Kubernetes/Install Master and nodes
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Revision as of 16:30, 6 July 2019 by Pio2pio (talk | contribs) (→Highly Available Kubernetes Cluster)
This example is based on Ubuntu 16 LTS
Install binaries
#Docker gpg key curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add - #Docker repository sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" #Kubernetes gpg key curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - #Kubernetes repository cat << EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list deb https://apt.kubernetes.io/ kubernetes-xenial main EOF #Install software sudo apt-get update sudo apt-get install -y docker-ce=18.06.1~ce~3-0~ubuntu kubelet=1.13.5-00 kubeadm=1.13.5-00 kubectl=1.13.5-00 # Set packages at the current versions so they won't autoupdate sudo apt-mark hold docker-ce kubelet kubeadm kubectl #Add the iptables rule to sysctl.conf; then enable imidiately echo "net.bridge.bridge-nf-call-iptables=1" | sudo tee -a /etc/sysctl.conf sudo sysctl -p
Initialize a cluster
Run only on the master to initialize the cluster
sudo kubeadm init --pod-network-cidr=10.100.0.0/16 I0705 06:23:54.675905 24293 version.go:237] remote version is much newer: v1.15.0; falling back to: stable-1.13 [init] Using Kubernetes version: v1.13.7 [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' [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] Activating the kubelet service [certs] Using certificateDir folder "/etc/kubernetes/pki" [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/peer" certificate and key [certs] etcd/peer serving cert is signed for DNS names [kubemaster.acme.com localhost] and IPs [172.31.115.255 127.0.0.1 ::1] [certs] Generating "etcd/healthcheck-client" certificate and key [certs] Generating "apiserver-etcd-client" certificate and key [certs] Generating "etcd/server" certificate and key [certs] etcd/server serving cert is signed for DNS names [kubemaster.acme.com localhost] and IPs [172.31.115.255 127.0.0.1 ::1] [certs] Generating "ca" certificate and key [certs] Generating "apiserver" certificate and key [certs] apiserver serving cert is signed for DNS names [kubemaster.acme.com kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 172.31.115.255] [certs] Generating "apiserver-kubelet-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 [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 20.002150 seconds [uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config-1.13" in namespace kube-system with the configuration for the kubelets in the cluster [patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "kubemaster.acme.com" as an annotation [mark-control-plane] Marking the node kubemaster.acme.com as control-plane by adding the label "node-role.kubernetes.io/master=''" [mark-control-plane] Marking the node kubemaster.acme.com as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule] [bootstrap-token] Using token: xkcoul.0i2m*******ockj [bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles [bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials [bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token [bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster [bootstraptoken] creating the "cluster-info" ConfigMap in the "kube-public" namespace [addons] Applied essential addon: CoreDNS [addons] Applied essential addon: kube-proxy Your Kubernetes master 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 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/ You can now join any number of machines by running the following on each node as root: kubeadm join 172.31.115.255:6443 --token xkcoul.0i2m*******ockj --discovery-token-ca-cert-hash sha256:808*******6a
Set up local kubeconfig:
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
Create Flannel CNI network overlay to allow nodes to communicate with each other
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/bc79dd1505b0c8681ece4de4c0d86c5cd2643275/Documentation/kube-flannel.yml clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.extensions/kube-flannel-ds-amd64 created daemonset.extensions/kube-flannel-ds-arm64 created daemonset.extensions/kube-flannel-ds-arm created daemonset.extensions/kube-flannel-ds-ppc64le created daemonset.extensions/kube-flannel-ds-s390x created
Join worker nodes
Run on worker nodes - join worker nodes to the master
sudo kubeadm join 172.31.115.255:6443 --token xkcoul.0i2m*******ockj --discovery-token-ca-cert-hash sha256:808*******6a [preflight] Running pre-flight checks [discovery] Trying to connect to API Server "172.31.115.255:6443" [discovery] Created cluster-info discovery client, requesting info from "https://172.31.115.255:6443" [discovery] Requesting info from "https://172.31.115.255:6443" again to validate TLS against the pinned public key [discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "172.31.115.255:6443" [discovery] Successfully established connection with API Server "172.31.115.255:6443" [join] Reading configuration from the cluster... [join] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml' [kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.13" ConfigMap in the kube-system namespace [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Activating the kubelet service [tlsbootstrap] Waiting for the kubelet to perform the TLS Bootstrap... [patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "kubeworker1.acme.com" as an annotation This node has joined the cluster: * Certificate signing request was sent to apiserver and a response was received. * The Kubelet was informed of the new secure connection details. Run 'kubectl get nodes' on the master to see this node join the cluster.
Verify nodes joined the cluster
$ kubectl get nodes NAME STATUS ROLES AGE VERSION kubemaster.acme.com Ready master 16m v1.13.5 kubeworker1.acme.com Ready <none> 2m45s v1.13.5 kubeworker2.acme.com Ready <none> 2m39s v1.13.5
Highly Available Kubernetes Cluster
#View cluster components kubectl get pods -o custom-columns=POD:metadata.name,NODE:spec.nodeName --sort-by spec.nodeName -n kube-system POD NODE coredns-86c58d9df4-cdl5a kube-master.acme.com coredns-86c58d9df4-csxca kube-master.acme.com etcd-kube-master.acme.com kube-master.acme.com kube-apiserver-kube-master.acme.com kube-master.acme.com kube-controller-manager-kube-master.acme.com kube-master.acme.com kube-scheduler-kube-master.acme.com kube-master.acme.com kube-flannel-ds-amd64-cwd74 kube-master.acme.com kube-proxy-z264w kube-master.acme.com kube-proxy-fxl6f kube-worker-1.acme.com kube-flannel-ds-amd64-c7hva kube-worker-1.acme.com kube-flannel-ds-amd64-c5p9a kube-worker-2.acme.com kube-proxy-jtbwm kube-worker-2.acme.com #View details of components kubectl get endpoints kube-scheduler -n kube-system -o yaml
References
- Creating Highly Available Kubernetes Clusters with kubeadm
- Highly Available Topologies in Kubernetes
- Operating a Highly Available etcd Cluster
References
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