Node.js applications are widely adopted for building scalable and performant web services and APIs. Managing and deploying these applications can be made easier with tools like PM2, a process manager for Node.js applications. However, as more organizations adopt container orchestration platforms like Kubernetes, using PM2 alongside Kubernetes can be an anti-pattern. In this blog post, we'll delve deeper into why using PM2 in a Kubernetes environment can lead to complications and explore best practices for managing Node.js applications in such environments.
PM2's core functionality is managing the lifecycle of Node.js applications, keeping them alive and restarting them in case of crashes. On the other hand, Kubernetes is responsible for managing the lifecycle of containers, including Node.js applications running within them.
Using PM2 alongside Kubernetes introduces redundancy, as both systems try to handle the same responsibilities. This can lead to potential conflicts, confusion, and increased complexity in managing your applications. In this case, it's best to let Kubernetes handle process management, adhering to the "one process per container" principle.
Both PM2 and Kubernetes provide mechanisms for scaling applications horizontally and distributing workloads among instances. PM2 offers clustering support to manage multiple instances of an application, while Kubernetes provides native scaling features using ReplicaSets and Deployments.
When deploying Node.js applications on Kubernetes, Kubernetes-native scaling features simplify the overall architecture and ensure better resource utilization. It also ensures that your application follows the best scaling and load-balancing practices in a containerized environment.
PM2 includes built-in logging and monitoring features, which are useful for managing Node.js applications. However, more sophisticated and standardized tools are available in a Kubernetes environment, such as Prometheus for monitoring and the Fluentd/Elasticsearch/Kibana (EFK) stack for logging. These tools provide a unified view of the entire system and offer advanced capabilities like alerting visualization and query languages.
Using Kubernetes-native tools for logging and monitoring provides better insight and compatibility with other components in your containerized environment.
PM2 provides a mechanism to achieve zero-downtime deployments through process reloading. Similarly, Kubernetes supports zero-downtime deployments using rolling updates for its Deployments. In a Kubernetes environment, using the platform's built-in rolling update feature is best, ensuring consistency and reliability across all deployed applications.
While PM2 is an excellent tool for managing Node.js applications, using it alongside a container orchestration platform like Kubernetes can create redundancies and unnecessary complexities. By relying on Kubernetes-native features for process management, scaling, load balancing, logging, and monitoring, you can simplify your application architecture, improve observability, and adhere to best practices for deploying Node.js applications in a containerized environment.
When transitioning your Node.js applications to Kubernetes, it's essential to recognize and avoid potential anti-patterns and leverage the capabilities provided by the platform to ensure a seamless and efficient deployment process.