1. Basic Concepts A Dockerfile is a collection of instructions for building a Docker image. Docker reads Dockerfile instructions to build an image automatically. A Dockerfile is similar to a Makefile: both are text files that organize all the instructions in the order the image is built. The command to build a Docker image:

1. Basic Website Performance Metrics Concurrency: the number of sessions the server handles per unit of time Throughput: the number of requests the server handles per unit of time Response time: the total elapsed time from when the user sends a request to when the response is fully received, made up of network transmission time, service processing time, and other parts Average response time: the average of the response times of all requests 2.

1. What Docker Is Docker was born in early 2013 as a side project inside dotCloud (the former name of Docker Inc.). Its source code is hosted on GitHub, it is written in Go, and it follows the Apache 2.0 open-source license. The goal of the Docker project is to provide a lightweight operating system virtualization solution.