Use Jekyll Sitemap to generate the sitemap.

Jekyll Sitemap (https://github.com/jekyll/jekyll-sitemap) is an
official Jekyll plugin, which should serve as a drop-in replacement
for the existing sitemap.xml. The resulting sitemap should be largely
similar to the existing sitemap, but with a shared, battle-tested
template that accounts for all sorts of edge cases, handles collections
and static files, etc.

_config.yml

@@ -31,3 +31,4 @@ permalink: pretty
 gems:
   - jekyll-redirect-from
   - jekyll-feed
+  - jekyll-sitemap

sitemap.xml

@@ -1,18 +0,0 @@
----
----
-<?xml version="1.0" encoding="UTF-8"?>
-<urlset
-      xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
-      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-      xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9
-            http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
-
-<url>
-  <loc>http://kubernetes.io/</loc>
-  <lastmod>{{ site.time | date_to_xmlschema }}</lastmod>
-</url>
-{% for page in site.pages %}{% if page.url != "/404.html" and page.url != "/sitemap.xml" and page.url != "/css/styles.css" %}<url>
-  <loc>http://kubernetes.io{{ page.url }}</loc>
-  <lastmod>{% if page.date %}{{ page.date | date_to_xmlschema }}{% else %}{{ site.time | date_to_xmlschema }}{% endif %}</lastmod>
-</url>{% endif %}{% endfor %}
-</urlset>