Add documentation for ImagePullBackOff

This commit is contained in:
Rishabh Jain 2021-06-24 17:58:32 +05:30
parent c4d103bf8e
commit 0e7810ad04
1 changed files with 14 additions and 0 deletions

View File

@ -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.