I installed kubernetes 1.2.4 on 3 REHEL7 servers (no internet access, everything is pushed by ansible).
EDIT: See the end of the question
I've got everything working great excepting the kube-dns example given in documentation. I made several tests, several configuraiton, recreate the entire pods... And I always have this "MissingClusterDNS" error:
enter code here20m 20m 2 {kubelet k8s-minion-1.XXXXXX} Warning MissingClusterDNS kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.
As you can see, kube-dns is running:
kubectl get svc kube-dns --namespace=kube-system
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kube-dns 172.16.0.99 <none> 53/UDP,53/TCP 15m
And kubelete has got correct options
KUBELET_ARGS=" --cluster-dns=172.16.0.99 --cluster-domain=kubernetes.local "
Proof:
ps ax | grep kubelet
6077 ? Ssl 0:07 /opt/kubernetes/bin/kubelet --logtostderr=true --v=0 --address=0.0.0.0 --port=10250 --hostname-override=k8s-minion-1.XXXXXX --api-servers=http://k8s-master.XXXXXX:8080 --allow-privileged=false --cluster-dns=172.16.0.99 --cluster-domain=kubernetes.local
But, the DNS pod as a not running container:
kubectl get pods --namespace=kube-system
NAME READY STATUS RESTARTS AGE
kube-dns-v11-f2f4a 3/4 CrashLoopBackOff 7 18m
And the log is explicit:
Warning Unhealthy Readiness probe failed: Get http://172.16.23.2:8081/readiness: dial tcp 172.16.23.2:8081: connection refused
...
Warning FailedSync Error syncing pod, skipping: failed to "StartContainer" for "kube2sky" with CrashLoopBackOff: "Back-off 5m0s restarting failed container=kube2sky pod=kube-dns-v11-f2f4a_kube-system(27d70b7c-36f9-11e6-b4fe-fa163ee85c45)"
If you need more information:
$ kubectl get pods --namespace=kube-system
NAME READY STATUS RESTARTS AGE
kube-dns-v11-f2f4a 3/4 CrashLoopBackOff 7 18m
-------------------------
$ kubectl describe rc --namespace=kube-system
Name: kube-dns-v11
Namespace: kube-system
Image(s): our.registry/gcr.io/google_containers/etcd-amd64:2.2.1,our.registry/gcr.io/google_containers/kube2sky:1.14,our.registry/gcr.io/google_containers/skydns:2015-10-13-8c72f8c,our.registry/gcr.io/google_containers/exechealthz:1.0
Selector: k8s-app=kube-dns,version=v11
Labels: k8s-app=kube-dns,kubernetes.io/cluster-service=true,version=v11
Replicas: 1 current / 1 desired
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Volumes:
etcd-storage:
Type: EmptyDir (a temporary directory that shares a pod's lifetime)
Medium:
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
19m 19m 1 {replication-controller } Normal SuccessfulCreate Created pod: kube-dns-v11-f2f4a
-------------------------------------------------------
$ kubectl get all --all-namespaces
NAMESPACE NAME DESIRED CURRENT AGE
kube-system kube-dns-v11 1 1 24m
NAMESPACE NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes 172.16.0.1 <none> 443/TCP 27m
kube-system kube-dns 172.16.0.99 <none> 53/UDP,53/TCP 24m
NAMESPACE NAME READY STATUS RESTARTS AGE
default busybox 1/1 Running 0 23m
kube-system kube-dns-v11-f2f4a 3/4 CrashLoopBackOff 9 24m
If someone can help me to understand the problem...
Note I'm using https://github.com/kubernetes/kubernetes/tree/release-1.2/cluster/addons/dns rc and svc where I only changed:
- clusterIp to a valid ip in my kubernetes ip range
- cluster domain: kubernetes.local
- cluster dns: 172.16.0.99
EDIT: The problem for the 3/4 kube-dns working comes from certificates. So I can confirm that SkyDNS is working now.
NAME READY STATUS RESTARTS AGE
kube-dns-v11-c96d5 4/4 Running 0 9m
Using cluster-api-tester:
kubectl logs --tail=80 kube-dns-v11-c96d5 kube2sky --namespace=kube-system
I0621 13:27:52.070730 1 kube2sky.go:462] Etcd server found: http://127.0.0.1:4001
I0621 13:27:53.073614 1 kube2sky.go:529] Using https://192.168.0.1:443 for kubernetes master
I0621 13:27:53.073632 1 kube2sky.go:530] Using kubernetes API <nil>
I0621 13:27:53.074020 1 kube2sky.go:598] Waiting for service: default/kubernetes
I0621 13:27:53.166188 1 kube2sky.go:660] Successfully added DNS record for Kubernetes service.
But others problems appear.
- now "Using kubernetes API nil" instead of the good version
- the busybox example from kubernetes documentation still won't resolv kubernetes.local
I will more investigate. But I resolved the skydns starting issue. Thanks