I have a Kubernetes cluster, in which different pods are running in different namespaces. How do I know if any pod failed?
Is there any single command to check the failed pod list or restated pod list?
And reason for the restart(logs)?
Depends if you want to have detailed information or you just want to check a few last failed pods.
I would recommend you to read about Logging Architecture.
In case you would like to have this detailed information you should use 3rd party software, as its described in Kubernetes Documentation - Logging Using Elasticsearch and Kibana or another one FluentD.
If you are using Cloud environment you can use Integrated with Cloud Logging tools (i.e. in Google Cloud Platform you can use Stackdriver).
In case you want to check logs to find reason why pod failed, it's good described in K8s docs Debug Running Pods.
If you want to get logs from specific pod
$ kubectl logs ${POD_NAME} -n {NAMESPACE}
First, look at the logs of the affected container:
$ kubectl logs ${POD_NAME} ${CONTAINER_NAME}
If your container has previously crashed, you can access the previous container's crash log with:
$ kubectl logs --previous ${POD_NAME} ${CONTAINER_NAME}
Additional information you can obtain using
$ kubectl get events -o wide --all-namespaces | grep <your condition>
Similar question was posted in this SO thread, you can check if for more details.
This'll work: kubectl get pods --all-namespaces | | grep -Ev '([0-9]+)/\1'
Also, Lens is pretty good in these situations.
Most of the times, the reason for app failure is printed in the lasting logs of the previous pod. You can see them by simply putting --previous flag along with your kubectl logs ... cmd.
Related
My software has a dashboard and there is system information (CPU, Ram, Disk). But in kubernetes pods completely Worker resources appear. How should my approach be here? As far as I researched, pods not has its assigned resources.
There are multiple ways please check based on your preference:
You can use this way by k9s which is very easy way to check all the details.
Or if you want to check them manually
Go to pod's exec mode kubectl exec -it pod_name -n namespace -- /bin/bash
Run cat /sys/fs/cgroup/cpu/cpuacct.usage for cpu usage
Run cat /sys/fs/cgroup/memory/memory.usage_in_bytes for memory usage
or
Deploying the dashboard is not default you can get by below command:
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.7.0/aio/deploy/recommended.yaml
Use kubectl proxy to enable access to the dashboard and it will be available in the following link and it will be accessed from the machine where you have executed the command. For more details please check this link.
As the question shows, I have very low knowledge about kubernetes. Following a tutorial, I made a Kubernetes cluster to run a web app on a local server using Minikube. I have applied the kubernetes components and they are running but the Web-Server does not respond to HTTP requests. My problem is that all the system that I have created is like a black box for me and I have literally no idea how to open it and see where the problem is. Can you explain how I can debug such implementaions in a wise way. Thanks.
use a tool like https://github.com/kubernetes/kubernetes-dashboard
You can install kubectl and kubernetes-dashboard in a k8s cluster (https://kubernetes.io/docs/tasks/tools/install-kubectl/), and then use the kubectl command to query information about a pod or container, or use the kubernetes-dashboard web UI to query information about the cluster.
For more information, please refer to https://kubernetes.io/
kubectl get pods
will show you all your pods and their status. A quick check to make sure that all is at least running.
If there are pods that are unhealthy, then
kubectl describe pod <pod name>
will give some more information.. eg image not found etc
kubectl log <pod name> --all
is often the next step , use -f to follow the logs as you exercise your api.
It is possible to link up images running in a pod with most ide debuggers, but instructions will differ depending on language and ide used...
If I look at my logs in GCP logs, I see for instance that I got a request that gave 500
log_message: "Method: some_cloud_goo.Endpoint failed: INTERNAL_SERVER_ERROR"
I would like to quickly go to that pod and do a kubectl logs on it. But I did not find a way to do this.
I am fairly new to k8s and GKE, any way to traceback the pod that handled that request?
You could run command "kubectl get pods " on each node to check the status of all pods and could figure out accordingly by running for detail description of an error " kubectl describe pod pod-name"
As mentioned in #Neelam answer, you can can get the pod names with the command kubectl get pods -A and log into all your pods to find the error.
Or, alternatively, you could deploy a custom monitoring system like Elastic GKE Logging available in GCP github Click-to-deploy.
See here to install from MarketPlace with few clicks.
It is a free alternative to have a complete monitoring system and you can filter your logs in Kibana dashboard after deployed.
How to check API access log in kubernetes.
I have an application with two pods. I want to see the access logs how it is getting distributed.
The answer depends on your architecture. Unfortunately, the question is not complete, so we can provide only general info here.
The common way acessing logs in Kubernetes is through kubectl logs <pod_name> command. That'll give you logs for the first container on that Pod. It's needed to specify particular container name if you are running some side-car containers there.
kubectl get pods
NAME READY STATUS
nginx-65f88748fd-scxzl 1/1 Running
kubectl logs nginx-65f88748fd-scxzl
<Nginx Logs from my pod>
Additionally (if your app supports internal logging) it is possible to connect to the Pod in interactive mode and run some command directly on pod (if supported).
kubectl exec <parameters> <pod_name> -- <command>
For example you can run some shell on Pod and check logs.
kubectl exec -it nginx-65f88748fd-scxzl -- bash
root#nginx-65f88748fd-scxzl:/#
-it initiates connection in interactive mode and command to run is placed after -- .
Hope that helps.
I am having a IBM cloud powered kubernetes cluster. That cluster currently have only 1 node.
I verified running the command kubectl get nodes.
There are few servers which are running in that node. I want to restart one of those server.
How can I get into the node and perform a restart for the required server?
I tried ssh, but this link says it cannot be done directly.
Seems like your main questions are:
"how to restart a pod", "how to ssh to a entity in which my service is running" and "how to see if I deleted a Pod".
First of all, most of this questions are already answered on StackOverflow. Second of all you need to get familiar with Kubernetes basic terminology and how things work in here. You can do that in any Kubernetes introduction or in documentation.
Answering the questions:
1) About restarting you can find information here. Or if you have running deployment, deleting a pod will result in pod recreation.
2) you can use kubectl execas described here:
kubectl exec -ti pod_name sh(or bash)
3) to see your pods, run kubectl get pods after you run kubectl delete pod name -n namespace you can run kubectl get pods -w to see changing status of deleted pod and new one being spawned. Or you will notice that there is a new pod running but with different NAME.