<p dir="auto">Secret key names like <strong>id_rsa</strong> and <strong>id_rsa.pub</strong> are illegal (see <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="103907197" data-permission-text="Title is private" data-url="https://github.com/kubernetes/kubernetes/issues/13357" data-hovercard-type="issue" data-hovercard-url="/kubernetes/kubernetes/issues/13357/hovercard" href="https://github.com/kubernetes/kubernetes/issues/13357">#13357</a>). This makes it impossible to use secrets for loading ssh keys and other files with underscores into your containers.</p>
<p dir="auto">Can the restrictions be loosened so it maps to linux filename restrictions instead of DNS_SUBDOMAIN?</p>
<p dir="auto">Currently the key of a piece of secret data has to be a DNS subdomain.  We went with DNS subdomains instead of defining a new format during the implementation because we assumed that a dns subdomain was a strict subset of the eventual format to use. It has been suggested in <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="74443715" data-permission-text="Title is private" data-url="https://github.com/kubernetes/kubernetes/issues/7974" data-hovercard-type="pull_request" data-hovercard-url="/kubernetes/kubernetes/pull/7974/hovercard" href="https://github.com/kubernetes/kubernetes/pull/7974">#7974</a> that we create a format to model file names use that format to validate keys in secrets.</p>