Coredns in CrashLoopBackOff (kubernetes 1.11)










2















I'm trying to install kubernetes on an Ubuntu 16.04 VM, followed instructions at https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/, using weave as my pod network add-on.



I'm seeing similar issue as coredns pods have CrashLoopBackOff or Error state, but I didn't see a solution there, and the versions I'm using are different:



kubeadm 1.11.4-00
kubectl 1.11.4-00
kubelet 1.11.4-00
kubernetes-cni 0.6.0-00
Docker version 1.13.1-cs8, build 91ca5f2
weave script 2.5.0
weave 2.5.0


I'm running behind a corporate firewall, so I set my proxy variables, then ran kubeadm init as follows:



# echo $http_proxy
http://135.28.13.11:8080
# echo $https_proxy
http://135.28.13.11:8080
# echo $no_proxy
127.0.0.1,135.21.27.139,135.0.0.0/8,10.96.0.0/12,10.32.0.0/12
# kubeadm init --pod-network-cidr=10.32.0.0/12 
# kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d 'n')" 
# kubectl taint nodes --all node-role.kubernetes.io/master-


Both coredns pods stay in CrashLoopBackOff



# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default hostnames-674b556c4-2b5h2 1/1 Running 0 5h 10.32.0.6 mtpnjvzonap001 <none>
default hostnames-674b556c4-4bzdj 1/1 Running 0 5h 10.32.0.5 mtpnjvzonap001 <none>
default hostnames-674b556c4-64gx5 1/1 Running 0 5h 10.32.0.4 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-s7rvx 0/1 CrashLoopBackOff 18 1h 10.32.0.7 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-vxwgv 0/1 CrashLoopBackOff 80 6h 10.32.0.2 mtpnjvzonap001 <none>
kube-system etcd-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-apiserver-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-controller-manager-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-proxy-2c4tx 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-scheduler-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system weave-net-bpx22 2/2 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>


coredns pods have this entry in their log




E1114 20:59:13.848196 1 reflector.go:205]
github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed
to list *v1.Service: Get
https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0:
dial tcp 10.96.0.1:443: i/o timeout




This suggests to me that coredns cannot access apiserver pod using its cluster IP:



# kubectl describe svc/kubernetes
Name: kubernetes
Namespace: default
Labels: component=apiserver
 provider=kubernetes
Annotations: <none>
Selector: <none>
Type: ClusterIP
IP: 10.96.0.1
Port: https 443/TCP
TargetPort: 6443/TCP
Endpoints: 135.21.27.139:6443
Session Affinity: None
Events: <none>


I also went through the troubleshooting steps at https://kubernetes.io/docs/tasks/debug-application-cluster/troubleshooting/



  • I created a busybox pod for testing

  • I created the hostnames deployment successfully

  • I exposed the hostnames deployment successfully

  • From the busybox pod, I accessed the hostnames service by its cluster IP successfully

  • from the node, I accessed the hostnames service by its cluster IP successfully

So in short, I created the hostnames service which had a cluster IP in 10.96.0.0/12 space (as expected), and it works, but for some reason, pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:



# wget --no-check-certificate https://10.96.0.1/hello
--2018-11-14 21:44:25-- https://10.96.0.1/hello
Connecting to 10.96.0.1:443... connected.
WARNING: cannot verify 10.96.0.1's certificate, issued by ‘CN=kubernetes’:
 Unable to locally verify the issuer's authority.
HTTP request sent, awaiting response... 403 Forbidden
2018-11-14 21:44:25 ERROR 403: Forbidden.


Some other things I checked, based on advice from others who reported a similar problem:



# sysctl net.ipv4.conf.all.forwarding
net.ipv4.conf.all.forwarding = 1
# sysctl net.bridge.bridge-nf-call-iptables
net.bridge.bridge-nf-call-iptables = 1
# iptables-save | egrep ':INPUT|:OUTPUT|:POSTROUTING|:FORWARD'
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [11:692]
:POSTROUTING ACCEPT [11:692]
:INPUT ACCEPT [1697:364811]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1652:363693]
# ls -l /usr/sbin/conntrack
-rwxr-xr-x 1 root root 65632 Jan 24 2016 /usr/sbin/conntrack
# systemctl status firewalld
● firewalld.service
 Loaded: not-found (Reason: No such file or directory)
 Active: inactive (dead)


I checked the log for kube-proxy, did not see any errors.
I also tried deleting coredns pods, apiserver pod; they are recreated (as expected), but the problem remains.



Here's a copy of the log from the weave container



# kubectl logs -n kube-system weave-net-bpx22 weave
DEBU: 2018/11/14 15:56:10.909921 [kube-peers] Checking peer "aa:53:be:75:71:f7" against list &
Peer not in list; removing persisted data
INFO: 2018/11/14 15:56:11.041807 Command line options: map[name:aa:53:be:75:71:f7 nickname:mtpnjvzonap001 ipalloc-init:consensus=1 ipalloc-range:10.32.0.0/12 db-prefix:/weavedb/weave-net docker-api: expect-npc:true host-root:/host http-addr:127.0.0.1:6784 metrics-addr:0.0.0.0:6782 conn-limit:100 datapath:datapath no-dns:true port:6783]
INFO: 2018/11/14 15:56:11.042230 weave 2.5.0
INFO: 2018/11/14 15:56:11.198348 Bridge type is bridged_fastdp
INFO: 2018/11/14 15:56:11.198372 Communication between peers is unencrypted.
INFO: 2018/11/14 15:56:11.203206 Our name is aa:53:be:75:71:f7(mtpnjvzonap001)
INFO: 2018/11/14 15:56:11.203249 Launch detected - using supplied peer list: [135.21.27.139]
INFO: 2018/11/14 15:56:11.216398 Checking for pre-existing addresses on weave bridge
INFO: 2018/11/14 15:56:11.229313 [allocator aa:53:be:75:71:f7] No valid persisted data
INFO: 2018/11/14 15:56:11.233391 [allocator aa:53:be:75:71:f7] Initialising via deferred consensus
INFO: 2018/11/14 15:56:11.233443 Sniffing traffic on datapath (via ODP)
INFO: 2018/11/14 15:56:11.234120 ->[135.21.27.139:6783] attempting connection
INFO: 2018/11/14 15:56:11.234302 ->[135.21.27.139:49182] connection accepted
INFO: 2018/11/14 15:56:11.234818 ->[135.21.27.139:6783|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.234843 ->[135.21.27.139:49182|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.236010 Listening for HTTP control messages on 127.0.0.1:6784
INFO: 2018/11/14 15:56:11.236424 Listening for metrics requests on 0.0.0.0:6782
INFO: 2018/11/14 15:56:11.990529 [kube-peers] Added myself to peer list &[aa:53:be:75:71:f7 mtpnjvzonap001]
DEBU: 2018/11/14 15:56:11.995901 [kube-peers] Nodes that have disappeared: map
10.32.0.1
135.21.27.139
DEBU: 2018/11/14 15:56:12.075738 registering for updates for node delete events
INFO: 2018/11/14 15:56:41.279799 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/14 20:52:47.025412 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 01:46:32.842792 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 09:06:03.624359 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout
INFO: 2018/11/15 14:34:02.070893 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout


Here are the events for the 2 coredns pods



# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-6f9q6
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
41m 20h 245 coredns-78fcdf6894-6f9q6.1568eab25f0acb02 Pod spec.containerscoredns Normal Killing kubelet, mtpnjvzonap001 Killing container with id docker://coredns:Container failed liveness probe.. Container will be killed and recreated.
26m 20h 248 coredns-78fcdf6894-6f9q6.1568ea920f72ddd4 Pod spec.containerscoredns Normal Pulled kubelet, mtpnjvzonap001 Container image "k8s.gcr.io/coredns:1.1.3" already present on machine
5m 20h 1256 coredns-78fcdf6894-6f9q6.1568eaa1fd9216d2 Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2963 coredns-78fcdf6894-6f9q6.1568eb75f2b1af3e Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-skjwz
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
6m 20h 1259 coredns-78fcdf6894-skjwz.1568eaa181fbeffe Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2969 coredns-78fcdf6894-skjwz.1568eb7578188f24 Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
#


Any help or further troubleshooting steps are welcome






kubernetes kubeadm







share|improve this question
























  • Hi jm9816, welcome to SO! I suspect that "pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:" is due to CNI failure. You might want to check your kubectl logs weave-net-bpx22 and see if weave failed to initialize. And in all circumstances, you'll want to check the situation on a Node, and not the master. Good luck!

    – Matthew L Daniel
    Nov 15 '18 at 6:24











  • @jm9816, issue probably connected with CNI as @Matthew L Daniel mentioned. Are you discovering any suspicious events in weave pod? kubectl logs weave-net-bpx22 -n kube-system -c weave; kubectl logs weave-net-bpx22 -n kube-system -c weave-npc

    – mk_sta
    Nov 15 '18 at 11:35












  • @MatthewLDaniel - thanks for the suggestions. I should mention I have a single node cluster. But that shouldn't trigger a problem with coredns, right? About weave: I updated my entry to include the weave container log, if that is of interest. I actually opened an issue with weave, but did not get a resolution. So I decided to try it with flannel. I ran kubeadm reset, rebooted my vm for good measure, then re-ran kubeadm init, ... kubectl apply .. this time, using flannel. Result was the same, coredns in CrashLoopBackOff with same error message.

    – jm9816
    Nov 15 '18 at 17:07







  • 1





    Hi, you can try iptables -P FORWARD ACCEPT to bypass the WeaveNet NPC temporarily.

    – Kitt Hsu
    Nov 16 '18 at 6:58











  • @KittHsu thanks, already have that in place # iptables-save | fgrep ':FORWARD' :FORWARD ACCEPT [0:0]

    – jm9816
    Nov 16 '18 at 19:35
















2















I'm trying to install kubernetes on an Ubuntu 16.04 VM, followed instructions at https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/, using weave as my pod network add-on.



I'm seeing similar issue as coredns pods have CrashLoopBackOff or Error state, but I didn't see a solution there, and the versions I'm using are different:



kubeadm 1.11.4-00
kubectl 1.11.4-00
kubelet 1.11.4-00
kubernetes-cni 0.6.0-00
Docker version 1.13.1-cs8, build 91ca5f2
weave script 2.5.0
weave 2.5.0


I'm running behind a corporate firewall, so I set my proxy variables, then ran kubeadm init as follows:



# echo $http_proxy
http://135.28.13.11:8080
# echo $https_proxy
http://135.28.13.11:8080
# echo $no_proxy
127.0.0.1,135.21.27.139,135.0.0.0/8,10.96.0.0/12,10.32.0.0/12
# kubeadm init --pod-network-cidr=10.32.0.0/12 
# kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d 'n')" 
# kubectl taint nodes --all node-role.kubernetes.io/master-


Both coredns pods stay in CrashLoopBackOff



# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default hostnames-674b556c4-2b5h2 1/1 Running 0 5h 10.32.0.6 mtpnjvzonap001 <none>
default hostnames-674b556c4-4bzdj 1/1 Running 0 5h 10.32.0.5 mtpnjvzonap001 <none>
default hostnames-674b556c4-64gx5 1/1 Running 0 5h 10.32.0.4 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-s7rvx 0/1 CrashLoopBackOff 18 1h 10.32.0.7 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-vxwgv 0/1 CrashLoopBackOff 80 6h 10.32.0.2 mtpnjvzonap001 <none>
kube-system etcd-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-apiserver-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-controller-manager-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-proxy-2c4tx 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-scheduler-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system weave-net-bpx22 2/2 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>


coredns pods have this entry in their log




E1114 20:59:13.848196 1 reflector.go:205]
github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed
to list *v1.Service: Get
https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0:
dial tcp 10.96.0.1:443: i/o timeout




This suggests to me that coredns cannot access apiserver pod using its cluster IP:



# kubectl describe svc/kubernetes
Name: kubernetes
Namespace: default
Labels: component=apiserver
 provider=kubernetes
Annotations: <none>
Selector: <none>
Type: ClusterIP
IP: 10.96.0.1
Port: https 443/TCP
TargetPort: 6443/TCP
Endpoints: 135.21.27.139:6443
Session Affinity: None
Events: <none>


I also went through the troubleshooting steps at https://kubernetes.io/docs/tasks/debug-application-cluster/troubleshooting/



  • I created a busybox pod for testing

  • I created the hostnames deployment successfully

  • I exposed the hostnames deployment successfully

  • From the busybox pod, I accessed the hostnames service by its cluster IP successfully

  • from the node, I accessed the hostnames service by its cluster IP successfully

So in short, I created the hostnames service which had a cluster IP in 10.96.0.0/12 space (as expected), and it works, but for some reason, pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:



# wget --no-check-certificate https://10.96.0.1/hello
--2018-11-14 21:44:25-- https://10.96.0.1/hello
Connecting to 10.96.0.1:443... connected.
WARNING: cannot verify 10.96.0.1's certificate, issued by ‘CN=kubernetes’:
 Unable to locally verify the issuer's authority.
HTTP request sent, awaiting response... 403 Forbidden
2018-11-14 21:44:25 ERROR 403: Forbidden.


Some other things I checked, based on advice from others who reported a similar problem:



# sysctl net.ipv4.conf.all.forwarding
net.ipv4.conf.all.forwarding = 1
# sysctl net.bridge.bridge-nf-call-iptables
net.bridge.bridge-nf-call-iptables = 1
# iptables-save | egrep ':INPUT|:OUTPUT|:POSTROUTING|:FORWARD'
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [11:692]
:POSTROUTING ACCEPT [11:692]
:INPUT ACCEPT [1697:364811]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1652:363693]
# ls -l /usr/sbin/conntrack
-rwxr-xr-x 1 root root 65632 Jan 24 2016 /usr/sbin/conntrack
# systemctl status firewalld
● firewalld.service
 Loaded: not-found (Reason: No such file or directory)
 Active: inactive (dead)


I checked the log for kube-proxy, did not see any errors.
I also tried deleting coredns pods, apiserver pod; they are recreated (as expected), but the problem remains.



Here's a copy of the log from the weave container



# kubectl logs -n kube-system weave-net-bpx22 weave
DEBU: 2018/11/14 15:56:10.909921 [kube-peers] Checking peer "aa:53:be:75:71:f7" against list &
Peer not in list; removing persisted data
INFO: 2018/11/14 15:56:11.041807 Command line options: map[name:aa:53:be:75:71:f7 nickname:mtpnjvzonap001 ipalloc-init:consensus=1 ipalloc-range:10.32.0.0/12 db-prefix:/weavedb/weave-net docker-api: expect-npc:true host-root:/host http-addr:127.0.0.1:6784 metrics-addr:0.0.0.0:6782 conn-limit:100 datapath:datapath no-dns:true port:6783]
INFO: 2018/11/14 15:56:11.042230 weave 2.5.0
INFO: 2018/11/14 15:56:11.198348 Bridge type is bridged_fastdp
INFO: 2018/11/14 15:56:11.198372 Communication between peers is unencrypted.
INFO: 2018/11/14 15:56:11.203206 Our name is aa:53:be:75:71:f7(mtpnjvzonap001)
INFO: 2018/11/14 15:56:11.203249 Launch detected - using supplied peer list: [135.21.27.139]
INFO: 2018/11/14 15:56:11.216398 Checking for pre-existing addresses on weave bridge
INFO: 2018/11/14 15:56:11.229313 [allocator aa:53:be:75:71:f7] No valid persisted data
INFO: 2018/11/14 15:56:11.233391 [allocator aa:53:be:75:71:f7] Initialising via deferred consensus
INFO: 2018/11/14 15:56:11.233443 Sniffing traffic on datapath (via ODP)
INFO: 2018/11/14 15:56:11.234120 ->[135.21.27.139:6783] attempting connection
INFO: 2018/11/14 15:56:11.234302 ->[135.21.27.139:49182] connection accepted
INFO: 2018/11/14 15:56:11.234818 ->[135.21.27.139:6783|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.234843 ->[135.21.27.139:49182|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.236010 Listening for HTTP control messages on 127.0.0.1:6784
INFO: 2018/11/14 15:56:11.236424 Listening for metrics requests on 0.0.0.0:6782
INFO: 2018/11/14 15:56:11.990529 [kube-peers] Added myself to peer list &[aa:53:be:75:71:f7 mtpnjvzonap001]
DEBU: 2018/11/14 15:56:11.995901 [kube-peers] Nodes that have disappeared: map
10.32.0.1
135.21.27.139
DEBU: 2018/11/14 15:56:12.075738 registering for updates for node delete events
INFO: 2018/11/14 15:56:41.279799 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/14 20:52:47.025412 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 01:46:32.842792 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 09:06:03.624359 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout
INFO: 2018/11/15 14:34:02.070893 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout


Here are the events for the 2 coredns pods



# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-6f9q6
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
41m 20h 245 coredns-78fcdf6894-6f9q6.1568eab25f0acb02 Pod spec.containerscoredns Normal Killing kubelet, mtpnjvzonap001 Killing container with id docker://coredns:Container failed liveness probe.. Container will be killed and recreated.
26m 20h 248 coredns-78fcdf6894-6f9q6.1568ea920f72ddd4 Pod spec.containerscoredns Normal Pulled kubelet, mtpnjvzonap001 Container image "k8s.gcr.io/coredns:1.1.3" already present on machine
5m 20h 1256 coredns-78fcdf6894-6f9q6.1568eaa1fd9216d2 Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2963 coredns-78fcdf6894-6f9q6.1568eb75f2b1af3e Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-skjwz
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
6m 20h 1259 coredns-78fcdf6894-skjwz.1568eaa181fbeffe Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2969 coredns-78fcdf6894-skjwz.1568eb7578188f24 Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
#


Any help or further troubleshooting steps are welcome






kubernetes kubeadm







share|improve this question
























  • Hi jm9816, welcome to SO! I suspect that "pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:" is due to CNI failure. You might want to check your kubectl logs weave-net-bpx22 and see if weave failed to initialize. And in all circumstances, you'll want to check the situation on a Node, and not the master. Good luck!

    – Matthew L Daniel
    Nov 15 '18 at 6:24











  • @jm9816, issue probably connected with CNI as @Matthew L Daniel mentioned. Are you discovering any suspicious events in weave pod? kubectl logs weave-net-bpx22 -n kube-system -c weave; kubectl logs weave-net-bpx22 -n kube-system -c weave-npc

    – mk_sta
    Nov 15 '18 at 11:35












  • @MatthewLDaniel - thanks for the suggestions. I should mention I have a single node cluster. But that shouldn't trigger a problem with coredns, right? About weave: I updated my entry to include the weave container log, if that is of interest. I actually opened an issue with weave, but did not get a resolution. So I decided to try it with flannel. I ran kubeadm reset, rebooted my vm for good measure, then re-ran kubeadm init, ... kubectl apply .. this time, using flannel. Result was the same, coredns in CrashLoopBackOff with same error message.

    – jm9816
    Nov 15 '18 at 17:07







  • 1





    Hi, you can try iptables -P FORWARD ACCEPT to bypass the WeaveNet NPC temporarily.

    – Kitt Hsu
    Nov 16 '18 at 6:58











  • @KittHsu thanks, already have that in place # iptables-save | fgrep ':FORWARD' :FORWARD ACCEPT [0:0]

    – jm9816
    Nov 16 '18 at 19:35














2












2








2








I'm trying to install kubernetes on an Ubuntu 16.04 VM, followed instructions at https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/, using weave as my pod network add-on.



I'm seeing similar issue as coredns pods have CrashLoopBackOff or Error state, but I didn't see a solution there, and the versions I'm using are different:



kubeadm 1.11.4-00
kubectl 1.11.4-00
kubelet 1.11.4-00
kubernetes-cni 0.6.0-00
Docker version 1.13.1-cs8, build 91ca5f2
weave script 2.5.0
weave 2.5.0


I'm running behind a corporate firewall, so I set my proxy variables, then ran kubeadm init as follows:



# echo $http_proxy
http://135.28.13.11:8080
# echo $https_proxy
http://135.28.13.11:8080
# echo $no_proxy
127.0.0.1,135.21.27.139,135.0.0.0/8,10.96.0.0/12,10.32.0.0/12
# kubeadm init --pod-network-cidr=10.32.0.0/12 
# kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d 'n')" 
# kubectl taint nodes --all node-role.kubernetes.io/master-


Both coredns pods stay in CrashLoopBackOff



# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default hostnames-674b556c4-2b5h2 1/1 Running 0 5h 10.32.0.6 mtpnjvzonap001 <none>
default hostnames-674b556c4-4bzdj 1/1 Running 0 5h 10.32.0.5 mtpnjvzonap001 <none>
default hostnames-674b556c4-64gx5 1/1 Running 0 5h 10.32.0.4 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-s7rvx 0/1 CrashLoopBackOff 18 1h 10.32.0.7 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-vxwgv 0/1 CrashLoopBackOff 80 6h 10.32.0.2 mtpnjvzonap001 <none>
kube-system etcd-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-apiserver-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-controller-manager-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-proxy-2c4tx 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-scheduler-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system weave-net-bpx22 2/2 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>


coredns pods have this entry in their log




E1114 20:59:13.848196 1 reflector.go:205]
github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed
to list *v1.Service: Get
https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0:
dial tcp 10.96.0.1:443: i/o timeout




This suggests to me that coredns cannot access apiserver pod using its cluster IP:



# kubectl describe svc/kubernetes
Name: kubernetes
Namespace: default
Labels: component=apiserver
 provider=kubernetes
Annotations: <none>
Selector: <none>
Type: ClusterIP
IP: 10.96.0.1
Port: https 443/TCP
TargetPort: 6443/TCP
Endpoints: 135.21.27.139:6443
Session Affinity: None
Events: <none>


I also went through the troubleshooting steps at https://kubernetes.io/docs/tasks/debug-application-cluster/troubleshooting/



  • I created a busybox pod for testing

  • I created the hostnames deployment successfully

  • I exposed the hostnames deployment successfully

  • From the busybox pod, I accessed the hostnames service by its cluster IP successfully

  • from the node, I accessed the hostnames service by its cluster IP successfully

So in short, I created the hostnames service which had a cluster IP in 10.96.0.0/12 space (as expected), and it works, but for some reason, pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:



# wget --no-check-certificate https://10.96.0.1/hello
--2018-11-14 21:44:25-- https://10.96.0.1/hello
Connecting to 10.96.0.1:443... connected.
WARNING: cannot verify 10.96.0.1's certificate, issued by ‘CN=kubernetes’:
 Unable to locally verify the issuer's authority.
HTTP request sent, awaiting response... 403 Forbidden
2018-11-14 21:44:25 ERROR 403: Forbidden.


Some other things I checked, based on advice from others who reported a similar problem:



# sysctl net.ipv4.conf.all.forwarding
net.ipv4.conf.all.forwarding = 1
# sysctl net.bridge.bridge-nf-call-iptables
net.bridge.bridge-nf-call-iptables = 1
# iptables-save | egrep ':INPUT|:OUTPUT|:POSTROUTING|:FORWARD'
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [11:692]
:POSTROUTING ACCEPT [11:692]
:INPUT ACCEPT [1697:364811]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1652:363693]
# ls -l /usr/sbin/conntrack
-rwxr-xr-x 1 root root 65632 Jan 24 2016 /usr/sbin/conntrack
# systemctl status firewalld
● firewalld.service
 Loaded: not-found (Reason: No such file or directory)
 Active: inactive (dead)


I checked the log for kube-proxy, did not see any errors.
I also tried deleting coredns pods, apiserver pod; they are recreated (as expected), but the problem remains.



Here's a copy of the log from the weave container



# kubectl logs -n kube-system weave-net-bpx22 weave
DEBU: 2018/11/14 15:56:10.909921 [kube-peers] Checking peer "aa:53:be:75:71:f7" against list &
Peer not in list; removing persisted data
INFO: 2018/11/14 15:56:11.041807 Command line options: map[name:aa:53:be:75:71:f7 nickname:mtpnjvzonap001 ipalloc-init:consensus=1 ipalloc-range:10.32.0.0/12 db-prefix:/weavedb/weave-net docker-api: expect-npc:true host-root:/host http-addr:127.0.0.1:6784 metrics-addr:0.0.0.0:6782 conn-limit:100 datapath:datapath no-dns:true port:6783]
INFO: 2018/11/14 15:56:11.042230 weave 2.5.0
INFO: 2018/11/14 15:56:11.198348 Bridge type is bridged_fastdp
INFO: 2018/11/14 15:56:11.198372 Communication between peers is unencrypted.
INFO: 2018/11/14 15:56:11.203206 Our name is aa:53:be:75:71:f7(mtpnjvzonap001)
INFO: 2018/11/14 15:56:11.203249 Launch detected - using supplied peer list: [135.21.27.139]
INFO: 2018/11/14 15:56:11.216398 Checking for pre-existing addresses on weave bridge
INFO: 2018/11/14 15:56:11.229313 [allocator aa:53:be:75:71:f7] No valid persisted data
INFO: 2018/11/14 15:56:11.233391 [allocator aa:53:be:75:71:f7] Initialising via deferred consensus
INFO: 2018/11/14 15:56:11.233443 Sniffing traffic on datapath (via ODP)
INFO: 2018/11/14 15:56:11.234120 ->[135.21.27.139:6783] attempting connection
INFO: 2018/11/14 15:56:11.234302 ->[135.21.27.139:49182] connection accepted
INFO: 2018/11/14 15:56:11.234818 ->[135.21.27.139:6783|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.234843 ->[135.21.27.139:49182|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.236010 Listening for HTTP control messages on 127.0.0.1:6784
INFO: 2018/11/14 15:56:11.236424 Listening for metrics requests on 0.0.0.0:6782
INFO: 2018/11/14 15:56:11.990529 [kube-peers] Added myself to peer list &[aa:53:be:75:71:f7 mtpnjvzonap001]
DEBU: 2018/11/14 15:56:11.995901 [kube-peers] Nodes that have disappeared: map
10.32.0.1
135.21.27.139
DEBU: 2018/11/14 15:56:12.075738 registering for updates for node delete events
INFO: 2018/11/14 15:56:41.279799 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/14 20:52:47.025412 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 01:46:32.842792 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 09:06:03.624359 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout
INFO: 2018/11/15 14:34:02.070893 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout


Here are the events for the 2 coredns pods



# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-6f9q6
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
41m 20h 245 coredns-78fcdf6894-6f9q6.1568eab25f0acb02 Pod spec.containerscoredns Normal Killing kubelet, mtpnjvzonap001 Killing container with id docker://coredns:Container failed liveness probe.. Container will be killed and recreated.
26m 20h 248 coredns-78fcdf6894-6f9q6.1568ea920f72ddd4 Pod spec.containerscoredns Normal Pulled kubelet, mtpnjvzonap001 Container image "k8s.gcr.io/coredns:1.1.3" already present on machine
5m 20h 1256 coredns-78fcdf6894-6f9q6.1568eaa1fd9216d2 Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2963 coredns-78fcdf6894-6f9q6.1568eb75f2b1af3e Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-skjwz
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
6m 20h 1259 coredns-78fcdf6894-skjwz.1568eaa181fbeffe Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2969 coredns-78fcdf6894-skjwz.1568eb7578188f24 Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
#


Any help or further troubleshooting steps are welcome






kubernetes kubeadm







share|improve this question
















I'm trying to install kubernetes on an Ubuntu 16.04 VM, followed instructions at https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/, using weave as my pod network add-on.



I'm seeing similar issue as coredns pods have CrashLoopBackOff or Error state, but I didn't see a solution there, and the versions I'm using are different:



kubeadm 1.11.4-00
kubectl 1.11.4-00
kubelet 1.11.4-00
kubernetes-cni 0.6.0-00
Docker version 1.13.1-cs8, build 91ca5f2
weave script 2.5.0
weave 2.5.0


I'm running behind a corporate firewall, so I set my proxy variables, then ran kubeadm init as follows:



# echo $http_proxy
http://135.28.13.11:8080
# echo $https_proxy
http://135.28.13.11:8080
# echo $no_proxy
127.0.0.1,135.21.27.139,135.0.0.0/8,10.96.0.0/12,10.32.0.0/12
# kubeadm init --pod-network-cidr=10.32.0.0/12 
# kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d 'n')" 
# kubectl taint nodes --all node-role.kubernetes.io/master-


Both coredns pods stay in CrashLoopBackOff



# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default hostnames-674b556c4-2b5h2 1/1 Running 0 5h 10.32.0.6 mtpnjvzonap001 <none>
default hostnames-674b556c4-4bzdj 1/1 Running 0 5h 10.32.0.5 mtpnjvzonap001 <none>
default hostnames-674b556c4-64gx5 1/1 Running 0 5h 10.32.0.4 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-s7rvx 0/1 CrashLoopBackOff 18 1h 10.32.0.7 mtpnjvzonap001 <none>
kube-system coredns-78fcdf6894-vxwgv 0/1 CrashLoopBackOff 80 6h 10.32.0.2 mtpnjvzonap001 <none>
kube-system etcd-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-apiserver-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-controller-manager-mtpnjvzonap001 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-proxy-2c4tx 1/1 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>
kube-system kube-scheduler-mtpnjvzonap001 1/1 Running 0 1h 135.21.27.139 mtpnjvzonap001 <none>
kube-system weave-net-bpx22 2/2 Running 0 6h 135.21.27.139 mtpnjvzonap001 <none>


coredns pods have this entry in their log




E1114 20:59:13.848196 1 reflector.go:205]
github.com/coredns/coredns/plugin/kubernetes/controller.go:313: Failed
to list *v1.Service: Get
https://10.96.0.1:443/api/v1/services?limit=500&resourceVersion=0:
dial tcp 10.96.0.1:443: i/o timeout




This suggests to me that coredns cannot access apiserver pod using its cluster IP:



# kubectl describe svc/kubernetes
Name: kubernetes
Namespace: default
Labels: component=apiserver
 provider=kubernetes
Annotations: <none>
Selector: <none>
Type: ClusterIP
IP: 10.96.0.1
Port: https 443/TCP
TargetPort: 6443/TCP
Endpoints: 135.21.27.139:6443
Session Affinity: None
Events: <none>


I also went through the troubleshooting steps at https://kubernetes.io/docs/tasks/debug-application-cluster/troubleshooting/



  • I created a busybox pod for testing

  • I created the hostnames deployment successfully

  • I exposed the hostnames deployment successfully

  • From the busybox pod, I accessed the hostnames service by its cluster IP successfully

  • from the node, I accessed the hostnames service by its cluster IP successfully

So in short, I created the hostnames service which had a cluster IP in 10.96.0.0/12 space (as expected), and it works, but for some reason, pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:



# wget --no-check-certificate https://10.96.0.1/hello
--2018-11-14 21:44:25-- https://10.96.0.1/hello
Connecting to 10.96.0.1:443... connected.
WARNING: cannot verify 10.96.0.1's certificate, issued by ‘CN=kubernetes’:
 Unable to locally verify the issuer's authority.
HTTP request sent, awaiting response... 403 Forbidden
2018-11-14 21:44:25 ERROR 403: Forbidden.


Some other things I checked, based on advice from others who reported a similar problem:



# sysctl net.ipv4.conf.all.forwarding
net.ipv4.conf.all.forwarding = 1
# sysctl net.bridge.bridge-nf-call-iptables
net.bridge.bridge-nf-call-iptables = 1
# iptables-save | egrep ':INPUT|:OUTPUT|:POSTROUTING|:FORWARD'
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [11:692]
:POSTROUTING ACCEPT [11:692]
:INPUT ACCEPT [1697:364811]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [1652:363693]
# ls -l /usr/sbin/conntrack
-rwxr-xr-x 1 root root 65632 Jan 24 2016 /usr/sbin/conntrack
# systemctl status firewalld
● firewalld.service
 Loaded: not-found (Reason: No such file or directory)
 Active: inactive (dead)


I checked the log for kube-proxy, did not see any errors.
I also tried deleting coredns pods, apiserver pod; they are recreated (as expected), but the problem remains.



Here's a copy of the log from the weave container



# kubectl logs -n kube-system weave-net-bpx22 weave
DEBU: 2018/11/14 15:56:10.909921 [kube-peers] Checking peer "aa:53:be:75:71:f7" against list &
Peer not in list; removing persisted data
INFO: 2018/11/14 15:56:11.041807 Command line options: map[name:aa:53:be:75:71:f7 nickname:mtpnjvzonap001 ipalloc-init:consensus=1 ipalloc-range:10.32.0.0/12 db-prefix:/weavedb/weave-net docker-api: expect-npc:true host-root:/host http-addr:127.0.0.1:6784 metrics-addr:0.0.0.0:6782 conn-limit:100 datapath:datapath no-dns:true port:6783]
INFO: 2018/11/14 15:56:11.042230 weave 2.5.0
INFO: 2018/11/14 15:56:11.198348 Bridge type is bridged_fastdp
INFO: 2018/11/14 15:56:11.198372 Communication between peers is unencrypted.
INFO: 2018/11/14 15:56:11.203206 Our name is aa:53:be:75:71:f7(mtpnjvzonap001)
INFO: 2018/11/14 15:56:11.203249 Launch detected - using supplied peer list: [135.21.27.139]
INFO: 2018/11/14 15:56:11.216398 Checking for pre-existing addresses on weave bridge
INFO: 2018/11/14 15:56:11.229313 [allocator aa:53:be:75:71:f7] No valid persisted data
INFO: 2018/11/14 15:56:11.233391 [allocator aa:53:be:75:71:f7] Initialising via deferred consensus
INFO: 2018/11/14 15:56:11.233443 Sniffing traffic on datapath (via ODP)
INFO: 2018/11/14 15:56:11.234120 ->[135.21.27.139:6783] attempting connection
INFO: 2018/11/14 15:56:11.234302 ->[135.21.27.139:49182] connection accepted
INFO: 2018/11/14 15:56:11.234818 ->[135.21.27.139:6783|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.234843 ->[135.21.27.139:49182|aa:53:be:75:71:f7(mtpnjvzonap001)]: connection shutting down due to error: cannot connect to ourself
INFO: 2018/11/14 15:56:11.236010 Listening for HTTP control messages on 127.0.0.1:6784
INFO: 2018/11/14 15:56:11.236424 Listening for metrics requests on 0.0.0.0:6782
INFO: 2018/11/14 15:56:11.990529 [kube-peers] Added myself to peer list &[aa:53:be:75:71:f7 mtpnjvzonap001]
DEBU: 2018/11/14 15:56:11.995901 [kube-peers] Nodes that have disappeared: map
10.32.0.1
135.21.27.139
DEBU: 2018/11/14 15:56:12.075738 registering for updates for node delete events
INFO: 2018/11/14 15:56:41.279799 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/14 20:52:47.025412 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 01:46:32.842792 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 74.125.196.121:443: i/o timeout
INFO: 2018/11/15 09:06:03.624359 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout
INFO: 2018/11/15 14:34:02.070893 Error checking version: Get https://checkpoint-api.weave.works/v1/check/weave-net?arch=amd64&flag_docker-version=none&flag_kernel-version=4.4.0-135-generic&flag_kubernetes-cluster-size=1&flag_kubernetes-cluster-uid=ce66cb23-e825-11e8-abc3-525400314503&flag_kubernetes-version=v1.11.4&os=linux&signature=EJdydeNysrC7LC5xAJAKyDvxXCvkeWUFzepdk3QDfr0%3D&version=2.5.0: dial tcp 172.217.9.147:443: i/o timeout


Here are the events for the 2 coredns pods



# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-6f9q6
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
41m 20h 245 coredns-78fcdf6894-6f9q6.1568eab25f0acb02 Pod spec.containerscoredns Normal Killing kubelet, mtpnjvzonap001 Killing container with id docker://coredns:Container failed liveness probe.. Container will be killed and recreated.
26m 20h 248 coredns-78fcdf6894-6f9q6.1568ea920f72ddd4 Pod spec.containerscoredns Normal Pulled kubelet, mtpnjvzonap001 Container image "k8s.gcr.io/coredns:1.1.3" already present on machine
5m 20h 1256 coredns-78fcdf6894-6f9q6.1568eaa1fd9216d2 Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2963 coredns-78fcdf6894-6f9q6.1568eb75f2b1af3e Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
# kubectl get events -n kube-system --field-selector involvedObject.name=coredns-78fcdf6894-skjwz
LAST SEEN FIRST SEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
6m 20h 1259 coredns-78fcdf6894-skjwz.1568eaa181fbeffe Pod spec.containerscoredns Warning Unhealthy kubelet, mtpnjvzonap001 Liveness probe failed: HTTP probe failed with statuscode: 503
1m 19h 2969 coredns-78fcdf6894-skjwz.1568eb7578188f24 Pod spec.containerscoredns Warning BackOff kubelet, mtpnjvzonap001 Back-off restarting failed container
#


Any help or further troubleshooting steps are welcome






kubernetes kubeadm




kubernetes kubeadm






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 21 '18 at 15:21







jm9816

















asked Nov 14 '18 at 22:27









jm9816jm9816

112




112












  • Hi jm9816, welcome to SO! I suspect that "pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:" is due to CNI failure. You might want to check your kubectl logs weave-net-bpx22 and see if weave failed to initialize. And in all circumstances, you'll want to check the situation on a Node, and not the master. Good luck!

    – Matthew L Daniel
    Nov 15 '18 at 6:24











  • @jm9816, issue probably connected with CNI as @Matthew L Daniel mentioned. Are you discovering any suspicious events in weave pod? kubectl logs weave-net-bpx22 -n kube-system -c weave; kubectl logs weave-net-bpx22 -n kube-system -c weave-npc

    – mk_sta
    Nov 15 '18 at 11:35












  • @MatthewLDaniel - thanks for the suggestions. I should mention I have a single node cluster. But that shouldn't trigger a problem with coredns, right? About weave: I updated my entry to include the weave container log, if that is of interest. I actually opened an issue with weave, but did not get a resolution. So I decided to try it with flannel. I ran kubeadm reset, rebooted my vm for good measure, then re-ran kubeadm init, ... kubectl apply .. this time, using flannel. Result was the same, coredns in CrashLoopBackOff with same error message.

    – jm9816
    Nov 15 '18 at 17:07







  • 1





    Hi, you can try iptables -P FORWARD ACCEPT to bypass the WeaveNet NPC temporarily.

    – Kitt Hsu
    Nov 16 '18 at 6:58











  • @KittHsu thanks, already have that in place # iptables-save | fgrep ':FORWARD' :FORWARD ACCEPT [0:0]

    – jm9816
    Nov 16 '18 at 19:35


















  • Hi jm9816, welcome to SO! I suspect that "pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:" is due to CNI failure. You might want to check your kubectl logs weave-net-bpx22 and see if weave failed to initialize. And in all circumstances, you'll want to check the situation on a Node, and not the master. Good luck!

    – Matthew L Daniel
    Nov 15 '18 at 6:24











  • @jm9816, issue probably connected with CNI as @Matthew L Daniel mentioned. Are you discovering any suspicious events in weave pod? kubectl logs weave-net-bpx22 -n kube-system -c weave; kubectl logs weave-net-bpx22 -n kube-system -c weave-npc

    – mk_sta
    Nov 15 '18 at 11:35












  • @MatthewLDaniel - thanks for the suggestions. I should mention I have a single node cluster. But that shouldn't trigger a problem with coredns, right? About weave: I updated my entry to include the weave container log, if that is of interest. I actually opened an issue with weave, but did not get a resolution. So I decided to try it with flannel. I ran kubeadm reset, rebooted my vm for good measure, then re-ran kubeadm init, ... kubectl apply .. this time, using flannel. Result was the same, coredns in CrashLoopBackOff with same error message.

    – jm9816
    Nov 15 '18 at 17:07







  • 1





    Hi, you can try iptables -P FORWARD ACCEPT to bypass the WeaveNet NPC temporarily.

    – Kitt Hsu
    Nov 16 '18 at 6:58











  • @KittHsu thanks, already have that in place # iptables-save | fgrep ':FORWARD' :FORWARD ACCEPT [0:0]

    – jm9816
    Nov 16 '18 at 19:35

















Hi jm9816, welcome to SO! I suspect that "pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:" is due to CNI failure. You might want to check your kubectl logs weave-net-bpx22 and see if weave failed to initialize. And in all circumstances, you'll want to check the situation on a Node, and not the master. Good luck!

– Matthew L Daniel
Nov 15 '18 at 6:24





Hi jm9816, welcome to SO! I suspect that "pods cannot access the apiserver's cluster IP of 10.96.0.1, though from the node I can access 10.96.0.1:" is due to CNI failure. You might want to check your kubectl logs weave-net-bpx22 and see if weave failed to initialize. And in all circumstances, you'll want to check the situation on a Node, and not the master. Good luck!

– Matthew L Daniel
Nov 15 '18 at 6:24













@jm9816, issue probably connected with CNI as @Matthew L Daniel mentioned. Are you discovering any suspicious events in weave pod? kubectl logs weave-net-bpx22 -n kube-system -c weave; kubectl logs weave-net-bpx22 -n kube-system -c weave-npc

– mk_sta
Nov 15 '18 at 11:35






@jm9816, issue probably connected with CNI as @Matthew L Daniel mentioned. Are you discovering any suspicious events in weave pod? kubectl logs weave-net-bpx22 -n kube-system -c weave; kubectl logs weave-net-bpx22 -n kube-system -c weave-npc

– mk_sta
Nov 15 '18 at 11:35














@MatthewLDaniel - thanks for the suggestions. I should mention I have a single node cluster. But that shouldn't trigger a problem with coredns, right? About weave: I updated my entry to include the weave container log, if that is of interest. I actually opened an issue with weave, but did not get a resolution. So I decided to try it with flannel. I ran kubeadm reset, rebooted my vm for good measure, then re-ran kubeadm init, ... kubectl apply .. this time, using flannel. Result was the same, coredns in CrashLoopBackOff with same error message.

– jm9816
Nov 15 '18 at 17:07






@MatthewLDaniel - thanks for the suggestions. I should mention I have a single node cluster. But that shouldn't trigger a problem with coredns, right? About weave: I updated my entry to include the weave container log, if that is of interest. I actually opened an issue with weave, but did not get a resolution. So I decided to try it with flannel. I ran kubeadm reset, rebooted my vm for good measure, then re-ran kubeadm init, ... kubectl apply .. this time, using flannel. Result was the same, coredns in CrashLoopBackOff with same error message.

– jm9816
Nov 15 '18 at 17:07





1




1





Hi, you can try iptables -P FORWARD ACCEPT to bypass the WeaveNet NPC temporarily.

– Kitt Hsu
Nov 16 '18 at 6:58





Hi, you can try iptables -P FORWARD ACCEPT to bypass the WeaveNet NPC temporarily.

– Kitt Hsu
Nov 16 '18 at 6:58













@KittHsu thanks, already have that in place # iptables-save | fgrep ':FORWARD' :FORWARD ACCEPT [0:0]

– jm9816
Nov 16 '18 at 19:35






@KittHsu thanks, already have that in place # iptables-save | fgrep ':FORWARD' :FORWARD ACCEPT [0:0]

– jm9816
Nov 16 '18 at 19:35













0






active

oldest

votes











Your Answer






StackExchange.ifUsing("editor", function ()
StackExchange.using("externalEditor", function ()
StackExchange.using("snippets", function ()
StackExchange.snippets.init();
);
);
, "code-snippets");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "1"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);













draft saved

draft discarded


















StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53309671%2fcoredns-in-crashloopbackoff-kubernetes-1-11%23new-answer', 'question_page');

);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes















draft saved

draft discarded
















































Thanks for contributing an answer to Stack Overflow!


  • Please be sure to answer the question. Provide details and share your research!

But avoid …


  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.

To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53309671%2fcoredns-in-crashloopbackoff-kubernetes-1-11%23new-answer', 'question_page');

);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







-

這個網誌中的熱門文章

Barbados

圖片
For other uses, see Barbados (disambiguation). Not to be confused with Barbuda. Coordinates: 13°10′N 59°33′W  /  13.167°N 59.550°W  / 13.167; -59.550 Barbados Flag Coat of arms Motto:  "Pride and Industry" Anthem:  In Plenty and In Time of Need Capital and largest city Bridgetown 13°06′N 59°37′W  /  13.100°N 59.617°W  / 13.100; -59.617 Official languages English Recognised regional languages Bajan Creole Ethnic groups (est. 2010 [1] ) 92.4% black 3.1% multiracial 2.7% white 1.3% East Indian 0.5% other/unspecified Religion 75.6% Christian 2.5% other 20.6% none 1.2% unspecified [1] Demonym(s) Barbadian Bajan (colloquial) Government Unitary parliamentary constitutional monarchy • Monarch Elizabeth II •  Governor-General Dame Sandra Mason • Prime Minister Mia Mottley Legislature Parliament • Upper house Senate • Lower house House of Assembly Independence • From the United Kingdom 30 November 1966 Area • Total 439 km 2 (169 sq mi) (183rd) • Water (%) Negligib
閱讀完整內容

How to read a connectionString WITH PROVIDER in .NET Core?

圖片
6 I added .AddJsonFile("Connections.json", optional: true, reloadOnChange: true) in public Startup(IHostingEnvironment env) Connections.json contains: "ConnectionStrings": "DefaultConnection": "Server=(localdb)\mssqllocaldb;Database=DATABASE;Trusted_Connection=True;MultipleActiveResultSets=true", "COR-W81-101": "Data Source=DATASOURCE;Initial Catalog=P61_CAFM_Basic;User Id=USERID;Password=PASSWORD;Persist Security Info=False;MultipleActiveResultSets=False;Packet Size=4096;", "COR-W81-100": "Data Source=DATASOURCE;Initial Catalog=Post_PS;User Id=USERID;Password=PASSWORD;Persist Security Info=False;MultipleActiveResultSets=False;Packet Size=4096;", "MSEDGEWIN10": "Data Source=DATASOURCE; Initial Catalog=COR_Basic; Persist Security Info=False;Integrated Security=true;MultipleActiveResultSets=False;Packet Size=4096;Application Name="COR_Basic"", "server&qu
閱讀完整內容

Node.js Script on GitHub Pages or Amazon S3

圖片
0 I'm wondering if I can run a Node.js script in my Jekyll page from GitHub Pages or Amazon S3? I think it can't run on GitHub Pages since it doesn't support server side code. Not too sure. The code is below: var Airtable = require('airtable'); var base = new Airtable(apiKey: 'YOUR_API_KEY').base('appAnZVyYqusNPV5Q'); base('Invitee list').select( // Selecting the first 3 records in Complete list: maxRecords: 3, view: "Complete list" ).eachPage(function page(records, fetchNextPage) // This function (`page`) will get called for each page of records. records.forEach(function(record) console.log('Retrieved', record.get('Email')); ); // To fetch the next page of records, call `fetchNextPage`. // If there are more records, `page` will get called again. // If there are no more records, `done` will get called. fetchNextPage(); , function done(err) if (err) console.error(err); return; ); node.js
閱讀完整內容