Is it possible to send a http Rest request to another K8 Pod that belongs to the same Service in Kubernetes?
E. G. Service name = UserService , 2 Pods (replica = 2)
Pod 1 --> Pod 2 //using pod ip not load balanced hostname
Pod 2 --> Pod 1
The connection is over Rest GET 1.2.3.4:7079/user/1
The value for host + port is taken from kubectl get ep
Both of the pod IP's work successfully outside of the pods but when I do a kubectl exec -it
into the pod and make the request via CURL, it returns a 404 not found for the endpoint.
Q What I would like to know if it is possible to make a request to another K8 Pod that is in the same Service?
Q Why am I able to get a successful ping 1.2.3.4
, but not hit the Rest API?
below is my config files
#values.yml
replicaCount: 1
image:
repository: "docker.hosted/app"
tag: "0.1.0"
pullPolicy: Always
pullSecret: "a_secret"
service:
name: http
type: NodePort
externalPort: 7079
internalPort: 7079
ingress:
enabled: false
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: {{ template "app.fullname" . }}
labels:
app: {{ template "app.name" . }}
chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
release: {{ .Release.Name }}
heritage: {{ .Release.Service }}
spec:
replicas: {{ .Values.replicaCount }}
template:
metadata:
labels:
app: {{ template "app.name" . }}
release: {{ .Release.Name }}
spec:
containers:
- name: {{ .Chart.Name }}
image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
imagePullPolicy: {{ .Values.image.pullPolicy }}
env:
- name: MY_POD_IP
valueFrom:
fieldRef:
fieldPath: status.podIP
- name: MY_POD_PORT
value: "{{ .Values.service.internalPort }}"
ports:
- containerPort: {{ .Values.service.internalPort }}
livenessProbe:
httpGet:
path: /actuator/alive
port: {{ .Values.service.internalPort }}
initialDelaySeconds: 60
periodSeconds: 10
timeoutSeconds: 1
successThreshold: 1
failureThreshold: 3
readinessProbe:
httpGet:
path: /actuator/ready
port: {{ .Values.service.internalPort }}
initialDelaySeconds: 60
periodSeconds: 10
timeoutSeconds: 1
successThreshold: 1
failureThreshold: 3
resources:
{{ toYaml .Values.resources | indent 12 }}
{{- if .Values.nodeSelector }}
nodeSelector:
{{ toYaml .Values.nodeSelector | indent 8 }}
{{- end }}
imagePullSecrets:
- name: {{ .Values.image.pullSecret }
kind: Service
metadata:
name: {{ template "app.fullname" . }}
labels:
app: {{ template "app.name" . }}
chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
release: {{ .Release.Name }}
heritage: {{ .Release.Service }}
spec:
type: {{ .Values.service.type }}
ports:
- port: {{ .Values.service.externalPort }}
targetPort: {{ .Values.service.internalPort }}
protocol: TCP
name: {{ .Values.service.name }}
selector:
app: {{ template "app.name" . }}
release: {{ .Release.Name }}
Yes as Mathew answered you can indeed communicate between pods in a Service with Kubernetes, the problem I was having was Istio was blocking the requests to each other.
Solution: Disabling Istio injection solved this problem for me , I then enabled it after wards and load balancing continued, hopefully it can help some one in the future.
see answer here: Envoy Pod to Pod communication within a Service in K8
Is it possible to send a http Rest request to another K8 Pod that belongs to the same Service in Kubernetes?
For sure, yes, that's actually exactly why every Pod in the cluster has a cluster-wide routable address. You can programmatically ask kubernetes for the list of the Pod's "peers" by requesting the Endpoint
object that is named the same as the Service
, then subtract out your own Pod's IP address. It seems like you kind of knew that from kubectl get ep
, but then you asked the question, so I thought I would be explicit that your experience wasn't an accident.
Q Why am I able to get a successful ping 1.2.3.4, but not hit the Rest API?
We can't help you troubleshoot your app without some app logs, but the fact that you got a 404 and not "connection refused" or 504 or such means your connectivity worked fine, it's just the app that is broken.