Preparing application backends

To create a load balanced application, we must first prepare the application where it is served by several replicas in our Docker Swarm service. In the following steps, we will deploy an application that is scaled in our Docker Swarm cluster:

1. First, we will provision additional nodes in our Docker Swarm cluster. This is to make sure we have enough capacity in our cluster to scale out our application later. In the following output, we can see that we have four nodes available:

dockerhost$ docker node ls
ID         HOSTNAME   STATUS AVAILA...  MANAGER...   ENGINE VERSION
9tcxzq45 * dockerhost Ready  Active     Leader       18.09.3
thxcn7ev   node-5lfg  Ready  Active                  18.09.0
7lyr93qf   node-ftc0  Ready  Active                  18.09.0
oydrnufp   node-hqvv  Ready  Active                  18.09.0

2. Next, we will prepare a simple Node.js application in a file called app.js. The following app logs additional information related on how our application is...