[Features]Node Topology awareness inside Database Application

[lancelot1989]

Some kind of databases have the ability to distribute data across different nodes according to the topology, like kafka’s broker.rack and replica.selector.class.

Currently, k8s's downward api cannot support node label(kubernetes/kubernetes#40610), so there is no official way to aware Node Topology inside Pod.

What if develop an api on kbagent to expose the Node Topology, and the startup scripts in addon can call this api and get Node Topology?

[shanshanying]

Hi @lancelot1989

As we discussed early this week, using KB-Agent to get Node Topology is not a good way (needs extra privileges and increates api-server burder). One alternative solutions in my mind is use postprovision action api mpd.spec.lifecycleActions.postProvision.

[lancelot1989]

Hi @lancelot1989

As we discussed early this week, using KB-Agent to get Node Topology is not a good way (needs extra privileges and increates api-server burder). One alternative solutions in my mind is use postprovision action api mpd.spec.lifecycleActions.postProvision.

Will postProvision be heavy too? As postProvision runs after Pods already running, some kind of engine's topology(like kafka) is set in properties file which can not be dynamically changed, maybe postProvision can not handle this situation. And as times goes on, Pod maybe deleted or evicted as Node Problems, Pod will be rescheduled to another node, can postProvition trigger with Pod rescheduled?

As mentioned above, is there a way we using a mutatingwebhook to hijack the /bind request, putting node's topology's json into pod's specific label, finally putting this pod label to downward api?

[github-actions]

This issue has been marked as stale because it has been open for 30 days with no activity