Learning Docker - Second Edition

The LABEL instruction

The LABEL instruction enables you to add key-value pairs as metadata to your Docker images. These metadata can be further leveraged to provide meaningful Docker image management and orchestration.

The syntax of the LABEL instruction is as follows:

LABEL <key-1>=<val-1> <key-2>=<val-2> ... <key-n>=<val-n> 

The LABEL instruction can have one or more key-value pairs. Though a Dockerfile can have more than one LABEL instruction, it is recommended that you use a single LABEL instruction with multiple key-value pairs.

Here is an example of the LABEL instruction:

LABEL version="2.0"        release-date="2016-08-05"  

The preceding label keys are very simple and this could result in naming conflicts. Hence Docker recommends using ...