This is a really odd issue I've started to experience. Everything was working with out issue, however, now when I startup a cluster (kubeadm), setup flannel, kube-dns never starts up. Eventually, it errors out with the following output from kubectl describe
Error: failed to start container "sidecar": Error response from daemon: {"message":"invalid header field value \"oci runtime error: container_linux.go:240: creating new parent process caused \\\"container_linux.go:1245: running lstat on namespace path \\\\\\\"/proc/7420/ns/ipc\\\\\\\" caused \\\\\\\"lstat /proc/7420/ns/ipc: no such file or directory\\\\\\\"\\\"\\n\""}
Any ideas what this error really means? I get the same looking error for dnsmasq and kubedns as well.
I am using the switch "--pod-network-cidr 10.244.0.0/16" as always. As I said ,this was working, and then a few days later, it's not....
Here's the get pods output:
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-machiato-0 1/1 Running 0 3m
kube-system kube-apiserver-machiato-0 1/1 Running 0 3m
kube-system kube-controller-manager-machiato-0 1/1 Running 0 2m
kube-system kube-dns-2258483030-pd8qj 0/3 ContainerCreating 0 3m
kube-system kube-flannel-ds-0z0dd 2/2 Running 0 1m
kube-system kube-flannel-ds-3dccg 2/2 Running 0 1m
kube-system kube-proxy-gc8ft 1/1 Running 0 3m
kube-system kube-proxy-tjgzn 1/1 Running 0 1m
kube-system kube-scheduler-machiato-0 1/1 Running 0 3m
Eventually, "ContainerCreating" switches to "CrashLoopBackOff" then I see the lstat error above.
most likely its overlay network issue. can you check the dns pods log message and see any error message?
kubectl logs -n kube-system kube-dns-2258483030-pd8qj -c kubedns
kubectl logs -n kube-system kube-dns-2258483030-pd8qj -c dnsmasq
kubectl logs -n kube-system kube-dns-2258483030-pd8qj -c sidecar
Related
I'm trying to understand how kubernetes works, so I tried to do this operation for my minikube:
~ kubectl delete pod --all -n kube-system
pod "coredns-f9fd979d6-5n4b6" deleted
pod "etcd-minikube" deleted
pod "kube-apiserver-minikube" deleted
pod "kube-controller-manager-minikube" deleted
pod "kube-proxy-879lg" deleted
pod "kube-scheduler-minikube" deleted
It's okay. Pods deleted as wish. But if I do kubectl get pods -n kube-system I will see:
NAME READY STATUS RESTARTS AGE
coredns-f9fd979d6-5d25r 1/1 Running 0 50s
etcd-minikube 1/1 Running 0 50s
kube-apiserver-minikube 1/1 Running 0 50s
kube-controller-manager-minikube 1/1 Running 0 50s
kube-proxy-nlw69 1/1 Running 0 43s
kube-scheduler-minikube 1/1 Running 0 49s
Okay. I thought it's ReplicaSet or DaemonSet:
➜ ~ kubectl get ds -n kube-system
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE
kube-proxy 1 1 1 1 1 kubernetes.io/os=linux 18m
➜ ~ kubectl get rs -n kube-system
NAME DESIRED CURRENT READY AGE
coredns-f9fd979d6 1 1 1 18m
It is true for coredns and kube-proxy. But what about others (apiserver, etcd, controller and scheduler)? Why are they still alive?
The control plane pods are run as static Pods - static Pods are not managed by the control plane controllers like e.g. DaemonSet and ReplicaSet. Static pods are instead managed by the Kubelet daemon on the local node directly.
I am following this tutorial: https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/
I have created the memory pod demo and I am trying to get the metrics from the pod but it is not working.
I installed the metrics server by cloning: https://github.com/kubernetes-incubator/metrics-server
And then running this command from top level:
kubectl create -f deploy/1.8+/
I am using kubernetes version 1.10.11.
The pod is definitely created:
λ kubectl get pod memory-demo --namespace=mem-example
NAME READY STATUS RESTARTS AGE
memory-demo 1/1 Running 0 6m
But the metics command does not work and gives an error:
λ kubectl top pod memory-demo --namespace=mem-example
Error from server (NotFound): podmetrics.metrics.k8s.io "mem-example/memory-demo" not found
What did I do wrong?
There are some patches to be done to metrics server deployment to get the metrics working.
Follow the below steps
kubectl delete -f deploy/1.8+/
wait till the metrics server gets undeployed
run the below command
kubectl create -f https://raw.githubusercontent.com/epasham/docker-repo/master/k8s/metrics-server.yaml
master $ kubectl get po -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-78fcdf6894-6zg78 1/1 Running 0 2h
coredns-78fcdf6894-gk4sb 1/1 Running 0 2h
etcd-master 1/1 Running 0 2h
kube-apiserver-master 1/1 Running 0 2h
kube-controller-manager-master 1/1 Running 0 2h
kube-proxy-f5z9p 1/1 Running 0 2h
kube-proxy-ghbvn 1/1 Running 0 2h
kube-scheduler-master 1/1 Running 0 2h
metrics-server-85c54d44c8-rmvxh 2/2 Running 0 1m
weave-net-4j7cl 2/2 Running 1 2h
weave-net-82fzn 2/2 Running 1 2h
master $ kubectl top pod -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-78fcdf6894-6zg78 2m 11Mi
coredns-78fcdf6894-gk4sb 2m 9Mi
etcd-master 14m 90Mi
kube-apiserver-master 24m 425Mi
kube-controller-manager-master 26m 62Mi
kube-proxy-f5z9p 2m 19Mi
kube-proxy-ghbvn 3m 17Mi
kube-scheduler-master 8m 14Mi
metrics-server-85c54d44c8-rmvxh 1m 19Mi
weave-net-4j7cl 2m 59Mi
weave-net-82fzn 1m 60Mi
Check and verify the below lines in metrics server deployment manifest.
command:
- /metrics-server
- --metric-resolution=30s
- --kubelet-preferred-address-types=InternalIP
- --kubelet-insecure-tls
On Minikube, I had to wait for 20-25 minutes after enabling the metrics-server addon. I was getting the same error for 20-25 minutes but later I could see the output without attempting for any solution.
I faced the similar issue of
Error from server (NotFound): podmetrics.metrics.k8s.io "default/apple-app" not found
I followed two steps and I was able to resolve the issue.
Download the latest customized components.yaml, which is their official file used for easy deployment.
Update the change
# - /metrics-server
- --kubelet-insecure-tls
- --kubelet-preferred-address-types=InternalIP
to the command section of the deployment specification. I have commented the first line because it is the entrypoint of the image used by kubernetes metrics-server.
$ docker image inspect k8s.gcr.io/metrics-server-amd64:v0.3.6 -f {{.ContainerConfig.Entrypoint}}
[/metrics-server]
Even If you use it or not, it doesn't matter.
Note: You have to wait for few seconds for it to properly work.
After this running the top command will work for you.
$ kubectl top pod apple-app
NAME CPU(cores) MEMORY(bytes)
apple-app 1m 3Mi
I know this is an old thread may be someone will find this answer useful.
You have to checkout the following repo:
https://github.com/kubernetes-incubator/metrics-server
Go to the root of the repo and checkout release-0.3.2.
Remove default metrics server by:
kubectl delete -f deploy/1.8+/
Download the container yaml
wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.6/components.yaml
Edit the container.yaml by adding the following lines to the argument section. You will see these two lines there
args:
- --kubelet-preferred-address-types=InternalIP
- --kubelet-insecure-tls=true
There is only one args parameter in that file.
Deploy your pod/deployment and you should be able to do:
kubectl top pod <pod-name>
I have just started a new Kubernetes 1.8.0 environment using minikube (0.27) on Windows 10.
I followed this steps but it didn't work:
https://kubernetes.io/docs/tasks/access-application-cluster/web-ui-dashboard/
When I list pods this is the result:
C:\WINDOWS\system32>kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-minikube 1/1 Running 0 23m
kube-system heapster-69b5d4974d-s9vrf 1/1 Running 0 5m
kube-system kube-addon-manager-minikube 1/1 Running 0 23m
kube-system kube-apiserver-minikube 1/1 Running 0 23m
kube-system kube-controller-manager-minikube 1/1 Running 0 23m
kube-system kube-dns-545bc4bfd4-xkt7l 3/3 Running 3 1h
kube-system kube-proxy-7jnk6 1/1 Running 0 23m
kube-system kube-scheduler-minikube 1/1 Running 0 23m
kube-system kubernetes-dashboard-5569448c6d-8zqnc 1/1 Running 2 52m
kube-system kubernetes-dashboard-869db7f6b4-ddlmq 0/1 CrashLoopBackOff 19 51m
kube-system monitoring-influxdb-78d4c6f5b6-b66m9 1/1 Running 0 4m
kube-system storage-provisioner 1/1 Running 2 1h
As you can see, I have 2 kubernets-dashboard pods now, one of then is running and the other one is CrashLookBackOff.
When I try to run minikube dashboard this is the result:
"Waiting, endpoint for service is not ready yet..."
I have tried to remove kubernetes-dashboard-869db7f6b4-ddlmq pod:
kubectl delete pod kubernetes-dashboard-869db7f6b4-ddlmq
This is the result:
"Error from server (NotFound): pods "kubernetes-dashboard-869db7f6b4-ddlmq" not found"
"Error from server (NotFound): pods "kubernetes-dashboard-869db7f6b4-ddlmq" not found"
You failed to delete the pod due to the lack of namespace (add -n kube-system). And it should be 1 dashboard pod if no modification's applied. If it still fails to run minikube dashboard after you delete the abnormal pod, more logs should be provided.
I followed the guide on "Using kubeadm to Create a Cluster" but I am not able to view logs using kubectl:
root#o1:~# kubectl logs -n kube-system etcd-o1
Error from server: Get https://149.156.11.4:10250/containerLogs/kube-system/etcd-o1/etcd: tls: first record does not look like a TLS handshake
The above IP address is the cloud frontend address not the address of the VM which probably causes the problem. Some other kubectl cmds seem to work:
root#o1:~# kubectl cluster-info
Kubernetes master is running at https://10.6.16.88:6443
KubeDNS is running at https://10.6.16.88:6443/api/v1/namespaces/kube-system/services/kube-dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
root#o1:~# kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-o1 1/1 Running 0 3h
kube-system kube-apiserver-o1 1/1 Running 0 3h
kube-system kube-controller-manager-o1 1/1 Running 0 3h
kube-system kube-dns-545bc4bfd4-mhbfb 3/3 Running 0 3h
kube-system kube-flannel-ds-lw87h 2/2 Running 0 1h
kube-system kube-flannel-ds-rkqxg 2/2 Running 2 1h
kube-system kube-proxy-hnhfs 1/1 Running 0 3h
kube-system kube-proxy-qql4r 1/1 Running 0 1h
kube-system kube-scheduler-o1 1/1 Running 0 3h
Please help.
Maybe change the address in the $HOME/admin.conf.
I am probably missing some of the basic. kubectl logs command usage is the following:
"kubectl logs [-f] [-p] POD [-c CONTAINER] [options]"
list of my pods is the following:
ubuntu#master:~$ kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-master 1/1 Running 0 24m
kube-system kube-apiserver-master 1/1 Running 0 24m
kube-system kube-controller-manager-master 1/1 Running 0 24m
kube-system kube-discovery-982812725-3kt85 1/1 Running 0 24m
kube-system kube-dns-2247936740-kimly 3/3 Running 0 24m
kube-system kube-proxy-amd64-gwv99 1/1 Running 0 20m
kube-system kube-proxy-amd64-r08h9 1/1 Running 0 24m
kube-system kube-proxy-amd64-szl6w 1/1 Running 0 14m
kube-system kube-scheduler-master 1/1 Running 0 24m
kube-system kubernetes-dashboard-1655269645-x3uyt 1/1 Running 0 24m
kube-system weave-net-4g1g8 1/2 CrashLoopBackOff 7 14m
kube-system weave-net-8zdm3 1/2 CrashLoopBackOff 8 20m
kube-system weave-net-qm3q5 2/2 Running 0 24m
I assume POD for logs command is anything from the second "name" column above. So, I try the following commands.
ubuntu#master:~$ kubectl logs etcd-master
Error from server: pods "etcd-master" not found
ubuntu#master:~$ kubectl logs weave-net-4g1g8
Error from server: pods "weave-net-4g1g8" not found
ubuntu#master:~$ kubectl logs weave-net
Error from server: pods "weave-net" not found
ubuntu#master:~$ kubectl logs weave
Error from server: pods "weave" not found
So, what is the POD in the logs command?
I have got the same question about services as well. How to identify a SERVICE to supply into a command, for example for 'describe' command?
ubuntu#master:~$ kubectl get services --all-namespaces
NAMESPACE NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes 100.64.0.1 <none> 443/TCP 40m
kube-system kube-dns 100.64.0.10 <none> 53/UDP,53/TCP 39m
kube-system kubernetes-dashboard 100.70.83.136 <nodes> 80/TCP 39m
ubuntu#master:~$ kubectl describe service kubernetes-dashboard
Error from server: services "kubernetes-dashboard" not found
ubuntu#master:~$ kubectl describe services kubernetes-dashboard
Error from server: services "kubernetes-dashboard" not found
Also, is it normal that weave-net-8zdm3 is in CrashLoopBackOff state? It seems I have got one for each connected worker. If it is not normal, how can I fix it? I have found similar question here: kube-dns and weave-net not starting but it does not give any practical answer.
Thanks for your help!
It seems you are running your pods in a different namespace than default.
ubuntu#master:~$ kubectl get pods --all-namespaces returns your pods but ubuntu#master:~$ kubectl logs etcd-masterreturns not found. Try running kubectl logs etcd-master --all-namespaces or if you know your namespace kubectl logs etcd-mastern --namespace=mynamespace.
The same thing goes for your services.