# ask-community

Oleg Akinin

05/25/2022, 3:06 PM
Hello to everyone! I launched dagster pipeline as docker container. Before that locally everything was ok. Now I get error with pymysql library:
pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'localhost' ([Errno 99] Cannot assign requested address)")
Target and source DB are docker containers too. I write option for connection like user, password, host, port, database_name. The pipeline worked ok before containerization. How can I fix the error? Please help!
dagster bot responded by community 2
🤖 1

Isaac Harris-Holt

05/25/2022, 4:07 PM
There's a few things this could be. You could consider having the containers in the same Docker network, make sure your ports are exposed, etc. Also, if you're not using the 'host' network option, you won't have access to ports exposed on your host (such as those used by other containers) without some extra configuration. Recommended approach is probably to use a Docker network. There's a good example of that here:


05/25/2022, 5:30 PM
Thanks Isaac for referring Oleg to the right docs. @Oleg Akinin have you been able to resolve your issue?

Oleg Akinin

05/25/2022, 9:48 PM
Thank you, Isaac! Well, I am trying to solve the issue. At this moment the best decision I see is union few containers in docker compose. Of course I won't see this decision without you, Sean and Isaac, thank you very much!