GSLB configuration scenarios - BlueCat Edge - Service Point v4.x.x

BlueCat Edge User Guide
ft:locale
en-US
Product name
BlueCat Edge
Version
Service Point v4.x.x

The following lists out different configuration scenarios for GSLB.

Reordering of responses with health check configurations

  1. When a client sends a query to the Service Point, the Service Point applies the policy and namespace evaluations on the query based on the configurations from the site.
  2. If GSLB is configured, the Service Point evaluate the whole query, including the answer and response, against the GSLB rule engine. The GSLB rule engine evaluates the incoming query to ensure that the query source IP address and query question domain matches the configured match criteria. If the query matches the criteria, the actions are applied to the query. Based on the diagram, the ordering actions removes the 204.0.1/24 IP space then prioritizes A records within the 10/8 IP space, followed by 172/8 and 192/8.
  3. The GSLB rule engine evaluates the updated query with the reordered A records based on the ordering actions to the GSLB health check engine, which continuously monitors the health status of the endpoint for configured domains and IP addresses. The GSLB rule health check engine performs the following before performing the check:
    1. Verifies the IP addresses within the query answers matches the configured IP addresses in the health check configuration
    2. Verifies the domain within the query question (the domain that the client would like to resolve) matches the configured domains in the health check configuration
      Attention: If the query question domain or query answer IP address of the query does not match what is configured in the health check configuration, the health check section of the GSLB rule is skipped and the action related to the health check is not applied. Based on the diagram, if a query was received for app1.example.com, the health check would not be performed as the only hostname or domain configured in the health check configuration is app.example.com. The answer for app1.example.com would only be sent to the client with the reordered A records since the GSLB rule matching criteria is matched.
  4. The GSLB health check engine receives the health status of the configured domains and endpoints and based on the configured Health actions, reorders the A records in the query based on the health status. Based on the diagram, 10.0.0.1 is prioritized as first, followed by 192.168.1.1 and 172.0.0.1.
  5. The Edge Cloud returns the reordered query back to the service point to respond to the client.

Reordering of responses with health check configurations (additional domain match)

  1. When a client sends a query to the Service Point, the Service Point applies the policy and namespace evaluations on the query based on the configurations from the site.
  2. If GSLB is configured, the Service Point evaluate the whole query, including the answer and response, against the GSLB rule engine. The GSLB rule engine evaluates the incoming query to ensure that the query source IP address and query question domain matches the configured match criteria. If the query matches the criteria, the actions are applied to the query. Based on the diagram, the action prioritizes A records within the 10/8 IP space, followed by 172/8 and 192/8. The 20
  3. The GSLB rule engine sends the updated query with the reordered A records based on the actions to the GSLB health check engine, which then performs a health check on the configured domains and endpoints. The GSLB health check engine performs the following before performing the check:
    1. Verifies the IP addresses within the query answers matches the configured IP addresses in the health check configuration
    2. Verifies the domain within the query question (the domain that the client would like to resolve) matches the configured domains in the health check configuration.. Based on the above, although the domain does not match the configured Hostname, the domain matches the Additional Domain so the health check is performed.
  4. The GSLB health check engine receives the health status of the configured domains and endpoints and based on the configured Health actions, reorders the A records in the query based on the health status. Based on the diagram, 10.0.0.1 is prioritized as first, followed by 192.168.1.1, 172.0.0.1, and 204.0.1.2.
  5. The Edge Cloud returns the reordered query back to the service point to respond to the client.

Reordering of responses only

  1. When a client sends a query to the Service Point, the Service Point applies the policy and namespace evaluations on the query based on the configurations from the site.
  2. If GSLB is configured, the Service Point evaluate the whole query, including the answer and response, against the GSLB rule engine. The GSLB rule engine evaluates the incoming query to ensure that the query source IP address and query question domain matches the configured match criteria. If the query matches the criteria, the actions are applied to the query. Based on the diagram, the actions remove 204.0.1/24 IP space then prioritizes A records within the 10/8 IP space, followed by 172/8 and 192/8.
  3. The Edge Cloud returns the reordered query back to the service point to respond to the client.

Reordering of responses only (domain does not match health check)

  1. When a client sends a query to the Service Point, the Service Point applies the policy and namespace evaluations on the query based on the configurations from the site.
  2. If GSLB is configured, the Service Point evaluate the whole query, including the answer and response, against the GSLB rule engine. The GSLB rule engine evaluates the incoming query to ensure that the query source IP address and query question domain matches the configured match criteria. If the query matches the criteria, the actions are applied to the query. Based on the diagram, the ordering actions prioritizes A records within the 10/8 IP space, followed by 172/8 and 192/8.
  3. The GSLB rule engine evaluates the updated query with the reordered A records based on the ordering actions to the GSLB health check engine, which continuously monitors the health status of the endpoint for configured domains and IP addresses. The GSLB rule health check engine performs the following before performing the check:
    1. Verifies the IP addresses within the query answers matches the configured IP addresses in the health check configuration
    2. Verifies the domain within the query question (the domain that the client would like to resolve) matches the configured domains in the health check configuration. In this scenario, the domain of the query does not match what is configured in the health check configuration. The query is ignored and the health check is not applied.
  4. The GSLB health check engine does not check the health status of the configured domains since it does not match and returns the originally prioritized records. Based on the diagram, 10.0.0.1 is prioritized as first, followed by 10.0.0.2, 172.0.0.1, 192.168.1.1 and 204.0.1.2.
  5. The Edge Cloud returns the reordered query back to the service point to respond to the client.

Health check configurations only

  1. When a client sends a query to the Service Point, the Service Point applies the policy and namespace evaluations on the query based on the configurations from the site.
  2. If GSLB is configured, the Service Point evaluate the whole query, including the answer and response, against the GSLB rule engine. The GSLB rule engine evaluates the incoming query to ensure that the query source IP address and query question domain matches the configured match criteria. If the query matches the criteria, the actions are applied to the query. Based on the diagram, all source IP addresses and domains match the criteria and all queries will be passed to the health check engine.
  3. The GSLB rule engine sends the query to the GSLB health check engine, which then performs a health check on the configured domains and endpoints. The GSLB health check engine performs the following before performing the check:
    1. Verifies the IP addresses within the query answers matches the configured IP addresses in the health check configuration
    2. Verifies the domain within the query question (the domain that the client would like to resolve) matches the configured domains in the health check configuration
      Attention: If the domain or IP address of the query does not match what is configured in the health check configuration, the query is ignored and the health check is not applied. Based on the diagram, if a query was received for app1.example.com, the health check would not be performed as the only hostname or domain configured is app.example.com. The DNS answer for app1.example.com would only be returned to the client with the same order as it has been resolved since there is no ordering action also set.
  4. The GSLB health check engine receives the health status of the configured domains and endpoints and based on the configured Health actions, reorders the A records in the query based on the health status. Based on the diagram, 192.168.1.1 is prioritized as first, followed by 10.0.0.1, 172.0.0.1, and lastly 204.0.1.2.
  5. The Edge Cloud returns the reordered query back to the service point to respond to the client.