CentOS Question posted in
The official documentation can be found here.

Pod deployment issue and query over Kubernetes cluster – CentOS

I have created a k8s cluster and network, using 1 master and 2 nodes. However during pod (nginx) deployment, the deployment happens only on one server i.e. node1 and not on other server i.e. node2, as the result shows below o/p

[root@controller Kubernetes]# kubectl get pods -o wide
NAME    READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
nginx   1/1     Running   0          10m   192.168.1.2   node1   <none>           <none>
[root@controller Kubernetes]#

which means nginx is deployed on only node1 and not on node2

Result of the nodes joining the master

NAME         STATUS   ROLES    AGE    VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
controller   Ready    master   142m   v1.16.0   192.168.33.20   <none>        CentOS Linux 7 (Core)   3.10.0-1062.1.1.el7.x86_64   docker://1.13.1
node1        Ready    <none>   134m   v1.16.0   192.168.33.10   <none>        CentOS Linux 7 (Core)   3.10.0-1062.1.1.el7.x86_64   docker://1.13.1
node2        Ready    <none>   46m    v1.16.0   192.168.33.30   <none>        CentOS Linux 7 (Core)   3.10.0-1062.1.1.el7.x86_64   docker://1.13.1
[root@controller Kubernetes]#

Pod file:

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
     name: nginx-web-application

spec:
  containers:
    - name: nginx-container
      image: nginx

I want to see the deployment happening on node2 as well when i run below command, can u please tell why it is not happening on both the nodes:

kubectl create -f pod.yml
Tags:

2

Answers


  1. 0

    Your setup creates a pod with one container on one of the nodes (which one is decided by kube-scheduler).

    If you want to run that pod on each node use DaemonSet which ensures that a copy of a pod runs on each node.

    Deployment with 2 or more replicas should work since you have two nodes if both of your nodes are capable of running that pod (look at kube-scheduler).

    And last thing – you can use Taints and Tolerations. Easiest way would be to taint your node1 to not allow shceduling pods on it (example from the documentation):

    kubectl taint nodes node1 key:NoSchedule-
    Login or Signup to reply.
  2. 0

    A Pod is exactly one copy of a container (rarely, multiple tightly-coupled containers). It will run on exactly one node.

    You almost never want to directly use a Pod; instead, prefer a higher-level controller object. Most often you’ll use a Deployment, which you can tell you want e.g. 3 replicas of a pod running somewhere in the cluster. If you actually need one copy running on each node (usually this is only needed for infrastructure-type pods) that’s the model of a DaemonSet.

    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search