Currently only pod IP is shown at Nginx status, I think to show the hostIP could make easier troubleshooting.

The sidecar container is configured to download its image from the public registry only. We have to think about a way for configuring this image for deployments where the public registry is not available and no mirrors are configured.

When configuring an effective cache on nginx web server, we will probably need to set up the proxy_cache_path to in-memory directory at filesystem, e.g. using a tmpfs mount.

Thus, I think we need to add a new string field at NginxSpec to store that cache path. At the first moment, a simple string it's enough but we could to store a slice of strings later.

apiVersion: nginx.tsuru.io/v1alpha1
kind: Nginx
metadata:
  name: nginx-with-cache
spec:
  cachePath: /var/nginx/cache

When deployed into the Kubernetes cluster, the nginx-controller should to add a new EmptyVolumeSource with the StorageMediumMemory type at nginx's pod template.