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Lab 3.21 replica added to master node

creedperry
creedperry Posts: 2
in LFS258 Class Forum

Is this expected behavior from the scale function? One new service is added to the worker node and one is added to the master node.

student@lfcs-controller:~$ kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-7848d4b86f-dfb58 1/1 Running 0 16m 192.168.119.199 lfcs-worker
nginx-7848d4b86f-l4mcp 1/1 Running 0 46s 192.168.248.80 lfcs-controller
nginx-7848d4b86f-pdxbr 1/1 Running 0 46s 192.168.119.200 lfcs-worker

Comments

  • chrispokorni
    chrispokorni Posts: 2,623

    Hi @creedperry,

    When deploying a multi-instance application, or when scaling an existing application to multiple replicas, the pod replicas are assigned to nodes by the kube-scheduler. The scheduler compares nodes' resources and ranks nodes based on their state in order to match nodes with the new pods to be deployed.

    Regards,
    -Chris

  • creedperry
    creedperry Posts: 2

    Thank you for the reply. I assumed the kube-scheduler would only deploy services only to worker nodes, not to the controller itself. Is this typical behavior of the kube-scheduler and is it potentially cause for concern (assigning running services and workloads to the controller)?

  • chrispokorni
    chrispokorni Posts: 2,623

    Hi @creedperry,

    You are correct, the scheduler would distribute workload between worker nodes in a production environment. However, in our learning environment, the control-plane/master node has been converted into a worker node as well, by removing the master taint in step 3 of lab exercise 3.3.

    Regards,
    -Chris

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