- "documentation":"<p>Amazon Route 53 behavior depends on whether you specify a value for <code>IPAddress</code>.</p> <p> <b>If you specify a value for</b> <code>IPAddress</code>:</p> <p>Amazon Route 53 sends health check requests to the specified IPv4 or IPv6 address and passes the value of <code>FullyQualifiedDomainName</code> in the <code>Host</code> header for all health checks except TCP health checks. This is typically the fully qualified DNS name of the endpoint on which you want Route 53 to perform health checks.</p> <p>When Route 53 checks the health of an endpoint, here is how it constructs the <code>Host</code> header:</p> <ul> <li> <p>If you specify a value of <code>80</code> for <code>Port</code> and <code>HTTP</code> or <code>HTTP_STR_MATCH</code> for <code>Type</code>, Route 53 passes the value of <code>FullyQualifiedDomainName</code> to the endpoint in the Host header. </p> </li> <li> <p>If you specify a value of <code>443</code> for <code>Port</code> and <code>HTTPS</code> or <code>HTTPS_STR_MATCH</code> for <code>Type</code>, Route 53 passes the value of <code>FullyQualifiedDomainName</code> to the endpoint in the <code>Host</code> header.</p> </li> <li> <p>If you specify another value for <code>Port</code> and any value except <code>TCP</code> for <code>Type</code>, Route 53 passes <code>FullyQualifiedDomainName:Port</code> to the endpoint in the <code>Host</code> header.</p> </li> </ul> <p>If you don't specify a value for <code>FullyQualifiedDomainName</code>, Route 53 substitutes the value of <code>IPAddress</code> in the <code>Host</code> header in each of the preceding cases.</p> <p> <b>If you don't specify a value for <code>IPAddress</code> </b>:</p> <p>Route 53 sends a DNS request to the domain that you specify for <code>FullyQualifiedDomainName</code> at the interval that you specify for <code>RequestInterval</code>. Using an IPv4 address that DNS returns, Route 53 then checks the health of the endpoint.</p> <note> <p>If you don't specify a value for <code>IPAddress</code>, Route 53 uses only IPv4 to send health checks to the endpoint. If there's no resource record set with a type of A for the name that you specify for <code>FullyQualifiedDomainName</code>, the health check fails with a \"DNS resolution failed\" error.</p> </note> <p>If you want to check the health of weighted, latency, or failover resource record sets and you choose to specify the endpoint only by <code>FullyQualifiedDomainName</code>, we recommend that you create a separate health check for each endpoint. For example, create a health check for each HTTP server that is serving content for www.example.com. For the value of <code>FullyQualifiedDomainName</code>, specify the domain name of the server (such as us-east-2-www.example.com), not the name of the resource record sets (www.example.com).</p> <important> <p>In this configuration, if you create a health check for which the value of <code>FullyQualifiedDomainName</code> matches the name of the resource record sets and you then associate the health check with those resource record sets, health check results will be unpredictable.</p> </important> <p>In addition, if the value that you specify for <code>Type</code> is <code>HTTP</code>, <code>HTTPS</code>, <code>HTTP_STR_MATCH</code>, or <code>HTTPS_STR_MATCH</code>, Route 53 passes the value of <code>FullyQualifiedDomainName</code> in the <code>Host</code> header, as it does when you specify a value for <code>IPAddress</code>. If the value of <code>Type</code> is <code>TCP</code>, Route 53 doesn't pass a <code>Host</code> header.</p>"
0 commit comments