Error map
Readiness probe failed Readiness probe failed: HTTP probe failed with statuscode: 503 / connect: connection refused
Kubernetes · layer 6, Platform & cloud
Centre: this error. First ring: errors it is linked with (8). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (8)
Liveness probe failed ... Container will be restarted (also Startup probe failed)
The kubelet’s liveness (or startup) check failed enough times that it killed and restarted the container.
deployment "x" exceeded its progress deadline (ProgressDeadlineExceeded)
A rollout didn’t make progress within progressDeadlineSeconds (default 600) — new pods never became ready.
Error from server: admission webhook "validate.nginx.ingress.kubernetes.io" denied the request
A validating admission webhook (ingress-nginx, Gatekeeper/OPA, Kyverno) inspected your object and rejected it; the reason follows…
Kubernetes: CrashLoopBackOff
The container starts, crashes (or exits), and Kubernetes keeps restarting it with increasing back-off delays.
Error from server (BadRequest): container "x" in pod "y" is waiting to start: ContainerCreating
kubectl logs has nothing to show yet — the container hasn’t started (still creating, pulling, or blocked).
ALB target unhealthy: Health checks failed with these codes: [404] / Request timed out
The load balancer’s health checks to your targets fail, so it stops sending traffic (and returns 502/503 if no targets are health…
Docker container is unhealthy (health check failing)
The container is running, but its HEALTHCHECK command keeps failing, so Docker (and dependent services) consider it unhealthy.
Service has no endpoints (no endpoints available for service / Endpoints: <none>)
The Service’s selector matches no ready pods, so traffic to it is refused or returns 503.
Two steps away (22)
Kubernetes: OOMKilled (exit code 137)
The container used more memory than its limit, and the kernel killed it.
Kubernetes: ImagePullBackOff / ErrImagePull
The node can’t pull the container image — wrong name/tag, missing registry credentials, or registry unreachable.
Stack is in ROLLBACK_COMPLETE state and can not be updated
The stack’s first creation failed and rolled back; a stack in ROLLBACK_COMPLETE can only be deleted, not updated.
CloudFormation stack in UPDATE_ROLLBACK_FAILED
An update failed, and then the rollback also failed, leaving the stack stuck until you continue the rollback.
Kubernetes: CreateContainerConfigError — secret / configmap not found
Kubernetes can’t build the container’s configuration — usually a referenced Secret, ConfigMap or key doesn’t exist in that namesp…
Pod status CreateContainerError
The image was pulled, but the container runtime failed to create the container — bad command, missing mount target, or a name/vol…
Namespace stuck in Terminating
A deleted namespace never disappears because some resource inside it, or the namespace’s own finalizer, can’t be cleaned up.
no space left on device (Docker / Linux)
The disk (or inode table) is full — Docker images, build cache, logs and volumes are common culprits.
Azure App Service: ":( Application Error" / container didn’t respond to HTTP pings
App Service started your app but it crashed or never listened on the expected port.
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
HTTP 499 Client Closed Request (Nginx)
Nginx-specific code logged when the client disconnected before the server finished responding.
kubectl: The connection to the server localhost:8080 was refused — did you specify the right host or port?
kubectl has no usable kubeconfig, so it falls back to localhost:8080 — or the cluster API server is unreachable.
HTTP 502 Bad Gateway
A proxy or gateway (Nginx, load balancer, CDN) got an invalid response — or no response — from the upstream server behind it.
HTTP 503 Service Unavailable
The server is temporarily unable to handle the request — overloaded, in maintenance, or has no healthy backends.
AccessDeniedException: User: arn:aws:iam::... is not authorized to perform: service:Action on resource: ...
The IAM user or role making the call has no permission for that action on that resource — the message names both.
Conflict. The container name "/x" is already in use by container …
A container (running or stopped) already has that name; Docker won’t create a second one with the same name.
docker compose: services.x Additional property y is not allowed / yaml: line N: mapping values are not allowed
The compose file is invalid YAML or uses a key Compose doesn’t recognise at that level (usually an indentation mistake).
Docker container exits immediately (Exited (0) / Exited (1) right after start)
The container started and its main process finished at once, so the container stopped — Docker containers only live as long as PI…
ECS task stopped: CannotPullContainerError: pull image manifest has been retried ... / ref pull has been retried
The ECS task couldn’t pull its image — no network route to the registry, missing ECR permissions, or a wrong image tag.
Ingress returns "404 Not Found" / "default backend - 404" (ingress-nginx)
The ingress controller received the request but no Ingress rule matched the host/path, so it answered with its default backend.
DNS not working inside a Kubernetes pod (could not resolve host / nslookup: can't resolve)
Pods can’t resolve service names or external hosts — CoreDNS is down, blocked by NetworkPolicy, or the upstream resolver fails.
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Popular: 4035004000xC000007BTypeErrorCritical error404NullPointerException