Let's discuss creating sitemap.xml with Jekyll

References

Generating a sitemap without a plugin.

Plugin

Start by disabling the plugin.

Edit _config.yml, change

gems: [jekyll-sitemap, jekyll-paginate]

to

gems: [jekyll-paginate]

and remove from Gemfile

# gem 'jekyll-sitemap'

Define some rules

Do not publish this page, exclude from sitemap.xml and exclude from feed.xml

To exclude, add to page yaml

sitemap: false

Generate Sitemap.xml

Create file sitemap.xml

---
layout: null
---
<?xml version="1.0" encoding="UTF-8"?>
<urlset 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" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">

  {% for post in site.posts %}
		{% if post.sitemap != false %}
			<url>
				<loc>{{ site.url }}{{ post.url }}</loc>
				<lastmod>{{ post.date | date_to_xmlschema }}</lastmod>
				<changefreq>weekly</changefreq>
				<priority>1.0</priority>
			</url>
		{% endif %}
  {% endfor %}



  {% for page in site.pages %}
    {% if page.sitemap != false %}
      <url>
        <loc>{{ site.url }}{{ page.url }}</loc>
        <lastmod>{{ site.time | date_to_xmlschema }}</lastmod>
        <changefreq>weekly</changefreq>
        <priority>1.0</priority>
       </url>
    {% endif %}
  {% endfor %}

</urlset>

Verify

Check destination/sitemap.xml

Note that Jekyll regenerating files does not always pick up changes to md files.

I have found it sometimes necessary to alter sitemap.xml to force a regeneration.