<p dir="auto">There is a lack of warning for incorrectly parsed configurations. In this case I set invalid values for the following configurations in elasticsearch.yml :</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="# incorrect values because booleans have to be lowercase
node.master: True
node.data: True
discovery.zen.ping.multicast.enabled: false
discovery.zen.ping.unicast.hosts: [&quot;localhost&quot;]"><pre class="notranslate"><code class="notranslate"># incorrect values because booleans have to be lowercase
node.master: True
node.data: True
discovery.zen.ping.multicast.enabled: false
discovery.zen.ping.unicast.hosts: ["localhost"]
</code></pre></div>
<p dir="auto">But elastic search starts and I am able to see the following cluster nodes:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="curl localhost:9200/_nodes/http?pretty=true
{
  &quot;cluster_name&quot; : &quot;elasticsearch&quot;,
  &quot;nodes&quot; : {
      ...
      &quot;attributes&quot; : {
        &quot;master&quot; : &quot;True&quot;,
        &quot;data&quot; : &quot;True&quot;
      },
     ...
    },"><pre class="notranslate"><code class="notranslate">curl localhost:9200/_nodes/http?pretty=true
{
  "cluster_name" : "elasticsearch",
  "nodes" : {
      ...
      "attributes" : {
        "master" : "True",
        "data" : "True"
      },
     ...
    },
</code></pre></div>
<p dir="auto">The only indication when I get that there is a problem is when I try to run other commands to access the data in the cluster. This is the error that I get back when I try to add a mapping to my_index:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="curl -X PUT localhost:9200/my_index -d @mapping.json'
{&quot;error&quot;:&quot;MasterNotDiscoveredException[waited for [30s]]&quot;,&quot;status&quot;:503}"><pre class="notranslate"><code class="notranslate">curl -X PUT localhost:9200/my_index -d @mapping.json'
{"error":"MasterNotDiscoveredException[waited for [30s]]","status":503}
</code></pre></div>
<p dir="auto">In this case, it would be useful to fail server start if there is an incorrect parameter or issue some sort of warning or have it logged. I ran this on elasticsearch 1.3.4.</p>
<p dir="auto">Currently there is no way of seeing all settings that are enforced.  For instance, defaults are not available and settings from the <code class="notranslate">config/elasticsearch.yml</code> are not available.</p>
<p dir="auto">Any setting which is different from the default should be returned by these APIs:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="GET /{index}/_settings
GET /_cluster/settings"><pre class="notranslate"><code class="notranslate">GET /{index}/_settings
GET /_cluster/settings
</code></pre></div>
<p dir="auto">Both should also support the <code class="notranslate">include_defaults</code> query string parameter, which would return all settings, including the defaults.</p>
<p dir="auto">Also, deleting a setting should reset the setting to the default.</p>
<p dir="auto">Setting an unknown setting, or a setting that can't be changed should throw an error.</p>
<p dir="auto">Relates to <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="26953933" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/5018" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/5018/hovercard" href="https://github.com/elastic/elasticsearch/issues/5018">#5018</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="19340352" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/3670" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/3670/hovercard" href="https://github.com/elastic/elasticsearch/issues/3670">#3670</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="11739095" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/2738" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/2738/hovercard" href="https://github.com/elastic/elasticsearch/issues/2738">#2738</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="11658370" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/2730" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/2730/hovercard" href="https://github.com/elastic/elasticsearch/issues/2730">#2730</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="18541655" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/3572" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/3572/hovercard" href="https://github.com/elastic/elasticsearch/issues/3572">#3572</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="10724452" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/2628" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/2628/hovercard" href="https://github.com/elastic/elasticsearch/issues/2628">#2628</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="19340512" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/3671" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/3671/hovercard" href="https://github.com/elastic/elasticsearch/issues/3671">#3671</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="26954220" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/5019" data-hovercard-type="pull_request" data-hovercard-url="/elastic/elasticsearch/pull/5019/hovercard" href="https://github.com/elastic/elasticsearch/pull/5019">#5019</a>, <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="34296305" data-permission-text="Title is private" data-url="https://github.com/elastic/elasticsearch/issues/6309" data-hovercard-type="issue" data-hovercard-url="/elastic/elasticsearch/issues/6309/hovercard" href="https://github.com/elastic/elasticsearch/issues/6309">#6309</a></p>