13: Volumes and persistent data

Stateful applications that persist data are becoming more and more important in the world of cloud-native and microservices applications. Docker is an important infrastructure technology in this space, so we’ll turn our attention in this chapter to investigating how Docker handles applications that write persistent data.

We’ll split the chapter into the usual three parts:

• The TLDR
• The deep dive
• The commands

Volumes and persistent data - The TLDR

There are two main categories of data — persistent and non-persistent.

Persistent is the data you need to keep. Things like; customer records, financial data, research results, audit logs, and even some types of application log data. Non-persistent is the data you don’t need to keep.

Both are important, and Docker has solutions for both.

To deal with non-persistent data, every Docker container gets its own non-persistent storage. This is automatically created for every...