From 634d3ff182f98deb91112467ffe5eb50399597ac Mon Sep 17 00:00:00 2001
From: Patrice Ferlet <metal3d@gmail.com>
Date: Wed, 1 Dec 2021 09:09:50 +0100
Subject: [PATCH] Add some doc (WIP)

---
 README.md | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 README.md

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+Katenary is a tool to help transforming `docker-compose` files to a working Helm Chart for Kubernetes.
+
+
+# Install
+
+If you've got `podman` or `docker`, you can build `katenary` by using:
+
+```bash
+make build
+```
+
+You can then install it with:
+```bash
+make install
+```
+
+It will use the default PREFIX (`~/.local/`) to install the binary in the `bin` subdirectory. You can force the PREFIX value at install time, but maybe you need to use "sudo":
+
+```bash
+sudo make install PREFIX=/usr/local
+```
+
+
+# Usage
+
+```bash
+Usage of katenary:
+  -appname string
+    	Give the helm chart app name (default "MyApp")
+  -appversion string
+    	Set the chart appVersion (default "0.1.1")
+  -compose string
+    	set the compose file to parse (default "docker-compose.yaml")
+  -version
+    	Show version and exist
+```
+
+Katenary will try to find a `docker-compose.yaml` file inside the current directory. It will then **delete** the `chart` directory to create a new Helm Chart.
+
+> It's important that you keep in mind that katenary will not alert you (for now) that it will remove the `chart` directory !
+
+It creates a subdirectory inside `chart` that is named with the `appname` option (default is `MyApp`)
+
+What can be interpreted by Katenary:
+
+- Services with "image" section (cannot work with "build" section)
+- **Named Volumes** are transformed to persistent volume claims - note that local volume will break the transformation to Helm Chart because there is (for now) no way to make it working (see below for resolution)
+- if `ports` and/or `expose` section, katenary will create Services and bind the port to the corresponding container port
+- `depends_on` will add init containers to wait for the depending service (using the first port)
+- some labels can help to bind values:
+    - `katernay.io/expose-ingress: true` will expose the first port or expose to an ingress
+    - `katernay.io/to-service: VARNAME` will convert the value to a variable `{{ .Release.Name }}-VARNAME` - it's usefull when you want to pass the name of a service as a variable (think about the service name for mysql to pass to a container that wants to connect to this)
+
+Exemple of a possible `docker-compose.yaml` file:
+
+```yaml
+version: "3"
+services:
+    webapp:
+        image: php:7-apache
+        environment:
+            # note that "database" is a service name
+            DB_HOST: database
+        expose:
+            - 80
+        depends_on:
+            # this will create a init container waiting for 3306 port
+            # because it's the "exposed" port
+            - database
+        labels:
+            # explain to katenary that "DB_HOST" value is variable (using release name)
+            katernay.io/to-servie: DB_HOST
+    database:
+        image: mariabd:10
+        environment:
+            MARIADB_ROOT_PASSWORD: foobar
+        expose:
+            # required to make katenary able to create the init container
+            - 3306
+```
+