Update _index.md

Make 100% clear, that according to the k8s networking model pods are supposed to get their own unique IP address. I always thought this was the case. But then faced debugging issue where some pods are being assigned the same IP addresses. Came here to review my understanding of it, and confirm this is expected behaviour or not. But it was not stated unequivocally. This change makes it so.
This commit is contained in:
sgpinkus
2022-03-19 13:17:50 +11:00
committed by GitHub
parent eda7edee82
commit fdfc64e861
@@ -7,26 +7,25 @@ description: >
## The Kubernetes network model
Every [`Pod`](/docs/concepts/workloads/pods/) gets its own IP address.
Every [`Pod`](/docs/concepts/workloads/pods/) in a cluster gets its own unique cluster wide IP address.
This means you do not need to explicitly create links between `Pods` and you
almost never need to deal with mapping container ports to host ports.
This creates a clean, backwards-compatible model where `Pods` can be treated
much like VMs or physical hosts from the perspectives of port allocation,
naming, service discovery, [load balancing](/docs/concepts/services-networking/ingress/#load-balancing), application configuration,
and migration.
naming, service discovery, [load balancing](/docs/concepts/services-networking/ingress/#load-balancing),
application configuration, and migration.
Kubernetes imposes the following fundamental requirements on any networking
implementation (barring any intentional network segmentation policies):
* pods on a [node](/docs/concepts/architecture/nodes/) can communicate with all pods on all nodes without NAT
* pods can communicate with all other pods on any other [node](/docs/concepts/architecture/nodes/)
without NAT
* agents on a node (e.g. system daemons, kubelet) can communicate with all
pods on that node
Note: For those platforms that support `Pods` running in the host network (e.g.
Linux):
* pods in the host network of a node can communicate with all pods on all
nodes without NAT
Linux), when pods are attached to the host network of a node they can still communicate
with all pods on all nodes without NAT.
This model is not only less complex overall, but it is principally compatible
with the desire for Kubernetes to enable low-friction porting of apps from VMs