Apache is listening on port 80 and MySQL is listening on port 3306. In the diagram below, Pod A is a multi-container pod running Apache (httpd) and MySQL containers. When the container terminates, the layers of graph storage will not be deleted by Kubernetes and logs will not be cleaned up by Kubernetes.

docker run -v 8080:80 httpd:latest) will open ports on the host, a limited and contended resource. As described in the previous post, the port mapping specification on the Docker command (e.g. Since the new container does not know anything about Pod networking, any open ports will not be reachable using the Pod's IP. If a named container is created using Docker commands, container creation might fail if the named container already exists. When Docker commands are sent to the host Docker daemon, Kubernetes does not know anything about this newly created container and rightfully does nothing to manage it. Let's see how DooD and DinD approaches differ when used in the context of a Pod. In the context of a Pod, if the user wants to have access to Docker, we have a choice between DooD and DinD. Kubernetes garbage collects pods after they are terminated, preventing nodes from running out of space.Also, both apache and mysql can be reached using the pod IP. Two containers say apache and mysql running on the same Pod, can talk to each other using 'localhost'. Containers running in Kubernetes Pods share the same network namespace, i.e.Each Kubernetes Pod gets a Pod IP that is reachable from all the nodes that form the Kubernetes cluster.

Kubernetes Pods have some very useful properties: A pod models an application-specific “logical host” - it contains one or more application containers which are relatively tightly coupled - in a pre-container world, they would have executed on the same physical or virtual machine. Pods are always co-located and co-scheduled, and run in a shared context. Kubernetes Podsįrom the Kubernetes website, a Pod is described in the following words:Ī pod (as in a pod of whales or pea pod) is a group of one or more containers (such as Docker containers), the shared storage for those containers, and options about how to run the containers. Each step in the workflow is a Kubernetes Pod. Our infrastructure runs on top of Kubernetes, and we also allow our users to create workflows that are composed of multiple steps. In this post, we will talk about how running the Docker daemon inside a Docker container, Docker-inside-Docker (DinD), works better with Kubernetes Pods as compared to DooD (If these terms are unfamiliar please check out the previous post). In the previous post, we examined some of the issues of using the host Docker daemon socket, Docker-outside-of-Docker (DooD), inside containers running on a CI/CD system.

Run docker on kubernetes secret