Kubernetes Pods Always ContainerCreating - kubernetes

I have installed a cluster of one master and one node using kubadm
kubeadm version: &version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.0", GitCommit:"fc32d2f3698e36b93322a3465f63a14e9f0eaead", GitTreeState:"clean", BuildDate:"2018-03-26T16:44:10Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}
Whenever I try and install a pod (ngix, gafana, influxdb, heapster, tiller), it always stays in a state of ContainerCreating.
I can't figure out how to diagnose the issue to try and get the containers to move to a Running state.

Use the following commands to check logs of Kubelet and diagnose the issue accordingly:
systemctl status kubelet
journalctl -xeu kubelet
For details:
https://kubernetes.io/docs/tasks/debug-application-cluster/debug-cluster/

Related

In K8s find what nodes do pods exist in

I want to know what nodes correspond to pods in a K8s cluster. I am working with a 3 node K8s cluster which has 2 specific pods among other pods.
How can I see which pod exists in which node using kubectl?
When I use kubectl get pods, I get the following:
NAME READY STATUS RESTARTS AGE
pod1-7485f58945-zq8tg 1/1 Running 2 2d
pod2-64c4564b5c-8rh5x 1/1 Running 0 2d1h
Following is the version of K8s (kubectl version) that I am using
Client Version: version.Info{Major:"1", Minor:"20", GitVersion:"v1.20.0", GitCommit:"af46c47ce925f4c4ad5cc8d1fca46c7b77d13b38", GitTreeState:"clean", BuildDate:"2020-12-08T17:59:43Z", GoVersion:"go1.15.5", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.13", GitCommit:"53c7b65d4531a749cd3a7004c5212d23daa044a9", GitTreeState:"clean", BuildDate:"2021-07-15T20:53:19Z", GoVersion:"go1.15.14", Compiler:"gc", Platform:"linux/amd64"}
Try kubectl get pods -o wide.
You can get more details in this very detailed Kubernetes cheatsheet.

kubernetes can not join workers centos 7

My issue is that I can not connect between our machines (master and slaves)
My connection command should be
kubeadm join xxx:xxx:xxx:xxx:6443 --token a72x22.ofmqdjyzi7ot4l70 --discovery-token-ca-cert-hash sha256:3cfd9ddb1e655ef2172c12d914e2bb001434cc4c8a756919a7a6a9f0603e3131
I have been execute
echo 1 >/proc/sys/net/bridge/bridge-nf-call-iptables
echo 1 >/proc/sys/net/ipv4/ip_forward
swapoff -a
and I got the error
[kubelet-start] Downloading configuration for the kubelet from the
"kubelet-config-1.15" ConfigMap in the kube-system namespace error
execution phase kubelet-start: configmaps "kubelet-config-1.15" is
forbidden: User "system:bootstrap:a61x22" can
not get resource "configmaps" in API group "" in the namespace
"kube-system"
master kubectl version
Client Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.0", GitCommit:"e8462b5b5dc2584fdcd18e6bcfe9f1e4d970a529", GitTreeState:"clean", BuildDate:"2019-06-19T16:40:16Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"} Server Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.3", GitCommit:"5e53fd6bc17c0dec8434817e69b04a25d8ae0ff0", GitTreeState:"clean", BuildDate:"2019-06-06T01:36:19Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
slaves kubectl version
Client Version: version.Info{Major:"1", Minor:"15", GitVersion:"v1.15.0", GitCommit:"e8462b5b5dc2584fdcd18e6bcfe9f1e4d970a529", GitTreeState:"clean", BuildDate:"2019-06-19T16:40:16Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
The connection to the server localhost:8080 was refused - did you specify the right host or port?
maybe my issue is connected to the host or port?
how can I solve this issue?
Check if configmaps "kubelet-config-1.15" exists with the command below.
kubectl -n kube-system get configmap kubelet-config-1.15
Maybe your master is at version 1.14 and your new node downloaded a kubelet version 1.15.
In that case your configmap didn't exists and you have a configmap kubelet-config-1.14.
Upgrade your master node to v 1.15 or install kubernetes v1.14 into your worker node.
You can see what version your nodes are with
kubectl get nodes
[root#master /]# k get nodes
NAME STATUS ROLES AGE VERSION
master Ready master 32d v1.14.0
node6 Ready 32d v1.14.2
nodo2 Ready 32d v1.14.2

Kubernetes version upgraded, but kubectl showing different versions

I just upgraded kubernetes cluster, but kubectl is very inconsistent in showing me the version. How can I verify this. Any source of truth?
[iahmad#web-prod-ijaz001 k8s-test]$ kubectl version
Client Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.3", GitCommit:"5e53fd6bc17c0dec8434817e69b04a25d8ae0ff0", GitTreeState:"clean", BuildDate:"2019-06-06T01:44:30Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"14", GitVersion:"v1.14.3", GitCommit:"5e53fd6bc17c0dec8434817e69b04a25d8ae0ff0", GitTreeState:"clean", BuildDate:"2019-06-06T01:36:19Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}
[iahmad#web-prod-ijaz001 k8s-test]$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
wp-np3-0b Ready worker 55d v1.14.1
wp-np3-0f Ready worker 55d v1.14.1
wp-np3-45 Ready master 104d v1.13.5
wp-np3-46 Ready worker 104d v1.13.5
wp-np3-47 Ready worker 104d v1.13.5
wp-np3-48 Ready worker 43d v1.14.1
wp-np3-49 Ready worker 95d v1.13.5
wp-np3-76 Ready worker 55d v1.14.1
[iahmad#web-prod-ijaz001 k8s-test]$
IIRC: kubectl version is telling you what version the APIServer is at (1.14.3). kubectl get nodes is telling you what version the kubelet is on those nodes.

kubectl losing connection to minikube

I am using
*$ minikube version
minikube version: v0.28.2
and
*$ kubectl version
Client Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.3", GitCommit:"a4529464e4629c21224b3d52edfe0ea91b072862", GitTreeState:"clean", BuildDate:"2018-09-09T18:02:47Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.0", GitCommit:"fc32d2f3698e36b93322a3465f63a14e9f0eaead", GitTreeState:"clean", BuildDate:"2018-03-26T16:44:10Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}
I am running a local cluster, while all of the sudden communication between the cluster and kubectl gets lost:
*$ kubectl get pods
No resources found.
Error from server (Timeout): the server was unable to return a response in the time allotted, but may still be processing the request (get pods)
The problem goes away after performing an explicit minikube stop && minikube start
Any ideas how to debug this?
It sounds to be a problem with your kubectl version.
When I have a server version too old, I usually download a kubectl of the same version.
Here the link (linux version):
curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.10.0/bin/linux/amd64/kubectl
The problem had to do with resources.
Resolved by stopping minikube and then starting it like this:
minikube --memory 8192 --cpus 2 start
This thread was helpful.

kubectl describe nodes, reports some error

I am gettting this error in kubectl describe nodes nodename. I just did a google search but nothing useful found , what does this mean.
Failed to update Node Allocatable Limits "": failed to set supported cgroup subsystems for cgroup : Failed to set config for supported subsystems : failed to write 3783778304 to memory.limit_in_bytes: write /rootfs/sys/fs/cgroup/memory/memory.limit_in_bytes: invalid argument
Do I need to change some kernel settings using sysctl ?
[iahmad#lxplus000 ~]$ kubectl --version
Kubernetes v1.5.2
[iahmad#lxplus000 ~]$
[iahmad#lxplus000 ~]$
[iahmad#lxplus000 ~]$ kubectl version
Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"269f928217957e7126dc87e6adfa82242bfe5b1e", GitTreeState:"clean", BuildDate:"2017-07-03T15:31:10Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.6", GitCommit:"4bc5e7f9a6c25dc4c03d4d656f2cefd21540e28c", GitTreeState:"clean", BuildDate:"2017-09-18T08:52:26Z", GoVersion:"go1.9", Compiler:"gc", Platform:"linux/amd64"}
[iahmad#lxplus000 ~]$
It depends on the kubectl/kubernetes version: this was seen (and fixed) in kubernetes issue 42701
1.6 should have been patched.
If this is not the same bug, the error message was also seen in issue 29166:
I just forgot to active back disk.uuid after creating back my new VMs!