In this chapter, we engaged with one of the most important aspects of deployment—monitoring running processes. Starting at the most basic and necessary level—catching errors—you learned how to trap errors at the individual process level and across processes. After discussing techniques to log errors with both UDP and third-party tools, we looked at how to build remote process monitors using Node's REPL, leading to a deeper discussion on how to do extensive application profiling and memory analysis. Finally, we looked at how to deploy the PM2 process runner in an effort to manage processes and visualize their activity. We also looked at how to use the cloud-based Nodetime and New Relic services to monitor your applications.

Direct monitoring provides crucial real-time insights into any potential threats, but we must also try to limit the possibility of future errors by writing resilient code that we can be confident of. In the next chapter, we will look at how to build and test our...