT
  • a positive value is an exact request-count limit shared by all gated writes.
  • default is 0: derive half of RUSTFS_OBJECT_MAX_CONCURRENT_DISK_READS, clamped to 32, as large-write slots. Each slot has eight units. A gated direct PUT or unknown-size multipart part uses eight units; known-size parts use one unit per 8 MiB, rounded up, with a minimum of one and maximum of eight.
  • stock settings therefore share 256 units across at most 32 large/unknown writes or 256 parts of up to 8 MiB. Mixed sizes consume the same budget. Admitted known parts of up to 64 MiB total at most 2 GiB of declared payload; larger streaming writes and queued bodies are separate. This is not a bound on total process or kernel memory.
  • admission snapshots report allocated or reserved units in active and the unit budget in limit under automatic sizing. Explicit and strict limits still report request-count permits.
• RUSTFS_PUT_LARGE_FOREGROUND_ADMISSION_MIN_SIZE_BYTES
  • smallest direct PutObject that takes a permit; unknown-size requests always do.
  • default is 33554432 (32 MiB).
• RUSTFS_PUT_LARGE_FOREGROUND_ADMISSION_WAIT_TIMEOUT_MS
  • how long a direct PutObject waits for a permit before returning S3 SlowDown.
  • default is 250.
• RUSTFS_PUT_MULTIPART_FOREGROUND_ADMISSION_MIN_SIZE_BYTES
  • smallest UploadPart that takes a permit; 0 gates every part.
  • default is 0.
• RUSTFS_PUT_MULTIPART_FOREGROUND_ADMISSION_WAIT_TIMEOUT_MS
  • how long an UploadPart or UploadPartCopy waits in the bounded queue for a permit before returning S3 SlowDown; 0 rejects immediately when the pool is full.
  • default is 10000. Parts wait before body ingest or source-object reads, so SDK-default clients that send every part of an upload concurrently drain through the pool instead of failing on a full pool.
  • RustFS does not read the request body while a part is queued, so the client's socket write stalls for the whole wait and whatever timeout the client or an intermediary has configured competes with this value. UploadPartCopy waits before taking bucket lifecycle locks or opening source readers, and uses the unknown-size weight because the authoritative copy length is available only after source metadata and range validation. Keep the wait with margin below the shortest client/proxy timeout in use (botocore applies its 60 s connect_timeout to the body write; the AWS SDK for Java v2 has a 30 s socket write timeout; reverse proxies add their own body timeouts); a wait that outlives the client timeout surfaces as a dropped connection instead of SlowDown.
• RUSTFS_PUT_MULTIPART_FOREGROUND_ADMISSION_MAX_PENDING
  • maximum UploadPart and UploadPartCopy requests waiting for a permit at once; parts beyond it return SlowDown without waiting.
  • default is 0, which derives 16 times the large-write slot count, or the explicit request-count limit (512 at stock settings). Automatic subdivision does not enlarge this queue.
  • each queued HTTP/1 part holds whatever unread body the client already pushed into the connection's kernel receive buffer (an HTTP/2 part holds up to its flow-control window in process memory). Autotuned receive buffers can remain large on reused connections; queue depth does not imply a fixed per-connection memory cost.
• RUSTFS_PUT_FOREGROUND_ADMISSION_ENABLE, RUSTFS_PUT_FOREGROUND_ADMISSION_LIMIT, RUSTFS_PUT_FOREGROUND_ADMISSION_WAIT_TIMEOUT_MS
  • experimental strict gate that applies to every foreground write regardless of size and replaces the pool above when enabled.
  • default is disabled; enabling it with limit 0 disables foreground write admission entirely.

HTTP listener socket environment variables

• RUSTFS_HTTP_SOCKET_RECV_BUFFER_BYTES
  • fixed SO_RCVBUF for the API listener, inherited by every accepted socket; 0 leaves the receive buffer to kernel autotuning.
  • default is 0. A fixed buffer disables receive autotuning. Linux doubles the requested value for socket-memory accounting, subject to kernel limits; that capacity is not a measurement of queued payload or allocated memory.
  • with autotuning the receive ceiling is controlled by the kernel (net.ipv4.tcp_rmem on Linux); its defaults vary with kernel version and memory. A connection can retain a buffer enlarged by previous requests while its next request is queued. Tune the kernel ceiling first, and set this variable only on kernels without receive-buffer autotuning (illumos/Solaris) or where the sysctl cannot be changed.
  • the send buffer remains fixed at 4 MiB; this setting only controls the receive side.

Remote tier timeout environment variables

• RUSTFS_TIER_REMOTE_CONNECT_TIMEOUT_SECS
  • remote tier TCP connect timeout.
  • default is 10.
  • must be positive; zero fails tier client initialization, while an invalid integer is logged and falls back to the default.
• RUSTFS_TIER_REMOTE_REQUEST_TIMEOUT_SECS
  • remote tier request timeout through response headers.
  • default is 86400 so large transition uploads keep a production-safe budget.
  • must be positive; zero fails tier client initialization, while an invalid integer is logged and falls back to the default. Very large values are accepted and act as a correspondingly long budget.
• RUSTFS_TIER_REMOTE_RESPONSE_BODY_IDLE_TIMEOUT_SECS
  • maximum idle time between remote tier response-body chunks.
  • default is 60; the timer resets only when non-empty body data keeps progressing.
  • must be positive; zero fails tier client initialization, while an invalid integer is logged and falls back to the default.

Drive timeout environment variables

• RUSTFS_DRIVE_METADATA_TIMEOUT_SECS
• RUSTFS_DRIVE_DISK_INFO_TIMEOUT_SECS
• RUSTFS_DRIVE_LIST_DIR_TIMEOUT_SECS
• RUSTFS_DRIVE_WALKDIR_TIMEOUT_SECS
• RUSTFS_DRIVE_WALKDIR_STALL_TIMEOUT_SECS

Legacy compatibility fallback:

• RUSTFS_DRIVE_MAX_TIMEOUT_DURATION This legacy variable is treated as a deprecated fallback for the operation-specific drive timeout variables above when a canonical variable is unset.

Drive timeout health-action policy:

• RUSTFS_DRIVE_TIMEOUT_HEALTH_ACTION
  • mark_failure (default): timeout marks failure and may transition drive runtime state.
  • ignore_scanner: timeout does not mark failure for scanner-sensitive operations (walk_dir, read_metadata, list_dir, disk_info).

Drive timeout profile preset:

• RUSTFS_DRIVE_TIMEOUT_PROFILE
  • default (default): keep current timeout defaults.
  • high_latency: use 60s default timeout for scanner-sensitive operations when no operation-specific override is set (read_metadata, disk_info, list_dir, walk_dir, walk_dir_stall, and object-capacity scan base/maximum budgets).
• Precedence:
  • Explicit per-operation timeout env (RUSTFS_DRIVE_*_TIMEOUT_SECS) takes highest precedence.
  • Explicit object-capacity timeout env (RUSTFS_CAPACITY_STAT_TIMEOUT, RUSTFS_CAPACITY_MAX_TIMEOUT) takes precedence for capacity scans.
  • Then RUSTFS_DRIVE_MAX_TIMEOUT_DURATION legacy fallback.
  • Then the profile-derived default (default or high_latency).

Admin peer probe timeout

• RUSTFS_ADMIN_PEER_PROBE_TIMEOUT_SECS
  • total per-peer budget for the server_info/storage_info admin probe round; server_info may reconnect once and storage_info remains a single attempt.
  • default is 10 seconds, preserving the previous two-attempt worst-case budget.
  • values must be positive; 0 or an invalid value falls back to the default, and values above 60 are clamped to 60.
  • the setting is read by the aggregating node only; it does not change the internode RPC wire contract. Any retry shares one round deadline rather than receiving a fresh timeout.

Startup filesystem boundary policy

• RUSTFS_UNSUPPORTED_FS_POLICY controls startup behavior when RustFS detects local endpoint filesystems that are outside the supported production boundary.
  • warn (default): log warning and continue startup.
  • fail: abort startup with an error.

RustFS production guidance remains direct-attached local POSIX filesystems. Network-mounted filesystems (for example nfs, cifs, smb2, and fuse.*) are treated as unsupported by this startup guard.

📄 License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.