kubernetes

https://www.katacoda.com/courses/kubernetes
minikube version # check version 1.2.0
minikube start

   1 $ minikube version
   2 minikube version: v1.2.0
   3 $ minikube start
   4 * minikube v1.2.0 on linux (amd64)
   5 * Creating none VM (CPUs=2, Memory=2048MB, Disk=20000MB) ...
   6 * Configuring environment for Kubernetes v1.15.0 on Docker 18.09.5
   7   - kubelet.resolv-conf=/run/systemd/resolve/resolv.conf
   8 * Pulling images ...
   9 * Launching Kubernetes ...
  10 
  11 * Configuring local host environment ...
  12 * Verifying: apiserver proxy etcd scheduler controller dns
  13 * Done! kubectl is now configured to use "minikube"

cluster details and health status

   1 $ kubectl cluster-info
   2 Kubernetes master is running at https://172.17.0.30:8443
   3 KubeDNS is running at https://172.17.0.30:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
   4 
   5 To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

get cluster nodes

   1 $ kubectl get nodes
   2 NAME       STATUS   ROLES    AGE    VERSION
   3 minikube   Ready    master   3m1s   v1.15.0

deploy containers

# deploy container
$ kubectl create deployment first-deployment --image=katacoda/docker-http-server
deployment.apps/first-deployment created
$ # deploy container in cluster
# check pods
$ kubectl get pods
NAME                               READY   STATUS    RESTARTS   AGE
first-deployment-8cbf74484-s2fkl   1/1     Running   0          25s
# expose deployment
$ kubectl expose deployment first-deployment --port=80 --type=NodePort
service/first-deployment exposed

$ kubectl get svc first-deployment
NAME               TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
first-deployment   NodePort   10.98.246.87   <none>        80:31219/TCP   105s
# do request to port 80 in cluster ip
$ curl 10.98.246.87:80
<h1>This request was processed by host: first-deployment-8cbf74484-s2fkl</h1>

$curl host01:31219
<h1>This request was processed by host: first-deployment-8cbf74484-s2fkl</h1>

dashboard

$ minikube addons enable dashboard 
#The Kubernetes dashboard allows you to view your applications
in a UI.
* dashboard was successfully enabled
$ kubectl apply -f /opt/kubernetes-dashboard.yaml 
# only in katacoda
service/kubernetes-dashboard-katacoda created

# check progress
$ kubectl get pods -n kube-system -w  #check progress
NAME                                    READY   STATUS    RESTARTS   AGE
coredns-5c98db65d4-b2kxm                1/1     Running   0          17m
coredns-5c98db65d4-mm567                1/1     Running   1          17m
etcd-minikube                           1/1     Running   0          16m
kube-addon-manager-minikube             1/1     Running   0          16m
kube-apiserver-minikube                 1/1     Running   0          16m
kube-controller-manager-minikube        1/1     Running   0          16m
kube-proxy-pngm9                        1/1     Running   0          17m
kube-scheduler-minikube                 1/1     Running   0          16m
kubernetes-dashboard-7b8ddcb5d6-xt5nt   1/1     Running   0          76s
storage-provisioner                     1/1     Running   0          17m

^C$
# dashboard url https://2886795294-30000-kitek05.environments.katacoda.com/
# how to launch a Single Node Kubernetes cluster.

Init master

   1 master $ kubeadm init --kubernetes-version $(kubeadm version -o short)
   2 [init] Using Kubernetes version: v1.14.0
   3 [preflight] Running pre-flight checks
   4 [preflight] Pulling images required for setting up a Kubernetes cluster
   5 [preflight] This might take a minute or two, depending on the speed of your internet connection
   6 [preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
   7 [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
   8 [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
   9 [kubelet-start] Activating the kubelet service
  10 [certs] Using certificateDir folder "/etc/kubernetes/pki"
  11 [certs] Generating "ca" certificate and key
  12 [certs] Generating "apiserver" certificate and key
  13 [certs] apiserver serving cert is signed for DNS names [master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 172.17.0.69]
  14 [certs] Generating "apiserver-kubelet-client" certificate and key
  15 [certs] Generating "front-proxy-ca" certificate and key
  16 [certs] Generating "front-proxy-client" certificate and key
  17 [certs] Generating "etcd/ca" certificate and key
  18 [certs] Generating "etcd/healthcheck-client" certificate and key
  19 [certs] Generating "apiserver-etcd-client" certificate and key
  20 [certs] Generating "etcd/server" certificate and key
  21 [certs] etcd/server serving cert is signed for DNS names [master localhost] and IPs [172.17.0.69 127.0.0.1 ::1]
  22 [certs] Generating "etcd/peer" certificate and key
  23 [certs] etcd/peer serving cert is signed for DNS names [master localhost] and IPs [172.17.0.69 127.0.0.1 ::1]
  24 [certs] Generating "sa" key and public key
  25 [kubeconfig] Using kubeconfig folder "/etc/kubernetes"
  26 [kubeconfig] Writing "admin.conf" kubeconfig file
  27 [kubeconfig] Writing "kubelet.conf" kubeconfig file
  28 [kubeconfig] Writing "controller-manager.conf" kubeconfig file
  29 [kubeconfig] Writing "scheduler.conf" kubeconfig file
  30 [control-plane] Using manifest folder "/etc/kubernetes/manifests"
  31 [control-plane] Creating static Pod manifest for "kube-apiserver"
  32 [control-plane] Creating static Pod manifest for "kube-controller-manager"
  33 [control-plane] Creating static Pod manifest for "kube-scheduler"
  34 [etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
  35 [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
  36 [apiclient] All control plane components are healthy after 16.503433 seconds
  37 [upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system"Namespace
  38 [kubelet] Creating a ConfigMap "kubelet-config-1.14" in namespace kube-system with the configuration for the kubelets in the cluster
  39 [upload-certs] Skipping phase. Please see --experimental-upload-certs
  40 [mark-control-plane] Marking the node master as control-plane by adding the label "node-role.kubernetes.io/master=''"
  41 [mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
  42 [bootstrap-token] Using token: xfvno5.q2xfb2m3nw7grdjm
  43 [bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
  44 [bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
  45 [bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approveCSRs from a Node Bootstrap Token
  46 [bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
  47 [bootstrap-token] creating the "cluster-info" ConfigMap in the "kube-public" namespace
  48 [addons] Applied essential addon: CoreDNS
  49 [addons] Applied essential addon: kube-proxy
  50 
  51 Your Kubernetes control-plane has initialized successfully!
  52 
  53 To start using your cluster, you need to run the following as a regular user:
  54 
  55   mkdir -p $HOME/.kube
  56   sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  57   sudo chown $(id -u):$(id -g) $HOME/.kube/config
  58 
  59 You should now deploy a pod network to the cluster.
  60 Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  61   https://kubernetes.io/docs/concepts/cluster-administration/addons/
  62 
  63 Then you can join any number of worker nodes by running the following on each as root:
  64 
  65 kubeadm join 172.17.0.69:6443 --token xfvno5.q2xfb2m3nw7grdjm \
  66     --discovery-token-ca-cert-hash sha256:26d11c038d236967630d401747f210af9e3679fb1638e8b599a2da4cb98ab159

master $ mkdir -p $HOME/.kube
master $ pwd
/root
master $ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
master $ sudo chown $(id -u):$(id -g) $HOME/.kube/config
master $ export KUBECONFIG=$HOME/.kube/config
master $ echo $KUBECONFIG/root/.kube/config

deploy cni weaveworks

Container Network Interface (CNI) defines how the different nodes and their workloads should communicate. Weave Net provides a network to connect all pods together, implementing the Kubernetes model. Kubernetes uses the Container Network Interface (CNI) to join pods onto Weave Net.

master $ kubectl apply -f /opt/weave-kube
serviceaccount/weave-net created
clusterrole.rbac.authorization.k8s.io/weave-net created
clusterrolebinding.rbac.authorization.k8s.io/weave-net created
role.rbac.authorization.k8s.io/weave-net created
rolebinding.rbac.authorization.k8s.io/weave-net created
daemonset.extensions/weave-net created

master $ kubectl get pod -n kube-system
NAME                             READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-b9rd7          1/1     Running   0          11m
coredns-fb8b8dccf-sfgbn          1/1     Running   0          11m
etcd-master                      1/1     Running   0          10m
kube-apiserver-master            1/1     Running   0          10m
kube-controller-manager-master   1/1     Running   0          10m
kube-proxy-l42wp                 1/1     Running   0          11m
kube-scheduler-master            1/1     Running   1          10m
weave-net-mcxml                  2/2     Running   0          84s

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