How to ping DaemonSet in kubernetes - kubernetes

Question

I've set up Kubernetes DaemonSet Manifest for handling metrics in my project, and having a little problem of pinging this DaemonSet, So my Eventual Question is, (If I have a daemonset in every pod of my project, how can I ping Specific One or Just the One In order to make sure that everything okay with it?) (Most Likely using curl, but would also consider some other ways too if it's possible:)
Example of DaemonSet I have
apiVersion: v1
kind: DaemonSet
metadata:
name: metrics-api-service
spec:
selector:
matchLabels:
app: api-metrics-app
template:
metadata:
labels:
app: api-metrics-app
spec:
terminationGracePeriodSeconds: 60
containers:
- name: api-metrics-service
image: image
livenessProbe:
exec:
< what I need to put here In order to ping the DaemonSet ? >
initialDelaySeconds: 60
resources:
limits:
cpu: "0.5"
memory: "500Mi"
requests:
cpu: "0.4"
memory: "200Mi"
Thanks

Answer 1

Healthcheck should be enough to making sure if its working or not, but if you still want to confirm from the external side then make sure your daemon set exposes the port and the security group allow internal traffic, you can ping/curl same node where the daemon set is running, every daemonset will get the node IP as an environment variable.
Pass the HOST_IP in the daemonset environment variable
env:
- name: HOST_IP
valueFrom:
fieldRef:
fieldPath: status.hostIP
and then update the liveness probe accordingly
livenessProbe:
exec:
command:
- sh
- -c
- curl -s $HOST_IP:PORT/healthcheck
I will recommend HTTP check over bash
healthcheck:
initialDelaySeconds: 100
periodSeconds: 10
timeoutSeconds: 5
httpGet:
path: /metrics
port: 3000
if /metrics seems working, just return 200 status code.

Answer 2

One way to do this would be to lookup for your Pods IP addresses, then query each of them.
for i in $(kubectl get pods -n logging get pods \
-l app=api-metrics-app \
-o jsonpath='{.items[*].status.podIP}')
do
curl http://$i:4242/metrics
done