feat(prometheus): support tsdb.retention.percentage

[rjhenry]

Configure storage.tsdb.retention in the configuration file for versions of Prometheus 3.11.0 and greater, rather than deprecated command line flags. This allows for configuring percentage-based retention.
This closes #790.

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• M prometheus_role.html

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diff --git a/home/runner/work/ansible/ansible/docsbuild/base/prometheus_role.html b/home/runner/work/ansible/ansible/docsbuild/head/prometheus_role.html
index f09f722..3593345 100644
--- a/home/runner/work/ansible/ansible/docsbuild/base/prometheus_role.html
+++ b/home/runner/work/ansible/ansible/docsbuild/head/prometheus_role.html
@@ -376,6 +376,16 @@ To check whether it is installed, run <code class="code docutils literal notrans
 </div></td>
 </tr>
 <tr class="row-even"><td><div class="ansible-option-cell">
+<div class="ansibleOptionAnchor" id="parameter-main--prometheus_storage_retention_percentage"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-storage-retention-percentage"><strong>prometheus_storage_retention_percentage</strong></p>
+<a class="ansibleOptionLink" href="#parameter-main--prometheus_storage_retention_percentage" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
+</div></td>
+<td><div class="ansible-option-cell"><p>Maximum percent of total disk space allowed for block storage</p>
+<p>Set to 0 to disable percentage-based retention</p>
+<p>Supported only on Prometheus &gt;= 3.11.0</p>
+<p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;0&quot;</span></code></p>
+</div></td>
+</tr>
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_storage_retention_size"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-storage-retention-size"><strong>prometheus_storage_retention_size</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_storage_retention_size" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -385,7 +395,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;0&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_system_group"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-system-group"><strong>prometheus_system_group</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_system_group" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -393,7 +403,7 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;prometheus&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_system_user"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-system-user"><strong>prometheus_system_user</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_system_user" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -401,14 +411,14 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;prometheus&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_targets"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-targets"><strong>prometheus_targets</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_targets" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">dictionary</span></p>
 </div></td>
 <td><div class="ansible-option-cell"><p>Targets which will be scraped.</p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_version"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-version"><strong>prometheus_version</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_version" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
@@ -417,21 +427,21 @@ To check whether it is installed, run <code class="code docutils literal notrans
 <p class="ansible-option-line"><strong class="ansible-option-default-bold">Default:</strong> <code class="ansible-option-default docutils literal notranslate"><span class="pre">&quot;3.11.3&quot;</span></code></p>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_web_config"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-web-config"><strong>prometheus_web_config</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_web_config" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">dictionary</span></p>
 </div></td>
 <td><div class="ansible-option-cell"><p>A Prometheus <a class="reference external" href="https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md">web config yaml</a> for configuring TLS and auth.</p>
 </div></td>
 </tr>
-<tr class="row-even"><td><div class="ansible-option-cell">
+<tr class="row-odd"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_web_external_url"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-web-external-url"><strong>prometheus_web_external_url</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_web_external_url" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>
 <td><div class="ansible-option-cell"><p>External address on which prometheus is available. Useful when behind reverse proxy. Ex. `http://example.org/prometheus`</p>
 </div></td>
 </tr>
-<tr class="row-odd"><td><div class="ansible-option-cell">
+<tr class="row-even"><td><div class="ansible-option-cell">
 <div class="ansibleOptionAnchor" id="parameter-main--prometheus_web_listen_address"></div><p class="ansible-option-title" id="ansible-collections-prometheus-prometheus-prometheus-role-parameter-main-prometheus-web-listen-address"><strong>prometheus_web_listen_address</strong></p>
 <a class="ansibleOptionLink" href="#parameter-main--prometheus_web_listen_address" title="Permalink to this option"></a><p class="ansible-option-type-line"><span class="ansible-option-type">string</span></p>
 </div></td>

[rjhenry]

I can't see any molecule tests that test for handling of the prometheus.yml config file (other than creation), or mention either prometheus_storage_retention or prometheus_storage_retention_size. That said, I'm not the most familar with Molecule, so it's entirely possible I'm missing something otherwise obvious!
As I couldn't see any tests to mimic, there aren't any introduced tests for the changes in this PR. I'm happy to add some if required, but would appreciate a pointer or two in the right direction (ie: at existing tests I can extend).