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kubedns container cannot connect to apiserver #193

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phagunbaya opened this issue Mar 3, 2017 · 50 comments

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@phagunbaya
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@phagunbaya phagunbaya commented Mar 3, 2017

kubedns logs:

I0303 20:17:56.595813       1 dns.go:42] version: v1.6.0-alpha.0.680+3872cb93abf948-dirty
I0303 20:17:56.596373       1 server.go:107] Using https://10.96.0.1:443 for kubernetes master, kubernetes API: <nil>
I0303 20:17:56.596882       1 server.go:68] Using configuration read from ConfigMap: kube-system:kube-dns
I0303 20:17:56.596925       1 server.go:113] FLAG: --alsologtostderr="false"
I0303 20:17:56.596943       1 server.go:113] FLAG: --config-map="kube-dns"
I0303 20:17:56.596949       1 server.go:113] FLAG: --config-map-namespace="kube-system"
I0303 20:17:56.596952       1 server.go:113] FLAG: --dns-bind-address="0.0.0.0"
I0303 20:17:56.596956       1 server.go:113] FLAG: --dns-port="10053"
I0303 20:17:56.596961       1 server.go:113] FLAG: --domain="cluster.local."
I0303 20:17:56.596967       1 server.go:113] FLAG: --federations=""
I0303 20:17:56.596971       1 server.go:113] FLAG: --healthz-port="8081"
I0303 20:17:56.596976       1 server.go:113] FLAG: --kube-master-url=""
I0303 20:17:56.596981       1 server.go:113] FLAG: --kubecfg-file=""
I0303 20:17:56.596985       1 server.go:113] FLAG: --log-backtrace-at=":0"
I0303 20:17:56.596992       1 server.go:113] FLAG: --log-dir=""
I0303 20:17:56.596996       1 server.go:113] FLAG: --log-flush-frequency="5s"
I0303 20:17:56.597001       1 server.go:113] FLAG: --logtostderr="true"
I0303 20:17:56.597005       1 server.go:113] FLAG: --stderrthreshold="2"
I0303 20:17:56.597009       1 server.go:113] FLAG: --v="2"
I0303 20:17:56.597014       1 server.go:113] FLAG: --version="false"
I0303 20:17:56.597019       1 server.go:113] FLAG: --vmodule=""
I0303 20:17:56.597113       1 server.go:155] Starting SkyDNS server (0.0.0.0:10053)
I0303 20:17:56.597414       1 server.go:165] Skydns metrics enabled (/metrics:10055)
I0303 20:17:56.597437       1 dns.go:144] Starting endpointsController
I0303 20:17:56.597443       1 dns.go:147] Starting serviceController
I0303 20:17:56.597531       1 logs.go:41] skydns: ready for queries on cluster.local. for tcp://0.0.0.0:10053 [rcache 0]
I0303 20:17:56.597554       1 logs.go:41] skydns: ready for queries on cluster.local. for udp://0.0.0.0:10053 [rcache 0]
E0303 20:17:57.601223       1 sync.go:105] Error getting ConfigMap kube-system:kube-dns err: Get https://10.96.0.1:443/api/v1/namespaces/kube-system/configmaps/kube-dns: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:17:57.601271       1 dns.go:190] Error getting initial ConfigMap: Get https://10.96.0.1:443/api/v1/namespaces/kube-system/configmaps/kube-dns: dial tcp 10.96.0.1:443: getsockopt: no route to host, starting with default values
I0303 20:17:57.601317       1 dns.go:163] Waiting for Kubernetes service
I0303 20:17:57.601331       1 dns.go:169] Waiting for service: default/kubernetes
E0303 20:17:59.605100       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:01.607159       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:04.617151       1 reflector.go:199] pkg/dns/config/sync.go:114: Failed to list *api.ConfigMap: Get https://10.96.0.1:443/api/v1/namespaces/kube-system/configmaps?fieldSelector=metadata.name%3Dkube-dns&resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:05.613089       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:07.617099       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:09.619173       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:11.621183       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:15.629124       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:17.633140       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:19.635211       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:21.637134       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:25.645156       1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: getsockopt: no route to host
E0303 20:18:26.598781       1 reflector.go:199] pkg/dns/dns.go:145: Failed to list *api.Endpoints: Get https://10.96.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout

kube-apiserver logs

I0303 20:02:55.656265       1 config.go:527] Will report 10.160.20.150 as public IP address.
E0303 20:02:55.658840       1 reflector.go:199] k8s.io/kubernetes/plugin/pkg/admission/serviceaccount/admission.go:103: Failed to list *api.ServiceAccount: Get http://127.0.0.1:8080/api/v1/serviceaccounts?resourceVersion=0: dial tcp 127.0.0.1:8080: getsockopt: connection refused
E0303 20:02:55.661056       1 reflector.go:199] k8s.io/kubernetes/plugin/pkg/admission/serviceaccount/admission.go:119: Failed to list *api.Secret: Get http://127.0.0.1:8080/api/v1/secrets?fieldSelector=type%3Dkubernetes.io%2Fservice-account-token&resourceVersion=0: dial tcp 127.0.0.1:8080: getsockopt: connection refused
E0303 20:02:55.661974       1 reflector.go:199] k8s.io/kubernetes/plugin/pkg/admission/storageclass/default/admission.go:75: Failed to list *storage.StorageClass: Get http://127.0.0.1:8080/apis/storage.k8s.io/v1beta1/storageclasses?resourceVersion=0: dial tcp 127.0.0.1:8080: getsockopt: connection refused
E0303 20:02:55.662031       1 reflector.go:199] k8s.io/kubernetes/plugin/pkg/admission/resourcequota/resource_access.go:83: Failed to list *api.ResourceQuota: Get http://127.0.0.1:8080/api/v1/resourcequotas?resourceVersion=0: dial tcp 127.0.0.1:8080: getsockopt: connection refused
E0303 20:02:55.709032       1 reflector.go:199] pkg/controller/informers/factory.go:89: Failed to list *api.LimitRange: Get http://127.0.0.1:8080/api/v1/limitranges?resourceVersion=0: dial tcp 127.0.0.1:8080: getsockopt: connection refused
E0303 20:02:55.709152       1 reflector.go:199] pkg/controller/informers/factory.go:89: Failed to list *api.Namespace: Get http://127.0.0.1:8080/api/v1/namespaces?resourceVersion=0: dial tcp 127.0.0.1:8080: getsockopt: connection refused
[restful] 2017/03/03 20:02:55 log.go:30: [restful/swagger] listing is available at https://10.160.20.150:6443/swaggerapi/
[restful] 2017/03/03 20:02:55 log.go:30: [restful/swagger] https://10.160.20.150:6443/swaggerui/ is mapped to folder /swagger-ui/
I0303 20:02:55.771165       1 serve.go:88] Serving securely on 0.0.0.0:6443
I0303 20:02:55.771302       1 serve.go:102] Serving insecurely on 127.0.0.1:8080
I0303 20:02:56.730792       1 trace.go:61] Trace "Update /api/v1/namespaces/kube-system/pods/kube-apiserver-wyml01/status" (started 2017-03-03 20:02:55.825739356 +0000 UTC):
[63.968µs] [63.968µs] About to convert to expected version
[275.186µs] [211.218µs] Conversion done
[283.347µs] [8.161µs] About to store object in database
[904.938318ms] [904.654971ms] Object stored in database
[904.9425ms] [4.182µs] Self-link added
[905.006032ms] [63.532µs] END
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@phagunbaya phagunbaya commented Mar 3, 2017

iptables

[root@wyml01 Falkonry-k8-installer]# iptables-save 
# Generated by iptables-save v1.4.21 on Fri Mar  3 13:23:40 2017
*nat
:PREROUTING ACCEPT [2:156]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
:KUBE-MARK-DROP - [0:0]
:KUBE-MARK-MASQ - [0:0]
:KUBE-NODEPORTS - [0:0]
:KUBE-POSTROUTING - [0:0]
:KUBE-SEP-SAGRE6MUSU7ISKH2 - [0:0]
:KUBE-SERVICES - [0:0]
:KUBE-SVC-ERIFXISQEP7F7OF4 - [0:0]
:KUBE-SVC-NPX46M4PTMTKRN6Y - [0:0]
:KUBE-SVC-TCOU7JCQXEZGVUNU - [0:0]
-A PREROUTING -m comment --comment "kubernetes service portals" -j KUBE-SERVICES
-A OUTPUT -m comment --comment "kubernetes service portals" -j KUBE-SERVICES
-A POSTROUTING -m comment --comment "kubernetes postrouting rules" -j KUBE-POSTROUTING
-A KUBE-MARK-DROP -j MARK --set-xmark 0x8000/0x8000
-A KUBE-MARK-MASQ -j MARK --set-xmark 0x4000/0x4000
-A KUBE-POSTROUTING -m comment --comment "kubernetes service traffic requiring SNAT" -m mark --mark 0x4000/0x4000 -j MASQUERADE
-A KUBE-SEP-SAGRE6MUSU7ISKH2 -s 10.160.20.150/32 -m comment --comment "default/kubernetes:https" -j KUBE-MARK-MASQ
-A KUBE-SEP-SAGRE6MUSU7ISKH2 -p tcp -m comment --comment "default/kubernetes:https" -m recent --set --name KUBE-SEP-SAGRE6MUSU7ISKH2 --mask 255.255.255.255 --rsource -m tcp -j DNAT --to-destination 10.160.20.150:6443
-A KUBE-SERVICES -d 10.96.0.10/32 -p udp -m comment --comment "kube-system/kube-dns:dns cluster IP" -m udp --dport 53 -j KUBE-SVC-TCOU7JCQXEZGVUNU
-A KUBE-SERVICES -d 10.96.0.10/32 -p tcp -m comment --comment "kube-system/kube-dns:dns-tcp cluster IP" -m tcp --dport 53 -j KUBE-SVC-ERIFXISQEP7F7OF4
-A KUBE-SERVICES -d 10.96.0.1/32 -p tcp -m comment --comment "default/kubernetes:https cluster IP" -m tcp --dport 443 -j KUBE-SVC-NPX46M4PTMTKRN6Y
-A KUBE-SERVICES -m comment --comment "kubernetes service nodeports; NOTE: this must be the last rule in this chain" -m addrtype --dst-type LOCAL -j KUBE-NODEPORTS
-A KUBE-SVC-NPX46M4PTMTKRN6Y -m comment --comment "default/kubernetes:https" -m recent --rcheck --seconds 10800 --reap --name KUBE-SEP-SAGRE6MUSU7ISKH2 --mask 255.255.255.255 --rsource -j KUBE-SEP-SAGRE6MUSU7ISKH2
-A KUBE-SVC-NPX46M4PTMTKRN6Y -m comment --comment "default/kubernetes:https" -j KUBE-SEP-SAGRE6MUSU7ISKH2
COMMIT
# Completed on Fri Mar  3 13:23:40 2017
# Generated by iptables-save v1.4.21 on Fri Mar  3 13:23:40 2017
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [8:452]
:KUBE-FIREWALL - [0:0]
:KUBE-SERVICES - [0:0]
:WEAVE-NPC - [0:0]
:WEAVE-NPC-DEFAULT - [0:0]
:WEAVE-NPC-INGRESS - [0:0]
-A INPUT -j KUBE-FIREWALL
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
-A OUTPUT -m comment --comment "kubernetes service portals" -j KUBE-SERVICES
-A OUTPUT -j KUBE-FIREWALL
-A KUBE-FIREWALL -m comment --comment "kubernetes firewall for dropping marked packets" -m mark --mark 0x8000/0x8000 -j DROP
-A KUBE-SERVICES -d 10.96.0.10/32 -p udp -m comment --comment "kube-system/kube-dns:dns has no endpoints" -m udp --dport 53 -j REJECT --reject-with icmp-port-unreachable
-A KUBE-SERVICES -d 10.96.0.10/32 -p tcp -m comment --comment "kube-system/kube-dns:dns-tcp has no endpoints" -m tcp --dport 53 -j REJECT --reject-with icmp-port-unreachable
-A WEAVE-NPC -m state --state RELATED,ESTABLISHED -j ACCEPT
-A WEAVE-NPC -d 224.0.0.0/4 -j ACCEPT
-A WEAVE-NPC -m state --state NEW -j WEAVE-NPC-DEFAULT
-A WEAVE-NPC -m state --state NEW -j WEAVE-NPC-INGRESS
-A WEAVE-NPC-DEFAULT -m set --match-set weave-k?Z;25^M}|1s7P3|H9i;*;MhG dst -j ACCEPT
-A WEAVE-NPC-DEFAULT -m set --match-set weave-iuZcey(5DeXbzgRFs8Szo]<@p dst -j ACCEPT
COMMIT
# Completed on Fri Mar  3 13:23:40 2017
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@pipejakob pipejakob commented Mar 7, 2017

I suspect you're hitting issue #196. You can verify that this is the root cause by manually editing /etc/kubernetes/manifests/kube-apiserver.yaml on the master and changing the liveness probe:

livenessProbe:
  failureThreshold: 8
  httpGet:
    host: 127.0.0.1
    path: /healthz
    port: 443           # was 6443
    scheme: HTTPS
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@pipejakob pipejakob commented Mar 7, 2017

@phagunbaya If you do try the above, I would also kill/restart kubelet for it to take effect faster. When I hit this problem myself, kubelet's exponential backoff was making it take forever to try to restart the kube-apiserver pod.

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@msavlani msavlani commented Mar 8, 2017

Did you try flushing your iptable rules and restart kubelet service ?

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@phagunbaya phagunbaya commented Mar 8, 2017

@msavlani Flushing iptable rules did not help.
@pipejakob Thanks ! that resolved.

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@errordeveloper errordeveloper commented Apr 12, 2017

Also killing DNS pod seems to resolve this for me...

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@errordeveloper errordeveloper commented Apr 12, 2017

I am not entierly sure this has to do with #196, I think there is a race condition elsewhere. I've just hit this in something I'm working on at the moment, I will update if I figure out what causes it, as seem to have a way of reproducing is reliably.

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@TracyBin TracyBin commented Apr 14, 2017

I setup a single-machine Kubernetes cluster for development and faced the same problem.But modifying the port does not solve the problem

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@jeffchanjunwei jeffchanjunwei commented Apr 25, 2017

Hi @TracyBin, how do you solve this problem at last?

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@TracyBin TracyBin commented Apr 25, 2017

@jeffchanjunwei It is the problem of iptables.Please try the blow command

iptables -P FORWARD ACCEPT

If the command solve your problem,please tell me.

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@jeffchanjunwei jeffchanjunwei commented Apr 25, 2017

@TracyBin It doesn't work. kubedns-amd64:1.9 images still can not start. Errors as follows:

kubectl describe pod kubedns
<invalid> <invalid> 1 {kubelet k8sminion1} spec.containers{kubedns} Warning Unhealthy Readiness probe failed: Get http://10.233.124.95:8081/readiness: dial tcp 10.233.124.95:8081: getsockopt: connection refused

docker logs kubedns-amd
E0425 02:28:03.129272 1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.233.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.233.0.1:443: i/o timeout
E0425 02:28:03.234570 1 reflector.go:199] pkg/dns/dns.go:145: Failed to list *api.Endpoints: Get https://10.233.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 10.233.0.1:443: i/o timeout

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@pineking pineking commented May 12, 2017

@jeffchanjunwei do you solve this problem?

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@jeffchanjunwei jeffchanjunwei commented May 15, 2017

@pineking yes. It is the cause of network that results into the problem.

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@frankruizhi frankruizhi commented May 16, 2017

I got the same issue,my kubedns log :

[root@k8s ~]# kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name) -c kubedns
I0516 07:38:31.041503 1 dns.go:42] version: v1.6.0-alpha.0.680+3872cb93abf948-dirty
I0516 07:38:31.042564 1 server.go:107] Using https://10.254.0.1:443 for kubernetes master, kubernetes API:
I0516 07:38:31.043625 1 server.go:68] Using configuration read from ConfigMap: kube-system:kube-dns
I0516 07:38:31.043729 1 server.go:113] FLAG: --alsologtostderr="false"
I0516 07:38:31.043762 1 server.go:113] FLAG: --config-map="kube-dns"
I0516 07:38:31.043773 1 server.go:113] FLAG: --config-map-namespace="kube-system"
I0516 07:38:31.043780 1 server.go:113] FLAG: --dns-bind-address="0.0.0.0"
I0516 07:38:31.043786 1 server.go:113] FLAG: --dns-port="10053"
I0516 07:38:31.043810 1 server.go:113] FLAG: --domain="cluster.local."
I0516 07:38:31.043821 1 server.go:113] FLAG: --federations=""
I0516 07:38:31.043829 1 server.go:113] FLAG: --healthz-port="8081"
I0516 07:38:31.043837 1 server.go:113] FLAG: --kube-master-url=""
I0516 07:38:31.043847 1 server.go:113] FLAG: --kubecfg-file=""
I0516 07:38:31.043853 1 server.go:113] FLAG: --log-backtrace-at=":0"
I0516 07:38:31.043863 1 server.go:113] FLAG: --log-dir=""
I0516 07:38:31.043870 1 server.go:113] FLAG: --log-flush-frequency="5s"
I0516 07:38:31.043880 1 server.go:113] FLAG: --logtostderr="true"
I0516 07:38:31.043887 1 server.go:113] FLAG: --stderrthreshold="2"
I0516 07:38:31.043901 1 server.go:113] FLAG: --v="2"
I0516 07:38:31.043908 1 server.go:113] FLAG: --version="false"
I0516 07:38:31.043918 1 server.go:113] FLAG: --vmodule=""
I0516 07:38:31.044094 1 server.go:155] Starting SkyDNS server (0.0.0.0:10053)
I0516 07:38:31.048954 1 server.go:165] Skydns metrics enabled (/metrics:10055)
I0516 07:38:31.048987 1 dns.go:144] Starting endpointsController
I0516 07:38:31.048997 1 dns.go:147] Starting serviceController
I0516 07:38:31.049354 1 logs.go:41] skydns: ready for queries on cluster.local. for tcp://0.0.0.0:10053 [rcache 0]
I0516 07:38:31.049383 1 logs.go:41] skydns: ready for queries on cluster.local. for udp://0.0.0.0:10053 [rcache 0]
E0516 07:39:01.051248 1 sync.go:105] Error getting ConfigMap kube-system:kube-dns err: Get https://10.254.0.1:443/api/v1/namespaces/kube-system/configmaps/kube-dns: dial tcp 10.254.0.1:443: i/o timeout
E0516 07:39:01.051307 1 dns.go:190] Error getting initial ConfigMap: Get https://10.254.0.1:443/api/v1/namespaces/kube-system/configmaps/kube-dns: dial tcp 10.254.0.1:443: i/o timeout, starting with default values
I0516 07:39:01.051338 1 dns.go:163] Waiting for Kubernetes service
I0516 07:39:01.051347 1 dns.go:169] Waiting for service: default/kubernetes
E0516 07:39:02.228560 1 reflector.go:199] pkg/dns/dns.go:145: Failed to list *api.Endpoints: Get https://10.254.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 10.254.0.1:443: i/o timeout
E0516 07:39:02.228646 1 reflector.go:199] pkg/dns/dns.go:148: Failed to list *api.Service: Get https://10.254.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.254.0.1:443: i/o timeout
E0516 07:39:32.229250 1 reflector.go:199] pkg/dns/config/sync.go:114: Failed to list *api.ConfigMap: Get https://10.254.0.1:443/api/v1/namespaces/kube-system/configmaps?fieldSelector=metadata.name%3Dkube-dns&resourceVersion=0: dial tcp 10.254.0.1:443: i/o timeout

I've tied a lot ,but none of them worked.

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@frankruizhi frankruizhi commented May 19, 2017

I have found the solution to my problem:

Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"a55267932d501b9fbd6d73e5ded47d79b5763ce5", GitTreeState:"clean", BuildDate:"2017-04-14T13:36:25Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"a55267932d501b9fbd6d73e5ded47d79b5763ce5", GitTreeState:"clean", BuildDate:"2017-04-14T13:36:25Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}

1.First,we should make sure the ip-forward enabled on the linux kernel of every node.Just execute command:
sysctl net.ipv4.conf.all.forwarding = 1

2.Secondly,if your docker's version >=1.13,the default FORWARD chain policy was DROP,you should set default policy of the FORWARD chain to ACCEPT:$ sudo iptables -P FORWARD ACCEPT.

3.Then the configuration of the kube-proxy must be pass in :
--cluster-cidr=.

ps: --cluster-cidr string The CIDR range of pods in the cluster. It is used to bridge traffic coming from outside of the cluster. If not provided, no off-cluster bridging will be performed.
Refer to this:kubernetes/kubernetes#36835

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@luxas luxas commented May 29, 2017

Closing this as fixed with v1.6

@luxas luxas closed this May 29, 2017
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@mhsabbagh mhsabbagh commented Aug 14, 2017

This is still here on 1.7.3 with Ubuntu 16.04. Same exact problem. Have been trying all the possible solutions from disabling apparmor, changing the ports, making sure nothing blocks it.. It still doesn't work.

I tried it on a completely fresh droplet from DigitalOcean and it's still the same. Doesn't look like a configuration problem from my side. I just ran the commands as they are in https://medium.com/@SystemMining/setup-kubenetes-cluster-on-ubuntu-16-04-with-kubeadm-336f4061d929

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@pengyue pengyue commented Aug 21, 2017

@mhsabbagh, I have the exact version as yours, 1 master, 3 nodes, the dashboard was setup on node 2 automatically when apply dashboard.yaml. and dashboard error looks like the same as others.

Using HTTP port: 8443 Using in-cluster config to connect to apiserver Using service account token for csrf signing No request provided. Skipping authorization header Error while initializing connection to Kubernetes apiserver. This most likely means that the cluster is misconfigured (e.g., it has invalid apiserver certificates or service accounts configuration) or the --apiserver-host param points to a server that does not exist. Reason: Get https://10.96.0.1:443/version: dial tcp 10.96.0.1:443: i/o timeout Refer to the troubleshooting guide for more information: https://github.com/kubernetes/dashboard/blob/master/docs/user-guide/troubleshooting.md

I have been searching for an solution, but still cannot find a solution. I could telnet to 10.96.0.1 on port 443 from any of the master and nodes

Are we sure it has been fixed in v1.6?

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@gogeof gogeof commented Aug 29, 2017

I also have this problem in kubernetes v1.7.4, and after I restart docker, it fix.

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@BenHall BenHall commented Sep 5, 2017

Also hitting this on a fair frequent basis with Kubernetes 1.7 on top of Docker 1.12.6

Running iptables -P FORWARD ACCEPT didn't resolve the issue.

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@luxas luxas commented Sep 5, 2017

@BenHall please open a new issue with relevant details.

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@lastboy1228 lastboy1228 commented Sep 17, 2017

systemctl stop kubelet
systemctl stop docker
iptables --flush
iptables -tnat --flush
systemctl start kubelet
systemctl start docker

The route problem can be solved by flush iptables.

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@P4otocol P4otocol commented Oct 13, 2017

Thanks @frankruizhi for the info. Worked for me!! (Used docker version >1.13)

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@WanChengHu WanChengHu commented Oct 15, 2017

I got the same problem when I use kubeadm to init a k8s v1.8 cluster with one master and one node.

Client Version: version.Info{Major:"1", Minor:"8", GitVersion:"v1.8.0", GitCommit:"6e937839ac04a38cac63e6a7a306c5d035fe7b0a", GitTreeState:"clean", BuildDate:"2017-09-28T22:57:57Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"8", GitVersion:"v1.8.0", GitCommit:"6e937839ac04a38cac63e6a7a306c5d035fe7b0a", GitTreeState:"clean", BuildDate:"2017-09-28T22:46:41Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"linux/amd64"}

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@WanChengHu WanChengHu commented Oct 15, 2017

kubectl get pod -n kube-system

NAME READY STATUS RESTARTS AGE
etcd-redis 1/1 Running 0 6h
kube-apiserver-redis 1/1 Running 0 6h
kube-controller-manager-redis 1/1 Running 0 6h
kube-dns-545bc4bfd4-zqv6j 2/3 CrashLoopBackOff 146 6h
kube-flannel-ds-8cphc 1/1 Running 0 6h
kube-flannel-ds-dqsbr 1/1 Running 7 6h
kube-proxy-fjhlf 1/1 Running 0 6h
kube-proxy-j5pwk 1/1 Running 0 6h
kube-scheduler-redis 1/1 Running 0 6h

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@WanChengHu WanChengHu commented Oct 15, 2017

kubectl logs kube-dns-545bc4bfd4-zqv6j -n kube-system -c kubedns --previous=true
I1015 13:25:06.436183 1 dns.go:48] version: 1.14.4-2-g5584e04
I1015 13:25:06.436763 1 server.go:70] Using configuration read from directory: /kube-dns-config with period 10s
I1015 13:25:06.436807 1 server.go:113] FLAG: --alsologtostderr="false"
I1015 13:25:06.436818 1 server.go:113] FLAG: --config-dir="/kube-dns-config"
I1015 13:25:06.436824 1 server.go:113] FLAG: --config-map=""
I1015 13:25:06.436826 1 server.go:113] FLAG: --config-map-namespace="kube-system"
I1015 13:25:06.436829 1 server.go:113] FLAG: --config-period="10s"
I1015 13:25:06.436833 1 server.go:113] FLAG: --dns-bind-address="0.0.0.0"
I1015 13:25:06.436835 1 server.go:113] FLAG: --dns-port="10053"
I1015 13:25:06.436843 1 server.go:113] FLAG: --domain="cluster.local."
I1015 13:25:06.436848 1 server.go:113] FLAG: --federations=""
I1015 13:25:06.436851 1 server.go:113] FLAG: --healthz-port="8081"
I1015 13:25:06.436854 1 server.go:113] FLAG: --initial-sync-timeout="1m0s"
I1015 13:25:06.436856 1 server.go:113] FLAG: --kube-master-url=""
I1015 13:25:06.436861 1 server.go:113] FLAG: --kubecfg-file=""
I1015 13:25:06.436864 1 server.go:113] FLAG: --log-backtrace-at=":0"
I1015 13:25:06.436868 1 server.go:113] FLAG: --log-dir=""
I1015 13:25:06.436874 1 server.go:113] FLAG: --log-flush-frequency="5s"
I1015 13:25:06.436876 1 server.go:113] FLAG: --logtostderr="true"
I1015 13:25:06.436886 1 server.go:113] FLAG: --nameservers=""
I1015 13:25:06.436888 1 server.go:113] FLAG: --stderrthreshold="2"
I1015 13:25:06.436891 1 server.go:113] FLAG: --v="2"
I1015 13:25:06.436893 1 server.go:113] FLAG: --version="false"
I1015 13:25:06.436898 1 server.go:113] FLAG: --vmodule=""
I1015 13:25:06.436994 1 server.go:176] Starting SkyDNS server (0.0.0.0:10053)
I1015 13:25:06.437258 1 server.go:198] Skydns metrics enabled (/metrics:10055)
I1015 13:25:06.437275 1 dns.go:147] Starting endpointsController
I1015 13:25:06.437284 1 dns.go:150] Starting serviceController
I1015 13:25:06.437361 1 logs.go:41] skydns: ready for queries on cluster.local. for tcp://0.0.0.0:10053 [rcache 0]
I1015 13:25:06.437368 1 logs.go:41] skydns: ready for queries on cluster.local. for udp://0.0.0.0:10053 [rcache 0]
I1015 13:25:06.937453 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:07.437470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:07.937473 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:08.437480 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:08.937473 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:09.437483 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:09.937481 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:10.437460 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:10.937489 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:11.437451 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:11.937473 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:12.437473 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:12.937484 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:13.437496 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:13.937474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:14.437485 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:14.937470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:15.437470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:15.937467 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:16.437474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:16.937469 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:17.437484 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:17.937492 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:18.437474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:18.937499 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:19.437459 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:19.937495 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:20.437475 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:20.937483 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:21.437476 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:21.937459 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:22.437477 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:22.937462 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:23.437508 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:23.937452 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:24.437490 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:24.937443 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:25.437472 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:25.937494 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:26.437496 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:26.937482 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:27.437452 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:27.937494 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:28.437492 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:28.937486 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:29.437470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:29.937467 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:30.437456 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:30.937489 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:31.437469 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:31.937458 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:32.437459 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:32.937459 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:33.437468 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:33.937467 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:34.437467 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:34.937496 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:35.437477 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:35.937481 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:36.437505 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
E1015 13:25:36.437852 1 reflector.go:199] k8s.io/dns/vendor/k8s.io/client-go/tools/cache/reflector.go:94: Failed to list *v1.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout
E1015 13:25:36.437865 1 reflector.go:199] k8s.io/dns/vendor/k8s.io/client-go/tools/cache/reflector.go:94: Failed to list *v1.Endpoints: Get https://10.96.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout
I1015 13:25:36.937466 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:37.437493 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:37.937476 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:38.437478 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:38.937487 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:39.437473 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:39.937470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:40.437487 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:40.937459 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:41.437504 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:41.937481 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:42.437470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:42.937469 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:43.437474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:43.937452 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:44.437449 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:44.937487 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:45.437460 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:45.937484 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:46.437500 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:46.937444 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:47.437488 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:47.937478 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:48.437479 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:48.937471 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:49.437485 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:49.937470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:50.437476 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:50.937475 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:51.437490 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:51.937446 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:52.437486 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:52.937470 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:53.437465 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:53.937482 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:54.437456 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:54.937469 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:55.437467 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:55.937489 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:56.437471 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:56.937464 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:57.437451 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:57.937504 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:58.437482 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:58.937474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:59.437479 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:59.937460 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:00.437505 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:00.937463 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:01.437480 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:01.937465 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:02.437468 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:02.937452 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:03.437474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:03.937474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:04.437474 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:04.937467 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:05.437473 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:26:05.937472 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...

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@WanChengHu WanChengHu commented Oct 15, 2017

kubectl logs kube-dns-545bc4bfd4-zqv6j -n kube-system -c dnsmasq --previous=true
I1015 13:25:06.494999 1 main.go:76] opts: {{/usr/sbin/dnsmasq [-k --cache-size=1000 --log-facility=- --server=/cluster.local/127.0.0.1#10053 --server=/in-addr.arpa/127.0.0.1#10053 --server=/ip6.arpa/127.0.0.1#10053] true} /etc/k8s/dns/dnsmasq-nanny 10000000000}
I1015 13:25:06.495117 1 nanny.go:86] Starting dnsmasq [-k --cache-size=1000 --log-facility=- --server=/cluster.local/127.0.0.1#10053 --server=/in-addr.arpa/127.0.0.1#10053 --server=/ip6.arpa/127.0.0.1#10053]
I1015 13:25:06.503314 1 nanny.go:111]
I1015 13:25:06.503330 1 nanny.go:108] dnsmasq[14]: started, version 2.78-security-prerelease cachesize 1000
W1015 13:25:06.503339 1 nanny.go:112] Got EOF from stdout
I1015 13:25:06.503343 1 nanny.go:108] dnsmasq[14]: compile time options: IPv6 GNU-getopt no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack ipset auth no-DNSSEC loop-detect inotify
I1015 13:25:06.503348 1 nanny.go:108] dnsmasq[14]: using nameserver 127.0.0.1#10053 for domain ip6.arpa
I1015 13:25:06.503352 1 nanny.go:108] dnsmasq[14]: using nameserver 127.0.0.1#10053 for domain in-addr.arpa
I1015 13:25:06.503355 1 nanny.go:108] dnsmasq[14]: using nameserver 127.0.0.1#10053 for domain cluster.local
I1015 13:25:06.503358 1 nanny.go:108] dnsmasq[14]: reading /etc/resolv.conf
I1015 13:25:06.503361 1 nanny.go:108] dnsmasq[14]: using nameserver 127.0.0.1#10053 for domain ip6.arpa
I1015 13:25:06.503364 1 nanny.go:108] dnsmasq[14]: using nameserver 127.0.0.1#10053 for domain in-addr.arpa
I1015 13:25:06.503402 1 nanny.go:108] dnsmasq[14]: using nameserver 127.0.0.1#10053 for domain cluster.local
I1015 13:25:06.503405 1 nanny.go:108] dnsmasq[14]: using nameserver 100.100.2.138#53
I1015 13:25:06.503409 1 nanny.go:108] dnsmasq[14]: using nameserver 100.100.2.136#53
I1015 13:25:06.503412 1 nanny.go:108] dnsmasq[14]: read /etc/hosts - 7 addresses

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@WanChengHu WanChengHu commented Oct 16, 2017

@TracyBin flannel 0.9.0, yes I use kubeadm
@frankruizhi let me try

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@WanChengHu WanChengHu commented Oct 16, 2017

@frankruizhi doesn't work

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@TracyBin TracyBin commented Oct 16, 2017

@WanChengHu Does pod bind with ip? Most of reason is iptables and flannel network.

systemctl disable firewalld;systemctl stop firewalld;iptables -P FORWARD ACCEPT
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@zxpower zxpower commented Oct 16, 2017

I have exactly the same problem - had it on K8s v1.8.0 and today I upgrade to v1.8.1 - still the same.

OS: CoreOS 1465.8.0 (with included Docker 1.12.6)
K8s: v1.8.1
Etcd: 3.0.17
Flannel: 0.7.1

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@WanChengHu WanChengHu commented Oct 19, 2017

@TracyBin my k8s cluster is installed in Aliyun, and they tell me that they don't support k8s 1.8
the firewalld is disabled, iptables allow all inboud and outboud traffic

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@TracyBin TracyBin commented Oct 19, 2017

@WanChengHu 加我QQ看一下 641555100

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@dl00 dl00 commented Oct 20, 2017

I am also having this problem. Spent over 2 hours on gitter trying to resolve it with someone. No luck.

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@luxas luxas commented Oct 20, 2017

@dl00 and others, if you do think you've found an issue, please open a new issue with actual details from your environment. Please don't comment on closed ones.

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@ikus060 ikus060 commented Nov 10, 2017

Running iptables -P FORWARD ACCEPT on master and nodes solved the problem for me.
I was running flannel.

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@kwaazaar kwaazaar commented Feb 4, 2018

Which pod network is preferred/works out of the box? I'm running into these same issues, but I have no clue how to fix them. I picked kube-router btw, but running into these same issues.

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@errordeveloper errordeveloper commented Feb 13, 2018

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@xiaoguazh xiaoguazh commented Jun 7, 2018

I set k8s cluster using virtualbox, 1-kube-master, 2-kube-workers.

When google, there are lots of similar issue, although many ticket shows closed, I tried a lot, but no luck.
I tried "$sudo iptables -P FORWARD ACCEPT", "$ sudo iptables --flush", this doesn't work for me.

The root cause should be in kube-dns, flannel and kube-proxy, anyone can tell exactly what is wrong in them ? :-)

kube-dns has 3 components/container: kubedns, dnsmasq,sidecar

`
kube-system kube-dns-598d7bf7d4-dzbn8 2/3 CrashLoopBackOff 43 10h
kube-system kube-dns-598d7bf7d4-v99tk 2/3 CrashLoopBackOff 45 10h
kube-system kube-flannel-ds-mvrt5 1/1 Running 8 20h
kube-system kube-flannel-ds-vt2w6 1/1 Running 5 20h
kube-system kube-flannel-ds-xrsq8 1/1 Running 5 20h
kube-system kube-proxy-jrw6f 1/1 Running 5 21h
kube-system kube-proxy-mt6mz 1/1 Running 8 21h
kube-system kube-proxy-wwd95 1/1 Running 5 21h

`

try use kubectl exec to check each container

(1) kubedns = always down with error in log.

` Waiting for services and endpoints to be initialized from apiserver...

reflector.go:201] k8s.io/dns/pkg/dns/dns.go:147: Failed to list *v1.Endpoints: Get https://10.96.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout

reflector.go:201] k8s.io/dns/pkg/dns/dns.go:150: Failed to list *v1.Service: Get https://10.96.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.96.0.1:443: i/o timeout

dns.go:173] Waiting for services and endpoints to be initialized from apiserver...

`

(2) dnsmasq = ok, but it seems the default /etc/resolv.conf might have issue, why it uses my HOST machine's DNS setting? should it use "nameserver 10.96.0.10" ?

`
dnsmasq[12]: using nameserver 127.0.0.1#10053 for domain ip6.arpa
dnsmasq[12]: using nameserver 127.0.0.1#10053 for domain in-addr.arpa
dnsmasq[12]: using nameserver 127.0.0.1#10053 for domain cluster.local
dnsmasq[12]: reading /etc/resolv.conf
dnsmasq[12]: using nameserver 127.0.0.1#10053 for domain ip6.arpa
dnsmasq[12]: using nameserver 127.0.0.1#10053 for domain in-addr.arpa
dnsmasq[12]: using nameserver 127.0.0.1#10053 for domain cluster.local
dnsmasq[12]: using nameserver 10.158.54.11#53
dnsmasq[12]: using nameserver 10.158.54.12#53
dnsmasq[12]: using nameserver 10.158.57.11#53
dnsmasq[12]: read /etc/hosts - 7 addresses

/ # cat /etc/resolv.conf
nameserver 10.158.54.11
nameserver 10.158.54.12
nameserver 10.158.57.11
search nokia.com china.nsn-net.net


/ # netstat -nl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:53              0.0.0.0:*               LISTEN
tcp        0      0 :::10053                :::*                    LISTEN
tcp        0      0 :::10054                :::*                    LISTEN
tcp        0      0 :::10055                :::*                    LISTEN
tcp        0      0 :::53                   :::*                    LISTEN
udp        0      0 0.0.0.0:53              0.0.0.0:*
udp        0      0 0.0.0.0:14494           0.0.0.0:*
udp        0      0 0.0.0.0:42680           0.0.0.0:*
udp        0      0 0.0.0.0:61748           0.0.0.0:*
udp        0      0 :::10053                :::*
udp        0      0 :::53                   :::*

`

(3)sidecar = ok, with failure on dnsProbe, this seems NOT a big issue.

`
dnsprobe.go:75] Starting dnsProbe {Label:kubedns Server:127.0.0.1:10053 Name:kubernetes.default.svc.cluster.local. Interval:5s Type:33}

dnsprobe.go:75] Starting dnsProbe {Label:dnsmasq Server:127.0.0.1:53 Name:kubernetes.default.svc.cluster.local. Interval:5s Type:33}

server.go:64] Error getting metrics from dnsmasq: read udp 127.0.0.1:45259->127.0.0.1:53: read: connection refused
server.go:64] Error getting metrics from dnsmasq: read udp 127.0.0.1:45932->127.0.0.1:53: read: connection refused


~ $ netstat -nl
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:53              0.0.0.0:*               LISTEN
tcp        0      0 :::10054                :::*                    LISTEN
tcp        0      0 :::53                   :::*                    LISTEN
udp        0      0 0.0.0.0:39749           0.0.0.0:*
udp        0      0 0.0.0.0:45937           0.0.0.0:*
udp        0      0 0.0.0.0:44462           0.0.0.0:*
udp        0      0 0.0.0.0:18938           0.0.0.0:*
udp        0      0 0.0.0.0:53              0.0.0.0:*
udp        0      0 0.0.0.0:20040           0.0.0.0:*
udp        0      0 :::53                   :::*
Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node Path

`

10.96.0.1:443 is the cluster ip of kubernetes service, this service is in "default" namespace, can kube-dns from namesapce "kube-system" able to access this in namespace "default" ? I suspect here might have problem ?

`
$ kubectl describe service kubernetes

Name:              kubernetes
Namespace:         default
Labels:            component=apiserver
                   provider=kubernetes
Annotations:       <none>
Selector:          <none>
Type:              ClusterIP
IP:                10.96.0.1                            #-service-cidr 10.96.0.0/12 
Port:              https  443/TCP
TargetPort:        6443/TCP
Endpoints:         192.168.56.101:6443
Session Affinity:  ClientIP
Events:            <none>

`

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@BenHall BenHall commented Jun 7, 2018

@xiangpengzhao We had an issue where it was a timing related bug with IPTables. Our solution was to upgrade to the latest CNI plugin (in our case Weave).

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@Nurza Nurza commented Aug 7, 2018

Same problem here with K8S 1.10.5 and weave 2.3.0.

The problem is solved temporarily thanks to lastboy1228 (#193 (comment))

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@xingjinglu xingjinglu commented Oct 29, 2018

@pineking yes. It is the cause of network that results into the problem.

Hi, How did you solve the problem? I encounter the same issue too.

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@charles820 charles820 commented Oct 31, 2018

@pineking yes. It is the cause of network that results into the problem.

Hi, How did you solve the problem? I encounter the same issue too.

kubectl delete svc kubernetes

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@ChangjunZhao ChangjunZhao commented Nov 22, 2018

For flannel network add-on to work correctly, you must pass --pod-network-cidr=10.244.0.0/16 to kubeadm init

@mosaicwang mosaicwang mentioned this issue Jan 30, 2019
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@o3o3o o3o3o commented Feb 12, 2019

systemctl stop kubelet
systemctl stop docker
iptables --flush
iptables -tnat --flush
systemctl start kubelet
systemctl start docker

The route problem can be solved by flush iptables.

You may need to execute the below command to ensure that the default policy is ACCEPT, to avoiding you are kicked out of your machine when using ssh.

iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

And then you can safely flush your rules:

iptables -F
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@tnimni tnimni commented Feb 13, 2019

if you are using rancher you can go to kubernetes>infrastructre stacks
search for kubernetes pod and restart it

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@vincent081 vincent081 commented Dec 4, 2019

@WanChengHu 加我QQ看一下 641555100

这个问题解决了吗?我也遇到这个问题.TKS!

go/tools/cache/reflector.go:94: Failed to list *v1.Service: Get https://10.9.0.1:443/api/v1/services?resourceVersion=0: dial tcp 10.9.0.1:443: i/o timeout
E1015 13:25:36.437865 1 reflector.go:199] k8s.io/dns/vendor/k8s.io/client-go/tools/cache/reflector.go:94: Failed to list *v1.Endpoints: Get https://10.96.0.1:443/api/v1/endpoints?resourceVersion=0: dial tcp 10.9.0.1:443: i/o timeout
I1015 13:25:36.937466 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserver...
I1015 13:25:37.437493 1 dns.go:174] Waiting for services and endpoints to be initialized from apiserv

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