Files
reverse-proxy/docs/architecture/open-questions.md
glm-5.1 7efc142406 Expand architecture: multi-site Phase 1, multi-domain TLS, fix review issues
Promote multi-site support from Phase 2 to Phase 1 (ADR-010): the proxy
must support git.alk.dev and alk.dev from initial release. Add multi-domain
TLS configuration (ADR-011): acme_domains array replaces acme_domain string,
single SAN certificate via rustls-acme.

Key changes:
- ADR-010: Multi-site in Phase 1 — avoids config format migration later
- ADR-011: Multi-domain TLS — single SAN cert, acme_domains Vec<String>
- ADR-002: Updated rationale for multi-site (one upstream per domain)
- overview.md: Phase 1 now includes multi-site, alk.dev pass-through,
  dual licensing (MIT OR Apache-2.0), real IP removed
- config.md: acme_domain → acme_domains, TOML example shows both sites,
  validation adds unique host check, real IP replaced with 203.0.113.10
- tls.md: Multi-domain SNI section moved from Future to current, manual
  mode uses ResolvesServerCert for SNI mapping, TOML header fixed
- proxy.md: Updated for multi-site, removed single-domain language
- operations.md: RFC 5737 documentation IPs, clarified rate limit eviction
  semantics (distinct scan interval vs eviction age)
- open-questions.md: OQ-05 resolved (single bind_addr sufficient), new
  OQ-07 (per-site TLS overrides)

Review fixes:
- acme_domains (plural) consistently used across all docs and diagram
- ADR-011 clearly scopes acme_domain as previous design
- Inline decision rationale extracted: tls.md hot-reload → ADR-004 ref,
  config.md static/dynamic → ADR-008 ref
- TOML section headers consistent (server.tls)
2026-06-11 08:50:03 +00:00

3.9 KiB

status, last_updated
status last_updated
draft 2026-06-11

Open Questions

TLS

OQ-01: Should cipher suites be restricted beyond rustls defaults?

  • Origin: tls.md
  • Status: open
  • Priority: medium
  • Context: Our current nginx config explicitly restricts cipher suites to four ECDHE-AES-GCM suites. rustls 0.23 with aws_lc_rs defaults to a conservative set that excludes all weak ciphers (no SHA-1, no 3DES, no RC4, no CBC-mode suites, no RSA key exchange). The defaults include TLS 1.3 suites which nginx also allows. Restricting further would reduce compatibility with older clients; not restricting means accepting a wider (but still safe) set than the current nginx config.
  • Cross-references: ADR-005

OQ-02: What log format should fail2ban consume?

  • Origin: operations.md, proxy.md
  • Status: resolved
  • Priority: high
  • Resolution: Custom structured log format with key=value pairs and RATE_LIMIT prefix. A corresponding custom fail2ban filter will be provided. See ADR-007.
  • Cross-references: ADR-007

OQ-07: Should per-site TLS overrides be supported for mixed ACME/manual domains?

  • Origin: tls.md, config.md
  • Status: open
  • Priority: low
  • Context: Phase 1 uses a single TLS configuration (ACME or manual) for all domains. All domains share the same ACME config and certificate. If a future domain needs a manual certificate (e.g., a corporate CA cert) while other domains use ACME, a per-site TLS override would be needed. This would require a custom ResolvesServerCert that combines ACME-provisioned certs with manually loaded certs. For now, all proxied domains use the same ACME config, so this is not needed.
  • Cross-references: ADR-011

Logging and Monitoring

OQ-03: Should the health check endpoint be on a separate port?

  • Origin: operations.md
  • Status: open
  • Priority: low
  • Context: Currently the health check is on the main HTTPS listener at /health. Alternatives: (a) separate unencrypted port for health checks (simpler for load balancers but less secure), (b) admin port with its own listener (more complex but isolates operational traffic), (c) on the main listener (simplest, proposed approach). For a single-server deployment behind no external load balancer, the main listener is fine.
  • Cross-references: None

Configuration

OQ-04: Should config reload support a Unix domain socket API in addition to SIGHUP?

  • Origin: config.md
  • Status: open
  • Priority: low
  • Context: Phase 1 uses SIGHUP for config reload, which is simple and proven. A Unix domain socket API would allow programmatic reload (e.g., from an admin tool or CI/CD pipeline) and could return success/failure status. This adds complexity and is not needed for Phase 1.
  • Cross-references: None

Deployment

OQ-05: Should the proxy bind to multiple addresses or just one?

  • Origin: overview.md
  • Status: resolved
  • Priority: low
  • Resolution: A single bind_addr is sufficient. The proxy binds to one explicit IP address (not 0.0.0.0). Multi-address binding is not needed for this single-server deployment. If needed in the future, bind_addr could be extended to an array. See config.md for the bind_addr field.
  • Cross-references: None

Proxy

OQ-06: Should upstream timeouts be configurable per-site?

  • Origin: proxy.md
  • Status: open
  • Priority: low
  • Context: Phase 1 uses global defaults (5s connect timeout, 60s request timeout) for all upstream connections. Per-site timeout configuration would allow tuning for different upstream services (e.g., a slow database-backed API vs. a fast static site). Not needed for Phase 1 with a single upstream.
  • Cross-references: None