I am not exactly sure what's going on which is why I am asking this question. When I run this command:
kubectl config get-clusters
I get:
arn:aws:eks:us-west-2:91xxxxx371:cluster/eks-cluster-1
arn:aws:eks:us-west-2:91xxxxx371:cluster/eks1
then I run:
kubectl config current-context
and I get:
arn:aws:eks:us-west-2:91xxxxx371:cluster/eks-cluster-1
and if I run kubectl get pods, I get the expected output.
But how do I switch to the other cluster/context? what's the difference between the cluster and context? I can't figure out how these commands differ:
When I run them, I still get the pods from the wrong cluster:
root#4c2ab870baaf:/# kubectl config set-context arn:aws:eks:us-west-2:913617820371:cluster/eks1
Context "arn:aws:eks:us-west-2:913617820371:cluster/eks1" modified.
root#4c2ab870baaf:/#
root#4c2ab870baaf:/# kubectl get pods
NAME READY STATUS RESTARTS AGE
apache-spike-579598949b-5bjjs 1/1 Running 0 14d
apache-spike-579598949b-957gv 1/1 Running 0 14d
apache-spike-579598949b-k49hf 1/1 Running 0 14d
root#4c2ab870baaf:/# kubectl config set-cluster arn:aws:eks:us-west-2:91xxxxxx371:cluster/eks1
Cluster "arn:aws:eks:us-west-2:91xxxxx371:cluster/eks1" set.
root#4c2ab870baaf:/# kubectl get pods
NAME READY STATUS RESTARTS AGE
apache-spike-579598949b-5bjjs 1/1 Running 0 14d
apache-spike-579598949b-957gv 1/1 Running 0 14d
apache-spike-579598949b-k49hf 1/1 Running 0 14d
so I really don't know how to properly switch between clusters or contexts and also switch the auth routine when doing so.
For example:
contexts:
- context:
cluster: arn:aws:eks:us-west-2:91xxxxx371:cluster/ignitecluster
user: arn:aws:eks:us-west-2:91xxxx371:cluster/ignitecluster
name: arn:aws:eks:us-west-2:91xxxxx371:cluster/ignitecluster
- context:
cluster: arn:aws:eks:us-west-2:91xxxx371:cluster/teros-eks-cluster
user: arn:aws:eks:us-west-2:91xxxxx371:cluster/teros-eks-cluster
name: arn:aws:eks:us-west-2:91xxxxx371:cluster/teros-eks-cluster
To clarify on the difference between set-context and use-context
A context is a group of access parameters. Each context contains a Kubernetes cluster, a user, and a namespace. So when you do set-context, you just adding context details to your configuration file ~/.kube/config, but it doesn't switch you to that context, while use-context actually does.
Thus, as Vasily mentioned, in order to switch between clusters run
kubectl config use-context <CONTEXT-NAME>
Also, if you run kubectl config get-contexts you will see list of contexts with indication of the current one.
Use
kubectl config use-context arn:aws:eks:us-west-2:91xxxxx371:cluster/eks-cluster-1
and
kubectl config use-context arn:aws:eks:us-west-2:91xxxxx371:cluster/eks
Consider using kubectx for managing your contexts.
Usage
View all contexts (the current context is bolded):
$kubectx
arn:aws:eks:us-east-1:12234567:cluster/eks_app
->gke_my_second_cluster
my-rnd
my-prod
Switch to other context:
$ kubectx my-rnd
Switched to context "my-rnd".
Bonus:
In the same link - check also the kubens tool.
This is the best command to switch between different EKS clusters.
I use it every day.
aws eks update-kubeconfig --name example
Documentation:
https://docs.aws.amazon.com/cli/latest/reference/eks/update-kubeconfig.html
Related
I am trying to deploy the aws-load-balancer-controller on my Kubernetes cluster on AWS = by following the steps given in https://docs.aws.amazon.com/eks/latest/userguide/aws-load-balancer-controller.html
After the yaml file is applied and while trying to check the status of the deployment , I get :
$ kubectl get deployment -n kube-system aws-load-balancer-controller
NAME READY UP-TO-DATE AVAILABLE AGE
aws-load-balancer-controller 0/1 1 0 6m39s
I tried to debug it and I got this :
$ kubectl logs -n kube-system deployment.apps/aws-load-balancer-controller
{"level":"info","logger":"controller-runtime.metrics","msg":"metrics server is starting to listen","addr":":8080"}
{"level":"error","logger":"setup","msg":"unable to create controller","controller":"Ingress","error":"the server could not find the requested resource"}
The yaml file is pulled directly from https://github.com/kubernetes-sigs/aws-load-balancer-controller/releases/download/v2.3.0/v2_3_0_full.yaml and apart from changing the Kubernetes cluster name, no other modifications are done.
Please let me know if I am missing some step in the configuration.
Any help would be highly appreciated.
I am not sure if this helps, but for me the issue was that the version of the aws-load-balancer-controller was not compatible with the version of Kubernetes.
aws-load-balancer-controller = v2.3.1
Kubernetes/EKS = 1.22
Github issue for more information:
https://github.com/kubernetes-sigs/aws-load-balancer-controller/issues/2495
root#x:~# kubectl get pods -A -o wide| grep nic
a k-e-f-v1-k-e-nic-s-r8tjn 1/1 Running 1 5d11h 192.168.99.1 master.k <none> <none>
a k-e-f-v1-k-e-nic-s-w6tk8 1/1 Running 0 5d11h 192.168.99.231 e-519-19121100100009 <none> <none>
a k-e-f-v1-k-e-nic-s-z8pmq 1/1 Running 0 5d11h 192.168.99.127 e-519-19121100100008 <none> <none>
want to restart all the pods other than the master in namespace a from the above result.
Is there can be a single syntax to do it?
Do those pods have any specific labels that can be used for identifying them ? If they are not labelled so far, I would recommend you to do that as grep-ing for a specific string in their names is neither very convinient nor elegant solution. And for sure you cannot select pods that contain a specific string in their name with pure kubectl command, without using an external tool like grep.
As to selecting all pods (either in a specific --namespace or in --all-namespaces), running on all nodes except the specific one, it can be done quite easily by using negation in --field-selector:
The following command will list Pods from --all-namespaces, running on any node other than master. Additionally it will list only Pods that are labelled with the key app and the value nginx:
kubectl get pods --all-namespaces -o wide --field-selector spec.nodeName!=master --selector=app=nginx
If you want to delete such Pods, run:
kubectl delete pods --all-namespaces --field-selector spec.nodeName!=master --selector=app=nginx
As you may know, deletion of Pods is basically the same as restarting/rebooting them. If those Pods are managed e.g. by a Deployment they will be simply recreated after deletion.
If you really have to use grep to search for a specific string in names of your Pods, you can use a fairly simple script to delete such specific Pods:
kubectl get pods --all-namespaces -o name --field-selector spec.nodeName!=master | grep nic | xargs kubectl delete
But as you can see, the above command is way more complicated than a single kubectl delete that uses a --selector flag to filter out only Pods with specific labels. This one uses grep, xargs, two pipes and two separate kubectl command runs.
I'm trying to create AWS ALB-Ingress through EKS following the steps in the document https://docs.aws.amazon.com/eks/latest/userguide/alb-ingress.html
I was successful till the step 7 in creating the controller:
[ec2-user#ip-X-X-X-X eks-cluster]$ kubectl apply -f v2_0_0_full.yaml
customresourcedefinition.apiextensions.k8s.io/targetgroupbindings.elbv2.k8s.aws created
mutatingwebhookconfiguration.admissionregistration.k8s.io/aws-load-balancer-webhook created
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
serviceaccount/aws-load-balancer-controller configured
role.rbac.authorization.k8s.io/aws-load-balancer-controller-leader-election-role created
clusterrole.rbac.authorization.k8s.io/aws-load-balancer-controller-role created
rolebinding.rbac.authorization.k8s.io/aws-load-balancer-controller-leader-election-rolebinding created
clusterrolebinding.rbac.authorization.k8s.io/aws-load-balancer-controller-rolebinding created
service/aws-load-balancer-webhook-service created
deployment.apps/aws-load-balancer-controller created
certificate.cert-manager.io/aws-load-balancer-serving-cert created
issuer.cert-manager.io/aws-load-balancer-selfsigned-issuer created
validatingwebhookconfiguration.admissionregistration.k8s.io/aws-load-balancer-webhook created
However, the controller does NOT get to "Ready" status:
[ec2-user#ip-X-X-X-X eks-cluster]$ kubectl get deployment -n kube-system aws-load-balancer-controller
NAME READY UP-TO-DATE AVAILABLE AGE
aws-load-balancer-controller 0/1 1 0 29m
I'm also able to list the pod associated with the controller which also shows NOT READY:
[ec2-user#ip-X-X-X-X eks-cluster]$ kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
aws-load-balancer-controller-XXXXXXXXXX-p4l7f 0/1 Pending 0 30m
I also can't seem to get its logs in order to try and debug the issue:
[ec2-user#ip-X-X-X-X eks-cluster]$ kubectl -n kube-system logs aws-load-balancer-controller-XXXXXXXXXX-p4l7f
[ec2-user#ip-X-X-X-X eks-cluster]$
Furthermore, the /var/log directory also does not have any related logs.
Please help me understand why it is not coming to READY state. Also let me know how to enable logging to debug these kind of issues.
I found the answer here. A faragate deployment requires the region and vpc-id.
helm upgrade -i aws-load-balancer-controller eks/aws-load-balancer-controller \
--set clusterName=<cluster-name> \
--set serviceAccount.create=false \
--set region=<region-code> \
--set vpcId=<vpc-xxxxxxxx>> \
--set serviceAccount.name=aws-load-balancer-controller \
-n kube-system
From the current LB conntroller manifest I found out that LB controller Pod specification doesn't have Readiness probe, only Liveness probe. That means that the Pod becomes Ready as soon as it pass the Liveness probe:
livenessProbe:
failureThreshold: 2
httpGet:
path: /healthz
port: 61779
scheme: HTTP
initialDelaySeconds: 30
timeoutSeconds: 10
But as we can see in the following output, LB controller's Pod is in Pending state:
[ec2-user#ip-X-X-X-X eks-cluster]$ kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
aws-load-balancer-controller-XXXXXXXXXX-p4l7f 0/1 Pending 0 30m
If Pod stays in Pending state, it means that kube-scheduler is unable to bind the Pod to a cluster node for whatever reason.
Kube-scheduler is a part of Kubernetes control plain that is responsible for assigning Pods to Nodes.
No Pod logs exist at this phase, because Pod's containers are not started yet.
The most convenient way to check the reason is using the kubectl describe command:
kubectl describe pod/podname -n namespacename
On the bottom of the output there are list of events related to the Pod life cycle. Here is an example for the generic Ubuntu Pod:
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 37s default-scheduler Successfully assigned default/ubuntu to k8s-w1
Normal Pulling 25s (x2 over 35s) kubelet, k8s-w1 Pulling image "ubuntu"
Normal Pulled 23s (x2 over 30s) kubelet, k8s-w1 Successfully pulled image "ubuntu"
Normal Created 23s (x2 over 30s) kubelet, k8s-w1 Created container ubuntu
Normal Started 23s (x2 over 29s) kubelet, k8s-w1 Started container ubuntu
kubectl get events command can also show the problem. For example:
LAST SEEN TYPE REASON OBJECT MESSAGE
21s Normal Scheduled pod/ubuntu Successfully assigned default/ubuntu to k8s-w1
9s Normal Pulling pod/ubuntu Pulling image "ubuntu"
7s Normal Pulled pod/ubuntu Successfully pulled image "ubuntu"
7s Normal Created pod/ubuntu Created container ubuntu
7s Normal Started pod/ubuntu Started container ubuntu
or there could be a reason why Scheduler can't assign Pod to a Node:
"No nodes are available that match all of the predicates: Insufficient cpu (2), Insufficient memory (2)".
In some cases errors could be found in kube-scheduler Pod logs in kube-system namespace. The logs could be listed using the following command:
kubectl logs $(kubectl get pods -l component=kube-scheduler,tier=control-plane -n kube-system -o name) -n kube-system
Most common reasons why pod isn't scheduled are the following:
lack of CPU or memory resources requested by a Pod on the Nodes.
Pod cannot tolerate Taints on the Nodes
Pod have Affinity/AntiAffinity configuration that prevents it from scheduling
Storage or other specific resource (like GPU) requirements in Pod spec cannot be satisfied
I am trying my hands on Kubernetes and I tried to deploy an image into k8s service
root#KubernetesMiniKube:/usr/local/bin# kubectl run hello-minikube --image=k8s.gcr.io/echoserver:1.10 --port=8080
pod/hello-minikube created
root#KubernetesMiniKube:/usr/local/bin# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-minikube 1/1 Running 0 16s
root#KubernetesMiniKube:/usr/local/bin# kubectl get deployments
No resources found in default namespace.
Why i am seeing No resource found but actually there is a resource running inside default namespace.
When you are using $ kubectl run it will create a pod.
In your example thats exactly what happned, it created pod, named hello-minikube.
pod/hello-minikube created
If you want to create deployment
Deployments represent a set of multiple, identical Pods with no unique identities. A Deployment runs multiple replicas of your application and automatically replaces any instances that fail or become unresponsive.
you can do it using command:
$ kubectl create deployment hello-minikube --image=k8s.gcr.io/echoserver:1.10 --port=8080
deployment.apps/hello-minikube created
user#cloudshell:$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
hello-minikube 1/1 1 1 8s
You can also create deployment using YAML.
Save YAML from this documentation example and use kubectl apply.
$ vi nginx.yaml
<paste proper YAML definition. Also you can use nano editor, or download ready yaml>
user#cloudshell:$ kubectl apply -f nginx.yaml
deployment.apps/nginx-deployment created
$ kubectl get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
hello-minikube 1/1 1 1 3m48s
nginx-deployment 3/3 3 3 64s
Please let me know if you have further questions regarding this answer.
Background
We're using Jenkins to deploy a new version of a Kubernetes (k8s) replication controller to our test or prod cluster. The test and prod (k8s) clusters are located under different (google cloud platform) projects. We have configured two profiles for our gcloud SDK on Jenkins, one for test (test-profile) and one for prod (prod-profile). We have defined a managed script in Jenkins that performs the rolling update for our replication controller. The problems is that I cannot find a way to control to which project I want to target the kubectl rolling-update command (you can specify which cluster but not which project afict). So right now our script that does the rolling update to our test server looks something like this:
gcloud config configurations activate test-profile && kubectl rolling-update ...
While this works it could be extremely dangerous if two jobs run concurrently for different environments. Say that job 1 targets the test environment and job 2 targets prod. If job2 switches the active profile to "prod-profile" before job 1 has executed its rolling-update command job 1 will target to wrong project and in worse case update the wrong replication controller (if the clusters have the same name).
Question
Is there a way to specify which project that a kubectl command is targeting (for example during a rolling update) that is safe to run concurrently?
You can pass the --cluster= or --context= flags to kubectl to set a single run. For example, if I have two clusters in my ~/.kube/config "foo" and "bar":
$ kubectl --cluster=foo get pods
NAME READY STATUS RESTARTS AGE
foo-ht1qh 1/1 Running 0 3h
foo-wf8f4 1/1 Running 0 3h
foo-yvgpd 1/1 Running 0 3h
vs
$ kubectl --cluster=bar get pods
NAME READY STATUS RESTARTS AGE
bar-de4h7 1/1 Running 0 9h
bar-c4g03 1/1 Running 0 9h
bar-2sprd 1/1 Running 0 9h
You may use gcloud config set project yourProject to set the project property. See https://cloud.google.com/sdk/gcloud/reference/config/set