Let’s look at how you can use networking to connect containers together! Communication between containers with networking Yep, I want to learn Docker & Kubernetes →
We’ll talk about how to set up a network, which allows Docker containers on the same host to communicate with other. for this article, we’ll look at applications that use networking as the primary way they either expose or consume services.
Or, two identical containers might even share the same files.įile sharing is great, but….
These kinds of applications can communicate by writing their files into a volume, which can also be shared with other containers.įor example: a data processing application might write a file to a shared volume which contains customer data, which is then read by another application. Sharing files on disk: Some applications communicate by reading and writing files. Or an application container might make a connection to a database container. But they can send and receive requests to other applications, using networking.įor example: a web server container might expose a port, so that it can receive requests on port 80. Two containers can talk to each other in one of two ways, usually:Ĭommunicating through networking: Containers are designed to be isolated.
In this article, we’ll look at simple communication between Docker containers, when they are running on the same host (which is sometimes called single-host networking). How do containers communicate with each other, if they’re supposed to be isolated? So if you want to run all of your components in containers, how can the applications talk to each other? A modern application typically consists of a few components – such as a database, a web server, or some microservices. In the real world, beyond the realm of the simple hello-world tutorial, running just one container isn’t enough for most apps. Modern apps consist of different components that need to communicate with each other. If Docker containers are isolated, then how the heck do they communicate with each other? But now you’re struggling to understand how to run more than one container at the same time. Also, port 29093 is published under the ports section so that it's reachable outside Docker.You’ve gone through the quickstarts and you’ve run your first Docker containers. We have to keep in mind that we can't use localhost because we are connecting from a different machine (local workstation in this case).
In KAFKA_ADVERTISED_LISTENERS, we also added the IP address of the cloud machine Kafka is running on. We created a new listener called EXTERNAL_DIFFERENT_HOST with security protocol PLAINTEXT and port 29093 associated. KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: INTERNAL:PLAINTEXT,EXTERNAL_SAME_HOST:PLAINTEXT,EXTERNAL_DIFFERENT_HOST:PLAINTEXT So instead, we need to define a new listener and advertise it: KAFKA_LISTENERS: EXTERNAL_SAME_HOST://:29092,EXTERNAL_DIFFERENT_HOST://:29093,INTERNAL://:9092 How would we connect to a Kafka broker if it's running on a different host machine? Unfortunately, we can't re-use existing listeners because they are only for the same Docker network or host connection.