Docker / Images, Dockerfiles & Build Reliability
Investigate registry TLS failures without disabling verification
A private registry can fail certificate validation because its name, chain or trust configuration is wrong. Test its public endpoint without sending credentials.
Environment and inputs: Docker Engine · Compose v2 and Buildx where specified; Linux containers unless noted. Verify daemon context, installed feature support and authorized host or Swarm manager access first.
Start with this check
Confirm the environment and replace sample objects, namespaces, images, paths and hosts with approved targets. Share only relevant, sanitized output. Follow the workload owner’s process for changes.
curl --head --connect-timeout 5 --max-time 15 https://registry.example.com/v2/Read the result
A bounded HTTPS request can expose TLS and HTTP behavior. An unauthenticated challenge may be expected and does not prove authorized image-layer access.
Resolve and verify
Compare the certificate and daemon-side trust path with the approved registry identity. Install only verified CA material through the supported host configuration and retest the actual pull.
Before changing production
Do not configure insecure registries or use insecure TLS flags merely to bypass a trust error.