d: ServiceRole
    name: &#34;external-api-caller&#34;
</code></pre><p>The <code>ServiceRole</code> and <code>ServiceRoleBinding</code> above expressed &ldquo;<em>who</em> is allowed to do <em>what</em> under <em>which conditions</em>”
(RBAC + conditions). Specifically:</p><ul><li><strong>&ldquo;who”</strong> are the services in the <code>frontend</code> namespace.</li><li><strong>&ldquo;what”</strong> is to call services in <code>backend</code> namespace.</li><li><strong>&ldquo;conditions”</strong>