 suggestions for improvement?<br><br><input id=feedback-textbox type=text placeholder='Help us improve...' data-lang=zh></div><div id=feedback-thankyou>Thanks for your feedback!</div></div><div id=endnotes-container aria-hidden=true><h2>链接</h2><ol id=endnotes></ol></div></div><div class=toc-container><nav class=toc aria-label="Table of Contents"><div id=toc><ol><li role=none aria-label=先决条件><a href=#prerequisites>先决条件</a><li role=none aria-label=验证镜像><a href=#validating-image>验