docs: docker image documentation (#573)

Co-authored-by: hackerman <3372410+aeneasr@users.noreply.github.com>

docs/docs/guides/docker.md

@@ -0,0 +1,61 @@
+---
+id: docker
+title: Docker Images
+---
+
+## Supported tags and respective `Dockerfile` links
+* [`latest`, `v0.4.3-alpha.1`, `v0.4.3`, `v0.4`, `v0`](https://github.com/ory/kratos/blob/v0.4.3-alpha.1/.docker/Dockerfile)
+* [`latest-sqlite`, `v0.4.3-alpha.1-sqlite`, `v0.4.3-sqlite`, `v0.4-sqlite`, `v0-sqlite`](https://github.com/ory/kratos/blob/v0.4.3-alpha.1/.docker/Dockerfile-sqlite)
+
+## Image Variants
+The `Kratos` Docker images come in two different falvors, one with and one without SQLite support. All Docker images with the postfix `kratos:<version>-sqlite` in the tag are compiled with embed SQLite support and uses libmusl. All Docker images (`kratos:<version>`) without the postfix `-sqlite` are compiled without SQLite support and therefore also don't include libmusl. 
+
+If you don't make use of the embedded SQLite support we recommend to use the Docker images without SQLite support as they are smaller in size, include fewer libraries and therefore have a smaller attack surface. 
+
+## How to use these images
+In order to make the provided Docker images as useful as possible they can be configured through a set of supported Environment variables. In addition the default configuration directoy can be bound to a directory of choice to make it simple to pass in your own configuration files.
+
+### Environment Variables
+#### `DSN`
+This environment variable allows you to specify the database source name. As the `DSN` normally consists of the url to the database system and the credentials to access the database it is recommended to specify the `DSN` using a Environment variable. 
+
+**Example:** 
+
+`docker run -e DSN="memory" oryd/kratos:latest`
+
+
+#### `SECRETS_DEFAULT`
+This environment variable allows you to specify the secret used to sign and verify signatures and encrypt things:
+
+**Example:** 
+
+`docker run -e SECRETS_DEFAULT="CHANGE-ME" oryd/kratos:v0.4.3-alpha.1`
+
+
+### Volumes
+If the file `$HOME/.kratos.yaml` exists, it will be used as the configuration file. The provided Kratos Docker images currently do not include a default configuration file, but make it easy to pass in your own configuration file(s) by either binding a local directory or by creating your own custom Docker Image and adding the configuration file(s) to the custom image. 
+
+#### Binding host directoy
+
+**Example:**
+In this example we start the standard Docker container with SQLite support and use the quickstart email-passwort example configuration files by bind mounting the local directory. This example assumes that you checked out the Kratos Git repo and execute the Docker command in the Kratos Git repo directory:
+
+``` 
+docker run -it -e DSN="memory" \
+       --mount type=bind,source="$(pwd)"/contrib/quickstart/kratos/email-password,target=/home/ory \
+       oryd/kratos:latest-sqlite
+```
+
+In general we only recommend this approach for local development.
+
+#### Creating custom Docker image
+You can create your own, custom Kratos Docker images which embeds your configuration files by simply using the official Kratos Docker images as the Base Image and just adding your configuration file(s) as shown in the example below:
+
+``` dockerfile
+FROM oryd/kratos:latest
+COPY contrib/quickstart/kratos/email-password/.kratos.yml /ory/home
+```
+
+
+### Examples
+Below you find different examples how to use the official Kratos Docker images.

docs/docs/install.md

@@ -15,6 +15,8 @@ $ docker pull oryd/kratos:v0.4.6-alpha.1
 $ docker run --rm -it oryd/kratos help
 ```
 
+You can find more detailed information on the official Kratos docker images [here](guides/docker).
+
 ## macOS
 
 You can install ORY Kratos using [homebrew](https://brew.sh/) on macOS:

docs/sidebar.js

@@ -1,6 +1,6 @@
 module.exports = {
   Introduction: [
-    "index", "quickstart", "install",
+    "index", "quickstart", "install"
   ],
   Concepts: [
     "concepts/index",
@@ -64,7 +64,8 @@ module.exports = {
     "guides/account-recovery-password-reset",
     "guides/account-activation-email-verification",
     "guides/multi-tenancy-multitenant",
-    "guides/high-availability-ha"
+    "guides/high-availability-ha", 
+    "guides/docker"
   ],
   "Reference": [
     "reference/configuration",