To check the failover mechanism, we will first go to master2, and stop the Docker instances using the following command:
sudo docker stop (Container ID)
Here, you can check in Marathon that cassandra1 has stopped.
On refreshing the page, you can see it has created the instance on master2, where we have stopped it. This is done automatically. Here, the scenario where we have seen one of the containers went down and a backup was automatically created. Now, let's validate this by running the following command:
sudo docker ps -a
You will find that your old container is down, and the new one, which was created automatically, will be up.
What happens if your server is down? For example, let's shut down our master2 server. To do that, let's go to AWS console, then EC2 Instances, click on master2 server, stop the server. On the Marathon app, you can...