WIP: Add Dapr with Docker docs (dapr#598)

* add howto for dapr with docker

* updated README

* updated README

* update docs to align with template

* expand intro

* add link to section

* fix typo

* align headers

* Style and tone updates

Removing first person phrasing and additional minor changes to style and tone.

* add not about host network mode

* added mount to run cmd

Co-authored-by: Young Bu Park <youngp@microsoft.com>
Co-authored-by: Ori Zohar <orzohar@microsoft.com>

Author: 3 people

howto/run-with-docker/README.md

@@ -0,0 +1,148 @@
+# Run with Docker
+This article provides guidance on running Dapr with Docker outside of Kubernetes. There are a number of different configurations in which you may wish to run Dapr with Docker that are documented below.
+
+## Prerequisites
+- [Docker](https://docs.docker.com/get-docker/)
+- [Docker-Compose](https://docs.docker.com/compose/install/) (optional)
+
+## Select a Docker image
+Dapr provides a number of prebuilt Docker images for different components, you should select the relevant image for your desired binary, architecture, and tag/version.
+
+### Images
+There are published Docker images for each of the Dapr components available on [Docker Hub](https://hub.docker.com/u/daprio).
+- [daprio/dapr](https://hub.docker.com/r/daprio/dapr) (contains all Dapr binaries)
+- [daprio/daprd](https://hub.docker.com/r/daprio/daprd)
+- [daprio/placement](https://hub.docker.com/r/daprio/placement)
+- [daprio/sentry](https://hub.docker.com/r/daprio/sentry)
+- [daprio/dapr-dev](https://hub.docker.com/r/daprio/dapr-dev)
+
+### Tags
+#### Linux/amd64
+- `latest`: The latest release version, **ONLY** use for development purposes.
+- `edge`: The latest edge build (master).
+- `major.minor.patch`: A release version.
+- `major.minor.patch-rc.iteration`: A release candidate.
+#### Linux/arm/v7
+- `latest-arm`: The latest release version for ARM, **ONLY** use for development purposes.
+- `edge-arm`: The latest edge build for ARM (master).
+- `major.minor.patch-arm`: A release version for ARM.
+- `major.minor.patch-rc.iteration-arm`: A release candidate for ARM.
+
+## Run Dapr in a Docker container with an app as a process
+> For development purposes ONLY
+
+If you are running Dapr in a Docker container and your app as a process on the host machine, then you need to configure
+Docker to use the host network so that Dapr and the app can share a localhost network interface. Unfortunately, the host networking driver for Docker is only supported on Linux hosts.
+If you are running your Docker daemon on a Linux host, you should be able to run the following to launch Dapr.
+```shell
+docker run --net="host" --mount type=bind,source="$(pwd)"/components,target=/components daprio/daprd:edge ./daprd -app-id <my-app-id> -app-port <my-app-port>
+```
+Then you can run your app on the host and they should connect over the localhost network interface.
+
+However, if you are not running your Docker daemon on a Linux host, it is recommended you follow the steps below to run
+both your app and the [Dapr runtime in Docker containers using Docker Compose](#run-dapr-in-a-docker-container-using-docker-compose).
+
+## Run Dapr and an app in a single Docker container
+> For development purposes ONLY
+
+It is not recommended to run both the Dapr runtime and an application inside the same container. However, it is possible to do so for local development scenarios.
+In order to do this, you'll need to write a Dockerfile that installs the Dapr runtime, Dapr CLI and your app code.
+You can then invoke both the Dapr runtime and your app code using the Dapr CLI.
+
+Below is an example of a Dockerfile which achieves this:
+```
+FROM python:3.7.1
+# Install dapr CLI
+RUN wget -q https://raw.githubusercontent.com/dapr/cli/master/install/install.sh -O - | /bin/bash
+
+# Install daprd
+ARG DAPR_BUILD_DIR
+COPY $DAPR_BUILD_DIR /opt/dapr
+ENV PATH="/opt/dapr/:${PATH}"
+
+# Install your app
+WORKDIR /app
+COPY python .
+RUN pip install requests
+ENTRYPOINT ["dapr"]
+CMD ["run", "--app-id", "nodeapp", "--app-port", "3000", "node", "app.js"]
+```
+
+Remember that if Dapr needs to communicate with other components i.e. Redis, these also need to
+be made accessible to it.
+
+## Run Dapr in a Docker container on a Docker network
+If you have multiple instances of Dapr running in Docker containers and want them to be able to
+communicate with each other i.e. for service invocation, then you'll need to create a shared Docker network
+and make sure those Dapr containers are attached to it.
+
+You can create a simple Docker network using
+```
+docker network create my-dapr-network
+```
+When running your Docker containers, you can attach them to the network using
+```
+docker run --net=my-dapr-network ...
+```
+Each container will receive a unique IP on that network and be able to communicate with other containers on that network.
+
+## Run Dapr in a Docker container using Docker-Compose
+[Docker Compose](https://docs.docker.com/compose/) can be used to define multi-container application
+configurations. If you wish to run multiple apps with Dapr sidecars locally without Kubernetes then it is recommended to use a Docker Compose definition (`docker-compose.yml`).
+
+The syntax and tooling of Docker Compose is outside the scope of this article, however, it is recommended you refer to the [offical Docker documentation](https://docs.docker.com/compose/) for further details.
+
+In order to run your applications using Dapr and Docker Compose you'll need to define the sidecar pattern in your `docker-compose.yml`. For example:
+
+```yaml
+version: '3'
+services:
+  nodeapp:
+    build: ./node
+    ports:
+      - "50001:50001" # Dapr instances communicate over gRPC so we need to expose the gRPC port
+    depends_on:
+      - redis
+      - placement
+    networks:
+      - hello-dapr
+  nodeapp-dapr:
+    image: "daprio/daprd:edge"
+    command: [
+      "./daprd",
+     "-app-id", "nodeapp",
+     "-app-port", "3000",
+     "-placement-address", "placement:50006" # Dapr's placement service can be reach via the docker DNS entry
+     ]
+    volumes:
+        - "./components/:/components" # Mount our components folder for the runtime to use
+    depends_on:
+      - nodeapp
+    network_mode: "service:nodeapp" # Attach the nodeapp-dapr service to the nodeapp network namespace
+
+  ... # Deploy other daprized services and components (i.e. Redis)
+
+  placement:
+    image: "daprio/dapr"
+    command: ["./placement", "-port", "50006"]
+    ports:
+      - "50006:50006"
+    networks:
+      - hello-dapr
+```
+
+> For those running the Docker daemon on a Linux host, you can also use `network_mode: host` to leverage host networking if needed.
+
+To further learn how to run Dapr with Docker Compose, see the [Docker-Compose Sample](https://github.com/dapr/samples/10.hello-docker-compose).
+
+## Run Dapr in a Docker container on Kubernetes
+If your deployment target is Kubernetes then you're probably better of running your applicaiton and Dapr sidecars directly on
+a Kubernetes platform. Running Dapr on Kubernetes is a first class experience and is documented separately. Please refer to the
+following references:
+- [Setup Dapr on a Kubernetes cluster](https://github.com/dapr/docs/blob/ea5b1918778a47555dbdccff0ed6c5b987ed10cf/getting-started/environment-setup.md#installing-dapr-on-a-kubernetes-cluster)
+- [Hello Kubernetes Sample](https://github.com/dapr/samples/tree/master/2.hello-kubernetes)
+- [Configuring the Dapr sidecar on Kubernetes](https://github.com/dapr/docs/blob/c88d247a2611d6824d41bb5b6adfeb38152dbbc6/howto/configure-k8s/README.md)
+- [Running Dapr in Kubernetes mode](https://github.com/dapr/docs/blob/a7668cab5e16d12f364a42d2fe7d75933c6398e9/overview/README.md#running-dapr-in-kubernetes-mode)
+
+## Related links
+- [Docker-Compose Sample](https://github.com/dapr/samples/10.hello-docker-compose)