dstack-nvidia-attest-proxy is a persistent, PCCS-like cache for the two NVIDIA services used by local GPU attestation:

• POST /ocsp caches DER OCSP responses by the request's certificate IDs. The per-request OCSP nonce is deliberately excluded from the key.
• GET /v1/rim/<id> caches version-addressed NVIDIA RIM documents.
• GET /healthz reports process health.
• GET /info reports fresh/stale entry counts per cache kind.

The proxy never signs or rewrites collateral. nvattest in the CVM still verifies NVIDIA's certificate chains, OCSP signatures, response validity window, RIM signatures, measurements, and the fresh GPU evidence nonce. Cache entries are persisted so a warm cache survives both proxy and VM restarts.

cargo build --release -p dstack-nvidia-attest-proxy
sudo install -m 0755 target/release/dstack-nvidia-attest-proxy /usr/local/bin/
sudo install -d -m 0750 /var/cache/dstack/nvidia-attest-proxy

sudo /usr/local/bin/dstack-nvidia-attest-proxy \
  --listen 0.0.0.0:8090 \
  --cache-dir /var/cache/dstack/nvidia-attest-proxy

All options have environment-variable equivalents; see --help. In particular, NV_ATTESTATION_SERVICE_KEY supplies an optional NVIDIA bearer token without placing it on the command line.

Configure the VMM with a URL reachable during early guest boot:

[cvm]
nvidia_attestation_proxy_url = "http://10.0.2.2:8090"

For QEMU user-mode networking, 10.0.2.2 is normally the host address. Other networking modes should use the corresponding host or fleet service address.

On a cold miss the original request is forwarded to NVIDIA. A successful OCSP response is cached no later than its signed nextUpdate and no longer than --ocsp-max-ttl (24 hours by default). Responses without nextUpdate use one hour from thisUpdate, matching the pinned NVIDIA SDK. RIM documents default to a 30-day TTL.

Two mechanisms keep entries warm, and they compose: a background sweep (every --refresh-interval, 10 minutes by default) renews entries that have consumed half their lifetime, so a warm cache rides through an NVIDIA outage with close to a full validity window instead of only the remainder; entries past their usefulness are dropped, not retried. As a synchronous fallback, an OCSP response with less than --ocsp-refresh-before validity remaining (five minutes by default) is refreshed in-line on the next request before it is served — concurrent refreshes for the same entry are coalesced. If an in-line refresh fails, the proxy keeps serving the old response only until its existing signed expiry; it never extends or serves an expired one.

Expired OCSP entries are never served. Therefore a warm cache removes the NVIDIA service from the boot path only for the signed validity period; it does not turn revocation checking into an indefinite fail-open. RIM documents are signed and version-addressed, so an expired RIM entry — unlike OCSP — may still be served for up to --rim-max-stale (7 days by default) when the upstream is unreachable or failing; the guest verifies its signature either way. Response headers expose X-Dstack-Cache: HIT|MISS|REFRESH|STALE, Age, and X-Dstack-Cache-Expires for operations. Each cache kind is capped at 10,000 entries by default; the oldest entry is evicted when the limit is reached. Use --max-cache-entries-per-kind to tune the bound for a deployment.

Because a cached response contains the nonce from the request that populated the cache, nvattest reports x-nvidia-cert-ocsp-nonce-matches = false on a hit. When the proxy URL is configured, dstack selects NVIDIA's packaged allow_trust_outpost_ocsp.rego policy. This relaxes only the OCSP nonce check; the GPU attestation report's independent nonce remains required by dstack.