I want to configure Kubernetes Dashboard on a remote server using this guide: https://k21academy.com/docker-kubernetes/kubernetes-dashboard/
I installed it using:
kubernetes#kubernetes1:~$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.6.1/aio/deploy/recommended.yaml
List service:
kubernetes#kubernetes1:~$ kubectl get all -n kubernetes-dashboard
NAME READY STATUS RESTARTS AGE
pod/dashboard-metrics-scraper-64bcc67c9c-q8f7j 1/1 Running 0 71m
pod/kubernetes-dashboard-66c887f759-pq58q 1/1 Running 0 71m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/dashboard-metrics-scraper ClusterIP 10.105.143.75 <none> 8000/TCP 71m
service/kubernetes-dashboard ClusterIP 10.102.209.213 <none> 443/TCP 71m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/dashboard-metrics-scraper 1/1 1 1 71m
deployment.apps/kubernetes-dashboard 1/1 1 1 71m
NAME DESIRED CURRENT READY AGE
replicaset.apps/dashboard-metrics-scraper-64bcc67c9c 1 1 1 71m
replicaset.apps/kubernetes-dashboard-66c887f759 1 1 1 71m
kubernetes#kubernetes1:~$
But when I try to edit the port according to the guide I get:
kubernetes#kubernetes1:~$ kubectl edit service/kubernetes-dashboard
Error from server (NotFound): services "kubernetes-dashboard" not found
kubernetes#kubernetes1:~$
Do you know how I can change the port?
Seems like you are looking into default or some other namespace.
you can try
kubectl edit service/kubernetes-dashboard -n kubernetes-dashboard
A nice tool for namespace switching
curl -LO https://github.com/kvaps/kubectl-use/raw/master/kubectl-use
chmod +x ./kubectl-use
sudo mv ./kubectl-use /usr/local/bin/kubectl-use
then
kubectl use kubernetes-dashboard
After this, you do not need to specify namespace -n kubernetes-dashboard in the edit command, or kubectl get pods, it will use kubernetes-dashboard as a default context.
kubectl-use
Related
I tried to deploy nginx server using kubernetes. I was able to create deployment and thn create service. But when i gave the curl command im facing an error. Im not able to curl and open nginx webpage in browser.
Below are the commands i used and error i got.
kubectl get pods
NAME READY STATUS RESTARTS AGE
curl 1/1 Running 8 15d
curl-deployment-646445496f-59fs9 1/1 Running 7 15d
hello-5d448ffc76-cwzcl 1/1 Running 13 23d
hello-node-7567d9fdc9-ffdkx 1/1 Running 8 20d
my-nginx-5b6fb7fb46-bdzdq 0/1 ContainerCreating 0 15d
mytestwebapp 1/1 Running 10 21d
nginx-6799fc88d8-w76cb 1/1 Running 5 13d
nginx-deployment-66b6c48dd5-9mkh8 1/1 Running 12 23d
nginx-test-795d659f45-d9shx 1/1 Running 4 13d
rss-site-7b6794856f-9586w 2/2 Running 40 15d
rss-site-7b6794856f-z59vn 2/2 Running 78 21d
jit#jit-Vostro-15-3568:~$ kubectl logs webserver
Error from server (NotFound): pods "webserver" not found
jit#jit-Vostro-15-3568:~$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
hello-node LoadBalancer 10.104.134.171 <pending> 8080:31733/TCP 13d
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 23d
my-nginx NodePort 10.103.114.92 <none> 8080:32563/TCP,443:32397/TCP 15d
nginx NodePort 10.110.113.60 <none> 80:30985/TCP 13d
nginx-test NodePort 10.109.16.192 <none> 8080:31913/TCP 13d
jit#jit-Vostro-15-3568:~$ curl kube-worker-1:30985
curl: (6) Could not resolve host: kube-worker-1
As you can see you have pod called nginx, that indicates that you have had nginx server already deployed in pod on your cluster. You don't have pod called webserver that's why you're getting
Error from server (NotFound): pods "webserver" not found error.
Also to access nginx service try to pass curl it via ip:port:
$ curl 10.110.113.60:30985
If you point a web browser to http://IP_OF_NODE:ASSIGNED_PORT (where IP_OF_NODE is an IP address of one of your nodes and ASSIGNED_PORT is the port assigned during the create service command), you should see the NGINX Welcome page!
Take a look: nginx-app-kubernetes.
I tried the above scenario locally.
do a kubectl describe svc <svc-name>
check whether it have any end-points.
probably it doesn't have any endpoints
I have a Cassandra/Kubernetes cluster on GCP
manuchadha25#cloudshell:~ (copper-frame-262317)$ kubectl get statefulsets --all-namespaces
NAMESPACE NAME READY AGE
cass-operator cluster1-dc1-default-sts 3/3 2d9h
manuchadha25#cloudshell:~ (copper-frame-262317)$ kubectl get all -n cass-operator
NAME READY STATUS RESTARTS AGE
pod/cass-operator-5f8cdf99fc-9c5g4 1/1 Running 0 2d9h
pod/cluster1-dc1-default-sts-0 2/2 Running 0 2d9h
pod/cluster1-dc1-default-sts-1 2/2 Running 0 2d9h
pod/cluster1-dc1-default-sts-2 2/2 Running 0 2d9h
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/cass-operator-metrics ClusterIP 10.51.243.147 <none> 8383/TCP,8686/TCP 2d9h
service/cassandra-loadbalancer LoadBalancer 10.51.240.24 34.91.214.233 9042:30870/TCP 37h
service/cassandradatacenter-webhook-service ClusterIP 10.51.243.86 <none> 443/TCP 2d9h
service/cluster1-dc1-all-pods-service ClusterIP None <none> <none> 2d9h
service/cluster1-dc1-service ClusterIP None <none> 9042/TCP,8080/TCP 2d9h
service/cluster1-seed-service ClusterIP None <none> <none> 2d9h
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/cass-operator 1/1 1 1 2d9h
NAME DESIRED CURRENT READY AGE
replicaset.apps/cass-operator-5f8cdf99fc 1 1 1 2d9h
NAME READY AGE
statefulset.apps/cluster1-dc1-default-sts 3/3 2d9h
manuchadha25#cloudshell:~ (copper-frame-262317)$
I want to scale it down from 3 nodes to 2 nodes. I am tried running the following commands but both failed.
manuchadha25#cloudshell:~ (copper-frame-262317)$ kubectl scale statefulsets cluster1-dc1-default-sts --replicas=2
Error from server (NotFound): statefulsets.apps "cluster1-dc1-default-sts" not found
What is the right command to scale down cluster?
Use -n parameter to specify correct namespace where the statfulset is deployed. Without the namespace it's trying to delete from default namespace where the statfulset cluster1-dc1-default-sts does not exist.
kubectl scale statefulsets cluster1-dc1-default-sts --replicas=2 -n cass-operator
Execute command in correct namespace using -n parameter (-n cass-operator in your case)
kubectl scale statefulsets cluster1-dc1-default-sts --replicas=2 -n cass-operator
You can also change namespace for all subsequent commands using
kubectl config set-context --current --namespace=cass-operator
I've installed Kubernetes on ubuntu 18.04 using this article. Everything is working fine and then I tried to install Kubernetes dashboard with these instructions.
Now when I am trying to run kubectl proxy then the dashboard is not cumming up and it gives following error message in the browser when trying to access it using default kubernetes-dashboard URL.
http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "no endpoints available for service \"https:kubernetes-dashboard:\"",
"reason": "ServiceUnavailable",
"code": 503
}
Following commands give this output where kubernetes-dashboard shows status as CrashLoopBackOff
$> kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
default amazing-app-rs-59jt9 1/1 Running 5 23d
default amazing-app-rs-k6fg5 1/1 Running 5 23d
default amazing-app-rs-qd767 1/1 Running 5 23d
default amazingapp-one-deployment-57dddd6fb7-xdxlp 1/1 Running 5 23d
default nginx-86c57db685-vwfzf 1/1 Running 4 22d
kube-system coredns-6955765f44-nqphx 0/1 Running 14 25d
kube-system coredns-6955765f44-psdv4 0/1 Running 14 25d
kube-system etcd-master-node 1/1 Running 8 25d
kube-system kube-apiserver-master-node 1/1 Running 42 25d
kube-system kube-controller-manager-master-node 1/1 Running 11 25d
kube-system kube-flannel-ds-amd64-95lvl 1/1 Running 8 25d
kube-system kube-proxy-qcpqm 1/1 Running 8 25d
kube-system kube-scheduler-master-node 1/1 Running 11 25d
kubernetes-dashboard dashboard-metrics-scraper-7b64584c5c-kvz5d 1/1 Running 0 41m
kubernetes-dashboard kubernetes-dashboard-566f567dc7-w2sbk 0/1 CrashLoopBackOff 12 41m
$> kubectl get services --all-namespaces
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes ClusterIP ---------- <none> 443/TCP 25d
default nginx NodePort ---------- <none> 80:32188/TCP 22d
kube-system kube-dns ClusterIP ---------- <none> 53/UDP,53/TCP,9153/TCP 25d
kubernetes-dashboard dashboard-metrics-scraper ClusterIP ---------- <none> 8000/TCP 24d
kubernetes-dashboard kubernetes-dashboard ClusterIP ---------- <none> 443/TCP 24d
$ kubectl get services --all-namespaces
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes ClusterIP ====== <none> 443/TCP 25d
default nginx NodePort ====== <none> 80:32188/TCP 22d
kube-system kube-dns ClusterIP ====== <none> 53/UDP,53/TCP,9153/TCP 25d
kubernetes-dashboard dashboard-metrics-scraper ClusterIP ====== <none> 8000/TCP 24d
kubernetes-dashboard kubernetes-dashboard ClusterIP ====== <none> 443/TCP 24d
$ kubectl get events -n kubernetes-dashboard
LAST SEEN TYPE REASON OBJECT MESSAGE
24m Normal Pulling pod/kubernetes-dashboard-566f567dc7-w2sbk Pulling image "kubernetesui/dashboard:v2.0.0-rc2"
4m46s Warning BackOff pod/kubernetes-dashboard-566f567dc7-w2sbk Back-off restarting failed container
$ kubectl describe services kubernetes-dashboard -n kubernetes-dashboard
Name: kubernetes-dashboard
Namespace: kubernetes-dashboard
Labels: k8s-app=kubernetes-dashboard
Annotations: kubectl.kubernetes.io/last-applied-configuration:
{"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"k8s-app":"kubernetes-dashboard"},"name":"kubernetes-dashboard"...
Selector: k8s-app=kubernetes-dashboard
Type: ClusterIP
IP: 10.96.241.62
Port: <unset> 443/TCP
TargetPort: 8443/TCP
Endpoints:
Session Affinity: None
Events: <none>
$ kubectl logs kubernetes-dashboard-566f567dc7-w2sbk -n kubernetes-dashboard
> 2020/01/29 16:00:34 Starting overwatch 2020/01/29 16:00:34 Using
> namespace: kubernetes-dashboard 2020/01/29 16:00:34 Using in-cluster
> config to connect to apiserver 2020/01/29 16:00:34 Using secret token
> for csrf signing 2020/01/29 16:00:34 Initializing csrf token from
> kubernetes-dashboard-csrf secret panic: Get
> https://10.96.0.1:443/api/v1/namespaces/kubernetes-dashboard/secrets/kubernetes-dashboard-csrf:
> dial tcp 10.96.0.1:443: i/o timeout
>
> goroutine 1 [running]:
> github.com/kubernetes/dashboard/src/app/backend/client/csrf.(*csrfTokenManager).init(0xc0003dac80)
> /home/travis/build/kubernetes/dashboard/src/app/backend/client/csrf/manager.go:40
> +0x3b4 github.com/kubernetes/dashboard/src/app/backend/client/csrf.NewCsrfTokenManager(...)
> /home/travis/build/kubernetes/dashboard/src/app/backend/client/csrf/manager.go:65
> github.com/kubernetes/dashboard/src/app/backend/client.(*clientManager).initCSRFKey(0xc000534200)
> /home/travis/build/kubernetes/dashboard/src/app/backend/client/manager.go:494
> +0xc7 github.com/kubernetes/dashboard/src/app/backend/client.(*clientManager).init(0xc000534200)
> /home/travis/build/kubernetes/dashboard/src/app/backend/client/manager.go:462
> +0x47 github.com/kubernetes/dashboard/src/app/backend/client.NewClientManager(...)
> /home/travis/build/kubernetes/dashboard/src/app/backend/client/manager.go:543
> main.main()
> /home/travis/build/kubernetes/dashboard/src/app/backend/dashboard.go:105
> +0x212
Any suggestions to fix this? Thanks in advance.
I noticed that the guide You used to install kubernetes cluster is missing one important part.
According to kubernetes documentation:
For flannel to work correctly, you must pass --pod-network-cidr=10.244.0.0/16 to kubeadm init.
Set /proc/sys/net/bridge/bridge-nf-call-iptables to 1 by running sysctl net.bridge.bridge-nf-call-iptables=1 to pass bridged IPv4 traffic to iptables’ chains. This is a requirement for some CNI plugins to work, for more information please see here.
Make sure that your firewall rules allow UDP ports 8285 and 8472 traffic for all hosts participating in the overlay network. see here .
Note that flannel works on amd64, arm, arm64, ppc64le and s390x under Linux. Windows (amd64) is claimed as supported in v0.11.0 but the usage is undocumented.
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml
For more information about flannel, see the CoreOS flannel repository on GitHub .
To fix this:
I suggest using the command:
sysctl net.bridge.bridge-nf-call-iptables=1
And then reinstall flannel:
kubectl delete -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Update: After verifying the the /proc/sys/net/bridge/bridge-nf-call-iptables value is 1 by default ubuntu-18-04-lts. So issue here is You need to access the dashboard locally.
If You are connected to Your master node via ssh. It could be possible to use -X flag with ssh in order to launch we browser via ForwardX11. Fortunately ubuntu-18-04-lts has it turned on by default.
ssh -X server
Then install local web browser like chromium.
sudo apt-get install chromium-browser
chromium-browser
And finally access the dashboard locally from node.
http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/
Hope it helps.
Per the documentation at: https://kubernetes.io/docs/tasks/web-ui-dashboard/
I ran :
kubectl create -f https://rawgit.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml
Then I tried running this to expose the service
cluster/kubectl.sh expose svc/kubernetes
but I keep getting an error:
error: couldn't retrieve selectors via --selector flag or introspection: the service has no pod selector set
See 'kubectl expose -h' for help and examples.
I have looked at the examples but can't understand what I am doing wrong.
kubernetes# cluster/kubectl.sh get all
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
svc/kubernetes 10.0.0.1 <none> 443/TCP 7h
kubernetes# cluster/kubectl.sh get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system kube-dns-806549836-r6wtk 0/3 Pending 0 7h
kube-system kubernetes-dashboard-2396447444-9675d 0/1 Pending 0 6h
To get access to the dashboard, usually you would just type:
kubectl cluster-info
Which then gives you all the required urls for accessing your cluster.
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.