CODEWITHSUNDEEP
kubernetesdaemonset
Oren Lalezari
Oren Lalezari

Reputation: 195

how to communicate with daemonset pod from another pod in the same node?

i want a daemonset-redis where every node will have it's own caching and each deployment pod will communicate with it's local daemonset-redis how to achieve it? how to reference daemonset pod in the same node from within docker-container?

UPDATE: i rather not use service option and make sure each pod access its local daemonset

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: redislocal
spec:
  selector:
    matchLabels:
      name: redislocal
  template:
    metadata:
      labels:
        name: redislocal
    spec:
      hostNetwork: true
      containers:
      - name: redislocal
        image: redis:5.0.5-alpine
        ports:
        - containerPort: 6379
          hostPort: 6379

Upvotes: 14

Views: 8454

Answers (3)

yuvi
yuvi

Reputation: 18427

This is an old question but I recently had to tackle the exact same problem, and just using the node IP did not really do it when deploying the redis Daemonset through the Bitnami\Redis helm chart. The solution was simpler - use internalTrafficPolicy: Local on the service configuration, which enforces calls made to the clusterIP associated with the service to be redirected locally (and only locally):

The kube-proxy filters the endpoints it routes to based on the spec.internalTrafficPolicy setting. When it's set to Local, only node local endpoints are considered. When it's Cluster (the default), or is not set, Kubernetes considers all endpoints.

source

Upvotes: 1

Crou
Crou

Reputation: 11388

There is a way of not using a service.

You can Expose Pod Information to Containers Through Environment Variables.

And you can use status.hostIP to know the ip address of node where pod is running. This was introduced in Kubernetes 1.7 link

You can add that to your pod or deployment yaml:

env:
- name: HOST_IP
  valueFrom:
    fieldRef:
      fieldPath: status.hostIP

It will set an variable HOST_IP which will have a value of node ip on which the pod is running, then you can use it to connect to a local DeamonSet.

Upvotes: 25

P Ekambaram
P Ekambaram

Reputation: 17615

you should define a service ( selecting all redis pods ) and then communicate with redis from other pods

Upvotes: 1

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