Introduction
Hi, I am Akshay Rao. This series will help you in hands on experience.
Pre-requisites
have done with create pod
https://dev.to/aksrao1998/k8s-hands-on-create-a-pod-8ef
Agenda
In the last blog we saw how to create a pod of single container but we were not able to access the nginx application. In this we will access the nginx and deploy multi-container pod.
Let's Start
- we our pod named pod1 running but to access it we need to connect the container port 80 -> node port 80. So when the container port is connect to node port then the container is exposed to the outside world.
- So to connect this ports we will use another k8s component that is service, in which using the labels we will tell the controller to connect.
- we will do some slight changes in the pod1.yaml, before that if the pod is running pls delete it.
apiVersion: v1
kind: Pod
metadata:
name: pod1
labels: <- add this line to pod1.yaml
type: webserver <- add this line to pod1.yaml
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
- now create another file
vi service.yamland fill it with the below content
apiVersion: v1
kind: Service
metadata:
name: basicservice #name of the service
spec:
selector:
type: webserver <- same as in the pod1.yaml
type: NodePort
ports:
- protocol: TCP
port: 80
- now deploy both of them
kubectl create -f pod1.yaml
kubectl create -f service.yaml
# verify
kubectl get po
[ts-akshay.rao@JP-FVFZ91DHL414 k8s-ckad (⎈|minikube:default)]$ k get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
basicservice NodePort 10.105.134.51 <none> 80:30933/TCP 106m
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 19h
- pick the ip address then ssh into the minikube as the cluster is running inside and curl the ip address.
[k8s-ckad (⎈|minikube:default)]$ minikube ssh
docker@minikube:~$ curl http://10.105.134.51:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
Multi-container Pod
- edit the pod1.yaml (first delete the existing pod)and deploy it.
apiVersion: v1
kind: Pod
metadata:
name: pod1
labels:
type: webserver
spec:
containers:
- name: nginx
image: nginx:latest
ports:
- containerPort: 80
- name: collector
image: fluentd
- here we are using fluentd and nginx container in one pod.
- now describe this pod
[k8s-ckad (⎈|minikube:default)]$ k describe pods pod1
Name: pod1
Namespace: default
Priority: 0
Service Account: default
Node: minikube/192.168.49.2
Start Time: Tue, 03 Oct 2023 18:08:00 +0900
Labels: type=webserver
Annotations: <none>
Status: Pending
IP:
IPs: <none>
Containers:
nginx:
Container ID:
Image: nginx:latest
Image ID:
Port: 80/TCP
Host Port: 0/TCP
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-hml2n (ro)
collector:
Container ID:
Image: fluentd
Image ID:
Port: <none>
Host Port: <none>
State: Waiting
Reason: ContainerCreating
Ready: False
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-hml2n (ro)
Conditions:
Type Status
Initialized True
Ready False
ContainersReady False
PodScheduled True
Volumes:
kube-api-access-hml2n:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 11s default-scheduler Successfully assigned default/pod1 to minikube
Normal Pulling 10s kubelet Pulling image "nginx:latest"
Normal Pulled 8s kubelet Successfully pulled image "nginx:latest" in 2.04728618s
Normal Created 8s kubelet Created container nginx
Normal Started 8s kubelet Started container nginx
Normal Pulling 8s kubelet Pulling image "fluentd
- you can see the the events and of nginx and fluentd.
Links for further undertanding
https://kubernetes.io/docs/concepts/services-networking/service/#type-nodeport
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