docs: add docs on running multiple IPFS nodes

resolves #1858

License: MIT
Signed-off-by: Alan Shaw <alan.shaw@protocol.ai>

examples/running-multiple-nodes/README.md

@@ -0,0 +1,66 @@
+# Running multiple JS IPFS nodes
+
+This example takes you through the process needed to run 2 or more JS IPFS nodes on the same computer.
+
+## Via the CLI
+
+Firstly, you'll want to use the `IPFS_PATH` env variable to get a different repo for each instance. Initialise a new IPFS repo like this:
+
+```sh
+# IPFS_PATH by default is `~/.jsipfs`.
+# The following instructs JS IPFS to use the path `~/.jsipfs2` instead:
+IPFS_PATH=~/.jsipfs2 jsipfs init
+
+# Repeat this for as many nodes as you want to run...
+```
+
+Secondly, you'll need them to bind to different ports because otherwise bad things happen.
+
+With the CLI, after you've run `ipfs init` you can either edit the config file at `~/.jsipfs/config` (replacing `~/.jsipfs` with the repo path you specified above) or use the config command to update the config e.g. `ipfs config Addresses.API /ip4/0.0.0.0/tcp/4012`. Then start the node with `ipfs daemon`:
+
+```sh
+# edit the address ports
+vi ~/.jsipfs2/config
+
+# OR
+
+IPFS_PATH=~/.jsipfs2 jsipfs config Addresses.API /ip4/127.0.0.1/tcp/5012
+
+# Repeat this for as many nodes as you want to run...
+```
+
+```sh
+# ...and then start the daemon
+IPFS_PATH=~/.jsipfs2 jsipfs daemon
+
+# Repeat this for as many nodes as you want to run...
+```
+
+## Programmatically
+
+Firstly, you'll want to pass the [`repo`](https://github.com/ipfs/js-ipfs#optionsrepo) option to the constructor to get a different repo for each instance:
+
+```js
+// The repo path by default is `os.homedir() + '/.jsipfs'`.
+new IPFS({ repo: os.homedir() + '/.jsipfs2' })
+```
+
+Secondly, you'll need them to bind to different ports because otherwise bad things happen.
+
+To do this, simply pass the different ports to the [`config`](https://github.com/ipfs/js-ipfs#optionsconfig) constructor option. All together:
+
+```js
+new IPFS({
+  repo: os.homedir() + '/.jsipfs2',
+  config: {
+    Addresses: {
+      Swarm: [
+        '/ip4/0.0.0.0/tcp/4012',
+        '/ip4/127.0.0.1/tcp/4013/ws'
+      ],
+      API: '/ip4/127.0.0.1/tcp/5012',
+      Gateway: '/ip4/127.0.0.1/tcp/9191'
+    }
+  }
+})
+```