Server health checking is the ability of the load balancer to run a test against the servers to determine if they are providing service.
Ping:Â This is the most simple method, however it is not very reliable as the server can be up whilst the web service could be down.
TCP connect:Â This is a more sophisticated method which can check if a service is up and running like a service on port 80 for web.
Simple HTTP GET:Â This will make a HTTP GET request to the web server and typically check for a header response such as 200 OK.
Full HTTP GET:Â This will make a HTTP GET and check the actual content body for a correct response. This feature is only available on some of the more advanced products but is the superior method for web apps as its will check that the actual application is available.
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