Values that you specify when you create or update health checks

When you create or update health checks, you specify the applicable values. Note that you can't change some values after you create a health check.

Name

Optional, but recommended: The name that you want to assign to the health check. If you specify a value for Name, Route 53 adds a tag to the health check, assigns the value Name to the tag key, and assigns the value that you specify to the tag value. The value of the Name tag appears in the list of health checks in the Route 53 console, which lets you easily distinguish health checks from one another.

For more information about tagging and health checks, see Naming and tagging health checks.

What to monitor

Whether you want this health check to monitor an endpoint or the status of other health checks:

• Endpoint – Route 53 monitors the health of an endpoint that you specify. You can specify the endpoint by providing either a domain name or an IP address and a port.

  Note

  If you specify a non-AWS endpoint, an additional charge applies. For more information, including a definition of AWS endpoints, see "Health Checks" on the Route 53 Pricing page.

• Status of other health checks (calculated health check) – Route 53 determines whether this health check is healthy based on the status of other health checks that you specify. You also specify how many of the health checks need to be healthy for this health check to be considered healthy.

• State of CloudWatch alarm data stream – Route 53 determines whether this health check is healthy by monitoring the data stream for a CloudWatch alarm.

Monitoring an endpoint

Note

We're updating the health checks console for Route 53. During the transition period, you can continue to use the old console.

Choose the tab for the console you are using.

• New console

• Old console

New console

If you want this health check to monitor an endpoint, specify the following values:

• Specify endpoints by

• IP address

• Domain name

Specify endpoint by

Whether you want to specify the endpoint using an IP address or using a domain name.

After you create a health check, you can't change the value of Specify endpoint by.

IP address ("Specify endpoint by IP address" Only)

Choose the protocol in the drop-down, enter the IP address, the port, and the path in the text box.

• The protocol can be one of the following:

  HTTP – Route 53 tries to establish a TCP connection. If successful, Route 53 submits an HTTP request and waits for an HTTP status code of 2xx or 3xx.

• HTTPS – Route 53 tries to establish a TCP connection. If successful, Route 53 submits an HTTPS request and waits for an HTTP status code of 2xx or 3xx.

  Important

  If you choose HTTPS, the endpoint must support TLS v1.0, v1.1, or v1.2.

  If you choose HTTPS for the value of Protocol, an additional charge applies. For more information, see Route 53 Pricing.

• TCP – Route 53 tries to establish a TCP connection.

For more information, see How Amazon Route 53 determines whether a health check is healthy.

After you create a health check, you can't change the value of Protocol.

For the IP address you can enter an IPv4 or IPv6 address of the endpoint on which you want Route 53 to perform health checks, if you chose Specify endpoint by IP address.

Route 53 cannot check the health of endpoints for which the IP address is in local, private, nonroutable, or multicast ranges. For more information about IP addresses that you can't create health checks for, see the following documents:

• RFC 5735, Special Use IPv4 Addresses

• RFC 6598, IANA-Reserved IPv4 Prefix for Shared Address Space.

• RFC 5156, Special-Use IPv6 Addresses

If the endpoint is an Amazon EC2 instance, we recommend that you create an Elastic IP address, associate it with your EC2 instance, and specify the Elastic IP address. This ensures that the IP address of your instance will never change. For more information, see Elastic IP addresses (EIP) in the Amazon EC2 User Guide.

If you delete the Amazon EC2 instance, make sure you also delete the health check associated to the EIP. For more information, see Best practices for Amazon Route 53 health checks.

Note

If you specify a non-AWS endpoint, an additional charge applies. For more information, including a definition of AWS endpoints, see "Health Checks" on the Route 53 Pricing page.

For the port you enter the port on the endpoint on which you want Route 53 to perform health checks.

For the path (HTTP and HTTPS Protocols Only) you enter the path that you want Route 53 to request when performing health checks. The path can be any value for which your endpoint will return an H TTP status code of 2xx or 3xx when the endpoint is healthy, such as the file /docs/route53-health-check.html. You can also include query string parameters, for example, /welcome.html?language=jp&login=y. If you don't include a leading slash (/) character, Route 53 automatically adds one.

Domain name ("Specify endpoint by domain name" Only, All Protocols)

The domain name (example.com) or subdomain name (backend.example.com) of the endpoint that you want Route 53 to perform health checks on, if you choose Specify endpoint by domain name.

If you choose to specify the endpoint by domain name, Route 53 sends a DNS query to resolve the domain name that you specify in Domain name at the interval that you specify in Request interval. Using an IP address that DNS returns, Route 53 then checks the health of the endpoint.

Note

If you specify the endpoint by domain name, Route 53 uses only IPv4 to send health checks to the endpoint. If there's no record with a type of A for the name that you specify for Domain name, the health check fails with a "DNS resolution failed" error.

If you want to check the health of failover, geolocation, geoproximity, latency, multivalue, or weighted records, and you choose to specify the endpoint by domain name, 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 Domain name, specify the domain name of the server (such as us-east-2-www.example.com), not the name of the records (www.example.com).

Important

In this configuration, if you create a health check for which the value of Domain name matches the name of the records and then associate the health check with those records, health check results will be unpredictable.

In addition, if the value of Protocol is HTTP or HTTPS, Route 53 passes the value of Domain name in the Host header as described in Host name, earlier in this list. If the value of Protocol is TCP, Route 53 doesn't pass a Host header.

Note

If you specify a non-AWS endpoint, an additional charge applies. For more information, including a definition of AWS endpoints, see "Health Checks" on the Route 53 Pricing page.

Old console

If you want this health check to monitor an endpoint, specify the following values:

• Specify endpoint by

• Protocol

• IP address

• Host name

• Port

• Domain name

• Path

Specify endpoint by

Whether you want to specify the endpoint using an IP address or using a domain name.

After you create a health check, you can't change the value of Specify endpoint by.

Protocol

The method that you want Route 53 to use to check the health of your endpoint:

• HTTP – Route 53 tries to establish a TCP connection. If successful, Route 53 submits an HTTP request and waits for an HTTP status code of 2xx or 3xx.

• HTTPS – Route 53 tries to establish a TCP connection. If successful, Route 53 submits an HTTPS request and waits for an HTTP status code of 2xx or 3xx.

  Important

  If you choose HTTPS, the endpoint must support TLS v1.0, v1.1, or v1.2.

  If you choose HTTPS for the value of Protocol, an additional charge applies. For more information, see Route 53 Pricing.

• TCP – Route 53 tries to establish a TCP connection.

For more information, see How Amazon Route 53 determines whether a health check is healthy.

After you create a health check, you can't change the value of Protocol.

IP address ("Specify endpoint by IP address" Only)

The IPv4 or IPv6 address of the endpoint on which you want Route 53 to perform health checks, if you chose Specify endpoint by IP address.

Route 53 cannot check the health of endpoints for which the IP address is in local, private, nonroutable, or multicast ranges. For more information about IP addresses that you can't create health checks for, see the following documents:

• RFC 5735, Special Use IPv4 Addresses

• RFC 6598, IANA-Reserved IPv4 Prefix for Shared Address Space.

• RFC 5156, Special-Use IPv6 Addresses

If the endpoint is an Amazon EC2 instance, we recommend that you create an Elastic IP address, associate it with your EC2 instance, and specify the Elastic IP address. This ensures that the IP address of your instance will never change. For more information, see Elastic IP addresses (EIP) in the Amazon EC2 User Guide.

If you delete the Amazon EC2 instance, make sure you also delete the health check associated to the EIP. For more information, see Best practices for Amazon Route 53 health checks.

Note

If you specify a non-AWS endpoint, an additional charge applies. For more information, including a definition of AWS endpoints, see "Health Checks" on the Route 53 Pricing page.

Host name ("Specify endpoint by IP address" Only, HTTP and HTTPS Protocols Only)

The value that you want Route 53 to pass in the Host header in HTTP and HTTPS health checks. This is typically the fully qualified DNS name of the website on which you want Route 53 to perform health checks. When Route 53 checks the health of an endpoint, here is how it constructs the Host header:

• If you specify a value of 80 for Port and HTTP for Protocol, Route 53 passes to the endpoint a Host header that contains the value of Host name.

• If you specify a value of 443 for Port and HTdTPS for Protocol, Route 53 passes to the endpoint a Host header that contains the value of Host name.

• If you specify another value for Port and either HTTP or HTTPS for Protocol, Route 53 passes to the endpoint a Host header that contains the value Host name:Port.

If you choose to specify the endpoint by IP address and you don't specify a value for Host name, Route 53 substitutes the value of IP address in the Host header in each of the preceding cases.

Port

The port on the endpoint on which you want Route 53 to perform health checks.

Domain name ("Specify endpoint by domain name" Only, All Protocols)

The domain name (example.com) or subdomain name (backend.example.com) of the endpoint that you want Route 53 to perform health checks on, if you choose Specify endpoint by domain name.

If you choose to specify the endpoint by domain name, Route 53 sends a DNS query to resolve the domain name that you specify in Domain name at the interval that you specify in Request interval. Using an IP address that DNS returns, Route 53 then checks the health of the endpoint.

Note

If you specify the endpoint by domain name, Route 53 uses only IPv4 to send health checks to the endpoint. If there's no record with a type of A for the name that you specify for Domain name, the health check fails with a "DNS resolution failed" error.

If you want to check the health of failover, geolocation, geoproximity, latency, multivalue, or weighted records, and you choose to specify the endpoint by domain name, 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 Domain name, specify the domain name of the server (such as us-east-2-www.example.com), not the name of the records (www.example.com).

Important

In this configuration, if you create a health check for which the value of Domain name matches the name of the records and then associate the health check with those records, health check results will be unpredictable.

In addition, if the value of Protocol is HTTP or HTTPS, Route 53 passes the value of Domain name in the Host header as described in Host name, earlier in this list. If the value of Protocol is TCP, Route 53 doesn't pass a Host header.

Note

If you specify a non-AWS endpoint, an additional charge applies. For more information, including a definition of AWS endpoints, see "Health Checks" on the Route 53 Pricing page.

Path (HTTP and HTTPS Protocols Only)

The path that you want Route 53 to request when performing health checks. The path can be any value for which your endpoint will return an HTTP status code of 2xx or 3xx when the endpoint is healthy, such as the file /docs/route53-health-check.html. You can also include query string parameters, for example, /welcome.html?language=jp&login=y. If you don't include a leading slash (/) character, Route 53 automatically adds one.

Monitoring other health checks (calculated health checks)

Note

We're updating the health checks console for Route 53. During the transition period, you can continue to use the old console.

Choose the tab for the console you are using.

• New console

• Old console

New console

If you want this health check to monitor the status of other health checks, specify the following values:

• Health checks to monitor

• Report healthy when

Health checks to monitor

The health checks that you want Route 53 to monitor to determine the health of this health check.

You can add up to 256 health checks to Health checks to monitor. To remove a health check from the list, choose the x at the right of the highlight for that health check.

Note

You can't configure a calculated health check to monitor the health of other calculated health checks.

If you disable a health check that a calculated health check is monitoring, Route 53 considers the disabled health check to be healthy as it calculates whether the calculated health check is healthy. If you want the disabled health check to be considered unhealthy, choose the Invert health check status check box.

Report healthy when

The calculation that you want Route 53 to perform to determine whether this health check is healthy:

• Report healthy when at least x of y selected health checks are healthy – Route 53 considers this health check to be healthy when the specified number of health checks that you added to Health checks to monitor are healthy. Note the following:

  • If you specify a number greater than the number of health checks in Health checks to monitor, Route 53 always considers this health check to be unhealthy.

  • If you specify 0, Route 53 always considers this health check to be healthy.

• Report healthy when all health checks are healthy (AND) – Route 53 considers this health check to be healthy only when all the health checks that you added to Health checks to monitor are healthy.

• Report healthy when one or more health checks are healthy (OR) – Route 53 considers this health check to be healthy when at least one of the health checks that you added to Health checks to monitor is healthy.

Old console

If you want this health check to monitor the status of other health checks, specify the following values:

• Health checks to monitor

• Report healthy when

• Invert health check status

• Disabled

Health checks to monitor

The health checks that you want Route 53 to monitor to determine the health of this health check.

You can add up to 256 health checks to Health checks to monitor. To remove a health check from the list, choose the x at the right of the highlight for that health check.

Note

You can't configure a calculated health check to monitor the health of other calculated health checks.

If you disable a health check that a calculated health check is monitoring, Route 53 considers the disabled health check to be healthy as it calculates whether the calculated health check is healthy. If you want the disabled health check to be considered unhealthy, choose the Invert health check status check box.

Report healthy when

The calculation that you want Route 53 to perform to determine whether this health check is healthy:

• Report healthy when at least x of y selected health checks are healthy – Route 53 considers this health check to be healthy when the specified number of health checks that you added to Health checks to monitor are healthy. Note the following:

  • If you specify a number greater than the number of health checks in Health checks to monitor, Route 53 always considers this health check to be unhealthy.

  • If you specify 0, Route 53 always considers this health check to be healthy.

• Report healthy when all health checks are healthy (AND) – Route 53 considers this health check to be healthy only when all the health checks that you added to Health checks to monitor are healthy.

• Report healthy when one or more health checks are healthy (OR) – Route 53 considers this health check to be healthy when at least one of the health checks that you added to Health checks to monitor is healthy.

Invert health check status (old console only)

To invert a health check on the new console, see Inverting health checks.

Choose whether you want Route 53 to invert the status of a health check. If you choose this option, Route 53 considers health checks to be unhealthy when the status is healthy and vice versa.

Disabled (old console only)

To disable a health check on the new console, see Disabling or enabling health checks .

Stops Route 53 from performing health checks. When you disable a health check, Route 53 stops aggregating the status of the referenced health checks.

After you disable a health check, Route 53 considers the status of the health check to always be healthy. If you configured DNS failover, Route 53 continues to route traffic to the corresponding resources. If you want to stop routing traffic to a resource, invert the health check.

Note

Charges for a health check still apply when the health check is disabled.

Monitoring a CloudWatch alarm

Note

We're updating the health checks console for Route 53. During the transition period, you can continue to use the old console.

Choose the tab for the console you are using.

• New console

• Old console

New console

If you want this health check to monitor the alarm state of a CloudWatch alarm, specify the following values:

• CloudWatch alarm

• Health check status

CloudWatch alarm

Choose the CloudWatch alarm that you want Route 53 to use to determine whether this health check is healthy. The CloudWatch alarm must be in the same AWS account as the health check.

Note

Route 53 supports CloudWatch alarms with the following features:

• Standard-resolution metrics. High-resolution metrics aren't supported. For more information, see High-resolution metrics in the Amazon CloudWatch User Guide.

• Statistics: Average, Minimum, Maximum, Sum, and SampleCount. Extended statistics aren't supported.

• Route 53 does not support "M out of N" alarms. For more information, see Evaluating an alarm in the Amazon CloudWatch guide.

Route 53 does not support alarms that use metric math to query multiple CloudWatch metrics.

If you want to create an alarm, perform the following steps:

1. Choose create. The CloudWatch console appears in a new browser tab.

2. Enter the applicable values. For more information, see Create or edit a CloudWatch alarm in the Amazon CloudWatch User Guide.

3. Return to the browser tab that the Route 53 console appears in.

4. Choose the refresh button next to the CloudWatch alarm list.

5. Choose the new alarm from the list.

Important

If you change settings for the CloudWatch alarm after you create a health check, you must update the health check. For more information, see Updating health checks when you change CloudWatch alarm settings (health checks that monitor a CloudWatch alarm only).

Health check status

Choose the status of the health check (healthy, unhealthy, or last known status) when CloudWatch has insufficient data to determine the state of the alarm that you chose for CloudWatch alarm. If you choose to use the last known status, Route 53 uses the status of the health check from the last time that CloudWatch had sufficient data to determine the alarm state. For new health checks that have no last known status, the default status for the health check is healthy.

The value of Health check status provides a temporary status when the data stream for a CloudWatch metric is briefly unavailable. (Route 53 monitors data streams for CloudWatch metrics, not the state of the corresponding alarm.) If the metric will be unavailable frequently or for long periods (longer than a few hours), we recommend that you not use the last known status.

Old console

If you want this health check to monitor the alarm state of a CloudWatch alarm, specify the following values:

• CloudWatch alarm

• Health check status

• Invert health check status

• Disabled

CloudWatch alarm

Choose the CloudWatch alarm that you want Route 53 to use to determine whether this health check is healthy. The CloudWatch alarm must be in the same AWS account as the health check.

Note

Route 53 supports CloudWatch alarms with the following features:

• Standard-resolution metrics. High-resolution metrics aren't supported. For more information, see High-resolution metrics in the Amazon CloudWatch User Guide.

• Statistics: Average, Minimum, Maximum, Sum, and SampleCount. Extended statistics aren't supported.

• Route 53 does not support "M out of N" alarms. For more information, see Evaluating an alarm in the Amazon CloudWatch guide.

Route 53 does not support alarms that use metric math to query multiple CloudWatch metrics.

If you want to create an alarm, perform the following steps:

1. Choose create. The CloudWatch console appears in a new browser tab.

2. Enter the applicable values. For more information, see Create or edit a CloudWatch alarm in the Amazon CloudWatch User Guide.

3. Return to the browser tab that the Route 53 console appears in.

4. Choose the refresh button next to the CloudWatch alarm list.

5. Choose the new alarm from the list.

Important

If you change settings for the CloudWatch alarm after you create a health check, you must update the health check. For more information, see Updating health checks when you change CloudWatch alarm settings (health checks that monitor a CloudWatch alarm only).

Health check status

Choose the status of the health check (healthy, unhealthy, or last known status) when CloudWatch has insufficient data to determine the state of the alarm that you chose for CloudWatch alarm. If you choose to use the last known status, Route 53 uses the status of the health check from the last time that CloudWatch had sufficient data to determine the alarm state. For new health checks that have no last known status, the default status for the health check is healthy.

The value of Health check status provides a temporary status when the data stream for a CloudWatch metric is briefly unavailable. (Route 53 monitors data streams for CloudWatch metrics, not the state of the corresponding alarm.) If the metric will be unavailable frequently or for long periods (longer than a few hours), we recommend that you not use the last known status.

Invert health check status (old console only)

To invert a health check on the new console, see Inverting health checks.

Choose whether you want Route 53 to invert the status of a health check. If you choose this option, Route 53 considers health checks to be unhealthy when the status is healthy and vice versa.

Disabled (old console only)

To disable a health check on the new console, see Disabling or enabling health checks.

Stops Route 53 from performing health checks. When you disable a health check, Route 53 stops monitoring the corresponding CloudWatch metrics.

After you disable a health check, Route 53 considers the status of the health check to always be healthy. If you configured DNS failover, Route 53 continues to route traffic to the corresponding resources. If you want to stop routing traffic to a resource, invert the health check..

Note

Charges for a health check still apply when the health check is disabled.

Advanced configuration ("Monitor an Endpoint" only)

Note

We're updating the health checks console for Route 53. During the transition period, you can continue to use the old console.

• New console

• Old console

New console

• Request Interval

• Failure threshold

• String matching

• Search strings

• Latency graphs

• Enable SNI

• Host name

Request interval

The number of seconds between the time that each Route 53 health checker gets a response from your endpoint and the time that it sends the next health check request. If you choose an interval of 30 seconds, each of the Route 53 health checkers in data centers around the world will send your endpoint a health check request every 30 seconds. On average, your endpoint will receive a health check request about every two seconds. If you choose an interval of 10 seconds, the endpoint will receive a request more than once per second.

Note that Route 53 health checkers in different data centers don't coordinate with one another, so you'll sometimes see several requests per second regardless of the interval you chose, followed by a few seconds with no health checks at all.

After you create a health check, you can't change the value of Request interval.

Note

If you choose Fast (10 seconds) for the value of Request interval, an additional charge applies. For more information, see Route 53 Pricing.

Failure threshold

The number of consecutive health checks that an endpoint must pass or fail for Route 53 to change the current status of the endpoint from unhealthy to healthy or vice versa. For more information, see How Amazon Route 53 determines whether a health check is healthy.

String matching (HTTP and HTTPS Only)

Whether you want Route 53 to determine the health of an endpoint by submitting an HTTP or HTTPS request to the endpoint and searching the response body for a specified string. If the response body contains the value that you specify in Search string, Route 53 considers the endpoint healthy. If not, or if the endpoint doesn't respond, Route 53 considers the endpoint unhealthy. The search string must appear entirely within the first 5,120 bytes of the response body.

After you create a health check, you can't change the value of String matching.

Note

If you choose Yes for the value of String matching, an additional charge applies. For more information, see Route 53 Pricing.

How health checkers handle a compressed response

If the endpoint is a web server that returns a response that is compressed, the Route 53 health checker will uncompress the response before checking for the specified search string only if the web server compressed the response using a compression algorithm that health checkers support. Health checkers support the following compression algorithms:

• Gzip

• Deflate

If the response is compressed using another algorithm, the health checker can't decompress the response before searching for the string. In this case, the search will almost always fail, and Route 53 will consider the endpoint unhealthy

Search string (Only When "String matching" Is Enabled)

The string that you want Route 53 to search for in the body of the response from your endpoint. The maximum length is 255 characters.

Route 53 considers case when searching for Search string in the response body.

Latency graphs

Choose whether you want Route 53 to measure the latency between health checkers in multiple AWS Regions and your endpoint. If you choose this option, CloudWatch latency graphs appear on the Latency tab on the Health checks page in the Route 53 console. If Route 53 health checkers can't connect to the endpoint, Route 53 can't display latency graphs for that endpoint.

After you create a health check, you can't change the value of Latency measurements.

Note

If you configure Route 53 to measure the latency between health checkers and your endpoint, an additional charge applies. For more information, see Route 53 Pricing.

Enable SNI (HTTPS Only)

Specify whether you want Route 53 to send the host name to the endpoint in the client_hello message during TLS negotiation. This allows the endpoint to respond to the HTTPS request with the applicable SSL/TLS certificate.

Some endpoints require that HTTPS requests include the host name in the client_hello message. If you don't enable SNI, the health check status might show failure. The error message will depend on how the server is configured to respond the request containing no SNI information. A health check can also have a failure status for other reasons. If SNI is enabled and you're still getting the error, check the SSL/TLS configuration on your endpoint and confirm that your certificate is valid.

Note the following requirements:

• The endpoint must support SNI.

• The SSL/TLS certificate on your endpoint includes a domain name in the Common Name field and possibly several more in the Subject Alternative Names field. One of the domain names in the certificate must match the value that you specify for Host name.

Health checker regions

Choose whether you want Route 53 to check the health of the endpoint by using health checkers in the recommended regions or by using health checkers in regions that you specify.

If you update a health check to remove a region that has been performing health checks, Route 53 continues to perform checks from that region for up to an hour. This ensures that some health checkers are always checking the endpoint (for example, if you replace three regions with four different regions).

If you choose Customize, choose the x for a region to remove it. Click the space at the bottom of the list to add a region back to the list. You must specify at least three regions.

Host name ("Specify endpoint by IP address" Only, HTTP and HTTPS Protocols Only)

The value that you want Route 53 to pass in the Host header in HTTP and HTTPS health checks. This is typically the fully qualified DNS name of the website on which you want Route 53 to perform health checks. When Route 53 checks the health of an endpoint, here is how it constructs the Host header:

• If you specify a value of 80 for Port and HTTP for Protocol, Route 53 passes to the endpoint a Host header that contains the value of Host name.

• If you specify a value of 443 for Port and HTdTPS for Protocol, Route 53 passes to the endpoint a Host header that contains the value of Host name.

• If you specify another value for Port and either HTTP or HTTPS for Protocol, Route 53 passes to the endpoint a Host header that contains the value Host name:Port.

If you choose to specify the endpoint by IP address and you don't specify a value for Host name, Route 53 substitutes the value of IP address in the Host header in each of the preceding cases.

Old console

If you choose the option to monitor an endpoint, you can also specify the following settings:

• Request Interval

• Failure threshold

• String matching

• Search string

• Latency graph

• Enable SNI

• Health checker Regions

• Invert health check status

• Disabled

Request interval

The number of seconds between the time that each Route 53 health checker gets a response from your endpoint and the time that it sends the next health check request. If you choose an interval of 30 seconds, each of the Route 53 health checkers in data centers around the world will send your endpoint a health check request every 30 seconds. On average, your endpoint will receive a health check request about every two seconds. If you choose an interval of 10 seconds, the endpoint will receive a request more than once per second.

Note that Route 53 health checkers in different data centers don't coordinate with one another, so you'll sometimes see several requests per second regardless of the interval you chose, followed by a few seconds with no health checks at all.

After you create a health check, you can't change the value of Request interval.

Note

If you choose Fast (10 seconds) for the value of Request interval, an additional charge applies. For more information, see Route 53 Pricing.

Failure threshold

The number of consecutive health checks that an endpoint must pass or fail for Route 53 to change the current status of the endpoint from unhealthy to healthy or vice versa. For more information, see How Amazon Route 53 determines whether a health check is healthy.

String matching (HTTP and HTTPS Only)

Whether you want Route 53 to determine the health of an endpoint by submitting an HTTP or HTTPS request to the endpoint and searching the response body for a specified string. If the response body contains the value that you specify in Search string, Route 53 considers the endpoint healthy. If not, or if the endpoint doesn't respond, Route 53 considers the endpoint unhealthy. The search string must appear entirely within the first 5,120 bytes of the response body.

After you create a health check, you can't change the value of String matching.

Note

If you choose Yes for the value of String matching, an additional charge applies. For more information, see Route 53 Pricing.

How health checkers handle a compressed response

If the endpoint is a web server that returns a response that is compressed, the Route 53 health checker will uncompress the response before checking for the specified search string only if the web server compressed the response using a compression algorithm that health checkers support. Health checkers support the following compression algorithms:

• Gzip

• Deflate

If the response is compressed using another algorithm, the health checker can't decompress the response before searching for the string. In this case, the search will almost always fail, and Route 53 will consider the endpoint unhealthy

Search string (Only When "String matching" Is Enabled)

The string that you want Route 53 to search for in the body of the response from your endpoint. The maximum length is 255 characters.

Route 53 considers case when searching for Search string in the response body.

Latency graphs

Choose whether you want Route 53 to measure the latency between health checkers in multiple AWS Regions and your endpoint. If you choose this option, CloudWatch latency graphs appear on the Latency tab on the Health checks page in the Route 53 console. If Route 53 health checkers can't connect to the endpoint, Route 53 can't display latency graphs for that endpoint.

After you create a health check, you can't change the value of Latency measurements.

Note

If you configure Route 53 to measure the latency between health checkers and your endpoint, an additional charge applies. For more information, see Route 53 Pricing.

Enable SNI (HTTPS Only)

Specify whether you want Route 53 to send the host name to the endpoint in the client_hello message during TLS negotiation. This allows the endpoint to respond to the HTTPS request with the applicable SSL/TLS certificate.

Some endpoints require that HTTPS requests include the host name in the client_hello message. If you don't enable SNI, the health check status might show failure. The error message depends on how the server is configured to respond the request containing no SNI information. A health check can also have a failure status for other reasons. If SNI is enabled and you're still getting the error, check the SSL/TLS configuration on your endpoint and confirm that your certificate is valid.

Note the following requirements:

• The endpoint must support SNI.

• The SSL/TLS certificate on your endpoint includes a domain name in the Common Name field and possibly several more in the Subject Alternative Names field. One of the domain names in the certificate must match the value that you specify for Host name.

Health checker regions

Choose whether you want Route 53 to check the health of the endpoint by using health checkers in the recommended regions or by using health checkers in regions that you specify.

If you update a health check to remove a region that has been performing health checks, Route 53 continues to perform checks from that region for up to an hour. This ensures that some health checkers are always checking the endpoint (for example, if you replace three regions with four different regions).

If you choose Customize, choose the x for a region to remove it. Click the space at the bottom of the list to add a region back to the list. You must specify at least three regions.

Invert health check status (old console only)

To invert a health check on the new console, see Inverting health checks.

Choose whether you want Route 53 to invert the status of a health check. If you choose this option, Route 53 considers a health check to be unhealthy when the status is healthy and vice versa. For example, you might want Route 53 to consider a health check unhealthy if you configure string matching and the endpoint returns a specified value.

Disabled (old console only)

To disable a health check on the new console, see Disabling or enabling health checks.

Stops Route 53 from performing health checks. When you disable a health check, Route 53 stops trying to establish a TCP connection with the endpoint.

After you disable a health check, Route 53 considers the status of the health check to always be healthy. If you configured DNS failover, Route 53 continues to route traffic to the corresponding resources. If you want to stop routing traffic to a resource, invert the health check.

Note

Charges for a health check still apply when the health check is disabled.

Get notified when a health check fails

Use the following options to configure email notification when a health check fails:

• Create alarm

• Send notification to

• Topic name

• Recipient email addresses

Create alarm (Only When Creating Health Checks)

Specify whether you want to create a default CloudWatch alarm. If you choose Yes, CloudWatch sends you an Amazon SNS notification when the status of this endpoint changes to unhealthy and Route 53 considers the endpoint unhealthy for one minute.

Note

If you want CloudWatch to send you another Amazon SNS notification when the status changes back to healthy, you can create another alarm after you create the health check. For more information, see Creating Amazon CloudWatch alarms in the Amazon CloudWatch User Guide.

If you want to create an alarm for an existing health check or you want to receive notifications when Route 53 considers the endpoint unhealthy for more or less than one minute (the default value), select No, and add an alarm after you create the health check. For more information, see Monitoring health checks using CloudWatch.

Send notification to (Only When Creating an Alarm)

Specify whether you want CloudWatch to send notifications to an existing Amazon SNS topic or to a new one:

• Existing SNS topic – Select the name of the topic from the list. The topic must be in the US East (N. Virginia) Region.

• New SNS topic – Enter a name for the topic in Topic name, and enter the email addresses that you want to send notifications to in Recipients. Separate multiple addresses with commas (,), semicolons (;), or spaces.

  Route 53 will create the topic in the US East (N. Virginia) Region.

Topic name (Only When Creating a New SNS Topic)

If you specified New SNS Topic, enter the name of the new topic.

Recipient email addresses (Only When Creating a New SNS Topic)

If you specified New SNS topic, enter the email addresses that you want to send notifications to. Separate multiple names with commas (,), semicolons (;), or spaces.