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'''''NOTE: the kubelet is currently broken on F28 due to https://bugzilla.redhat.com/show_bug.cgi?id=1558425 -- I'm not aware of a workaround at the moment.''''' | |||
* Use package layering to install kubeadm on each host: | * Use package layering to install kubeadm on each host: | ||
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* kubernetes wants to create a flex volume driver dir at <code>/usr/libexec/kubernetes</code>, but this is a read-only location on atomic hosts. Modify <code>/etc/systemd/system/kubelet.service.d/kubeadm.conf</code> to match the following line, and then run <code>systemctl daemon-reload</code> to pick up the change: | |||
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Environment="KUBELET_EXTRA_ARGS=--cgroup-driver=systemd --volume-plugin-dir=/etc/kubernetes/volumeplugins" | |||
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* Start the kubelet and initialize the kubernetes cluster. We specify a pod-network-cidr because flannel, which we'll use in this test, requires it, and we skip preflight checks because | * Start the kubelet and initialize the kubernetes cluster. We specify a pod-network-cidr because flannel, which we'll use in this test, requires it, and we skip preflight checks because because kubeadm looks in the [https://github.com/kubernetes/kubernetes/pull/49410 wrong place] for kernel config. | ||
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Revision as of 00:16, 11 April 2018
Description
Install Kubernetes on Fedora Atomic Host using kubeadm.
Setup
- Install one or more Fedora Atomic Hosts.
How to test
NOTE: the kubelet is currently broken on F28 due to https://bugzilla.redhat.com/show_bug.cgi?id=1558425 -- I'm not aware of a workaround at the moment.
- Use package layering to install kubeadm on each host:
rpm-ostree install kubernetes-kubeadm ethtool ebtables -r
- Unfortunately, as of 1.7.3, SELinux again needs to be in permissive mode for kubeadm to work:
# setenforce 0
- kubernetes wants to create a flex volume driver dir at
/usr/libexec/kubernetes, but this is a read-only location on atomic hosts. Modify/etc/systemd/system/kubelet.service.d/kubeadm.confto match the following line, and then runsystemctl daemon-reloadto pick up the change:
Environment="KUBELET_EXTRA_ARGS=--cgroup-driver=systemd --volume-plugin-dir=/etc/kubernetes/volumeplugins"
- Start the kubelet and initialize the kubernetes cluster. We specify a pod-network-cidr because flannel, which we'll use in this test, requires it, and we skip preflight checks because because kubeadm looks in the wrong place for kernel config.
# systemctl enable --now kubelet # kubeadm init --pod-network-cidr=10.244.0.0/16 --skip-preflight-checks
- Follow the directions in the resulting output to configure kubectl:
# mkdir -p $HOME/.kube # sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config # sudo chown $(id -u):$(id -g) $HOME/.kube/config
- Deploy the flannel network plugin:
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
- 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 run:
# kubectl taint nodes --all node-role.kubernetes.io/master-
- If desired, join additional nodes to the master using the kubeadm join command provided in the kubeadm init output. For instance:
# kubeadm join --token 2a247c.f357bc09c56b12c8 atomic1:6443
- Check on the install:
# kubectl get nodes NAME STATUS AGE VERSION atomic1 Ready 6m v1.7.3
# kubectl get pods --all-namespaces NAMESPACE NAME READY STATUS RESTARTS AGE kube-system etcd-atomic1 1/1 Running 0 5m kube-system kube-apiserver-atomic1 1/1 Running 0 6m kube-system kube-controller-manager-atomic1 1/1 Running 0 5m kube-system kube-dns-2425271678-lpqlt 3/3 Running 0 6m kube-system kube-flannel-ds-fcmbb 1/1 Running 0 4m kube-system kube-proxy-mrdf4 1/1 Running 0 6m kube-system kube-scheduler-atomic1 1/1 Running 0 6m
- Run some test apps
# kubectl run nginx --image=nginx --port=80 --replicas=3
deployment "nginx" created
# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
nginx-158599303-dbkjw 1/1 Running 0 19s 10.244.0.3 atomic1
nginx-158599303-g4q7c 1/1 Running 0 19s 10.244.0.4 atomic1
nginx-158599303-n0mwm 1/1 Running 0 19s 10.244.0.5 atomic1
# kubectl expose deployment nginx --type NodePort
service "nginx" exposed
# kubectl get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes 10.254.0.1 <none> 443/TCP 40m
nginx 10.254.52.120 <nodes> 80:32681/TCP 14s
# curl http://atomic1:32681
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
Expected Results
- kubeadm runs without error.
- You're able to run Kubernetes apps using the cluster.