Kubernetes Ingress Errors

Understanding Ingress errors

An Ingress failure is a routing failure, and there are only a few places it can break: the IngressClass is missing so no controller claims the resource, the path or host does not match, the backing Service has no endpoints, or the TLS secret is absent or in the wrong namespace. The "default backend - 404" page is the controller saying it received the request but found no rule for it.

How to debug Ingress errors

1. Work backwards from the pod: kubectl get endpoints <service>. If it is empty, the Service selector does not match any ready pod and no Ingress configuration will help.
2. Check that a controller has claimed the Ingress: kubectl describe ingress <name> should show events and an assigned address. No address means no controller is watching that IngressClass.
3. Read the controller's own logs (kubectl logs -n ingress-nginx deploy/ingress-nginx-controller). They log rejected configuration and certificate problems explicitly.
4. Remember TLS secrets must live in the same namespace as the Ingress. This is the single most common TLS mistake.
5. Verify path type semantics: Prefix, Exact and ImplementationSpecific match differently, and regex behaviour varies between controllers.

Tools worth reaching for

• kubectl describe ingress
• kubectl get endpoints
• controller logs
• curl -H 'Host: …'
• openssl s_client -servername

All 8 Ingress errors

• cert-manager: Order is pending / challenge failed to propagate Newcert-manager created an ACME order but the challenge never validated. For HTTP-01 the challenge path is not reachable…
• Ingress: configuration-snippet annotation cannot be used Newingress-nginx 1.9 turned allow-snippet-annotations off by default after snippets were shown to let any namespace…
• Ingress: default backend - 404No Ingress rule matched the request, so it was routed to the default backend which returned 404. The host or path may…
• Ingress: path not matching any backendThe request path does not match any rule defined in the Ingress resource. May be a pathType (Prefix vs Exact) or regex…
• Ingress: TLS secret not foundThe TLS secret referenced in the Ingress spec does not exist in the same namespace. HTTPS termination will fail.
• Ingress: too many redirects (redirect loop)An infinite redirect loop between the ingress controller and backend, usually caused by SSL redirect annotations…
• IngressClass not foundThe specified IngressClass does not exist or no ingress controller is installed that handles that class.
• Kubernetes Ingress errorIngress controller cannot route traffic to the specified service, often due to misconfigured rules.

Other categories

• AI 35Rate limits, context windows, GPU memory and model-serving failures.
• Ansible 10Unreachable hosts, become passwords, undefined variables and Jinja2 failures.
• API 14Auth headers, payload limits, versioning, idempotency and webhook signatures.
• Apple 10Command line tools, dyld, Homebrew permissions, notarisation and Keychain.
• Auth 11OIDC, SAML, Auth0, Okta, Keycloak, passkeys and MFA failures.
• BigData 11Spark, Kafka, Airflow, Snowflake, Flink and Databricks failures.
• C# 12NuGet restore, null references, EF Core migrations, async deadlocks and Blazor…
• C++ 11Segfaults, linker errors, memory corruption and template deduction failures.
• Caching 10Cache stampedes, stale content, Varnish and CloudFront failures.
• CI/CD 18GitHub Actions, GitLab CI, Jenkins, CircleCI: permissions, runners and…
• Client 21CORS, mixed content, module resolution, memory limits and framework runtime…
• Cloud 25IAM permissions, quotas, service limits and credential failures.
• Dart 10Null safety, pub version solving and build toolchain problems.
• Database 41Connections, deadlocks, constraints, replication and memory limits.
• DNS 10NXDOMAIN, SERVFAIL, timeouts, propagation and delegation problems.
• Docker 27Daemon connectivity, disk space, image pulls, ports and architecture mismatches.
• Elixir 9GenServer timeouts, supervision failures and Mix compilation problems.
• Email 8Delivery failures, relay denial, authentication, SPF, DKIM and DMARC.
• Frontend 23Hydration mismatches, bundler resolution, layout shift and font loading.
• Git 20Merge conflicts, rejected pushes, detached HEAD, LFS and repository corruption.
• Go 19Nil map assignment, concurrent map access, context cancellation and deadlocks.
• GraphQL 13Validation, depth limits, N+1 queries and fragment problems.
• gRPC 10Status codes, deadlines, message limits, TLS and HTTP/2 transport failures.
• HTTP 494xx client errors, 5xx server errors, redirects, headers and protocol problems.
• ICMP 23Destination unreachable, time exceeded, fragmentation needed and redirects.
• Java 19Class loading, dependency resolution, connection pools and JVM version…
• JavaScript 42npm resolution, async pitfalls, hydration, memory limits and runtime type…
• Kubernetes 34CrashLoopBackOff, ImagePullBackOff, OOMKilled, RBAC, scheduling and storage.
• Logging 9Log4j, Logback, Fluentd, Logstash and CloudWatch ingestion problems.
• MessageQueue 14Kafka, RabbitMQ, SQS, NATS and Celery: lag, rebalancing and poison messages.
• Mobile 17Gradle, CocoaPods, Xcode signing, Metro bundler and toolchain mismatches.
• Monitoring 12Prometheus scrapes, Grafana data sources, OpenTelemetry exporters and agent…
• Network 35Refused connections, timeouts, resets, MTU problems and port exhaustion.
• Performance 6GC pauses, thread pool starvation and event loop blocking.
• PHP 11Memory limits, execution timeouts, autoloading, Composer and PDO connections.
• Proxy 17nginx, Envoy, HAProxy, Traefik, Caddy and Cloudflare upstream failures.
• Python 35Imports, virtual environments, encoding, concurrency and dependency conflicts.
• Regex 8Catastrophic backtracking, back references, escaping and engine differences.
• Ruby 11Bundler, migrations, native extensions, encoding and asset compilation.
• Rust 19Borrow checker, ownership moves, trait bounds and lifetime mismatches.
• Scala 6Dependency resolution, binary compatibility and type inference failures.
• Security 25JWT validation, CSRF, OAuth grants, SELinux, SSH host keys and CSP.
• Serverless 11Lambda timeouts, package size limits, VPC networking and cold starts.
• Shell 13Command not found, permissions, quoting, expansion and Makefile syntax.
• Storage 13S3 permissions, NFS mounts, quotas, signed URLs and volume attachment.
• Svelte 10Store subscriptions, load functions and server/client boundaries.
• System 26Disk space, systemd units, file descriptors, OOM killer and scheduled jobs.
• Terraform 18State locks, provider auth, drift, dependency cycles and plan-time unknowns.
• Testing 18Jest, pytest, JUnit, Cypress and Playwright: fixtures, snapshots and timeouts.
• TLS 24Untrusted authorities, expiry, hostname mismatch, chains and cipher negotiation.
• TypeScript 19Assignability, missing declarations, strict null checks and generic constraints.
• Virtualization 8VirtualBox, VMware, Hyper-V, WSL, KVM and hypervisor conflicts.
• Web3 7Gas estimation, nonce management and reverted transactions.
• WebAssembly 7Compile errors, memory bounds and host binding mismatches.
• WebServer 10nginx, Apache, IIS and Caddy: binding, permissions, rewrites and TLS.
• Windows 10Installer failures, missing runtimes, update errors and permission problems.