Understanding Modern Application Architecture - Part 1
This is part 1 of a series. Here are the other parts: Understanding Modern Application Architecture - Part 2 Understanding Modern Application Architecture - Part 3 Over the past decade, there has been a change taking place in how applications are built. As applications become more expansive in capabilities and more critical to how a business operates, (or in many cases, the application is the business itself) a new style of architecture has allowed for increased scalability, portability, resiliency, and agility. To support the goals of a modern application, the surrounding infrastructure has had to evolve as well. Platforms like Kubernetes have played a big role in unlocking the potential of modern applications and is a new paradigm in itself for how infrastructure is managed and served. To help our community transition the skillset they've built to deal with monolithic applications, we've put together a series of videos to drive home concepts around modern applications. This article highlights some of the details found within the video series. In these first three videos, we breakdown the definition of a Modern Application. One might think that by name only, a modern application is simply an application that is current. But we're actually speaking in comparison to a monolithic application. Monolithic applications are made up of a single, or a just few pieces. They are rigid in how they are deployed and fragile in their dependencies. Modern applications will instead incorporate microservices. Where a monolithic application might have all functions built into one broad encompassing service, microservices will break down the service into smaller functions that can be worked on separately. A modern application will also incorporate 4 main pillars. Scalability ensures that the application can handle the needs of a growing user base, both for surges as well as long term growth. Portability ensures that the application can be transportable from its underlying environment while still maintaining all of its functionality and management plane capabilities. Resiliency ensures that failures within the system go unnoticed or pose minimal disruption to users of the application. Agility ensures that the application can accommodate for rapid changes whether that be to code or to infrastructure. There are also 6 design principles of a modern application. Being agnostic will allow the application to have freedom to run on any platform. Leveraging open source software where it makes sense can often allow you to move quickly with an application but later be able to adopt commercial versions of that software when full support is needed. Defining by code allows for more uniformity of configuration and move away rigid interfaces that require specialized knowledge. Automated CI/CD processes ensures the quick integration and deployment of code so that improvements are constantly happening while any failures are minimized and contained. Secure development ensures that application security is integrated into the development process and code is tested thoroughly before being deployed into production. Distributed Storage and Infrastructure ensures that applications are not bound by any physical limitations and components can be located where they make the most sense. These videos should help set the foundation for what a modern application is. The next videos in the series will start to define the fundamental technical components for the platforms that bring together a modern application. Continued in Part 2Understanding Modern Application Architecture - Part 3
In this last article of the series discussing Modern Application Architecture, we will be discussion manageability with respect to the traffic. As the traffic patterns grow and look quite different from monolithic applications, different approaches need to take place in order to maintain the stability of the application. Understanding Modern Application Architecture - Part 1 Understanding Modern Application Architecture - Part 2 In this next video, we discuss Service Mesh. As modern applications expand and their communications change to microservice to microservice, a service mesh can be introduced to provide control, security and visibility to that traffic. Since individual microservices can be written by different individuals or groups, the service mesh can be the intermediary that allows them to understand what is happening when one piece of code needs to speak to another piece of code. At the same time, trust and verification can happen between the microservices to ensure they are talking to what they should be talking to. In this next video we discuss Sidecar Proxies. As mentioned in the Service Mesh video, the sidecar proxy is a key piece of the mesh implementation. It is responsible for functions such as TLS termination, mutual TLS and authentication. It can also be used for tracing and other observability. This means these functions don't have to be performed by the microservice itself. In this final video, we review NGINX as a Production Grade Kubernetes Solution. While Modern Applications will adopt Open Source Solutions where possible, these applications can be mission critical ones that require the highest level of service. As mentioned in the previous videos in this series, there are a number of important pieces of a Kubernetes cluster that can be augmented, or replaced by enhanced services. NGINX can actually perform as an enhanced Ingress Controller, giving a high level of control as well as performance for inbound traffic to the cluster. NGINX with App Protect can also provide finer grain controlled web application security for the inbound web based components of the application. And finally, NGINX Service Mesh can help with the microservice to microservice control, security and visibility, offloading that function from the microservice itself. We hope that this video series has helped shed some light for those who are curious about modern application architecture. As you have questions, don't hesistate to ask in our Technical Forums!
Understanding Modern Application Architecture - Part 2
To help our Community transfer their skills to handle Modern Applications, we've released a video series to explain the major points. This article is part 2 and here are the other parts: Understanding Modern Application Architecture - Part 1 Understanding Modern Application Architecture - Part 3 This next set of videos discuss the platforms and components that make up modern applications. In this video, we review containers. These have become a key building block of microservices. They help achieve the application portability by neatly packaging up everything needing to bring up an application within a container runtime such as Docker. One great example of a container is the f5-demo-httpd container. This small lightweight container can be downloaded quickly to run a web server. It's incorporated into a lot of F5 demo environments because it is lightweight and can be customized by simply forking the repository and making your own changes. In this next video, we talk about Kubernetes (or k8s for short). While there are container runtimes like Docker that can work individually on a server, the Kubernetes project has brought the concept into a form that can be scaled out. Worker nodes, where containers are run on, can be brought together into clusters. Commands can be issued to a Master Node via YAML files and have affect across the cluster. Containers can be scheduled efficiently across a cluster which is managed as one. In this next video, we break down the Kubernetes API. The Kubernetes API is the main interface to a k8s cluster. While there are GUI solutions that can be added to a k8s cluster, they are still interfacing with the API so it is important to understand what the API is capable of and what it is doing with the cluster. The main way to issue commands to the API is through YAML files and the kubectl command. From there, the API server will interact with the other parts of the cluster to perform operations. In this next video, we discuss Securing a Kubernetes cluster. There are a number of attack vectors that need to be understood and so we review them along with some of the actions that can be taken in order to increase the security for them. In this next video, we go over Ingress Controller. An Ingres Controller is one of the main ways that traffic is brought from outside of the cluster, into a pod. This role is of particular interest to F5 customers as they can use NGINX, NGINX+ or BIG-IP to play this strategic role within a Kubernetes cluster. In this next video, we talk about Microservices. As applications are decomposed from monolithic applications to modern applications, they are broken up into microservices that carry out individual functions of an application. The microservices then communicate with each other in order to deliver the overall application. It's important to then understand this service to service communication so that you can design application services around them such as load balancing, routing, visibility and security. We hope that you've enjoyed this video series so far. In the next article, we'll be reviewing the components that aid in the management of a Kubernetes platform.Understanding Modern Application Architecture - Part 3
NGINX ingress proxy for Consul Service Mesh
Disclaimer: This blog post is an abridged (NGINX specific) version of the original blog by John Eikenberry at HashiCorp. Consul service mesh provides service-to-service connection authorization and encryption using mutual Transport Layer Security (mTLS). Secure mesh networks require ingress points to act as gateways to enable external traffic to communicate with the internal services. NGINX supports mTLS and can be configured as a robust ingress proxy for your mesh network. For Consul service mesh environments, you can use Consul-template to configure NGINX as a native ingress proxy. This can be beneficial when performance is of utmost importance. Below you can walk through a complete example setup. The examples use consul-template to dynamically generate the proxy configuration and the required certificates for the NGINX to communicate directly with the services inside the mesh network. This blog post is only meant to demonstrate features and may not be a production ready or secure deployment. Each of the services are configured for demonstration purposes and will run in the foreground and output its logs to that console. They are all designed to run from files in the same directory. In this blog post, we use the term ingress proxy to describe Nginx. When we use the term sidecar proxy, we mean the Consul Connect proxy for the internal service. Common Infrastructure The example setup below requires Consul, NGINX, and Python. The former is available at the link provided, NGINX and Python should be easily installable with the package manager on any Linux system. The Ingress proxy needs a service to proxy to, for that you need Consul, a service (E.g., a simple webserver), and the Connect sidecar proxy to connect it to the mesh. The ingress proxy will also need the certificates to make the mTLS connection. Start Consul Connect, Consul’s service mesh feature, requires Consul 1.2.0 or newer. First start your agent. $ consul agent -dev Start a Webserver For the webserver you will use Python’s simple built-in server included in most Linux distributions and Macs. $ python -m SimpleHTTPServer Python’s webserver will listen on port 8000 and publish an index.html by default. For demo purposes, create an index.html for it to publish. $ echo "Hello from inside the mesh." > index.html Next, you’ll need to register your “webserver” with Consul. Note, the Connect option registers a sidecar proxy with the service. $ echo '{ "service": { "name": "webserver", "connect": { "sidecarservice": {} }, "port": 8000 } }' > webserver.json $ consul services register webserver.json You also need to start the sidecar. $ consul connect proxy -sidecar-for webserver Note, the service is using the built-in sidecar proxy. In production you would probably want to consider using Envoy or NGINX instead. Create the Certificate File Templates To establish a connection with the mesh network, you’ll need to use consul-template to fetch the CA root certificate from the Consul servers as well as the applications leaf certificates, which Consul will generate. You need to create the templates that consul-template will use to generate the certificate files needed for NGINX ingress proxy. The template functions caRoots and caLeaf require consul-template version 0.23.0 or newer. Note, the name, “nginx” used in the leaf certificate templates. It needs to match the name used to register the ingress proxy services with Consul below. ca.crt NGINX requires the CA certificate. $ echo '{{range caRoots}}{{.RootCertPEM}}{{end}}' > ca.crt.tmpl Nginx cert.pem and cert.key NGINX requires the certificate and key to be in separate files. $ echo '{{with caLeaf "nginx"}}{{.CertPEM}}{{end}}' > cert.pem.tmpl $ echo '{{with caLeaf "nginx"}}{{.PrivateKeyPEM}}{{end}}' > cert.key.tmpl Setup The Ingress Proxies NGINX proxy service needs to be registered with Consul and have a templated configuration file. In each of the templated configuration files, the connect function is called and returns a list of the services with the passed name “webserver” (matching the registered service above). The list Consul creates is used to create the list of back-end servers to which the ingress proxy connections. The ports are set to different values so you can have both proxies running at the same time. First, register the NGINX ingress proxy service with the Consul servers. $ echo '{ "service": { "name": "nginx", "port": 8081 } }' > nginx-service.json $ consul services register nginx-service.json Next, configure the NGINX configuration file template. Set it to listen on the registered port and route to the Connect-enabled servers retrieved by the Connect call. nginx-proxy.conf.tmpl $ cat > nginx-proxy.conf.tmpl << EOF daemon off; master_process off; pid nginx.pid; error_log /dev/stdout; events {} http { access_log /dev/stdout; server { listen 8081 defaultserver; location / { {{range connect "webserver"}} proxy_pass https://{{.Address}}:{{.Port}}; {{end}} # these refer to files written by templates above proxy_ssl_certificate cert.pem; proxy_ssl_certificate_key cert.key; proxy_ssl_trusted_certificate ca.crt; } } } EOF Consul Template The final piece of the puzzle, tying things together are the consul-template configuration files! These are written in HCL, the Hashicorp Configuration Language, and lay out the commands used to run the proxy, the template files, and their destination files. nginx-ingress-config.hcl $ cat > nginx-ingress-config.hcl << EOF exec { command = "/usr/sbin/nginx -p . -c nginx-proxy.conf" } template { source = "ca.crt.tmpl" destination = "ca.crt" } template { source = "cert.pem.tmpl" destination = "cert.pem" } template { source = "cert.key.tmpl" destination = "cert.key" } template { source = "nginx-proxy.conf.tmpl" destination = "nginx-proxy.conf" } EOF Running and Testing You are now ready to run the consul-template managed NGINX ingress proxy. When you run consul-template, it will process each of the templates, fetching the certificate and server information from consul as needed, and render them to their destination files on disk. Once all the templates have been successfully rendered it will run the command starting the proxy. Run the NGINX managing consul-template instance. $ consul-template -config nginx-ingress-config.hcl Now with everything running, you are finally ready to test the proxies. $ curl http://localhost:8081 Hello from inside the mesh! Conclusion F5 technologies work very well in your Consul environments. In this blog post you walked through setting up NGINX to work as a proxy to provide ingress to services contained in a Consul service mesh. Please reach out to me and the F5-HashiCorp alliance team here if you have any questions, feature requests, or any feedback to make this solution better.
