I run an .NET Core 2.1 in a container. It writes logs to a file within the container. I am able to run a docker exec bash command to inspect the log file, locally.
This application is then deployed with Kubernetes to a pod with more than one container.
How can I inspect the log file within each one of these containers?
You can exec into container within pod:
kubectl -n <namespace> exec -it <pod name> -c <container name> bash
But the better approach is to make your application stream logs to stdout or stderr, so you can access it directly with:
kubectl -n <namespace> logs <pod name> -c <container name>
Related
I need to execute a .cql file inside a kubernetes pod.
I did not try anything
To execute the .cql file inside a pod:
1>copy the file to a pod:
kubectl cp /path/of/the/file/.cql/ -n keyspace-name pod-name:/file/path/inside/the/pod -c name-of-container
2>ssh to cassandra pod:
kubectl exec -it pod-name -n keyspace-name -- bash
3>run the .cql file:
cqlsh -f/file/path/inside/the/pod
I was able to view the app container logs using kubectl -f logs and was able to login to the container using "k exec --stdin --tty -- /bin/bash".
After injecting linkerd, I could not login to the container. However my goal is to check the app logs.
When I use this "k logs -f linkerd-proxy" I could not see the app-related logs.
I tried injecting debug-sidecar as well.
Tried this - "k logs deploy/ linkerd-debug - " and as well as this "k exec -it -c linkerd-debug -- tshark -i any -f "tcp" -V -Y "http.request"
still I couldn't see the exact logs for my app in the pod. Please suggest.
Linkerd works by injecting an additional container into your pods; this is known as the "sidecar" pattern. Your application (or better said container) logs are still accessible, however, as a result of having more than one container in the pod, kubectl requires you to explicitly specify the container name.
For example, assuming you have a pod with two containers (linkerd-proxy and app), you'd have to specify app as the name of the container:
$ kubectl logs -f <pod-name> -c app
# You can specify the container name without the -c flag
$ kubectl logs -f <pod-name> app
# This will work for 'exec' too
$ kubectl exec <pod-name> -c app -it -- sh
In k9s: Is there a way to configure the command which is used when starting a shell inside the pod?
I have looked their docu and briefly browsed the source without hints how a shell command could be specified.
kubectl command-line tool must be configured to communicate with your cluster.
Create the Pod:
kubectl apply -f https://k8s.io/examples/application/shell-demo.yaml
Verify that the container is running:
kubectl get pod shell-demo
Get a shell to the running container:
kubectl exec --stdin --tty shell-demo -- /bin/bash
In your shell, list the root directory:
Run this command inside the container:
ls /
Please refer to this document Configure command to use for shell on pod
Currently if I'm about to inspect my container, I have to do three steps:
kubectl get all -n {NameSpace}
kubectl describe {Podname from step 1} -n {NameSpace}
Find the Node Host and the container ID (My eyes are complaning!)
Switch to the host and execute "docker exec -ti -u root {Container ID} bash"
I am so mad about it right now. Wish somebody could offer some help to me and those who may share the same issue.
Pods are the smallest deployable units of computing that you can
create and manage in Kubernetes.
So, if you want to "enter" a container, you just need to "exec" into the pod in a particular namespace. Kubernetes will get you the shell/command for that pod.
kubectl -n somenamespace exec -it podname -- bash
There is no need to mention the node here as Kubernetes internally knows on which node the pod is scheduled.
If a Pod has more than one container, use --container or -c to specify
a container in the kubectl exec command. For example, suppose you have
a Pod named my-pod, and the Pod has two containers named main-app and
helper-app. The following command would open a shell to the main-app
container.
kubectl exec -it my-pod -c main-app -- /bin/bash
https://kubernetes.io/docs/tasks/debug-application-cluster/get-shell-running-container/
I have problem login into one container of a multi-container pod.
I get the container id from the kubectl describe pod <pod-name>
kubectl describe pod ipengine-net-benchmark-488656591-gjrpc -c <container id>
When i try:
kubectl exec -ti ipengine-net-benchmark-488656591-gjrpc -c 70761432854f /bin/bash
It says: Error from server: container 70761432854f is not valid for pod ipengine-net-benchmark-488656591-gjrpc
Ah once more detailed reading the man page of kubectl exec :
Flags:
-c, --container="": Container name. If omitted, the first container in the pod will be chosen
-p, --pod="": Pod name
-i, --stdin[=false]: Pass stdin to the container
-t, --tty[=false]: Stdin is a TTY
So i just used the container name from my manifest.yaml and it worked like charm.
Name of the container: ipengine-net-benchmark-iperf-server
kubectl exec -ti ipengine-net-benchmark-488656591-gjrpc -c ipengine-net-benchmark-iperf-server /bin/bash