Problems with http forwarding policy

[Ken_Edgar]

I am helping our integrations team migrate API endpoints from one integrations load-balanced cluster to another. In doing so, they are slowly moving just specific applications. I have created an http forwarding rule to forward certain URIs to the new integration cluster VIP. For some reason, it appears that the policy is somehow be affecting URIs that are not in scope of the rule. I enabled logging on the policy to show me all of the URIs hitting the policy... it appears that only the in-scope ones are hitting it.

That said, certain out of scope API endpoints are returning 404 errors intermittently. When we disassociate the policy from the VIP, there is no issue. I am not sure how the policy could be affecting those URIs (and only sometimes) when they do not appear to be hitting the policy.

I have added a screenshot of the simple policy, the strategy is to execute the first matching rule

[AlexBCT]

Hi Ken,

That's an interesting one... I don't have an answer for you, but a couple of ideas / troubleshooting tips to hopefully help you further;

• I see that you are looking for paths that "contains" /api. Is there any chance that some of the out-of-scope requests contain /api somewhere else in their API path?
• Alternatively, if all requests start with /api, can you switch the policy to "starts_with"?
• Can you find out which Virtual Server is processing the 404 errors? You can have a look at the HTTP headers of the responses to see which server it came from (old backend server, new backend server or F5)
• Alternatively, have a look in the VS statistics, under Statistics ›› Module Statistics : Local Traffic ›› Virtual Servers : <vs-name>, select the HTTP profile, and check under Responses - Client Errors (these should include the 400-errors)
• In your LTP (or in a new LTP), you can match on any 404 response, then log some details about it. That may also give you an indication of any pattern that may be to them.

Hope any of these are useful 😉

[Ken_Edgar]

Thanks, I will take a look at your suggestions