Kubernetes deployment not reachable via browser exposed with service - docker

Question

I'm following below to launch a multi-container app (db and web-app). Following is based on this.
--- BLOW STEPS ARE COPIED FROM ANSWER PROVIDED BY THIS USER docker mysql in kuberneted ERROR 2005 (HY000): Unknown MySQL server host '' (-3) ---
First, use your favorite editor to start a eramba-cm.yaml file:
apiVersion: v1
kind: ConfigMap
metadata:
name: eramba
namespace: eramba-1
data:
c2.8.1.sql: |
CREATE DATABASE IF NOT EXISTS erambadb;
USE erambadb;
## IMPORTANT: MUST BE INDENT 2 SPACES AFTER c2.8.1.sql ##
<copy & paste content from here: https://raw.githubusercontent.com/markz0r/eramba-community-docker/master/sql/c2.8.1.sql>
kubectl create -f eramba-cm.yaml
Create the storage for MariaDB:
cat << EOF > eramba-storage.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: eramba-storage
spec:
storageClassName: eramba-storage
capacity:
storage: 5Gi
accessModes:
- ReadWriteOnce
hostPath:
path: /home/osboxes/eramba/erambadb
type: DirectoryOrCreate
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: eramba-storage
namespace: eramba-1
spec:
storageClassName: eramba-storage
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 5Gi
...
EOF
kubectl create -f eramba-storage.yaml
Install bitnami/mariadb using Helm
helm repo add bitnami https://charts.bitnami.com/bitnami
helm upgrade -i eramba bitnami/mariadb --set auth.rootPassword=eramba,auth.database=erambadb,initdbScriptsConfigMap=eramba,volumePermissions.enabled=true,primary.persistence.existingClaim=eramba-storage --namespace eramba-1 --set mariadb.volumePermissions.enabled=true
Run eramba web application:
apiVersion: apps/v1
kind: Deployment
metadata:
name: eramba-web
namespace: eramba-1
labels:
app.kubernetes.io/name: eramba-web
spec:
replicas: 1
selector:
matchLabels:
app: eramba-web
template:
metadata:
labels:
app: eramba-web
spec:
containers:
- name: eramba-web
image: markz0r/eramba-app:c281
imagePullPolicy: IfNotPresent
env:
- name: MYSQL_HOSTNAME
value: eramba-mariadb
- name: MYSQL_DATABASE
value: erambadb
- name: MYSQL_USER
value: root
- name: MYSQL_PASSWORD
value: eramba
- name: DATABASE_PREFIX
value: ""
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: eramba-web
namespace: eramba-1
labels:
app.kubernetes.io/name: eramba-web
spec:
ports:
- name: http
nodePort: 30045
port: 8080
protocol: TCP
targetPort: 8080
selector:
app.kubernetes.io/name: eramba-web
type: NodePort
...
Now browse eramba-web via port-forward or http://<node ip>:30045.
The kubectl get cm,pvc,pv,svc,pods output is:
root#osboxes:~# kubectl get cm,pvc,pv,svc,pods -o wide -n eramba-1
NAME DATA AGE
configmap/eramba 1 134m
configmap/eramba-mariadb 1 131m
configmap/kube-root-ca.crt 1 29h
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE VOLUMEMODE
persistentvolumeclaim/eramba-storage Bound eramba-storage 5Gi RWO eramba-storage 133m Filesystem
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE VOLUMEMODE
persistentvolume/eramba-storage 5Gi RWO Retain Bound eramba-1/eramba-storage eramba-storage 133m Filesystem
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/eramba-mariadb ClusterIP 10.104.161.85 <none> 3306/TCP 131m app.kubernetes.io/component=primary,app.kubernetes.io/instance=eramba,app.kubernetes.io/name=mariadb
service/eramba-web NodePort 10.100.185.75 <none> 8080:30045/TCP 129m app.kubernetes.io/name=eramba-web
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/eramba-mariadb-0 1/1 Running 0 131m 10.20.0.6 osboxes <none> <none>
pod/eramba-web-6cc9c687d8-k6r9j 1/1 Running 0 129m 10.20.0.7 osboxes <none> <none>
When I tried to access 10.100.185.75:30045, the browser is says not reachable.
root#osboxes:/home/osboxes/eramba# kubectl describe service/eramba-web -n eramba-1
Name: eramba-web
Namespace: eramba-1
Labels: app.kubernetes.io/name=eramba-web
Annotations: <none>
Selector: app.kubernetes.io/name=eramba-web
Type: NodePort
IP Family Policy: SingleStack
IP Families: IPv4
IP: 10.100.185.75
IPs: 10.100.185.75
Port: http 8080/TCP
TargetPort: 8080/TCP
NodePort: http 30045/TCP
Endpoints: <none>
Session Affinity: None
External Traffic Policy: Cluster
Events:
the logs for the web-app pod:
root#osboxes:~# kubectl logs eramba-web-6cc9c687d8-k6r9j -n eramba-1
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 10.20.0.7. Set the 'ServerName' directive globally to suppress this message
root#osboxes:~#
I've noticed the lack of endpoint for the Eramba-web service. When I changed the selector app to eramba-web, the endpoint has an IP, but the browser still cant reach the app.

Answer 1

This is a community wiki answer posted for better visibility. Feel free to expand it.
The requester uses the NodePort type for the eramba-web service. To access the application, it necessary to use the IP addresses of the nodes in the cluster, instead of using the internal IP address 10.100.x.y.
From Kubernetes documentation:
NodePort: Exposes the Service on each Node's IP at a static port (the
NodePort). A ClusterIP Service, to which the NodePort Service routes,
is automatically created. You'll be able to contact the NodePort
Service, from outside the cluster, by requesting <NodeIP>:<NodePort>.