Managing container stdout and stderr logs

In the Unix and Linux OSs, there are three I/O streams, called STDIN, STDOUT, and STDERR. Here, we’ll talk about STDOUT and STERR in Linux containers, which are typically what the kubectl logs command shows to us.

STDOUT is usually a command’s normal output, and STDERR is typically used to output error messages. Kubernetes uses the kubectl logs <podname> command to log STDOUT and STDERR. It looks like the following when we use the command to log the nginx pod that we deployed in this chapter:

kubectl logs nginx

The output should look like the following:

Figure 8.10 – kubectl logs nginx pod

Now, we’ll use a container to write text to the standard output stream with a frequency of once per second. We can do this by deploying a new pod. The following is an example of a YAML manifest for this pod:

apiVersion: v1

kind: Pod

metadata:

  name: logger

spec...