<인프런> 대세는 쿠버네티스 [초급] - No.4 Kubernetes Overview

Overview

이제 쿠버네티스 실습에 들어가보자!

 

아래는 시나리오이다.

 

 

N/W

서버 유형	Hostname	OS	CPU	메모리	서비스망 IP	내부망 IP	계정
가상 머신	dh-kube-master	CentOS 7	2 Cores	4G	192.168.21.112 (/24)	10.1.1.112 (/8)	root, clex
가상 머신	dh-kube-node	CentOS 7	2 Cores	4G	192.168.21.113 (/24)	10.1.1.113 (/8)	root, clex

 

 

 

VM은 KVM으로 구성한다.

 

$ qemu-img create -f qcow2 centos7.qcow2 50G
Formatting 'centos7.qcow2', fmt=qcow2 size=10737418240 cluster_size=65536 lazy_refcounts=off refcount_bits=16

 

 

virt-install --virt-type kvm --name centos7 \
  --ram 2048 \
  --cpu=host \
  --vcpus=2 \
  --os-type=centos \
  --os-variant=centos7.0 \
  --disk path=/data/dong/disk/centos7.qcow2,format=qcow2,bus=virtio \
  --cdrom=/data/dong/iso/CentOS-7-x86_64-Minimal-2009.iso  \
  --network bridge=mgmt,model=virtio \
  --network bridge=external,model=virtio \
  --graphics vnc,listen=0.0.0.0,password=xxx(비밀)

 

$ cat dh-k8s-master.sh
virt-clone \
--original centos7 \
--name dh-k8s-master \
--file /data/dong/disk/dh-k8s-master.qcow2

$ cat dh-k8s-node.sh 
virt-clone \
--original centos7 \
--name dh-k8s-node \
--file /data/dong/disk/dh-k8s-node.qcow2

$ virsh start dh-k8s-master
$ virsh start dh-k8s-node

 

1. Linux

---

CentOS에 nodejs 설치 :

yum -y update
yum install epel-release
yum -y install nodejs

1-1) hello.js

var http = require('http');
var content = function(req, resp) {
 resp.end("Hello Kubernetes!" + "\n");
 resp.writeHead(200);
}
var w = http.createServer(content);
w.listen(8000);

 

node hello.js

# 공용서버를 사용하고 있기 때문에 터널링으로 확인

 ssh -p [포트번호] -L localhost:9999:192.168.21.113:8000 [server id]@[server ip]

---

 

2. Docker

---

2-1) Dockerfile

vi Dockerfile

FROM node:slim
EXPOSE 8000
COPY hello.js .
CMD node hello.js

 

2-2) Docker Hub Site

https://hub.docker.com/

Docker Hub Container Image Library | App Containerization

2-3) Docker install

yum repolist
yum install -y yum-utils
# --config-manager 사용하기 위한 패키지 설치

yum-config-manager --add-repo \
> https://download.docker.com/linux/centos/docker-ce.repo
# repository 추가

yum install docker-ce docker-ce-cli containerd.io -y
# docker 설치

systemctl start docker
# docker 실행
systemctl enable docker
# reboot해도 유지되게 enable(활성화)

systemctl status docker
# docker 엔진 상태 확인

 

2-4) Docker Container Run

docker build -t tmkube/hello .
-t : 레파지토리/이미지명:버전

docker images
REPOSITORY     TAG       IMAGE ID       CREATED       SIZE
somaz94/hello  latest    360e02156cdb   5 weeks ago   248MB
kubetm/hello   latest    360e02156cdb   5 weeks ago   248MB
node           slim      99defcfc3a10   6 weeks ago   248MB
tmkube/hello   latest    e5137372eeab   3 years ago   150MB

docker run -d -p 8100:8000 tmkube/hello
-d : 백그라운드 모드
-p : 포트변경

docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS                                       NAMES
c589216cc396   tmkube/hello   "docker-entrypoint.s…"   4 minutes ago   Up 4 minutes   0.0.0.0:8100->8000/tcp, :::8100->8000/tcp   eager_hamilton

docker exec -it c589216cc396 /bin/bash

# 동일하게 터널링으로 확인
 ssh -p [포트번호] -L localhost:9999:192.168.21.112:8100 [server id]@[server ip]

 

2-5) Docker Image Push

docker login
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: somaz94
Password: 
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

docker push somaz94/hello
Using default tag: latest
The push refers to repository [docker.io/somaz94/hello]
2fa21bb903cd: Pushed 
91664b9ef030: Mounted from library/node 
ccfc9c391c3f: Mounted from library/node 
9ae1f99bd2f3: Mounted from library/node 
fe5ae6be2231: Mounted from library/node 
43b3c4e3001c: Mounted from library/node 
latest: digest: sha256:e93ba9dcd7e9f41b988f9adb9319ba429de978a9136371df5b860328198031df size: 1574

위의 이미지를 통해서 kubernetes pod를 배포해 보려고 한다.

 

---

3. Kubernetes

---

 

 

3-1) Pod

apiVersion: v1
kind: Pod
metadata:
  name: hello-pod
  labels:
    app: hello
spec:
  containers:
  - name: hello-container
    image: somaz94/hello
    ports:
    - containerPort: 8000

 

3-2) Service

 

v1.15

apiVersion: v1
kind: Service
metadata:
  name: hello-svc
spec:
  selector:
    app: hello
  ports:
    - port: 8200
      targetPort: 8000
  externalIPs:
  - 192.168.21.112