Multi container applications

• Lets add a database to our application.

• Where should we run the database? Same container?

• Problems with same container, multiple processes:

  • Multiple processes in same container requires extra code to manage it. Scaling up / down, starting & closing. What happens if one process crashes out?
  • What happens if only one process changes but other doesn’t? Means we have to redeploy the entire application.
  • Your scaling will differ depending on process. Usually you’d have different scaling on a front end compared to a back end.

---

Database container

Mac

docker run -d \
     -v todo-mysql-data:/var/lib/mysql \
     -e MYSQL_ROOT_PASSWORD=secret \
     -e MYSQL_DATABASE=todos \
     mysql:5.7
docker ps
docker exec -it ${containerName} mysql -u root -p

Mac M1

docker run -d \
     --platform "linux/amd64" \
     -v todo-mysql-data:/var/lib/mysql \
     -e MYSQL_ROOT_PASSWORD=secret \
     -e MYSQL_DATABASE=todos \
     mysql:5.7

Windows

docker run -d `
     --network todo-app --network-alias mysql `
     -v todo-mysql-data:/var/lib/mysql `
     -e MYSQL_ROOT_PASSWORD=secret `
     -e MYSQL_DATABASE=todos `
     mysql:5.7

Lets jump into the DB

Note

Keeping in mind the password is secret as we set in the MYSQL_ROOT_PASSWORD environment variable

SHOW DATABASES;

exit

docker rm -f ${containerName}