100 Days of DevOps — Day 59- Introduction to DockerFile

Welcome to Day 59 of 100 Days of DevOps, Focus for today is DockerFile

What is DockerFile?

• A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image
• Basic Dockerfile look like this

#My first test docker file
FROM centos:7
LABEL maintainer="plakhera@example.com"
RUN yum -y install httpd

• When we build a dockerfile it should name as Dockerfile(case-sensitive)
• FROM specify from where we building this image
• LABEL refer to the person who is maintaining/creating this image(earlier maintainer option is deprecated and it’s label now)
• RUN refer to the command we are running
• Now we are going to build in the context(. indicate the current directory)

# docker build -t myfirstimage:v1 .
Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM centos:7
---> e934aafc2206
Step 2/3 : LABEL maintainer="plakhera@example.com"
---> a4f7e2fbcc92
Step 3/3 : RUN yum -y install httpd
---> Running in 57199dabb5ec

• Here step refers to the layer