The CenturyLink Cloud platform provides load balancing services using the Citrix Netscaler VPX product. Customers who leverage this platform can use a variety of health checks to validate the availability of infrastructure services.
- Tcp (default): The NetScaler appliance establishes a 3-way handshake with the monitor destination, and then closes the connection.
- Ping (default): The NetScaler appliance sends an ICMP echo request to the destination of the monitor and expects an ICMP echo response.
- HTTP-ECV (upon special exception approval): The NetScaler establishes a TCP connection with the monitor destination. By default the monitor will issue an http /get request and expect a valid status 200 OK. Customers wishing to define specific -send and -receive parameters (strings) can elect to do so.
By default Tcp and Ping monitors are created as part of any load balancing group. Customers who elect to leverage custom parameters (strings) for the HTTP-ECV monitor should provide valid -send and -receive parameters as part of the load balancing request. CenturyLink Cloud encourages the use of status pages to perform the HTTP-ECV health check. Examples are shown below:
- -Send Parameter (string): Get /serverstatus.html
- -Receive Parameter (string): Website Online
Customers who require special health checks outside the items listed in this KB or require further information should contact the NOC.