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Revision 21 as of 2019-07-27 17:16:28
  • kubernetes

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

   1 # deploy container
   2 $ kubectl create deployment first-deployment --image=katacoda/docker-http-server
   3 deployment.apps/first-deployment created
   4 $ # deploy container in cluster
   5 # check pods
   6 $ kubectl get pods
   7 NAME                               READY   STATUS    RESTARTS   AGE
   8 first-deployment-8cbf74484-s2fkl   1/1     Running   0          25s
   9 # expose deployment
  10 $ kubectl expose deployment first-deployment --port=80 --type=NodePort
  11 service/first-deployment exposed
  12 
  13 $ kubectl get svc first-deployment
  14 NAME               TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
  15 first-deployment   NodePort   10.98.246.87   <none>        80:31219/TCP   105s
  16 # do request to port 80 in cluster ip
  17 $ curl 10.98.246.87:80
  18 <h1>This request was processed by host: first-deployment-8cbf74484-s2fkl</h1>
  19 
  20 $curl host01:31219
  21 <h1>This request was processed by host: first-deployment-8cbf74484-s2fkl</h1>

dashboard

   1 $ minikube addons enable dashboard 
   2 #The Kubernetes dashboard allows you to view your applications
   3 in a UI.
   4 * dashboard was successfully enabled
   5 $ kubectl apply -f /opt/kubernetes-dashboard.yaml 
   6 # only in katacoda
   7 service/kubernetes-dashboard-katacoda created
   8 
   9 # check progress
  10 $ kubectl get pods -n kube-system -w  #check progress
  11 NAME                                    READY   STATUS    RESTARTS   AGE
  12 coredns-5c98db65d4-b2kxm                1/1     Running   0          17m
  13 coredns-5c98db65d4-mm567                1/1     Running   1          17m
  14 etcd-minikube                           1/1     Running   0          16m
  15 kube-addon-manager-minikube             1/1     Running   0          16m
  16 kube-apiserver-minikube                 1/1     Running   0          16m
  17 kube-controller-manager-minikube        1/1     Running   0          16m
  18 kube-proxy-pngm9                        1/1     Running   0          17m
  19 kube-scheduler-minikube                 1/1     Running   0          16m
  20 kubernetes-dashboard-7b8ddcb5d6-xt5nt   1/1     Running   0          76s
  21 storage-provisioner                     1/1     Running   0          17m
  22 
  23 ^C$
  24 # dashboard url https://2886795294-30000-kitek05.environments.katacoda.com/
  25 # how to launch a Single Node Kubernetes cluster. 
  26 

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

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

deploy cni weaveworks - deploy a pod network to the cluster

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.

   1 master $ kubectl apply -f /opt/weave-kube
   2 serviceaccount/weave-net created
   3 clusterrole.rbac.authorization.k8s.io/weave-net created
   4 clusterrolebinding.rbac.authorization.k8s.io/weave-net created
   5 role.rbac.authorization.k8s.io/weave-net created
   6 rolebinding.rbac.authorization.k8s.io/weave-net created
   7 daemonset.extensions/weave-net created
   8 
   9 master $ kubectl get pod -n kube-system
  10 NAME                             READY   STATUS    RESTARTS   AGE
  11 coredns-fb8b8dccf-b9rd7          1/1     Running   0          11m
  12 coredns-fb8b8dccf-sfgbn          1/1     Running   0          11m
  13 etcd-master                      1/1     Running   0          10m
  14 kube-apiserver-master            1/1     Running   0          10m
  15 kube-controller-manager-master   1/1     Running   0          10m
  16 kube-proxy-l42wp                 1/1     Running   0          11m
  17 kube-scheduler-master            1/1     Running   1          10m
  18 weave-net-mcxml                  2/2     Running   0          84s

join cluster

   1 master $ kubeadm token list # check tokens
   2 TOKEN                     TTL       EXPIRES                USAGES                   DESCRIPTION
   3                     EXTRA GROUPS
   4 xfvno5.q2xfb2m3nw7grdjm   23h       2019-07-28T16:19:18Z   authentication,signing   The default bootstrap token generated b
   5 y 'kubeadm init'.   system:bootstrappers:kubeadm:default-node-token

   1 # in node01
   2 # join cluster
   3 kubeadm join --discovery-token-unsafe-skip-ca-verification --token=xfvno5.q2xfb2m3nw7grdjm 172.17.0.69:6443
   4 [preflight] Running pre-flight checks
   5 [preflight] Reading configuration from the cluster...
   6 [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
   7 [kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" ConfigMap in the kube-system namespace
   8 [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
   9 [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
  10 [kubelet-start] Activating the kubelet service
  11 [kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
  12 
  13 This node has joined the cluster:
  14 * Certificate signing request was sent to apiserver and a response was received.
  15 * The Kubelet was informed of the new secure connection details.
  16 
  17 Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
  18 # The --discovery-token-unsafe-skip-ca-verification tag is used to bypass the Discovery Token verification. 
  19 
  20 # in master
  21 master $ kubectl get nodes
  22 NAME     STATUS   ROLES    AGE    VERSION
  23 master   Ready    master   17m    v1.14.0
  24 node01   Ready    <none>   107s   v1.14.0                                                       bootstrap token generated b
  25 master $
  26 
  27 # in node01
  28 node01 $ kubectl get nodesThe connection to the server localhost:8080 was refused - did you specify the right host or port
  29 ?
  30 node01 $

deploy container in cluster

   1 master $ kubectl create deployment http --image=katacoda/docker-http-server:latest
   2 deployment.apps/http created
   3 master $ kubectl get pods
   4 NAME                    READY   STATUS    RESTARTS   AGE
   5 http-7f8cbdf584-74pd9   1/1     Running   0          11s
   6 
   7 master $ docker ps | grep http-server
   8 master $
   9 
  10 node01 $ docker ps | grep http-serveradb3cde7f861        katacoda/docker-http-server   "/app"                   About a minute ago
  11 Up About a minute                       k8s_docker-http-server_http-7f8cbdf584-74pd9_default_04a
  12 17065-b08d-11e9-bff1-0242ac110045_0
  13 
  14 # expose deployment
  15 master $ kubectl get pods
  16 NAME                    READY   STATUS    RESTARTS   AGE
  17 http-7f8cbdf584-74pd9   1/1     Running   0          17m                                        bootstrap token generated b
  18 master $ kubectl expose deployment http  --port=80 --type=NodePort
  19 service/http exposed
  20 
  21 master $ kubectl get service http
  22 NAME   TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
  23 http   NodePort   10.101.65.149   <none>        80:30982/TCP   49s
  24 
  25 master $ curl 10.101.65.149:80
  26 <h1>This request was processed by host: http-7f8cbdf584-74pd9</h1>
  27 
  28 master $ curl http://10.101.65.149
  29 <h1>This request was processed by host: http-7f8cbdf584-74pd9</h1>

apply dashboard in cluster

master $ kubectl apply -f dashboard.yamlsecret/kubernetes-dashboard-certs created
serviceaccount/kubernetes-dashboard createdrole.rbac.authorization.k8s.io/kubernetes-dashboard-minimal createdrolebinding.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created
deployment.apps/kubernetes-dashboard createdservice/kubernetes-dashboard createdmaster $ kubectl get pods -n kube-system
NAME                                    READY   STATUS              RESTARTS   AGEcoredns-fb8b8dccf-b9rd7                 1/1     Running             0          42mcoredns-fb8b8dccf-sfgbn                 1/1     Running             0          42m
etcd-master                             1/1     Running             0          41m
kube-apiserver-master                   1/1     Running             0          40m
kube-controller-manager-master          1/1     Running             0          40m
kube-proxy-gwrps                        1/1     Running             0          26m
kube-proxy-l42wp                        1/1     Running             0          42m
kube-scheduler-master                   1/1     Running             1          40m
kubernetes-dashboard-5f57845f9d-ls7q2   0/1     ContainerCreating   0          2s
weave-net-gww8b                         2/2     Running             0          26m
weave-net-mcxml                         2/2     Running             0          31m

Create service accoun for dashboard

cat <<EOF | kubectl create -f - 
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kube-system
EOF

# Get login token
kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}')

When the dashboard was deployed, it used externalIPs to bind the service to port 8443. This makes the dashboard available to outside of the cluster and viewable at https://2886795335-8443-kitek05.environments.katacoda.com/

# Use the admin-user token to access the dashboard.
https://2886795335-8443-kitek05.environments.katacoda.com/#!/login
# sign in using token
eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi11c2VyLXRva2VuLXNzcTl4Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImFkbWluLXVzZXIiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiI2Y2RiNGZmMy1iMDkwLTExZTktYmZmMS0wMjQyYWMxMTAwNDUiLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06YWRtaW4tdXNlciJ9.R2OtDYxXaR0Pgluzq1m8FMZflF2tdYtJdG5XhkVC28vf1WkJu-Zo51I5ONUiK2WdBEMPw-N2PW_R9l6lak1clvlxfUSn777nThYSxhmR5pfxi6GmDlFo928KJvWVPDen1jrzAaQOEUZ1maOzPcnjKGpR-CRTgmYDnxZY84rqi68y0vfdn16ER8HeW-wkJ-hfGyUAhryk_ob1CUBjjbs-vefpaLcHLdrWNaKaFi1j5fCc_eJi10FpSTmuBsb04xgN0I17hkTlSw2fyOAj7LtC3pBDrK0nOdHCJkBEtsg89rkvLufYph5AFeoWQVKdW9JZH8BYS91BFla7pZnTwdBVeA

https://2886795335-8443-kitek05.environments.katacoda.com/#!/overview?namespace=default

services

   1 master $ kubectl get service
   2 NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
   3 http         NodePort    10.101.65.149   <none>        80:30982/TCP   17m
   4 kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        56m
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