쿠버네티스 클러스터 초기화


1) 방화벽 해제
sudo ufw disable # 방화벽 해제

2) swap 해제
sudo ufw disable ## 스왑 확인
sudo ufw disable ## 스왑 해체 / 영구적인 아닌 현재 실행 중인 상태의 swap off
sudo reboot # 하면 다시 swap 살아남
sudo vi /et/fstab ## 여기로 가서 swap부분 주석처리해도 영구적 x
crontab -e -> @reboot swapoff -a

3) ntp 설정
sudo apt -y install ntp
sudo systemctl enable ntp
sudo systemctl restart ntp
sudo ntpq -p ## 시간 동기화서버들 리스트

4) CNI중 calico plugin 사용 -> l3 기반 통신 수행 -> 패킷을 ip 기반으로 트래픽 제어 -> ip forward
student@k8s-master:~$ sudo -i
[sudo] password for student: 
root@k8s-master:~# cat /proc/sys/net/ipv
ipv4/ ipv6/ 
root@k8s-master:~# cat /proc/sys/net/ipv4/ip_forward
0
root@k8s-master:~# echo '1' > /proc/sys/net/ipv4/ip_forward
root@k8s-master:~# cat /proc/sys/net/ipv4/ip_forward
1

5) container는 bridge 기반 네트워크 통신 -> iptables에 등
student@k8s-master:~$ sudo vi  /etc/modules-load.d/containerd.conf
student@k8s-master:~$ cat  /etc/modules-load.d/containerd.conf
overlay
br_netfilter # iptables의 모듈이 netfilter

student@k8s-master:~$ sudo modprobe overlay
student@k8s-master:~$ sudo modprobe br_netfilter

student@k8s-master:~$ sudo vi /etc/sysctl.d/99-kubernetes-cri.conf
student@k8s-master:~$ cat vi /etc/sysctl.d/99-kubernetes-cri.conf
cat: vi: No such file or directory
net.bridge.bridge-nf-call-iptables  = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-ip6tables = 1

student@k8s-master:~$ sudo sysctl --system ## 방금 설정한 파일에 에러 안나면 정상 작동

— container image build 를 위한 docker-ce 설치


student@k8s-master:~$ sudo apt -y install apt-transport-https curl ca-certificates software-properties-common gnupg2  ## 패키지 설치

~~~~sudo install -m 0755 -d /etc/apt/keyrings
sudo curl -fsSL <https://download.docker.com/linux/ubuntu/gpg> -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc

# Add the repository to Apt sources:
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] <https://download.docker.com/linux/ubuntu> \
  $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update

student@k8s-master:~$  sudo apt-get install docker-ce docker-ce-cli containerd.io

student@k8s-master:~$ docker --version
student@k8s-master:~$ sudo usermod -aG docker student
student@k8s-master:~$ sudo systemctl daemon-reload
student@k8s-master:~$ sudo systemctl enable docker
student@k8s-master:~$ sudo systemctl restart docker
student@k8s-master:~$ sudo systemctl status docker

student@k8s-master:~$ sudo -i
root@k8s-master:~# containerd config default | tee /etc/containerd/config.toml 
root@k8s-master:~# vi /etc/containerd/config.toml 
student@k8s-master:~$ sudo systemctl restart containerd.service
student@k8s-master:~$ sudo systemctl enable containerd.service
student@k8s-master:~$ sudo systemctl status containerd.service

Installing kubeadm

위 링크에서 4번의 update까지만 하고 install은 따로 버전 지정해서 진행
 
student@k8s-master:~$ apt-cache policy kubeadm
kubeadm:
  Installed: (none)
  Candidate: 1.28.8-1.1
  Version table:
     1.28.8-1.1 500
...
        500 <https://pkgs.k8s.io/core:/stable:/v1.28/deb>  Packages
student@k8s-master:~$ apt-cache policy kubectl
kubectl:
  Installed: (none)
  Candidate: 1.28.8-1.1
  Version table:
     1.28.8-1.1 500
        500 <https://pkgs.k8s.io/core:/stable:/v1.28/deb>  Packages
   ... 
        500 <https://pkgs.k8s.io/core:/stable:/v1.28/deb>  Packages
student@k8s-master:~$ apt-cache policy kubelet
kubelet:
  Installed: (none)
  Candidate: 1.28.8-1.1
  Version table:
     1.28.8-1.1 500
        500 <https://pkgs.k8s.io/core:/stable:/v1.28/deb>  Packages
     1.28.7-1.1 500
...le:/v1.28/deb  Packages
     1.28.1-1.1 500

student@k8s-master:~$ 

## 버전 지정 안하면 후보로 됨
student@k8s-master:~$ sudo apt-get install -y kubelet=1.28.8-1.1 kubeadm=1.28.8-1.1 kubectl=1.28.8-1.1

### 등
student@k8s-master:~$ sudo systemctl daemon-reload
student@k8s-master:~$ sudo systemctl enable kubelet

### 업데이트로부터 격
student@k8s-master:~$ kubelet --version
Kubernetes v1.28.8
student@k8s-master:~$ sudo apt-mark hold kubeadm kubelet kubectl
kubeadm set on hold.
kubelet set on hold.
kubectl set on hold.
student@k8s-master:~$ 

student@k8s-master:~$ sudo vi /etc/hosts
student@k8s-master:~$ sudo cat /etc/hosts
127.0.0.1       localhost
127.0.1.1       k8s-master

192.168.56.100 k8s-master
192.168.56.101 k8s-node1
192.168.56.102 k8s-node2
192.168.56.103 k8s-node3

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
student@k8s-master:~$

vm 복제 후 워커노드로 지정 hostname, vi hosts 편집 필요

run common

student@k8s-master:~$ sudo hostnamectl set-hostname k8s-node1
student@k8s-master:~$ sudo vi /etc/hosts
student@k8s-master:~$ reboot

current_ version : 1.28.8-1.1

sudo kubeadm init --apiserver-advertise-address=192.168.56.100 --pod network-cidr=10.96.0.0/12 --service-cidr=172.100.0.0/12

kubeadm init

student@k8s-master:~$ sudo kubeadm init --apiserver-advertise-address=192.168.56.100 --pod-network-cidr=10.96.0.0/12 --service-cidr=172.100.0.0/12
I0409 16:33:04.829264    3874 version.go:256] remote version is much newer: v1.29.3; falling back to: stable-1.28
[init] Using Kubernetes version: v1.28.8
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
W0409 16:34:16.356115    3874 checks.go:835] detected that the sandbox image "registry.k8s.io/pause:3.6" of the container runtime is inconsistent with that used by kubeadm. It is recommended that using "registry.k8s.io/pause:3.9" as the CRI sandbox image.
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [172.96.0.1 192.168.56.100]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.56.100 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master localhost] and IPs [192.168.56.100 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 28.521740 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node k8s-master as control-plane by adding the labels: [node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
[mark-control-plane] Marking the node k8s-master as control-plane by adding the taints [node-role.kubernetes.io/control-plane:NoSchedule]
[bootstrap-token] Using token: y5hn7x.fq1olshrswin530l
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:
## master에서만
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  <https://kubernetes.io/docs/concepts/cluster-administration/addons/>

Then you can join any number of worker nodes by running the following on each as root:

## 워커노드에서
kubeadm join 192.168.56.100:6443 --token z6w4co.uqm97ue6o96bzmm4         --discovery-token-ca-cert-hash sha256:bf710118a2458ec34e8527d4c436a9786fb5a83415450ffb8403c8d7a6b40f83

## 파드 노드 확인 시 에러나면, 

## 모든 노드에
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/g' /etc/containerd/config.toml

## 파드 다시 확인
kubectl get po -A

##CNI calico pull
curl -O <https://raw.githubusercontent.com/projectcalico/calico/v3.25.0/manifests/calico.yaml>

docker pull docker.io/calico/cni:v3.25.0
docker pull docker.io/calico/node:v3.25.0
docker pull docker.io/calico/kube-controllers:v3.25.0

## Reset 하는 명령어
sudo kubeadm reset 
sudo systemctl restart kubelet

sudo kubeadm reset
sudo rm -rf /etc/kubernetes/
sudo rm -rf /var/lib/etcd/
sudo rm -rf /var/lib/kubelet

##6443에러(join후)
sudo -i
containerd config default | tee /etc/containerd/config.toml
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/g' /etc/containerd/config.toml
sudo systemctl restart containerd
sudo systemctl restart kubelet

kubectl -n kube-system exec -it etcd-k8s-master2 -- sh -c "ETCDCTL_API=3 ETCDCTL_CACERT=/etc/kubernetes/pki/etcd/ca.crt \
ETCDCTL_CERT=/etc/kubernetes/pki/etcd/server.crt \
ETCDCTL_KEY=/etc/kubernetes/pki/etcd/server.key \
etcdctl member list -w table"
-> 멤버 조회 etcd

##조회
sudo netstat -nltp | grep LISTEN

sudo kubeadm join k8s-loadbalance:6443 --apiserver-advertise-address=192.168.56.112 --token he969n.oirl1gxhn9ookuu6         --discovery-token-ca-cert-hash sha256:4bb3099903723855b4cbfae12247845fecc1c2b77432bbf6a1e27d383ab8b684         --control-plane --certificate-key 0c2af77add74cbb25673a13a8856d70c6aae3280a48fa1315852b4860525740f
sudo kubeadm join k8s-loadbalance:6443 --apiserver-advertise-address=192.168.56.113 --token he969n.oirl1gxhn9ookuu6         --discovery-token-ca-cert-hash sha256:4bb3099903723855b4cbfae12247845fecc1c2b77432bbf6a1e27d383ab8b684         --control-plane --certificate-key 0c2af77add74cbb25673a13a8856d70c6aae3280a48fa1315852b4860525740f