Docker Server Setup

Who’s this guide for?

• Have you ever wanted to test an app with a ‘throw-away’ database?
• Inherited a suspicious codebase? Prefer not sharing access to your existing database?
• Work with security sensitive clients? Don’t risk cross-contamination! Use containers & control data persistance!
• Can’t upgrade your dev environment to the latest database version because your legacy apps depend on a 12 year old version of mysql?

Never let those reasons get in your way again!

Quick Links To 1-liners

This article features 1-line commands to start some of the most popular databases, including:

Note: The commands work in production. However they are mainly designed to accelerate your development workflow.

Advanced Docker Users: If you are familiar with docker-compose you may want to convert the shell commands below for use in your docker-compose.yml files.

Postgres Server

Start a container, naming it pg-server

# Store db files on a local path, outside the container
mkdir -p $HOME/.postgres-data

docker run \
  --name pg-server \
  -v $HOME/.postgres-data:/var/lib/postgresql/data \
  -p 127.0.0.1:5432:5432 \
  --restart on-failure:5 \
  --detach \
  --shm-size=256mb \
  postgres:12-alpine \
  postgres -c 'listen_addresses=*' \
    -c 'password_encryption=scram-sha-256' \
    -c 'shared_memory_type=sysv' \
    -c 'shared_buffers=256MB' \
    -c 'max_connections=200'

Adjust the command line options as needed. (The postgres daemon arguments start following the docker image name postgres:12-alpine. See postgres -c 'listen_addresses=*'...)

Access the psql prompt as postgres user

docker exec --user postgres -it pg-server psql

Access the container’s shell as root

docker exec -it pg-server bash

Note: The above command uses the official Alpine Linux base images. It is not your typical debian environment.

To use the debian/ubuntu base image, change postgres:12-alpine to postgres:12.

MongoDB Server

mkdir -p $HOME/.mongodb/data

docker run -d \
  --name mongodb \
  --restart on-failure:5 \
  -p 127.0.0.1:27017:27017 \
  -v $HOME/.mongodb:/data \
  mongo:4 bash -c 'mongod --bind_ip 0.0.0.0 --storageEngine=wiredTiger'

Now that your server is setup, verify your data is at $HOME/.mongodb with:

ls -lach $HOME/.mongodb

Let’s connect to the server with mongo CLI tool. (If you don’t have it installed see below.)

#> Using default arguments:
mongo

And you should see something like this:

Setup mongo CLI tools

Using brew & OSX

brew tap mongodb/brew
brew install mongodb-community-shell

Mysql Server

WARNING: CHANGE THE PASSWORD IN MYSQL_ROOT_PASSWORD BELOW.

mkdir -p $HOME/.mysql

docker run -d \
  -v $HOME/.mysql:/var/lib/mysql \
  -p 127.0.0.1:3306:3306 \
  --name mysql-$USER \
  -e MYSQL_DATABASE=$USER \
  -e MYSQL_ROOT_HOST='172.*.*.*' \
  -e MYSQL_ROOT_PASSWORD='p@ssw0rd' \
  mysql/mysql-server:8

ElasticSearch Server

mkdir -p $HOME/.elastic

docker run -d \
  --name elastic \
  -p 127.0.0.1:9200:9200 \
  -p 127.0.0.1:9300:9300 \
  -v $HOME/.elastic:/data \
  elasticsearch bash -c 'elasticsearch --cluster.name elastic_cluster --node.name elastic01 --path.data /data/elastic-data --path.logs /data/elastic-logs '

Security Notes

NOTE: the -p 127.0.0.1:27017:27017-style port option prevents access to your instance except from the docker server’s localhost network. To ‘publish’ the exposed ports, remove the local IP address prefix to allow external access: -p 27017:27017. Make sure you have taken necessary security precautions.

Recommended: Always use a port scanning tool (like nmap/masscan) to verify your network configuration (from separate system on another network.)

Now that you have the commands to start your database servers, the next step is to package up your application as a docker image. Part 2 continued below:

Packaging a NodeJS Web App

1. Add a blank file named Dockerfile in your project root.
2. (Optional, Recommended) Add a .dockerignore using .gitignore rules to exclude large non-essential paths. By default all project files are included.

Create a Dockerfile in your apps root

# Example for NodeJS
FROM node:12
EXPOSE [3000]
COPY . /app/
WORKDIR /app
RUN apt-get update && apt-get dist-upgrade -yqq
RUN ["npm", "install"]

# Overridable Command
CMD ["npm", "start"]

It’s easier to show how to start using the Dockerfile and demonstrate the results via console (see commands below).

In terminal, cd to your project folder and run the following build command everytime you deploy changes - or want to change/upgrade OS or Env config)

docker build -t app-name-here .

Key Docker Commands Reference

Build Docker Image

docker build -t app-name-here .

Create/Run Web App w/ Links to DB Servers

docker run -d --name webapp01 -p 3000:3000 --link mongo:mongo --link elastic:elastic app-name-here

Run Interactively (non-daemon, in terminal)

docker run -it --name webapp01 -p 3000:3000 --link mongo:mongo --link elastic:elastic app-name-here bash

Delete Container Instance or Image

Important: Any data not stored on a mounted volume path will be lost!!

# Delete Image
docker rmi -f app-name-here
docker rm -f webapp01
# now re-run your `docker run...` from ^^^
# So for example, let's kill your db instances above, run: ( start with something like `docker stop {mongo,elastic}` )
docker rm -f mongo elastic