Last login: Thu Mar 1 00:45:37 2018 from 192.168.1.248
\n[root@clusterserver1 ~]# uname -a
\nLinux clusterserver1.rmohan.com 3.10.0-693.17.1.el7.x86_64 #1 SMP Thu Jan 25 20:13:58 UTC 2018 x86_64 x86_64 x86_64 GNU\/Linux
\n[root@clusterserver1 ~]#<\/p>\n
Master : 192.168.1.20
\nWorker1 : 192.168.1.21
\nWorker2 : 192.168.1.23
\nworker3 : 192.168.1.24<\/p>\n
hostnamectl set-hostname ‘clusterserver1.rmohan.com’
\nexec bash
\nsetenforce 0
\nsed -i –follow-symlinks ‘s\/SELINUX=enforcing\/SELINUX=disabled\/g’ \/etc\/sysconfig\/selinux<\/p>\n
[root@clusterserver1 ~]# cat \/etc\/redhat-release
\nCentOS Linux release 7.4.1708 (Core)
\n[root@clusterserver1 ~]#<\/p>\n
CentOS Linux release 7.4.1708 (Core)
\n[root@clusterserver1 ~]# cat \/etc\/hosts
\n127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
\n::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
\n192.168.1.20 clusterserver1.rmohan.com clusterserver1 master
\n192.168.1.21 clusterserver2.rmohan.com clusterserver2 worker1
\n192.168.1.22 clusterserver3.rmohan.com clusterserver3 worker2
\n192.168.1.23 clusterserver4.rmohan.com clusterserver4 worker3
\n[root@clusterserver1 ~]#<\/p>\n
[root@clusterserver1 ~]#systemctl stop firewalld && systemctl disable firewalld<\/p>\n
[root@clusterserver1 ~]#yum update -y
\n[root@clusterserver1 ~]# modprobe br_netfilter
\n[root@clusterserver1 ~]#sysctl net.bridge.bridge-nf-call-iptables=1
\n[root@clusterserver1 ~]#sysctl net.bridge.bridge-nf-call-ip6tables=1<\/p>\n
[root@clusterserver1 ~]# cat <<EOF > \/etc\/sysctl.d\/k8s.conf
\nnet.bridge.bridge-nf-call-ip6tables = 1
\nnet.bridge.bridge-nf-call-iptables = 1
\nEOF
\n[root@clusterserver1 ~]# sysctl –system<\/p>\n
cat <<EOF > \/etc\/yum.repos.d\/virt7-dockerrelease.repo
\n[virt7-docker-common-release]
\nname=virt7-docker-common-release
\nbaseurl=http:\/\/cbs.centos.org\/repos\/virt7-docker-common-release\/x86_64\/os\/
\ngpgcheck=0
\nEOF<\/p>\n
cat <<eof > \/etc\/yum.repos.d\/kubernetes.repo
\n[kubernetes]
\nname=kubernetes
\nbaseurl=https:\/\/packages.cloud.google.com\/yum\/repos\/kubernetes-el7-x86_64
\nenabled=1
\ngpgcheck=1
\nrepo_gpgcheck=1
\ngpgkey=https:\/\/packages.cloud.google.com\/yum\/doc\/yum-key.gpg
\nhttps:\/\/packages.cloud.google.com\/yum\/doc\/rpm-package-key.gpg
\neof<\/p>\n
[root@clusterserver1 ~]# yum install ebtables ethtool<\/p>\n
[root@clusterserver1 ~]# yum install -y kubelet kubeadm kubectl docker<\/p>\n
#systemctl enable kubelet && systemctl start kubelet<\/p>\n
After this Check Kubelet is running fine<\/p>\n
#systemctl status kubelet -l<\/p>\n
[root@clusterserver1 ~]# systemctl status kubelet -l
\n? kubelet.service – kubelet: The Kubernetes Node Agent
\nLoaded: loaded (\/etc\/systemd\/system\/kubelet.service; enabled; vendor preset: disabled)
\nDrop-In: \/etc\/systemd\/system\/kubelet.service.d
\n??10-kubeadm.conf
\nActive: activating (auto-restart) (Result: exit-code) since Thu 2018-03-01 16:16:40 +08; 8s ago
\nDocs: http:\/\/kubernetes.io\/docs\/
\nProcess: 2504 ExecStart=\/usr\/bin\/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_SYSTEM_PODS_ARGS $KUBELET_NETWORK_ARGS $KUBELET_DNS_ARGS $KUBELET_AUTHZ_ARGS $KUBELET_CADVISOR_ARGS $KUBELET_CGROUP_ARGS $KUBELET_CERTIFICATE_ARGS $KUBELET_EXTRA_ARGS (code=exited, status=1\/FAILURE)
\nMain PID: 2504 (code=exited, status=1\/FAILURE)<\/p>\n
Mar 01 16:16:40 clusterserver1.rmohan.com systemd[1]: kubelet.service: main process exited, code=exited, status=1\/FAILURE
\nMar 01 16:16:40 clusterserver1.rmohan.com systemd[1]: Unit kubelet.service entered failed state.
\nMar 01 16:16:40 clusterserver1.rmohan.com systemd[1]: kubelet.service failed.
\n[root@clusterserver1 ~]# ystemctl status kubelet -l
\n-bash: ystemctl: command not found
\n[root@clusterserver1 ~]# systemctl status kubelet -l
\n? kubelet.service – kubelet: The Kubernetes Node Agent
\nLoaded: loaded (\/etc\/systemd\/system\/kubelet.service; enabled; vendor preset: disabled)
\nDrop-In: \/etc\/systemd\/system\/kubelet.service.d
\n??10-kubeadm.conf
\nActive: activating (auto-restart) (Result: exit-code) since Thu 2018-03-01 16:17:01 +08; 1s ago
\nDocs: http:\/\/kubernetes.io\/docs\/
\nProcess: 2517 ExecStart=\/usr\/bin\/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_SYSTEM_PODS_ARGS $KUBELET_NETWORK_ARGS $KUBELET_DNS_ARGS $KUBELET_AUTHZ_ARGS $KUBELET_CADVISOR_ARGS $KUBELET_CGROUP_ARGS $KUBELET_CERTIFICATE_ARGS $KUBELET_EXTRA_ARGS (code=exited, status=1\/FAILURE)
\nMain PID: 2517 (code=exited, status=1\/FAILURE)<\/p>\n
Can verify errors in \/var\/log\/message
\n[root@clusterserver1 ~]# tail -f \/var\/log\/messages
\nMar 1 16:17:11 clusterserver1 systemd: kubelet.service holdoff time over, scheduling restart.
\nMar 1 16:17:11 clusterserver1 systemd: Started kubelet: The Kubernetes Node Agent.
\nMar 1 16:17:11 clusterserver1 systemd: Starting kubelet: The Kubernetes Node Agent…
\nMar 1 16:17:11 clusterserver1 kubelet: I0301 16:17:11.580912 2523 feature_gate.go:226] feature gates: &{{} map[]}
\nMar 1 16:17:11 clusterserver1 kubelet: I0301 16:17:11.581022 2523 controller.go:114] kubelet config controller: starting controller
\nMar 1 16:17:11 clusterserver1 kubelet: I0301 16:17:11.581030 2523 controller.go:118] kubelet config controller: validating combination of defaults and flags
\nMar 1 16:17:11 clusterserver1 kubelet: error: unable to load client CA file \/etc\/kubernetes\/pki\/ca.crt: open \/etc\/kubernetes\/pki\/ca.crt: no such file or directory
\nMar 1 16:17:11 clusterserver1 systemd: kubelet.service: main process exited, code=exited, status=1\/FAILURE
\nMar 1 16:17:11 clusterserver1 systemd: Unit kubelet.service entered failed state.
\nMar 1 16:17:11 clusterserver1 systemd: kubelet.service failed.
\nMar 1 16:17:21 clusterserver1 systemd: kubelet.service holdoff time over, scheduling restart.
\nMar 1 16:17:21 clusterserver1 systemd: Started kubelet: The Kubernetes Node Agent.
\nMar 1 16:17:21 clusterserver1 systemd: Starting kubelet: The Kubernetes Node Agent…
\nMar 1 16:17:21 clusterserver1 kubelet: I0301 16:17:21.830092 2535 feature_gate.go:226] feature gates: &{{} map[]}
\nMar 1 16:17:21 clusterserver1 kubelet: I0301 16:17:21.830201 2535 controller.go:114] kubelet config controller: starting controller
\nMar 1 16:17:21 clusterserver1 kubelet: I0301 16:17:21.830209 2535 controller.go:118] kubelet config controller: validating combination of defaults and flags
\nMar 1 16:17:21 clusterserver1 kubelet: error: unable to load client CA file \/etc\/kubernetes\/pki\/ca.crt: open \/etc\/kubernetes\/pki\/ca.crt: no such file or directory
\nMar 1 16:17:21 clusterserver1 systemd: kubelet.service: main process exited, code=exited, status=1\/FAILURE
\nMar 1 16:17:21 clusterserver1 systemd: Unit kubelet.service entered failed state.
\nMar 1 16:17:21 clusterserver1 systemd: kubelet.service failed.<\/p>\n
So here Issue is “error: unable to load client CA file \/etc\/kubernetes\/pki\/ca.crt” As we have not installed kubeadm here<\/p>\n
So now if this you are trying on worker node and already installed kubeadm on master then you can try Copying files from Master.<\/p>\n
If this is you Master Node setup then let Start Master Node setup here<\/p>\n
If kubernates was tried\/installed any time on your machine then you need to reset kubeadm
\nrun command on Master Node<\/p>\n
[root@clusterserver1 ~]# kubeadm reset
\n[preflight] Running pre-flight checks.
\n[reset] Stopping the kubelet service.
\n[reset] Unmounting mounted directories in “\/var\/lib\/kubelet”
\n[reset] Removing kubernetes-managed containers.
\n[reset] Docker doesn’t seem to be running. Skipping the removal of running Kubernetes containers.
\n[reset] No etcd manifest found in “\/etc\/kubernetes\/manifests\/etcd.yaml”. Assuming external etcd.
\n[reset] Deleting contents of stateful directories: [\/var\/lib\/kubelet \/etc\/cni\/net.d \/var\/lib\/dockershim \/var\/run\/kubernetes]
\n[reset] Deleting contents of config directories: [\/etc\/kubernetes\/manifests \/etc\/kubernetes\/pki]
\n[reset] Deleting files: [\/etc\/kubernetes\/admin.conf \/etc\/kubernetes\/kubelet.conf \/etc\/kubernetes\/controller-manager.conf \/etc\/kubernetes\/scheduler.conf]
\n[root@clusterserver1 ~]#<\/p>\n
[root@clusterserver1 ~]# kubeadm init
\n[init] Using Kubernetes version: v1.9.3
\n[init] Using Authorization modes: [Node RBAC]
\n[preflight] Running pre-flight checks.
\n[preflight] The system verification failed. Printing the output from the verification:
\nKERNEL_VERSION: 3.10.0-693.17.1.el7.x86_64
\nCONFIG_NAMESPACES: enabled
\nCONFIG_NET_NS: enabled
\nCONFIG_PID_NS: enabled
\nCONFIG_IPC_NS: enabled
\nCONFIG_UTS_NS: enabled
\nCONFIG_CGROUPS: enabled
\nCONFIG_CGROUP_CPUACCT: enabled
\nCONFIG_CGROUP_DEVICE: enabled
\nCONFIG_CGROUP_FREEZER: enabled
\nCONFIG_CGROUP_SCHED: enabled
\nCONFIG_CPUSETS: enabled
\nCONFIG_MEMCG: enabled
\nCONFIG_INET: enabled
\nCONFIG_EXT4_FS: enabled (as module)
\nCONFIG_PROC_FS: enabled
\nCONFIG_NETFILTER_XT_TARGET_REDIRECT: enabled (as module)
\nCONFIG_NETFILTER_XT_MATCH_COMMENT: enabled (as module)
\nCONFIG_OVERLAY_FS: enabled (as module)
\nCONFIG_AUFS_FS: not set – Required for aufs.
\nCONFIG_BLK_DEV_DM: enabled (as module)
\nOS: Linux
\nCGROUPS_CPU: enabled
\nCGROUPS_CPUACCT: enabled
\nCGROUPS_CPUSET: enabled
\nCGROUPS_DEVICES: enabled
\nCGROUPS_FREEZER: enabled
\nCGROUPS_MEMORY: enabled
\n[WARNING FileExisting-crictl]: crictl not found in system path
\n[WARNING Service-Docker]: docker service is not enabled, please run ‘systemctl enable docker.service’
\n[preflight] Some fatal errors occurred:
\n[ERROR SystemVerification]: failed to get docker info: Cannot connect to the Docker daemon at unix:\/\/\/var\/run\/docker.sock. Is the docker daemon running?
\n[ERROR Swap]: running with swap on is not supported. Please disable swap
\n[ERROR Service-Docker]: docker service is not active, please run ‘systemctl start docker.service’
\n[preflight] If you know what you are doing, you can make a check non-fatal with `–ignore-preflight-errors=…`<\/p>\n
Disable swap<\/p>\n
swapoff -a<\/p>\n
enable docker and start the docker services<\/p>\n
[root@clusterserver1 ~]# kubeadm init
\n[init] Using Kubernetes version: v1.9.3
\n[init] Using Authorization modes: [Node RBAC]
\n[preflight] Running pre-flight checks.
\n[WARNING FileExisting-crictl]: crictl not found in system path
\n[preflight] Starting the kubelet service
\n[certificates] Generated ca certificate and key.
\n[certificates] Generated apiserver certificate and key.
\n[certificates] apiserver serving cert is signed for DNS names [clusterserver1.rmohan.com kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.1.20]
\n[certificates] Generated apiserver-kubelet-client certificate and key.
\n[certificates] Generated sa key and public key.
\n[certificates] Generated front-proxy-ca certificate and key.
\n[certificates] Generated front-proxy-client certificate and key.
\n[certificates] Valid certificates and keys now exist in “\/etc\/kubernetes\/pki”
\n[kubeconfig] Wrote KubeConfig file to disk: “admin.conf”
\n[kubeconfig] Wrote KubeConfig file to disk: “kubelet.conf”
\n[kubeconfig] Wrote KubeConfig file to disk: “controller-manager.conf”
\n[kubeconfig] Wrote KubeConfig file to disk: “scheduler.conf”
\n[controlplane] Wrote Static Pod manifest for component kube-apiserver to “\/etc\/kubernetes\/manifests\/kube-apiserver.yaml”
\n[controlplane] Wrote Static Pod manifest for component kube-controller-manager to “\/etc\/kubernetes\/manifests\/kube-controller-manager.yaml”
\n[controlplane] Wrote Static Pod manifest for component kube-scheduler to “\/etc\/kubernetes\/manifests\/kube-scheduler.yaml”
\n[etcd] Wrote Static Pod manifest for a local etcd instance to “\/etc\/kubernetes\/manifests\/etcd.yaml”
\n[init] Waiting for the kubelet to boot up the control plane as Static Pods from directory “\/etc\/kubernetes\/manifests”.
\n[init] This might take a minute or longer if the control plane images have to be pulled.
\n[apiclient] All control plane components are healthy after 85.002972 seconds
\n[uploadconfig]\u00a0Storing the configuration used in ConfigMap “kubeadm-config” in the “kube-system” Namespace
\n[markmaster] Will mark node clusterserver1.rmohan.com as master by adding a label and a taint
\n[markmaster] Master clusterserver1.rmohan.com tainted and labelled with key\/value: node-role.kubernetes.io\/master=””
\n[bootstraptoken] Using token: 8c45ed.70033b8135e5439a
\n[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
\n[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
\n[bootstraptoken] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
\n[bootstraptoken] Creating the “cluster-info” ConfigMap in the “kube-public” namespace
\n[addons] Applied essential addon: kube-dns
\n[addons] Applied essential addon: kube-proxy<\/p>\n
Your Kubernetes master has initialized successfully!<\/p>\n
To start using your cluster, you need to run the following as a regular user:<\/p>\n
mkdir -p $HOME\/.kube
\nsudo cp -i \/etc\/kubernetes\/admin.conf $HOME\/.kube\/config
\nsudo chown $(id -u):$(id -g) $HOME\/.kube\/config<\/p>\n
You should now deploy a pod network to the cluster.
\nRun “kubectl apply -f [podnetwork].yaml” with one of the options listed at:
\nhttps:\/\/kubernetes.io\/docs\/concepts\/cluster-administration\/addons\/<\/p>\n
You can now join any number of machines by running the following on each node
\nas root:<\/p>\n
kubeadm join –token 8c45ed.70033b8135e5439a 192.168.1.20:6443 –discovery-token-ca-cert-hash sha256:1df9c0250f28e5a4d137f29307b787954948fc417f2fa9a06a195d65f41b959d<\/p>\n
[root@clusterserver1 ~]# mkdir -p $HOME\/.kube
\n[root@clusterserver1 ~]# cp -i \/etc\/kubernetes\/admin.conf $HOME\/.kube\/config
\n[root@clusterserver1 ~]# chown $(id -u):$(id -g) $HOME\/.kube\/config<\/p>\n
[root@clusterserver1 ~]# kubectl get nodes
\nNAME STATUS ROLES AGE VERSION
\nclusterserver1.rmohan.com NotReady master 2m v1.9.3
\n[root@clusterserver1 ~]#<\/p>\n
Install kubeadm and docker package on both nodes<\/p>\n
[root@clusterserver2 ~]# yum install kubeadm docker -y
\n[root@clusterserver3 ~]# yum install kubeadm docker -y
\n[root@clusterserver4 ~]# yum install kubeadm docker -y<\/p>\n
Start and enable docker service<\/p>\n
[root@clusterserver2 ~]# systemctl restart docker && systemctl enable docker
\n[root@clusterserver3 ~]# systemctl restart docker && systemctl enable docker
\n[root@clusterserver4 ~]# systemctl restart docker && systemctl enable docker<\/p>\n
Step 4: Now Join worker nodes to master node<\/p>\n
To join worker nodes to Master node, a token is required. Whenever kubernetes master initialized , then in the output we get command and token. Copy that command and run on both nodes.<\/p>\n
[root@worker-node1 ~]# kubeadm join –token 8c45ed.70033b8135e5439a 192.168.1.20:6443 –discovery-token-ca-cert-hash sha256:1df9c0250f28e5a4d137f29307b787954948fc417f2fa9a06a195d65f41b959d<\/p>\n
yum install epel-release -y<\/p>\n
yum install ansible -y<\/p>\n","protected":false},"excerpt":{"rendered":"
Last login: Thu Mar 1 00:45:37 2018 from 192.168.1.248 [root@clusterserver1 ~]# uname -a Linux clusterserver1.rmohan.com 3.10.0-693.17.1.el7.x86_64 #1 SMP Thu Jan 25 20:13:58 UTC 2018 x86_64 x86_64 x86_64 GNU\/Linux [root@clusterserver1 ~]#<\/p>\n
Master : 192.168.1.20 Worker1 : 192.168.1.21 Worker2 : 192.168.1.23 worker3 : 192.168.1.24<\/p>\n
hostnamectl set-hostname ‘clusterserver1.rmohan.com’ exec bash setenforce 0 sed -i –follow-symlinks ‘s\/SELINUX=enforcing\/SELINUX=disabled\/g’ \/etc\/sysconfig\/selinux<\/p>\n
[root@clusterserver1 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/7570"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7570"}],"version-history":[{"count":1,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/7570\/revisions"}],"predecessor-version":[{"id":7571,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/7570\/revisions\/7571"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7570"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7570"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7570"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}