Add basic documentation

README.md

@@ -1,2 +1,44 @@
-# kubectl-node-logs
-Kubectl plugin for viewing node logs
+# Kubernetes Node Log viewer
+`kubectl-node-logs` is a kubectl plugin for viewing and filtering node logs based on the 
+[oc adm node-logs](https://github.com/openshift/oc/blob/master/pkg/cli/admin/node/logs.go)
+implementation.
+
+## Prerequisites
+- Kubernetes cluster 1.27+
+  - `NodeLogQuery` [feature gate](https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/) is
+     enabled on the node(s)
+  - [Kubelet configuration options](https://kubernetes.io/docs/reference/config-api/kubelet-config.v1beta1/#kubelet-config-k8s-io-v1beta1-KubeletConfiguration)
+    `enableSystemLogHandler` and `enableSystemLogQuery` are both set to true
+  - Authorized to interact with node objects
+- [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/) version 1.27+
+- [Go](https://golang.org/doc/install) version 1.21
+
+## Installation
+
+### From source
+```shell
+$ git clone https://github.com/aravindhp/kubectl-node-logs.git
+$ cd kubectl-node-logs
+$ go build -o kubectl-node_logs cmd/kubectl_node_logs.go
+$ mv kubectl-node_logs /$USER/.local/bin # or any other directory in $PATH
+```
+
+## Usage
+Here is an example to retrieve the kubelet service logs from a node:
+```shell
+# Fetch kubelet logs from a node named node-1.example
+$ kubectl node-logs node-1.example --query=kubelet
+```
+
+You can also fetch files, provided that the files are in a directory that the kubelet allows for log fetches. For
+example, you can fetch a log from /var/log/ on a node:
+```shell
+ kubectl node-logs node-1.example --query /foo.log
+```
+
+For further options, please see `kubectl node-logs --help`
+
+## Further reading
+
+- [Kubernetes Cluster Administration -> System Logs -> Log query](https://kubernetes.io/docs/concepts/cluster-administration/system-logs/#log-query)
+- Kubernetes 1.27 Blog post: [Query Node Logs Using The Kubelet API](https://www.openshift.com/blog/kubernetes-1-27-query-node-logs-using-the-kubelet-api)