Some of the scenario questions here are based on Kodekloud's CKA course labs.
Note
CKAD and CKA can have similar scenario questions. It is recommended to go through the CKAD practice tests.
Shortcuts
First run the two commands below for shortcuts.
export do="--dry-run=client -o yaml"
export now="--force --grace-period=0" Questions
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Install the kubeadm and kubelet packages on the controlplane and node01 nodes.
Use the exact version of 1.27.0-2.1 for both.
Answer
Complete steps can be found here: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
sudo apt-get update # apt-transport-https may be a dummy package; if so, you can skip that package sudo apt-get install -y apt-transport-https ca-certificates curl gpgCheck if OS is Ubuntu,if it is, then need to create the /etc/apt/keyrings.
controlplane ~ ➜ cat /etc/os-release NAME="Ubuntu" VERSION="20.04.6 LTS (Focal Fossa)" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 20.04.6 LTS" VERSION_ID="20.04" HOME_URL="https://www.ubuntu.com/" SUPPORT_URL="https://help.ubuntu.com/" BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/" PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy" VERSION_CODENAME=focal UBUNTU_CODENAME=focal controlplane ~ ➜ sudo mkdir -m 755 /etc/apt/keyrings
Continue with the steps from the docs.
controlplane ~ ➜ curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.27/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg # This overwrites any existing configuration in /etc/apt/sources.list.d/kubernetes.list echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.27/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list sudo apt-get install -y \ kubelet=1.27.0-2.1 \ kubeadm=1.27.0-2.1 \ kubectl=1.27.0-2.1
Verify.
controlplane ~ ➜ kubeadm version kubeadm version: &version.Info{Major:"1", Minor:"27", GitVersion:"v1.27.0", GitCommit:"1b4df30b3cdfeaba6024e81e559a6cd09a089d65", GitTreeState:"clean", BuildDate:"2023-04-11T17:09:06Z", GoVersion:"go1.20.3", Compiler:"gc", Platform:"linux/amd64"} controlplane ~ ➜ kubectl version WARNING: This version information is deprecated and will be replaced with the output from kubectl version --short. Use --output=yaml|json to get the full version. Client Version: version.Info{Major:"1", Minor:"27", GitVersion:"v1.27.0", GitCommit:"1b4df30b3cdfeaba6024e81e559a6cd09a089d65", GitTreeState:"clean", BuildDate:"2023-04-11T17:10:18Z", GoVersion:"go1.20.3", Compiler:"gc", Platform:"linux/amd64"} Kustomize Version: v5.0.1 Error from server (NotFound): the server could not find the requested resource
Repeat the same steps to setup node01.
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After installing the required tools in the previous question, bootstrap the Kubernetes cluster using kubeadm. Initialize Control Plane Node (Master Node). Use the following options:
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apiserver-advertise-address - Use the IP address allocated to eth0 on the controlplane node
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apiserver-cert-extra-sans - Set it to controlplane
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pod-network-cidr - Set to 10.244.0.0/16
Once done, set up the default kubeconfig file and wait for node to be part of the cluster.
Answer
Complete steps can be found here: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/
Get the controlplane's IP first.
controlplane ~ ✖ ip addr | grep eth0 5817: eth0@if5818: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP group default inet 192.17.66.9/24 brd 192.17.66.255 scope global eth0
Then run kube init with the supplied values.
kubeadm init \ --apiserver-advertise-address 192.17.66.9 \ --apiserver-cert-extra-sans controlplane \ --pod-network-cidr 10.244.0.0/16
To make kubectl work for your non-root user, setup the default kubeconfig file. Run these commands, which are also part of the kubeadm init output:
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
Take note of the output:
Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.17.66.9:6443 --token n3131u.ndrbw41snadbex5r \ --discovery-token-ca-cert-hash sha256:0d557809cfe18f10cbba69fe455aa3b03dad336824cbba62a29fe81ee8a18d9f
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After controlplane is bootstrapped, join the node01 to the cluster.
Answer
Run the kubeadm join command which was returned by the kubeadm output.
kubeadm join 192.17.66.9:6443 --token n3131u.ndrbw41snadbex5r \ --discovery-token-ca-cert-hash sha256:0d557809cfe18f10cbba69fe455aa3b03dad336824cbba62a29fe81ee8a18d9fOnce it's done running, return to the controlplane and verify if it can see the node01 in the cluster.
controlplane ~ ➜ k get no NAME STATUS ROLES AGE VERSION controlplane NotReady control-plane 3m37s v1.27.0 node01 NotReady <none> 35s v1.27.0
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To install a network plugin, we will go with Flannel as the default choice. For inter-host communication, we will utilize the eth0 interface.
Please ensure that the Flannel manifest includes the appropriate options for this configuration.
Answer
Download the YAML file.
curl -LO https://raw.githubusercontent.com/flannel-io/flannel/v0.20.2/Documentation/kube-flannel.yml
Modify the file:
args: - --ip-masq - --kube-subnet-mgr - --iface=eth0controlplane ~ ➜ k get no NAME STATUS ROLES AGE VERSION controlplane NotReady control-plane 3m37s v1.27.0 node01 NotReady <none> 35s v1.27.0 controlplane ~ ➜ curl -LO https://raw.githubusercontent.com/flannel-io/flannel/v0.20.2/Documentation/kube-flannel.yml % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 4591 100 4591 0 0 34780 0 --:--:-- --:--:-- --:--:-- 34780 controlplane ~ ➜ vi kube-flannel.yml controlplane ~ ➜ kubectl apply -f kube-flannel.yml namespace/kube-flannel 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
Both nodes should change to Ready status now.
controlplane ~ ➜ k get no NAME STATUS ROLES AGE VERSION controlplane Ready control-plane 6m27s v1.27.0 node01 Ready <none> 3m25s v1.27.0