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by Master Seo Feb 16. 2023

2. 오라클 클라우드 - 쿠버네티스- 노드,파드

Cloud Shell 시스템에는 홈 디렉토리를 위한 5GB의 스토리지가 제공됩니다.

<1> 쿠버네티스 노드와 Pod와 관계 알아 보기

<2> 컨테이너 2개 가진 Pod생성하기

<3> 컨테이너 접속해 설정하기

<1> 쿠버네티스 노드와 Pod와 관계 알아 보기

노드 상태 확인

노드 서버 안에 Pod가 생성된다.

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl get nodes
NAME          STATUS   ROLES   AGE   VERSION
10.0.10.141   Ready    node    34h   v1.25.4
10.0.10.80    Ready    node    34h   v1.25.4

kubectl run으로 yaml 파일 만들기

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl run myweb --image nginx --dry-run=client -o yaml > myweb.yaml

topasvga@cloudshell:~ (ap-seoul-1)$ cat myweb.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: myweb
  name: myweb
spec:
  containers:
  - image: nginx
    name: myweb
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

파일만 만들었지 pod로 만든건 아니다.

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl get pods
No resources found in default namespace.

myweb.yaml 파일로 만들기

topasvga@cloudshell:~ (ap-seoul-1)$ cat << EOF > myweb.yaml
>  apiVersion: v1
>  kind: Pod
>  metadata:
>    name: myweb
>  spec:
>    containers:
>    - image: nginx:latest
>      name: myweb-container
>      ports:
>      - containerPort: 80
>        protocol: TCP
>  EOF

40 pod 80.txt

만들어진 myweb.yaml 파일로 배포하기

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl apply -f myweb.yaml && kubectl get pod -w
pod/myweb created

6

pod 1개 만들어 졌다. 컨테이너도 1개

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl get pods
NAME READY STATUS RESTARTS AGE
myweb 1/1 Running 0 33s

파일로 다시 만들어도, pod는 이미 만들어져서 추가로 만들어 지진 않는다.

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl apply -f myweb.yaml
pod/myweb unchanged

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
myweb 1/1 Running 0 85s 10.244.0.12 10.0.10.80 <none> <none>

Pod삭제 하기

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl delete pod myweb
pod "myweb" deleted

<2> 컨테이너 2개 가진 Pod생성하기

1
topasvga@cloudshell:~ (ap-seoul-1)$ cat << EOF | kubectl apply -f -
> apiVersion: v1
> kind: Pod
> metadata:
>   name: myweb2
> spec:
>   containers:
>   - name: myweb2-nginx
>     image: nginx
>     ports:
>     - containerPort: 80
>        protocol: TCP
>    - name: myweb2-netshoot
>     image: nicolaka/netshoot
>     command: ["/bin/bash"]
>     args: ["-c", "while true; do sleep 5; curl localhost; done"]
> EOF
pod/myweb2 created

50 pod 2.txt

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl get pods
NAME READY STATUS RESTARTS AGE
myweb2 2/2 Running 0 66s

3
자세히 보기

pod에 컨테이너 2개가 생성 되었다.

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl describe pod myweb2

Name:         myweb2
Namespace:    default
Priority:     0
Node:         10.0.10.80/10.0.10.80
Start Time:   Wed, 15 Feb 2023 21:23:59 +0000
Labels:       <none>
Annotations:  <none>
Status:       Running
IP:           10.244.0.13
IPs:
  IP:  10.244.0.13
Containers:
  myweb2-nginx:

Events:
  Type    Reason     Age    From               Message
  ----    ------     ----   ----               -------
  Normal  Scheduled  3m33s  default-scheduler  Successfully assigned default/myweb2 to 10.0.10.80
  Normal  Pulling    3m33s  kubelet            Pulling image "nginx"
  Normal  Pulled     3m30s  kubelet         Successfully pulled image "nginx" in 3.324741465s
  Normal  Created    3m30s  kubelet         Created container myweb2-nginx
  Normal  Started    3m30s  kubelet          Started container myweb2-nginx
  Normal  Pulling    3m30s  kubelet            Pulling image "nicolaka/netshoot"
  Normal  Pulled     3m12s  kubelet            Successfully pulled image "nicolaka/netshoot" in 17.662017124s
  Normal  Created    3m12s  kubelet            Created container myweb2-netshoot
  Normal  Started    3m12s  kubelet            Started container myweb2-netshoot

접속 로그로 확인하기

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl logs -f myweb2 -c myweb2-nginx
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/
2023/02/15 21:24:03 [notice] 1#1: nginx/1.23.3
2023/02/15 21:24:03 [notice] 1#1: built by gcc 10.2.1 20210110 (Debian 10.2.1-6)
2023/02/15 21:24:03 [notice] 1#1: OS: Linux 5.4.17-2136.314.6.2.el8uek.x86_64
2023/02/15 21:24:03 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/02/15 21:24:03 [notice] 1#1: start worker processes
2023/02/15 21:24:03 [notice] 1#1: start worker process 28
2023/02/15 21:24:03 [notice] 1#1: start worker process 29
127.0.0.1 - - [15/Feb/2023:21:24:26 +0000] "GET / HTTP/1.1" 200 615 "-" "curl/7.87.0" "-"
127.0.0.1 - - [15/Feb/2023:21:24:31 +0000] "GET / HTTP/1.1" 200 615 "-" "curl/7.87.0" "-"

<3> 컨테이너 접속해 설정하기

-c 옵션으로 컨테이너에 접속해보자.
topasvga@cloudshell:~ (ap-seoul-1)$ kubectl exec -it myweb2 -c myweb2-netshoot -- zsh

myweb2 컨테이너에 접속이 된다.

myweb2# curl -s localhost |grep nginx
<title>Welcome to nginx!</title>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
<a href="http://nginx.org/">nginx.org</a>.<br/>
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>

myweb2# cat /etc/hosts
# Kubernetes-managed hosts file.
127.0.0.1       localhost
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
10.244.0.13     myweb2

ip확인

10.244.0.13

myweb2# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: eth0@if16: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 8950 qdisc noqueue state UP group default
    link/ether 0e:77:89:1c:d9:d2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.244.0.13/25 brd 10.244.0.127 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::c77:89ff:fe1c:d9d2/64 scope link
       valid_lft forever preferred_lft forever

컨테이너에서 데몬 떠있는것 확인

80포트 떠있음을 확인함.

myweb2# ss -tln
State                           Recv-Q                          Send-Q                                                   Local Address:Port                                                     Peer Address:Port                          Process
LISTEN                          0                               511                                                            0.0.0.0:80                                                            0.0.0.0:*
LISTEN                          0                               511                                                               [::]:80                                                               [::]:*
myweb2#

나가기

myweb2# exit

다른 nginx 컨테이너로 들어가 업데이트 하기

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl exec -it myweb2 -c myweb2-nginx -- /bin/bash

root@myweb2:/# apt update
Get:1 http://deb.debian.org/debian bullseye InRelease [116 kB]
Get:2 http://deb.debian.org/debian-security bullseye-security InRelease [48.4 kB]
Get:3 http://deb.debian.org/debian bullseye-updates InRelease [44.1 kB]
Get:4 http://deb.debian.org/debian bullseye/main amd64 Packages [8183 kB]
Get:5 http://deb.debian.org/debian-security bullseye-security/main amd64 Packages [226 kB]
Get:6 http://deb.debian.org/debian bullseye-updates/main amd64 Packages [14.6 kB]
Fetched 8632 kB in 1s (7443 kB/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
1 package can be upgraded. Run 'apt list --upgradable' to see it.

컨테이너에서 툴 설치하기

root@myweb2:/# apt install -y procps net-tools
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done

Setting up procps (2:3.3.17-5) ...
Processing triggers for libc-bin (2.31-13+deb11u5) ...

컨테이너에서 웹 서비스 확인하기

root@myweb2:/# curl -s localhost |grep nginx
<title>Welcome to nginx!</title>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
<a href="http://nginx.org/">nginx.org</a>.<br/>
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>

컨테이너 IP 확인하기

컨테이너 2개 모두 IP가 10.244.0.13 로 동일 하다.

모두 Pod안에 있기 때문에 IP는 동일한게 정상이다.

root@myweb2:/# cat /etc/hosts
# Kubernetes-managed hosts file.
127.0.0.1       localhost
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
10.244.0.13     myweb2

root@myweb2:/# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 8950
        inet 10.244.0.13  netmask 255.255.255.128  broadcast 10.244.0.127
        inet6 fe80::c77:89ff:fe1c:d9d2  prefixlen 64  scopeid 0x20<link>
        ether 0e:77:89:1c:d9:d2  txqueuelen 0  (Ethernet)
        RX packets 602  bytes 9967394 (9.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 434  bytes 31591 (30.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

root@myweb2:/# exit
exit
command terminated with exit code 127

Pod 삭제하기

topasvga@cloudshell:~ (ap-seoul-1)$ kubectl delete pod myweb2
pod "myweb2" deleted

pod 삭제 확인하기
topasvga@cloudshell:~ (ap-seoul-1)$ kubectl get pods
No resources found in default namespace.

감사합니다.

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