Ambassador upgrade caused an increase in memory use(x8)

Describe the bug On our Ambassador API Gateway deploy we noticed a severe memory use increase(approximately 8x) when we upgraded the Helm chart version from 6.5.10 -> 6.6.2(Ambassador version from 1.8.1 to 1.12.2). After we reviewed our setup and checked various changelog/docs we found the env config AMBASSADOR_LEGACY_MODE, after setting its value to true, the memory dropped back to “normal/before the upgrade”.

To Reproduce Steps to reproduce the behavior:

1. Upgrade Ambassador to version 1.12.2

Expected behavior Memory use shouldn’t increase if AMBASSADOR_LEGACY_MODE remains to false

Versions (please complete the following information):

• Ambassador: 1.12.2
• Kubernetes environment: AWS KOPS setup
• Version: v1.18.14

Additional context More information about our setup can be provided as needed, but for starters:

• currently we have ~36 mappings
• pod limits are set to 1cpu & 512mb RAM (these resources are ok for “normal/expected” mem use, if the feature flag is set to “false” we had to bump ram to 2gb)
• we have auto scaling enabled, minimum 3 replicas, max 8

[guongle-ssense]

@dzkaraka @guongle-ssense We solved our issues when we set AMBASSADOR_LEGACY_MODE env variable to TRUE. Then new version behaves the same as old version. But this is not appropriate solution, but it works for us as tmp solution.

BR

Thanks for the input, but seeing that from the official doc it is not recommended I’m a bit iffy on it, ill keep on poking for perma solution

worse case, at least its been validated that it does help

[SimonOlenik]

@dzkaraka @guongle-ssense We solved our issues when we set AMBASSADOR_LEGACY_MODE env variable to TRUE. Then new version behaves the same as old version. But this is not appropriate solution, but it works for us as tmp solution.

BR