Introduction to ETCD

Using ectdctl to create a simple key-value store

Joe Cardillo
2 min readJan 30, 2022
Keys laying on a table, all facing the same direction
Photo by Alp Duran on Unsplash

What is ETCD?

The technical definition is: “etcd is a consistent and highly-available key value store used as Kubernetes’ backing store for all cluster data.” What does that mean, though? Let’s see if we can take a look under the hood and start with the basics.

What is a key-value store?

We most often see databases in tabular format. Which, in other words, is just data stored in rows and columns. For example, you might have a column for “Name”, and second for “Age”, a third for “Favorite food”, and so on.

A key-value store is a bit different in that you cannot have duplicate keys. In other words, there can only be one key called “Name”. Each key has an associated value.

Key: Name
Value: John

Key: Age
Value: 34

Key: Favorite-food
Value: Ice cream

This is useful for storing small chunks of data that require fast read/write.

Installing and running etcd

To test out using etcd as a key-value store on your own, install it locally on a Linux machine. At the time…