kubernetes - centos 7 에서 설치

 

 

[root@kube ~]# hostnamectl set-hostname master

[root@master ~]# vi /etc/hosts

192.168.x.x master

 

[root@master ~]# yum install -y yum-utils device-mapper-persistent-data lvm2

[root@master ~]# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

[root@master ~]# yum -y install docker-ce

 

 

[root@master ~]# systemctl stop firewalld
[root@master ~]# systemctl disable firewalld

[root@master ~]# sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

[root@master ~]# setenforce 0

[root@master ~]# getenforce
Permissive

 

default값이 0 이다. bridge 네트워크 송수신 패킷이 iptable을 우회함

그래서 1로 활성화 시킴 즉, kubernetes에서는 iptable을 사용할 수 있게 enable해주는것

[root@master ~]# modprobe br_netfilter

[root@master sysctl.d]# ll /proc/sys/net/
total 0
dr-xr-xr-x. 1 root root 0 May 22 10:29 bridge

 

[root@master ~]# echo '1' > /proc/sys/net/bridge/bridge-nf-call-iptables

[root@master ~]# modprobe br_netfilter

또는

[root@master ~]# vi /etc/sysctl.d/k8s.conf

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

[root@master ~]# sysctl --system

확인 # sysctl -a | grep iptables

 

[root@master sysctl.d]# echo 1 > /proc/sys/net/ipv4/ip_forward
[root@master sysctl.d]# sysctl -a | grep ip_forward
net.ipv4.ip_forward = 1

 

 

 

kubelet 동작위해 swap off 시킴

[root@master sysctl.d]# swapoff -a
[root@master sysctl.d]# vi /etc/fstab   //아래 주석처리

#/dev/mapper/centos-swap swap                    swap    defaults        0 0

 

 

k8s repo 추가

[root@master sysctl.d]# vi /etc/yum.repos.d/kubernetes.repo

[kubernetes]

name=Kubernetes

baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64

enabled=1

gpgcheck=1

repo_gpgcheck=1

gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gp

 

 

 

docker, kubelet 데몬 활성화

[root@master sysctl.d]# systemctl start docker && systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master sysctl.d]# systemctl start kubelet && systemctl enable kubelet
Created symlink from /etc/systemd/system/multi-user.target.wants/kubelet.service to /usr/lib/systemd/system/kubelet.service.

 

 

kube관련 설치

[root@master sysctl.d]# yum -y install kubelet kubeadm kubectl --disableexcludes=kubernetes

 

 

쿠버네티스 클러스터 초기화

[root@master ~]# kubeadm init --apiserver-advertise-address=192.168.200.150 --pod-network-cidr=10.244.0.0/16

[root@master ~]# kubeadm init --apiserver-advertise-address=192.168.200.150 --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.21.1
[preflight] Running pre-flight checks
        [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[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'
[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 [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local master] and IPs [10.96.0.1 192.168.200.150]
[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 [localhost master] and IPs [192.168.200.150 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost master] and IPs [192.168.200.150 127.0.0.1 ::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
[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
[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"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[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 33.508927 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.21" 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 master as control-plane by adding the labels: [node-role.kubernetes.io/master(deprecated) node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
[mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: whrnkx.ew8481lg7fvn7ypx
[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:

  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:

//아래 명령어는 worker 노드들 조인할때 사용
kubeadm join 192.168.200.150:6443 --token whrnkx.ew8481lg7fvn7ypx \
        --discovery-token-ca-cert-hash sha256:68ed03cfcc60e22e58dbb5587e9961ebf636087ff78998bc88c98cc56f100c85

 

따로 복사 그룹 변경

[root@master ~]# mkdir -p $HOME/.kube
[root@master ~]# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@master ~]# chown $(id -u):$(id -g) $HOME/.kube/config

[root@master ~]# ls -als  ~/.kube/config
8 -rw-------. 1 root root 5599 May 22 10:46 /root/.kube/config

 

 

cni는 플라넬 사용

[root@master ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Warning: policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created

 

확인

[root@master ~]# kubectl get pods --all-namespaces
NAMESPACE     NAME                             READY   STATUS    RESTARTS   AGE
kube-system   coredns-558bd4d5db-mxj4t         1/1     Running   0          8m7s
kube-system   coredns-558bd4d5db-w9s4w         1/1     Running   0          8m7s
kube-system   etcd-master                      1/1     Running   0          8m13s
kube-system   kube-apiserver-master            1/1     Running   0          8m13s
kube-system   kube-controller-manager-master   1/1     Running   0          8m13s
kube-system   kube-flannel-ds-2xtzc            1/1     Running   0          44s
kube-system   kube-proxy-k2v27                 1/1     Running   0          8m8s
kube-system   kube-scheduler-master            1/1     Running   0          8m13s
[root@master ~]# kubectl get nodes
NAME     STATUS   ROLES                  AGE     VERSION
master   Ready    control-plane,master   8m29s   v1.21.1

 

 

worker 노드에 붙일려면 ..

아래 명령어 입력

#kubeadm join 192.168.200.150:6443 --token whrnkx.ew8481lg7fvn7ypx \
        --discovery-token-ca-cert-hash sha256:68ed03cfcc60e22e58dbb5587e9961ebf636087ff78998bc88c98cc56f100c85

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

참고: https://gruuuuu.github.io/cloud/k8s-install/

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