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When the backend server is down (for maintenance), the ELB rightfully returns the 503 status. However, when the server is back, and it is listed as InService in the Instances tab of the ELB, the URL still returns 503. Is this because of some kind of caching of the status in the browser, or some other factors are involved?

Thanks

imriss
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  • Browsers should not cache error responses at all. To verify, consider using a command-line tool like curl, which does not perform any caching between requests. – cdhowie Aug 12 '19 at 22:54

1 Answers1

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Browsers dont cache any error responses. GET requests are generally cached, POST requests are not cached by default and other requests such as PUT, DELETE do not have any cache facility.

It should mostly be the ELB taking time to perform health checks on your machine and pass on the request to the server and returning out of service(5XX) response instead.

koushikmln
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