[Kubernetes] 클러스터 구성 (CRI-O)

References

https://kubernetes.io/docs/setup/ (kubernetes.io)
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Node Settings

Master / node1 / node2 로 구성

# vi /etc/hosts             ---> master/node1/node2
<IP> master.example.com master
<IP> node1.example.com node1
<IP> node2.example.com node2


# hostnamectl set-hostname master.example.com
                           node1.example.com
                           node2.example.com

CRI-O 컨테이너 런타임 레파지토리 설정 및 설치

# yum install wget -y
# cd /etc/yum.repos.d/
# wget https://raw.githubusercontent.com/tangt64/training_memos/main/skt-ansible-intermediate/k8s-crio-stable-repository -O  /etc/yum.repos.d/k8s-crio-stable-repository.repo
# wget https://raw.githubusercontent.com/tangt64/training_memos/main/skt-ansible-intermediate/k8s-libcontainer-stable-repository -O /etc/yum.repos.d/k8s-libcontainer-stable-repository.repo
# yum search cri
cri-o.x86_64 : Kubernetes Container Runtime Interface for OCI-based containers
# yum install cri-o -y
# yum repolist
devel_kubic_libcontainers_stable                                      Stable Releases of Upstream github.com/containers packages (CentOS_7)
devel_kubic_libcontainers_stable_cri-o_1.18_1.18.3                    Release 1.18.3 (CentOS_7)

Swap 메모리 off, SELINUX Disable, 방화벽 Disable, OS 파라미터 설정

# swapoff -a            --> vi /etc/fstab -> swap 라인 UUID 주석처리
# setenforce 0          --> vi /etc/selinux/config -> SELINUX = disabled or permissive
# systemctl stop firewalld --> systemctl disable firewalld
# nmcli connection show --> nmcli co sh 
# nmtui                 --> Network Configure Modification command 
# cat <<EOF> /etc/sysctl.d/kubernetes-sys.conf

net.bridge.bridge-nf-call-iptables  = 1

net.ipv4.ip_forward                 = 1

net.bridge.bridge-nf-call-ip6tables = 1

EOF



# sysctl -p --system

Kubernetes 레파지토리 연결 및 다운로드

# cat <<EOF> /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
enabled=1
gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
exclude=kubelet kubeadm kubectl
EOF
# yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes

Master Node

# systemctl enable --now kubelet 
# systemctl is-active kubelet
activating
# systemctl -t service 
# systemctl enable crio --now
# kubeadm init 


# cat <<EOF> /etc/sysctl.d/kubernetes-sys.conf
net.bridge.bridge-nf-call-iptables  = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF


# sysctl -p --system


# cat <<EOF> /etc/modules-load.d/kubernetes-mod.conf
br_netfilter
overlay
EOF
# systemctl restart systemd-modules-load

Node Join (node1 / node2)

master# kubeadm token list
master# kubeadm token create --print-join-command
kubeadm join 192.168.90.171:6443 --token fkv0uf.2bzmt3rsu3ppa3lx --discovery-token-ca-cert-hash sha256:2fde3b6a891973ed7073a998385e1363eb9f38c67bd92ca24ec9ee5540004730




nodeX# kubeadm join 192.168.90.171:6443 --token fkv0uf.2bzmt3rsu3ppa3lx --discovery-token-ca-cert-hash sha256:2fde3b6a891973ed7073a998385e1363eb9f38c67bd92ca24ec9ee5540004730


master# kubectl get nodes
NAME                 STATUS   ROLES           AGE   VERSION
master.example.com   Ready    control-plane   52m   v1.24.3
node1.example.com    Ready    <none>          49m   v1.24.3

추가 스터디

https://kubernetes.io/docs/tutorials/hello-minikube/

master# mkdir -p $HOME/.kube
master# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
master# kubectl get nodes
master# kubectl get pods -A
master# kubectl get svc -A
master# kubectl get deployment -A

master# kubectl apply -f https://k8s.io/examples/service/load-balancer-example.yaml
master# kubectl get pods
master# kubectl get svc  --> pending때문에 외부에서 접근이 안됨
master# kubectl edit svc/hello-world
master# kubectl expose deployment hello-world --type=LoadBalancer --name=my-service
master# curl localhost:8080

쿠버네티스 초기화

# kubeadm reset --force