2 instances - both running similar ubuntu server projects and both inaccessible from web gui, ssh slow

Question

Happy New Year!
I've two ubuntu servers, one 16.04 and the other 20.04 running dedicated Unifi controller software. Both are on different versions of Unifi and both have been solid since build in 2020.  Last couple days both have had limited web access to the Unifi gui and ssh connection is there but slow.  Top shows 30% cpu usage, 90% memory and 40% swap, pretty normal.  I can't find any smoking gun on the server side and it would seem its a aws issue beings they both crapped out at the same time.  I have tried to connect from several different pcs and isp to make sure its not on my connection.  Any tips on where to start looking?

Answer

You don't mention what instance types you're using. If you're using the T-series instances then it's possible that you're running out of CPU credits. Even though the operating system is showing low CPU usage it may still be throttled. Check CloudWatch Metrics for those instances and see what the CPU Credit metric displays.

If that is the problem: To fix it, either change the instance to "Unlimited" (but you'll be charged 50 cents per hour if the CPU credits are exhausted); choose a larger instance size; or choose a different (non-T) instance type.

2 instances - both running similar ubuntu server projects and both inaccessible from web gui, ssh slow

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