<p>I am using kubectl to connect remote kubernetes cluster(v1.15.2),I am copy config from remote server to local macOS:</p>

<pre><code>scp -r root@ip:~/.kube/config ~/.kube
</code></pre>

<p>and change the url to <code>https://kube-ctl.example.com</code>,I exposed the api server to the internet:</p>

<pre><code>apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://k8s-ctl.example.com
  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    namespace: kube-system
    user: admin
  name: kubernetes
current-context: kubernetes
kind: Config
preferences: {}
users:
- name: admin
  user:
</code></pre>

<p>when I get cluster pod info in my local Mac:</p>

<pre><code>kubectl get pods --all-namespaces
</code></pre>

<p>give this error:</p>

<pre><code>Unable to connect to the server: x509: certificate signed by unknown authority
</code></pre>

<p>when I access <code>https://k8s-ctl.example.com</code> in google chrome,the result is:</p>

<pre><code>{
kind: "Status",
apiVersion: "v1",
metadata: { },
status: "Failure",
message: "Unauthorized",
reason: "Unauthorized",
code: 401
}
</code></pre>

<p>what should I do to make access remote k8s cluster sucess using kubectl client?</p>

<p>One way I have tried to using this <code>.kube/config</code> generate by command,but get the same result:</p>

<pre><code>apiVersion: v1
clusters:
- cluster:
    certificate-authority: ssl/ca.pem
    server: https://k8s-ctl.example.com
  name: default
contexts:
- context:
    cluster: default
    user: admin
  name: default
current-context: default
kind: Config
preferences: {}
users:
- name: admin
  user:
    client-certificate: ssl/admin.pem
    client-key: ssl/admin-key.pem
</code></pre>

Dolphin
<p>When kubectl interacts with kube API server it will validate the kube API server certificate as well as send the certificate in <code>client-certificate</code>  to the kube API server for mutual TLS authentication. I believe the problem is either of below.</p>

<ol>
<li>the ca that you have used to generate the  <code>client-certificate</code> is not the ca that has been used to startup the kube API server.</li>
<li>The ca in <code>certificate-authority-data</code> is not the ca used to generate kube API server certificate.</li>
</ol>

<p><strong>If you make sure that you are using same ca to generate all the certificates consistently across the board then it should work</strong>.</p>
