diff --git a/content/en/docs/concepts/containers/images.md b/content/en/docs/concepts/containers/images.md index 1cd678e4a8..64d239ff0e 100644 --- a/content/en/docs/concepts/containers/images.md +++ b/content/en/docs/concepts/containers/images.md @@ -77,6 +77,20 @@ the pull policy of any object after its initial creation. When `imagePullPolicy` is defined without a specific value, it is also set to `Always`. +### ImagePullBackOff + +When a kubelet starts creating containers for a Pod using a container runtime, +it might be possible the container is in [Waiting](/docs/concepts/workloads/pods/pod-lifecycle/#container-state-waiting) +state because of `ImagePullBackOff`. + +The status `ImagePullBackOff` means that a container could not start because Kubernetes +could not pull a container image (for reasons such as invalid image name, or pulling +from a private registry without `imagePullSecret`). The `BackOff` part indicates +that Kubernetes will keep trying to pull the image, with an increasing back-off delay. + +Kubernetes raises the delay between each attempt until it reaches a compiled-in limit, +which is 300 seconds (5 minutes). + ## Multi-architecture images with image indexes As well as providing binary images, a container registry can also serve a [container image index](https://github.com/opencontainers/image-spec/blob/master/image-index.md). An image index can point to multiple [image manifests](https://github.com/opencontainers/image-spec/blob/master/manifest.md) for architecture-specific versions of a container. The idea is that you can have a name for an image (for example: `pause`, `example/mycontainer`, `kube-apiserver`) and allow different systems to fetch the right binary image for the machine architecture they are using.