x509 certificate signed by unknown authority- Kubernetes

docker kubernetes coreos
Nakshatra picture Nakshatra · Apr 29, 2016 · Viewed 35.9k times · Source

I am configuring a Kubernetes cluster with 2 nodes in CoreOS as described in https://coreos.com/kubernetes/docs/latest/getting-started.html without flannel. Both servers are in the same network.

But I am getting: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kube-ca") while running kubelet in worker.

I configured the TLS certificates properly on both the servers as discussed in the doc.

The master node is working fine. And the kubectl is able to fire containers and pods in master.

Question 1: How to fix this problem?

Question 2: Is there any way to configure a cluster without TLS certificates?

Coreos version:
VERSION=899.15.0
VERSION_ID=899.15.0
BUILD_ID=2016-04-05-1035
PRETTY_NAME="CoreOS 899.15.0"

Etcd conf:

 $ etcdctl member list          
ce2a822cea30bfca: name=78c2c701d4364a8197d3f6ecd04a1d8f peerURLs=http://localhost:2380,http://localhost:7001 clientURLs=http://172.24.0.67:2379

Master: kubelet.service:

[Service]
ExecStartPre=/usr/bin/mkdir -p /etc/kubernetes/manifests
Environment=KUBELET_VERSION=v1.2.2_coreos.0
ExecStart=/opt/bin/kubelet-wrapper \
  --api-servers=http://127.0.0.1:8080 \
  --register-schedulable=false \
  --allow-privileged=true \
  --config=/etc/kubernetes/manifests \
  --hostname-override=172.24.0.67 \
  --cluster-dns=10.3.0.10 \
  --cluster-domain=cluster.local
Restart=always
RestartSec=10
[Install]
WantedBy=multi-user.target

Master: kube-controller.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kube-controller-manager
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-controller-manager
    image: quay.io/coreos/hyperkube:v1.2.2_coreos.0
    command:
    - /hyperkube
    - controller-manager
    - --master=http://127.0.0.1:8080
    - --leader-elect=true 
    - --service-account-private-key-file=/etc/kubernetes/ssl/apiserver-key.pem
    - --root-ca-file=/etc/kubernetes/ssl/ca.pem
    livenessProbe:
      httpGet:
        host: 127.0.0.1
        path: /healthz
        port: 10252
      initialDelaySeconds: 15
      timeoutSeconds: 1
    volumeMounts:
    - mountPath: /etc/kubernetes/ssl
      name: ssl-certs-kubernetes
      readOnly: true
    - mountPath: /etc/ssl/certs
      name: ssl-certs-host
      readOnly: true
  volumes:
  - hostPath:
      path: /etc/kubernetes/ssl
    name: ssl-certs-kubernetes
  - hostPath:
      path: /usr/share/ca-certificates
    name: ssl-certs-host

Master: kube-proxy.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kube-proxy
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-proxy
    image: quay.io/coreos/hyperkube:v1.2.2_coreos.0
    command:
    - /hyperkube
    - proxy
    - --master=http://127.0.0.1:8080
    securityContext:
      privileged: true
    volumeMounts:
    - mountPath: /etc/ssl/certs
      name: ssl-certs-host
      readOnly: true
  volumes:
  - hostPath:
      path: /usr/share/ca-certificates
    name: ssl-certs-host

Master: kube-apiserver.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kube-apiserver
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-apiserver
    image: quay.io/coreos/hyperkube:v1.2.2_coreos.0
    command:
    - /hyperkube
    - apiserver
    - --bind-address=0.0.0.0
    - --etcd-servers=http://172.24.0.67:2379
    - --allow-privileged=true
    - --service-cluster-ip-range=10.3.0.0/24
    - --secure-port=443
    - --advertise-address=172.24.0.67
    - --admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota
    - --tls-cert-file=/etc/kubernetes/ssl/apiserver.pem
    - --tls-private-key-file=/etc/kubernetes/ssl/apiserver-key.pem
    - --client-ca-file=/etc/kubernetes/ssl/ca.pem
    - --service-account-key-file=/etc/kubernetes/ssl/apiserver-key.pem
    ports:
    - containerPort: 443
      hostPort: 443
      name: https
    - containerPort: 8080
      hostPort: 8080
      name: local
    volumeMounts:
    - mountPath: /etc/kubernetes/ssl
      name: ssl-certs-kubernetes
      readOnly: true
    - mountPath: /etc/ssl/certs
      name: ssl-certs-host
      readOnly: true
  volumes:
  - hostPath:
      path: /etc/kubernetes/ssl
    name: ssl-certs-kubernetes
  - hostPath:
      path: /usr/share/ca-certificates
    name: ssl-certs-host

Master: kube-scheduler.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kube-scheduler
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-scheduler
    image: quay.io/coreos/hyperkube:v1.2.2_coreos.0
    command:
    - /hyperkube
    - scheduler
    - --master=http://127.0.0.1:8080
    - --leader-elect=true
    livenessProbe:
      httpGet:
        host: 127.0.0.1
        path: /healthz
        port: 10251
      initialDelaySeconds: 15
      timeoutSeconds: 1

Slave: kubelet.service

[Service]
ExecStartPre=/usr/bin/mkdir -p /etc/kubernetes/manifests

Environment=KUBELET_VERSION=v1.2.2_coreos.0 
ExecStart=/opt/bin/kubelet-wrapper \
  --api-servers=https://172.24.0.67:443 \
  --register-node=true \
  --allow-privileged=true \
  --config=/etc/kubernetes/manifests \
  --hostname-override=172.24.0.63 \
  --cluster-dns=10.3.0.10 \
  --cluster-domain=cluster.local \
  --kubeconfig=/etc/kubernetes/worker-kubeconfig.yaml \
  --tls-cert-file=/etc/kubernetes/ssl/worker.pem \
  --tls-private-key-file=/etc/kubernetes/ssl/worker-key.pem
Restart=always
RestartSec=10
[Install]
WantedBy=multi-user.target

Slave: kube-proxy.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kube-proxy
  namespace: kube-system
spec:
  hostNetwork: true
  containers:
  - name: kube-proxy
    image: quay.io/coreos/hyperkube:v1.2.2_coreos.0
    command:
    - /hyperkube
    - proxy
    - --master=https://172.24.0.67:443
    - --kubeconfig=/etc/kubernetes/worker-kubeconfig.yaml
    - --proxy-mode=iptables
    securityContext:
      privileged: true
    volumeMounts:
      - mountPath: /etc/ssl/certs
        name: "ssl-certs"
      - mountPath: /etc/kubernetes/worker-kubeconfig.yaml
        name: "kubeconfig"
        readOnly: true
      - mountPath: /etc/kubernetes/ssl
        name: "etc-kube-ssl"
        readOnly: true
  volumes:
    - name: "ssl-certs"
      hostPath:
        path: "/usr/share/ca-certificates"
    - name: "kubeconfig"
      hostPath:
        path: "/etc/kubernetes/worker-kubeconfig.yaml"
    - name: "etc-kube-ssl"
      hostPath:
        path: "/etc/kubernetes/ssl"

Answer

yasin lachini picture yasin lachini · Feb 17, 2019 
mkdir -p $HOME/.kube   
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config   
sudo chown $(id -u):$(id -g) $HOME/.kube/config

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