Symfony cannot connect to mysql DB on docker ECS container - symfony

Question

I'm using amazon-ecs to launch docker containers that I have. Everything works fine locally, but when I'm running the containers on ECS I'm getting the following error:
"NOTICE: PHP message: Unable to open PDO connection [wrapped: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known]"
I'm linking the containers in the docker-compose file, and I'm able to ping the the mysql container from the nginx container, so I know their linked.
docker-compose
version: '2'
services:
nginx:
image: "xxxx.dkr.ecr.us-east-2.amazonaws.com/nginx:latest"
ports:
- "8086:80"
links:
- fpm
- mysql
fpm:
image: "xxxx.dkr.ecr.us-east-2.amazonaws.com/php-fpm:latest"
links:
- redis
mysql:
image: "xxxx.dkr.ecr.us-east-2.amazonaws.com/mysql:latest"
environment:
MYSQL_DATABASE: strix
MYSQL_USER: strix
MYSQL_PASSWORD: rRCd29b3fG76ypM3
MYSQL_ROOT_PASSWORD: root
redis:
image: redis:latest
My symfony database.yml has the following:
dev:
propel:
param:
classname: DebugPDO
debug: { realmemoryusage: true, details: { time: { enabled: true }, slow: { enabled: true, threshold: 0.1 }, mem: { enabled: true }, mempeak: { enabled: true }, memdelta: { enabled: true } } }
task:
propel:
param:
profiler: false
test:
propel:
param:
classname: DebugPDO
all:
propel:
class: sfPropelDatabase
param:
classname: PropelPDO
dsn: 'mysql:host=mysql;dbname=strix'
username: strix
password: xxxx
encoding: utf8
persistent: true
pooling: true
I'm not sure if there's some network config that I have wrong on ECS or if I'm pointing to the wrong hostname. Any help would be appreciated. I am not familiar with symfony and am trying to raise an old application from the dead.

Answer 1

Turns out when I was running docker on my local machine, all the containers could talk to each other even though I hadn't explicitly linked them. In this case the fpm container needed to connect to the mysql container (and was doing so locally) but I didn't know this. When it was up on ECS, because it was not explicitly linked, it was throwing the connection error.
I simply fixed it by adding mysql to the fpm links
fpm:
image: "xxxx.dkr.ecr.us-east-2.amazonaws.com/php-fpm:latest"
links:
- redis
- mysql