Add documentation

README.md

@@ -1 +1,60 @@
-# prometheus-pkgs
+# prometheus-pkgs
+
+This repository provides some utilities to package `prometheus` and `exporters` for Debian(-likes) and RedHat(-likes). 
+
+## How to build
+
+These packages are build with `nfpm` and require docker (and docker compose) to build locally. 
+
+Build all packages : 
+```
+$ make all 
+```
+
+Build prometheus packages : 
+```
+$ make prometheus-pkgs
+```
+
+Build altermanager packages : 
+```
+$ make prometheus-alertmanager
+```
+
+Build postgres_exporter packages : 
+```
+$ make postgres_exporter
+```
+
+Build node_exporter packages : 
+```
+$ make node_exporter 
+```
+
+## How to update versions 
+
+The version of each component is stored in the `build.sh` script. 
+E.g. For prometheus : 
+```
+build_prometheus() {
+  # Prometheus version
+  VERSION="2.48.0"
+  wget https://github.com/prometheus/prometheus/releases/download/v${VERSION}/prometheus-${VERSION}.linux-amd64.tar.gz -O _build/prometheus-${VERSION}.tar.gz -c
+
+  mkdir -p _build/prometheus
+  tar xvzf _build/prometheus-${VERSION}.tar.gz -C _build/
+  mv _build/prometheus-${VERSION}.linux-amd64/* _build/prometheus/
+  cp prometheus/prometheus.service _build/prometheus/
+  chown -R 1000:1000 _build
+  rm -rf _build/prometheus-${VERSION}.tar.gz _build/prometheus-${VERSION}.linux-amd64/
+
+}
+```
+
+To get the latest version, go to the prometheus project repository and apply the latest version number to the `$VERSION` variable in the `build.sh` script. 
+
+## Releases 
+
+Each package is available in Release page of this repository. 
+When creating a new tag starting with a letter "v" (e.g. v2023-11-30), the GitHub Workflow will create a new release with new packages. 
+For more details, please consult the `.github/workflows` directory.