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05-kubernetes-controller.md

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Bootstrapping an H/A Kubernetes Control Plane

In this lab you will bootstrap a 3 node Kubernetes controller cluster. The following virtual machines will be used:

  • controller0
  • controller1
  • controller2

In this lab you will also create a frontend load balancer with a public IP address for remote access to the API servers and H/A.

Why

The Kubernetes components that make up the control plane include the following components:

  • API Server
  • Scheduler
  • Controller Manager

Each component is being run on the same machine for the following reasons:

  • The Scheduler and Controller Manager are tightly coupled with the API Server
  • Only one Scheduler and Controller Manager can be active at a given time, but it's ok to run multiple at the same time. Each component will elect a leader via the API Server.
  • Running multiple copies of each component is required for H/A
  • Running each component next to the API Server eases configuration.

Provision the Kubernetes Controller Cluster

Run the following commands on controller0, controller1, controller2:

Login to each machine using the gcloud compute ssh command

Copy the bootstrap token into place:

sudo mkdir -p /var/lib/kubernetes/

sudo mv token.csv /var/lib/kubernetes/

TLS Certificates

The TLS certificates created in the Setting up a CA and TLS Cert Generation lab will be used to secure communication between the Kubernetes API server and Kubernetes clients such as kubectl and the kubelet agent. The TLS certificates will also be used to authenticate the Kubernetes API server to etcd via TLS client auth.

Copy the TLS certificates to the Kubernetes configuration directory:

sudo mv ca.pem ca-key.pem kubernetes-key.pem kubernetes.pem /var/lib/kubernetes/

Download and install the Kubernetes controller binaries

Download the official Kubernetes release binaries:

wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-rc.1/bin/linux/amd64/kube-apiserver

wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-rc.1/bin/linux/amd64/kube-controller-manager

wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-rc.1/bin/linux/amd64/kube-scheduler

wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-rc.1/bin/linux/amd64/kubectl

Install the Kubernetes binaries:

chmod +x kube-apiserver kube-controller-manager kube-scheduler kubectl

sudo mv kube-apiserver kube-controller-manager kube-scheduler kubectl /usr/bin/

Kubernetes API Server

Capture the internal IP address of the machine:

INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)

Create the systemd unit file:

cat > kube-apiserver.service <<EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-apiserver \\
  --admission-control=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota \\
  --advertise-address=${INTERNAL_IP} \\
  --allow-privileged=true \\
  --apiserver-count=3 \\
  --audit-log-maxage=30 \\
  --audit-log-maxbackup=3 \\
  --audit-log-maxsize=100 \\
  --audit-log-path=/var/lib/audit.log \\
  --authorization-mode=RBAC \\
  --bind-address=0.0.0.0 \\
  --client-ca-file=/var/lib/kubernetes/ca.pem \\
  --enable-swagger-ui=true \\
  --etcd-cafile=/var/lib/kubernetes/ca.pem \\
  --etcd-certfile=/var/lib/kubernetes/kubernetes.pem \\
  --etcd-keyfile=/var/lib/kubernetes/kubernetes-key.pem \\
  --etcd-servers=https://10.240.0.10:2379,https://10.240.0.11:2379,https://10.240.0.12:2379 \\
  --event-ttl=1h \\
  --experimental-bootstrap-token-auth \\
  --insecure-bind-address=0.0.0.0 \\
  --kubelet-certificate-authority=/var/lib/kubernetes/ca.pem \\
  --kubelet-client-certificate=/var/lib/kubernetes/kubernetes.pem \\
  --kubelet-client-key=/var/lib/kubernetes/kubernetes-key.pem \\
  --kubelet-https=true \\
  --runtime-config=rbac.authorization.k8s.io/v1alpha1 \\
  --service-account-key-file=/var/lib/kubernetes/ca-key.pem \\
  --service-cluster-ip-range=10.32.0.0/24 \\
  --service-node-port-range=30000-32767 \\
  --tls-cert-file=/var/lib/kubernetes/kubernetes.pem \\
  --tls-private-key-file=/var/lib/kubernetes/kubernetes-key.pem \\
  --token-auth-file=/var/lib/kubernetes/token.csv \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Start the kube-apiserver service:

sudo mv kube-apiserver.service /etc/systemd/system/

sudo systemctl daemon-reload

sudo systemctl enable kube-apiserver

sudo systemctl start kube-apiserver

sudo systemctl status kube-apiserver --no-pager

Kubernetes Controller Manager

cat > kube-controller-manager.service <<EOF
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-controller-manager \\
  --address=0.0.0.0 \\
  --allocate-node-cidrs=true \\
  --cluster-cidr=10.200.0.0/16 \\
  --cluster-name=kubernetes \\
  --cluster-signing-cert-file=/var/lib/kubernetes/ca.pem \\
  --cluster-signing-key-file=/var/lib/kubernetes/ca-key.pem \\
  --leader-elect=true \\
  --master=http://${INTERNAL_IP}:8080 \\
  --root-ca-file=/var/lib/kubernetes/ca.pem \\
  --service-account-private-key-file=/var/lib/kubernetes/ca-key.pem \\
  --service-cluster-ip-range=10.32.0.0/16 \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Start the kube-controller-manager service:

sudo mv kube-controller-manager.service /etc/systemd/system/

sudo systemctl daemon-reload

sudo systemctl enable kube-controller-manager

sudo systemctl start kube-controller-manager

sudo systemctl status kube-controller-manager --no-pager

Kubernetes Scheduler

cat > kube-scheduler.service <<EOF
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-scheduler \\
  --leader-elect=true \\
  --master=http://${INTERNAL_IP}:8080 \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Start the kube-scheduler service:

sudo mv kube-scheduler.service /etc/systemd/system/

sudo systemctl daemon-reload

sudo systemctl enable kube-scheduler

sudo systemctl start kube-scheduler

sudo systemctl status kube-scheduler --no-pager

Verification

kubectl get componentstatuses

NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok                   
scheduler            Healthy   ok                   
etcd-0               Healthy   {"health": "true"}   
etcd-1               Healthy   {"health": "true"}   
etcd-2               Healthy   {"health": "true"}

Remember to run these steps on controller0, controller1, and controller2

Setup Kubernetes API Server Frontend Load Balancer

The virtual machines created in this tutorial will not have permission to complete this section. Run the following commands from the same place used to create the virtual machines for this tutorial.

gcloud compute http-health-checks create kube-apiserver-health-check \
  --description "Kubernetes API Server Health Check" \
  --port 8080 \
  --request-path /healthz

gcloud compute target-pools create kubernetes-target-pool \
  --http-health-check=kube-apiserver-health-check

gcloud compute target-pools add-instances kubernetes-target-pool \
  --instances controller0,controller1,controller2

KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
  --region us-central1 \
  --format 'value(address)')

gcloud compute forwarding-rules create kubernetes-forwarding-rule \
  --address ${KUBERNETES_PUBLIC_ADDRESS} \
  --ports 6443 \
  --target-pool kubernetes-target-pool \
  --region us-central1