filebeat add_kubernetes_metadata and IPv6

[hhoover]

When using filebeat in a Kubernetes cluster as a pod, using the add_kubernetes_metadata processor, the processor can't handle IPv6 addresses if an IPv6 address resolves from https://kubernetes.default.svc.cluster.local. The parser freaks out on the colons in the address. I don't know if this is an issue in an underlying library or Filebeat itself.

Secondary to this issue, it would be nice to provide a custom Kubernetes API endpoint to use, so I could try something like https://[2001:0db8:85a3:0000:0000:8a2e:0370:7334]:443 (and force the use of brackets). It looks like I can only do this if I set in_cluster to "false" and provide a kubeconfig file.

Error:

2018-10-25T14:45:51.809Z    ERROR    instance/beat.go:743    Exiting: performing request: Get https://fd00:1234::1:443/api/v1/pods?fieldSelector=spec.nodeName%3Dlocalhost&resourceVersion=0: invalid URL port "1234::1:443"

Exiting: performing request: Get https://fd00:1234::1:443/api/v1/pods?fieldSelector=spec.nodeName%3Dlocalhost&resourceVersion=0: invalid URL port "1234::1:443"

For confirmed bugs, please report:

• Version: docker.elastic.co/beats/filebeat:6.4.2
• Discuss Forum URL: https://discuss.elastic.co/t/filebeat-add-kubernetes-metadata-and-ipv6/154018
• Steps to Reproduce: Run Kubernetes v1.11 in an IPv6-only environment (can be run locally with KDinD, deploy the Filebeat daemonset.

[hhoover]

more errors:

2018-10-25T14:45:51.806Z    ERROR    kubernetes/util.go:90    kubernetes: Querying for pod failed with error: %!(EXTRA string=performing request: Get https://fd00:1234::1:443/api/v1/namespaces/logging/pods/filebeat-d9rsz: invalid URL port "1234::1:443")
2018-10-25T14:45:51.806Z    INFO    kubernetes/watcher.go:180    kubernetes: Performing a resource sync for *v1.PodList
2018-10-25T14:45:51.806Z    ERROR    kubernetes/watcher.go:183    kubernetes: Performing a resource sync err performing request: Get https://fd00:1234::1:443/api/v1/pods?fieldSelector=spec.nodeName%3Dlocalhost&resourceVersion=0: invalid URL port "1234::1:443" for *v1.PodList

[jsoriano]

I think that at least a related problem can be in the client library (https://github.com/ericchiang/k8s/blob/d1bbc0cffaf9849ddcae7b9efffae33e2dd52e9a/client.go#L225), I'll investigate this one.