In a previous post, we saw how to create a digital ocean droplet and provision it with Ansible. Creating multiple droplets is very similar, you mostly just have to pay attention to the response object that you get back, which is different in the single vs. the many case.

Ansible allows you to provision servers in an idempotent fashion. It lets you see the state of your VM configuration as it resides in code, which is light years better than the sysadmin ways of yesterday.

You can see the sample code for this post on Github.

Consul Watches offer a way to hook into changes to the Consul cluster state at runtime.The specific type of changes we will be looking at hooking into in this post are checks. Whenever a node or service comes online and registers to Consul, whenever an existing node or service leaves Consul, or whenever an existing node or service becomes unresponsive, Consul will emit a check event. This check event can invoke a process to monitor the health of our services, alerting human being that action might soon be necessary.

The source code for this blog post can be found on GitHub.

Consul can run in either client or server mode. As far as Consul is concerned, the primary difference between client and server mode are that Consul Servers participate in the consensus quorum, store cluster state, and handle queries. Consul Agents are often deployed to act as middle-men between the services and the Consul Servers, which need to be highly available by design.

You can find the source code for this post on GitHub.

Consul is a distributed service discovery engine. It’s primary purpose is to track and manage services that interact with it–usually via an HTTP API. It monitors the health of services in near real time, providing a more robust way of routing services to healthy and responsive nodes.

You can see the sample code associated with this post on Github.

In two previous posts, we looked at how to provision a reverse proxy using nginx and then how to add caching to the nginx reverse proxy. The implementation we ended up with at the end of the last post was a “dumb” cache, meaning that it doesn’t know when or if any data gets updated–it just times out after 60 seconds and then asks for a new payload from the application it’s acting as proxy for.

The source code for this post can be found on Github.

In my last post, I provided an example for how to set up an Nginx Reverse Proxy for a Spring MVC application. One such reason to set up a reverse proxy is to utilize caching of resources. If you have dynamically generated content that doesn’t change very often, then adding caching at the site entry point can dramatically improve site responsiveness and reduce load on critical resources.

Nginx is a popular webserver, excellent at serving up static content, and commonly used as a load balancer or reverse proxy. This post will set up a basic Spring Boot MVC web application, and use Nginx as a reverse proxy. The source code can be found on GitHub.

You can view the sample code associated with this post on GitHub.

In a previous post on Provisioning a Server with Kibana, we saw that it’s very straightforward to get kibana on a box.

You can see the source code for this post on GitHub.

In a previous post on How to Provision Multiple Logstash Hosts Using Ansible, we saw that provisioning logstash is pretty straightforward. However, what do we do with it after it’s been out there transforming messages this entire time? Given that elastic comes out with a new version of Logstash every fifteen or twenty minutes, a wise person would look to automate the upgrade process as soon as possible.

You can see the source code for this blog post on GitHub.

In a previous post, we saw how to provision a multi-node elasticsearch cluster using ansible. The problem with that post is that, by the time I was done writing it, Elastic had already come out with a new version of elasticsearch. I’m being mildly facetious, but not really. They release new versions very quickly, even by the standards of modern software engineering.

The corresponding source code for this post is available on GitHub.

Kibana is a fancy pants web application that tries to make data in Elasticsearch user-friendly. Rounding out the previous two posts on how to install an elasticsearch cluster and how to install multiple logstash hosts, I will now show you how to stack kibana on top of them.