title: AWS EC2 PHP SDK - DescribeInstances With Tag Key and Value
body: <p>I have EC2 instances tagged with key <code>environment</code> and value <code>production</code>. I am trying to return them using the following:</p>
  
  <pre><code>$result = $ec2_client-&gt;describeInstances(array(
      "Filters" =&gt; array(
          array(
              "Name" =&gt; "tag",
              "Value" =&gt; array(
                  "environment=production"
              )
          )
      )
  ));
  </code></pre>
  
  <p>The above errors out. </p>
  
  <p>How do I specify this method call in the correct manner?</p>