3 ms·

Don't you need to setup network paths? And connect containers to each other.. Then setup/teardown in specific order.. and if you have state, keep a subset of c

• hosh 8y ago
  Kuberneted is designed in a way where stateless pods (collection of containers sharing the same ip and identity) are decoupled from stateful ones. There are concepts designed into K8S that allows components to attempt to self-heal. For example, a pod that requires a postgresql pod to connect to will fail and crash out. The scheduler will start a new one. If the postgresql pod is up by that point, then the rescheduled pod will no longer crash. As far as the network paths, one of the really cool things about pods running inside a k8s cluster is that they can access any of the other pods, even if they are on a different node. However, pods typically reference services (such as postgresql) by dns name. You specify the set of pods that belong to the service by label selector. This allows the pods to come up, tear down, crash, moved to another node, while the service maintains a stable point of contact. It is quite brilliant, and other orchestrators quickly tried to copy it. Stateful workloads are still difficult. Each distributed stateful system has its own way of setup and teardown. What we will probably see are custom Operators designed for each distributed stateful system, coming out over the years.