add docker swarm tutorial

Author: anjmao

README.md

@@ -97,6 +97,86 @@ Detailed run output will be emitted when using the LinodeGo `LINODE_DEBUG=1` opt
 LINODE_DEBUG=1 docker-machine --debug  create -d linode --linode-token=$LINODE_TOKEN --linode-root-pass=$ROOT_PASS machinename
 ```
 
+## Provisioning Docker Swarm
+
+Let's create a docker swarm with master and worker node using private networking. Before starting make sure you have `docker-machine` and `jq` installed.
+
+1. Create install.sh bash script and replace LINODE_TOKEN with your actual linode access token.
+```sh
+#!/bin/bash
+set -e
+
+LINODE_TOKEN=<YOUR LINODE TOKEN>
+LINODE_ROOT_PASSWORD=$(openssl rand -base64 32); echo Password for root: $LINODE_ROOT_PASSWORD
+LINODE_REGION=eu-central
+
+create_node() {
+    local name=$1
+    docker-machine create \
+    -d linode \
+    --linode-label=$name \
+    --linode-instance-type=g6-nanode-1 \
+    --linode-image=linode/ubuntu18.04 \
+    --linode-region=$LINODE_REGION \
+    --linode-token=$LINODE_TOKEN \
+    --linode-root-pass=$LINODE_ROOT_PASSWORD \
+    --linode-create-private-ip \
+    $name
+}
+
+get_private_ip() {
+    local name=$1
+    echo $(docker-machine inspect $name | jq -r '.Driver.PrivateIPAddress')
+}
+
+init_swarm_master() {
+    local name=$1
+    local ip=$(get_private_ip $name)
+    docker-machine ssh $name "docker swarm init --advertise-addr ${ip}"
+}
+
+init_swarm_worker() {
+    local master_name=$1
+    local worker_name=$2
+    local master_addr=$(get_private_ip $master_name):2377
+    local join_token=$(docker-machine ssh $master_name "docker swarm \join-token worker -q")
+    docker-machine ssh $worker_name "docker swarm join --token=${join_token} ${master_addr}"
+}
+
+# create master node
+create_node master01
+
+# create worker node
+create_node worker01
+
+# init swarm master
+init_swarm_master master01
+
+# init swarm worker
+init_swarm_worker master01 worker01
+```
+
+2. After provision is successful check docker swarm status.
+
+```sh
+docker-machine ssh master01 "docker node ls"
+```
+
+Output should show active swarm leader and worker.
+
+```
+ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS      ENGINE VERSION
+f8x7zutegt2dn1imeiw56v9hc *   master01            Ready               Active              Leader              18.09.0
+ja8b3ut6uaivz5hf98gah469y     worker01            Ready               Active                                  18.09.0
+```
+
+3. Cleanup resources
+
+```sh
+docker-machine rm worker01 -y
+docker-machine rm master01 -y
+```
+
 ## Discussion / Help
 
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