kubeadm init --apiserver-advertise-address=
Using the flannel driver
If you are planning on using the flannel driver, make sure to add the –pod-network-cidr option.
Your output will look something like below.
kubeadm init
# For flannel use.
kubeadm init --pod-network-cidr=10.244.0.0/16
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[init] Using Kubernetes version: v1.7.2
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks
[preflight] WARNING: docker version is greater than the most recently validated version. Docker version: 17.06.0-c
e. Max validated version: 1.12
[preflight] Starting the kubelet service
[certificates] Generated CA certificate and key.
[certificates] Generated API server certificate and key.
[certificates] API Server serving cert is signed for DNS names [your-kub-host kubernetes kubernetes.default kubernetes.d
efault.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.10.10.50]
[certificates] Generated API server kubelet client certificate and key.
[certificates] Generated service account token signing key and public key.
[certificates] Generated front-proxy CA certificate and key.
[certificates] Generated front-proxy client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[apiclient] Created API client, waiting for the control plane to become ready
[apiclient] All control plane components are healthy after 54.501595 seconds
[token] Using token: 0e80f0.289b222173a39a53
[apiconfig] Created RBAC rules
Your Kubernetes master has initialized successfully!
To start using your cluster, you need to run (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:
http://kubernetes.io/docs/admin/addons/
You can now join any number of machines by running the following on each node
as root:
kubeadm join --token 7ec887.b4312a332eeddbb0 10.10.10.50:644
To be able to manipulate and connect locally to the cluster, run the below (or copy to other node).
cp /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
In my case I working on only one physical node, in order to continue with the rest of the steps the below role change is required.
kubectl taint nodes --all node-role.kubernetes.io/master-
Note: By default, your cluster will not schedule pods on the master for security reasons. If you want to be able to schedule pods on the master, e.g. for a single-machine Kubernetes cluster for development, you will have the to run the above.
Next, you have to decide which network driver you are going to use.
Below I will first show you how to use the flannel driver. I will then destroy the configuration and to re-do with the calico driver.
Flannel driver configuration
Lets jump right in.
First we need to get the Flannel yaml configuration files.
Tip You can specify the Flannel yaml web url directly if you have Internet access.
For Flannel we also need the RBAC policy file.
To use / apply the flannel driver just run the below (or specify a local yml file if you don’t have web access).
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel-rbac.yml
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Current pods with Flannel network and policy engine.
kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system etcd-your-kub-host 1/1 Running 0 9m
kube-system kube-apiserver-your-kub-host 1/1 Running 0 9m
kube-system kube-controller-manager-your-kub-host 1/1 Running 0 9m
kube-system kube-dns-2425271678-gsq8d 3/3 Running 1 10m
kube-system kube-flannel-ds-z5hbz 2/2 Running 0 10m
kube-system kube-proxy-knhtz 1/1 Running 0 10m
kube-system kube-scheduler-your-kub-host 1/1 Running 0 9m
Next verify if the node is ready to join the cluster, by running the below.
kubectl get nodes
NAME STATUS AGE VERSION
your-kub-host NotReady 9m v1.7.1
You are now ready to join the cluster.
Note: This would normally run on the nodes (not the master as in my case).
kubeadm join --token 7ec887.b4312a332eeddbb0 10.10.10.50:6443
Note: In Kubernetes stock(version 1.7.1) on Ubuntu 17.04 there is a bug by trying to join the cluster you will get something like to error below.
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[preflight] Running pre-flight checks
[preflight] WARNING: docker version is greater than the most recently validated version. Docker version: 17.06.0-ce. Max validated version: 1.12
[preflight] WARNING: hostname "" could not be reached
[preflight] WARNING: hostname "" lookup : no such host
[preflight] Some fatal errors occurred:
hostname "" a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')
Port 10250 is in use
/etc/kubernetes/manifests is not empty
/var/lib/kubelet is not empty
/etc/kubernetes/pki/ca.crt already exists
/etc/kubernetes/kubelet.conf already exists
[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`
For the time being, you have the below two options:
- Add –skip-preflight-checks to the join options
- Upgrade / Install the binary from Goggle directly as outlined in part 1 – Installing Minikube / Kubectl
Installing / adding the kubernetes dashboard (optionally).
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml
To access the dashboard, just run the below
kubectl proxy
Now go to http://localhost:8001/ui to access the dashboard.
To find what your kubernetes-dashboard ip is, run the below.
kubectl get svc --all-namespaces
NAMESPACE NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes 10.96.0.1 443/TCP 7m
kube-system calico-etcd 10.96.232.136 6666/TCP 6m
kube-system kube-dns 10.96.0.10 53/UDP,53/TCP 7m
kube-system kubernetes-dashboard 10.100.139.19 80/TCP 6m
Tip: Your dashboard will normally only be available from withing your cluster, to see how to get around this click here – kubectl proxy options
I created a quick simple script to bring up a fresh cluster, the script can be find at the end of this post.
Cluster tear down (Flannel)- Remove all nodes / pods
To play with the Calico network driver, I am going to tear down the cluster, then re-create with the Calico network driver.
The simple steps below should do it.
kubectl delete deployment kube-dns --namespace=kube-system
kubectl delete deployment kubernetes-dashboard --namespace=kube-system
kubectl delete -f kube-flannel.yml
kubectl delete -f kube-flannel-rbac.yml
kubectl drain your-kub-host --delete-local-data --force --ignore-daemonsets
kubeadm reset
kubernetes using the Calico network driver
First lets initialize / re-create the cluster (same steps above).
For complete output check above at the Flenel configuration, as the steps are the same I am not going to repeat.
kubeadm init
[..] snip
cp /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
kubectl taint nodes --all node-role.kubernetes.io/master-
Now, we need to install / apply the calico driver.
kubectl apply -f http://docs.projectcalico.org/v2.3/getting-started/kubernetes/installation/hosted/kubeadm/1.6/calico.yaml
Thats it, after a few minutes, your cluster is ready to be used.
You will need to join the node to the cluster same as above.
Optional, you can add the dashboard – same as above.
Your current pods with Calico network and policy engine.
kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
default nginx-1803751077-r9whg 1/1 Running 0 10d
kube-system calico-etcd-6k7b1 1/1 Running 0 10d
kube-system calico-node-9sqtv 2/2 Running 0 10d
kube-system calico-policy-controller-1727037546-s0fst 1/1 Running 0 10d
kube-system etcd-your-kub-host 1/1 Running 0 10d
kube-system kube-apiserver-your-kub-host 1/1 Running 0 10d
kube-system kube-controller-manager-your-kub-host 1/1 Running 0 10d
kube-system kube-dns-2425271678-x1wrp 3/3 Running 0 10d
kube-system kube-proxy-1z3hj 1/1 Running 0 10d
kube-system kube-scheduler-your-kub-host 1/1 Running 0 10d
kube-system kubernetes-dashboard-3313488171-1bgd2 1/1 Running 0 10d
Cluster tear down (Calico) – Remove all nodes / pods
To tear down the cluster just run the below.
kubectl delete deployment kube-dns --namespace=kube-system
kubectl delete deployment calico-policy-controller --namespace=kube-system
kubectl delete deployment kubernetes-dashboard --namespace=kube-system
kubectl delete -f calico.yaml
kubectl drain your-kub-host --delete-local-data --force --ignore-daemonsets
kubeadm reset
Common helpful tips in your Kubernetes cluster
Get logs flannel, calico
# Get logs - flannel
kubectl logs kube-flannel-ds-ss4sz --namespace=kube-system kube-flannel
# Get logs - calico
kubectl logs kube-flannel-ds-ss4sz --namespace=kube-system kube-flannel
List all nodes
kubectl get nodes
List all pod namespaces
kubectl get pods --all-namespaces
Delete all pods in one namespace
kubectl delete pod --all --namespace=kube-system
To list all deployments
kubectl get deployments --all-namespaces
To list all services
kubectl get svc --all-namespaces
List config contexts
kubectl config get-contexts
Kubectl Cheatsheet/
Other helpful tips
Controlling your cluster from machines other than the master
scp root@:/etc/kubernetes/admin.conf .
kubectl --kubeconfig ./admin.conf get nodes
# Proxying API Server to localhost
scp root@:/etc/kubernetes/admin.conf .
kubectl --kubeconfig ./admin.conf proxy
Installing a sample application from Goggle
Goggle has a sample application that can be used to test/play with kubernetes.
kubectl create namespace sock-shop
kubectl apply -n sock-shop -f "https://github.com/microservices-demo/microservices-demo/blob/master/deploy/kubernetes/complete-demo.yaml?raw=true"
Get front-end service ip.
kubectl -n sock-shop get svc front-end
Get pod info for the sock-shop applaication
kubectl get pods -n sock-shop
kubectl delete namespace sock-shop
Appendix – Kubernetes Script
Flannel script
token=`kubeadm init --pod-network-cidr=10.244.0.0/16|grep 10.10.10.50|tail -1|awk '{n = 3; for (--n; n >= 0; n--){ printf "%s\t",$(NF-n)} print ""}'`
cp /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
sleep 5
kubectl taint nodes --all node-role.kubernetes.io/master-
kubectl get pods --all-namespaces
sleep 2
kubectl apply -f kube-flannel-rbac.yml
kubectl apply -f kube-flannel.yml
kubectl create --namespace kube-system -f kube-flannel.yml
## Or get remote directly...
##kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel-rbac.yml
##kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
sleep 5
kubectl get pods --all-namespaces
kubectl get nodes
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml
# Add (--skip-preflight-checks) if your client version 1.7.1, you can downgrade to 1.7.0 or upgrade to 1.7.2 has the issue fixed.
kubeadm join --skip-preflight-checks $token
Calico script
token=`kubeadm init |grep 10.10.10.50|tail -1|awk '{n = 3; for (--n; n >= 0; n--){ printf "%s\t",$(NF-n)} print ""}'`
cp /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
kubectl taint nodes --all node-role.kubernetes.io/master-
while [[ `kubectl get pods --all-namespaces 2>&1` == *"No resources found."* ]]; do
kubectl get pods --all-namespaces
echo "-----------
Coming up... Please stand by..."
sleep 1
done
sleep 2
while [ `kubectl get pods --all-namespaces|grep Run|awk '{print $4}'|wc -l` -lt 5 ]; do
kubectl get pods --all-namespaces
echo "-----------
Please wait... still in process..."
sleep 2
done
kubectl apply -f calico.yaml
### Or get remote directly...
## kubectl apply -f http://docs.projectcalico.org/v2.3/getting-started/kubernetes/installation/hosted/kubeadm/1.6/calico.yaml
while [ `kubectl get pods --all-namespaces|grep Run|awk '{print $4}'|wc -l` -lt 7 ]; do
kubectl get pods --all-namespaces
echo "-----------
Please wait... still in process..."
sleep 5
done
kubectl get nodes
kubectl get pods --all-namespaces
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/kubernetes-dashboard.yaml
kubectl get pods --all-namespaces
kubeadm join --skip-preflight-checks $token
kubectl get nodes
Compile kubernetes your self
git clone https://github.com/kubernetes/kubernetes
cd kubernetes
make quick-release
You might also like:
Master Index – Related Posts To Docker, Kubernetes And Micro-Services.
Whats tools/scripts are you using to manage your Kubernetes Cluster? please let me know in the comments below.
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To find what your kubernetes-dashboard ip is, run the below.