<p>When I deploy a docker image to <a href="https://cloud.google.com/kubernetes-engine/" rel="nofollow noreferrer">Kubernetes Engine</a>,</p>

<p><a href="https://i.stack.imgur.com/LtwaW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LtwaW.png" alt="enter image description here"></a>
 the pods can't be initialize, pods are just making a simple get request to <a href="https://jsonplaceholder.typicode.com/" rel="nofollow noreferrer">https://jsonplaceholder.typicode.com/</a> 
<a href="https://i.stack.imgur.com/qtxIt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qtxIt.png" alt="code"></a></p>

<p>I get an error message <code>certificate signed by unknown authority</code></p>

<p><a href="https://i.stack.imgur.com/jeX7D.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jeX7D.png" alt="enter image description here"></a></p>

<p>From the comments in your question, I expect you are running up against the common problem of Alpine base images not being populated with the <code>ca-certificates</code> package, which contains a number of root CA certificates to anchor your root of trust.</p>

<p>Add the following command to your <code>Dockerfile</code> to ensure these are installed in the produced image:</p>

<pre><code>RUN apk update &amp;&amp; apk add ca-certificates &amp;&amp; rm -rf /var/cache/apk/*
</code></pre>

<p>(we run multiple operations in a single <code>RUN</code> step to <a href="https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#run" rel="noreferrer">avoid introducing unnecessary bloat</a> in the layers of your final image).</p>

<p>Base images which include the CA certificates package are also available in the container registry (although with this statement I make no claims as to their suitability or provenance).</p>
