Can't access kube-ui service

Question

Whenever I try to access kube-ui from my desktops(not a kube cluster node) web browser Kubernetes returns:

Error: 'dial tcp 18.16.24.2:8080: connection refused'
Trying to reach: 'http://18.16.24.2:8080/'

I can access the APIServer and all the rest API without any issue from my desktop.

Environment:

Kube Version: 1.2.0-alpha.5
Node's Environment: Virtual Machines with CentOS as the OS.
Node Layout: 1 master, 2 minions/workers
Kube UI: Started using service and replica controllers found in the 1.2.0-alpha.5 repo's addons folder.
- Flannel Configuration Verified using: https://github.com/kubernetes/kubernetes/blob/v1.2.0-alpha.5/docs/getting-started-guides/fedora/flannel_multi_node_cluster.md I verified that containers can talk to each other.
- DNS Addon is enabled and verified: https://github.com/kubernetes/kubernetes/blob/v1.2.0-alpha.5/cluster/addons/dns/README.md

The URL I am using was obtained from doing:

$ kubeclt cluster-info 
Kubernetes master is running at http://172.28.128.8:8080
KubeDNS is running at http://172.28.128.8:8080/api/v1/proxy/namespaces/kube-system/services/kube-dns
KubeUI is running at http://172.28.128.8:8080/api/v1/proxy/namespaces/kube-system/services/kube-ui

Configure View produces:

$ kubectl config view
apiVersion: v1
clusters:
- cluster:
    insecure-skip-tls-verify: true
    server: http://172.28.128.8:8080
  name: centos
contexts:
- context:
    cluster: centos
    user: centos
  name: centos
current-context: centos
kind: Config
preferences: {}
users:
- name: centos
  user:
    password: <password>
    username: admin

I am able to access the kube-ui if I access it from a minion node using its internal IP address. However, it doesn't seem to be reporting anything: no nodes, services..etc. The internal ip address was found by:

$ kubectl describe svc kube-ui --namespace=kube-system
Name:           kube-ui
Namespace:      kube-system
Labels:         k8s-app=kube-ui,kubernetes.io/cluster-service=true,kubernetes.io/name=KubeUI
Selector:       k8s-app=kube-ui
Type:           ClusterIP
IP:         10.0.17.103
Port:           <unnamed>   80/TCP
Endpoints:      18.16.24.2:8080
Session Affinity:   None
No events.

Any ideas as to why I can't access it from my desktop via the URL provided by kubeclt cluster info? Could it be because I am running with insecure-skip-tls-verify?

It looks like the error is the apiserver is unable to reach the endpoint for the kube-ui service. From the master node, can you connect to 18.16.24.2:8080? — Robert Bailey
I can not. I don't have flannel setup on the master node could that be the issue? I only thought flannel was suppose to be setup on the minion/worker nodes. — tbs

tbs tbs · Accepted Answer · 2016-01-13T17:43:33

Flannel wasn't setup on the master node, which was the issue. The documentation can be a little misleading/confussing: https://github.com/kubernetes/kubernetes/blob/v1.2.0-alpha.5/docs/getting-started-guides/fedora/flannel_multi_node_cluster.md

It does say to setup flannel on all Kubernetes nodes. However, the node setup section is directly after the Master Node setup section, so I was unsure if this applied to the master node as well. They appeared to be two separate sections, so I thought maybe this didn't apply to the master.

Also, when you get down to the "Test the cluster flannel configuration" the second bullet point states:

If you set up a 1 master and 3 nodes cluster, you should see one block for each node showing the subnets they have been assigned.

Then shows curling the etcd that only produces 3 address. If you have 1 master and 3 nodes, then it should probably show 4 addresses. This lead me to believe in this doc that master and nodes where different.

Figured I would highlight my confusion on these points in case anyone else has the same experience.

Can't access kube-ui service

1 Answers