installation-steps">installation steps</a>.</li></ul><h2 id="plugging-in-the-existing-certificate-and-key">Plugging in the existing certificate and key</h2><p>Suppose we want to have Istio CA use the existing certificate <code>ca-cert.pem</code> and key <code>ca-key.pem</code>. Furthermore, the certificate <code>ca-cert.pem</code> is signed by the root certificate <code>root-cert.pem</code>, and we would like to use <code>root-cert.pem</code> as the root certificate for Istio workloads.</p><p>In this exampl