Question
Kubernetes how to get error messages/logs
- Posted October 16, 2020
- KubernetesLoggingConfiguration Management
Hi guys, I have created an api service for my website that pulls the image from docker hub. That is all working fine, but the container isn’t running properly and I wanted to take a look inside the container for some kind of error message. Is there a way of doing that? What is the proper way to inspect logs for each pod/service/container?
Also, what do I use to create environment variables? Is this done via Config Maps?
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Hi, You can use kubectl logs to retrieve logs from a previous instantiation of a container with --previous flag, in case the container has crashed. If your pod has multiple containers, you should specify which container’s logs you want to access by appending a container name to the command.
@christianstrang If you’re wanting to look inside the container and view its logs, you can do one of the following:
Using Docker
shell into container
docker run --rm -it <image-name> bash
view container’s logs
docker logs <container-name>
Note: If you’re using Alpine based image, you will need to use sh instead of bash.
Using Kubernetes
shell into container
kubectl exec -i -t <pod-name> --container <container-name> -- /bin/bash
Note: If you’re using Alpine based image, you will need to use sh instead of bash.
view container’s logs
kubectl logs <pod-name> -c <container-name>
Note: A Kubernetes pod can consist of 1 or more running containers. Also, I would recommend taking a look at a tool called stern for viewing logs within K8s cluster.
Next, you can use K8s ConfigMaps for your environment variables and K8s Secrets for your sensitive credentials. Finally, I would highly recommend testing your Docker container(s) prior to using them within your K8s cluster.
Well, I wish that the above information was helpful and I wish you all the best.
–
Think different and code well,
-Conrad
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