How do I know when my docker mysql container is up and mysql is ready for taking queries?

Question

I am deploying a few different docker containers, mysql being the first one. I want to run scripts as soon as database is up and proceed to building other containers. The sc

Answer 1

You can install mysql-client package and use mysqladmin to ping target server. Useful when working with multiple docker container. Combine with sleep and create a simple wait-loop:

while ! mysqladmin ping -h"$DB_HOST" --silent; do
    sleep 1
done

Answer 2

I've found that using the mysqladmin ping approach isn't always reliable, especially if you're bringing up a new DB. In that case, even if you're able to ping the server, you might be unable to connect if the user/privilege tables are still being initialized. Instead I do something like the following:

while ! docker exec db-container mysql --user=foo --password=bar -e "SELECT 1" >/dev/null 2>&1; do
    sleep 1
done

So far I haven't encountered any problems with this method. I see that something similar was suggested by VinGarcia in a comment to one of the mysqladmin ping answers.