WordPress site behind AWS ALB went down without warning (504 error)

Keywords: WordPress - AWS - Technical issue - Other

bnsupport ID: e232d6a7-106c-8464-901a-c4976134da62

bndiagnostic output:

? Apache: Found possible issues
? Connectivity: Found possible issues
? Wordpress: Found possible issues
? Resources: Found possible issues
https://docs.bitnami.com/general/apps/wordpress/troubleshooting/debug-errors-apache/
https://docs.bitnami.com/bch/apps/moodle/troubleshooting/deny-connections-bots-apache/
https://docs.bitnami.com/general/faq/administration/use-firewall/
https://docs.bitnami.com/installer/faq/linux-faq/administration/increase-memory-linux/

Description:
I stopped/started Apache and that solved the problem. I ran the tool. Can you guys take a look at the logs and let me know what might be happening? It doesn’t seem like Apache went down, but a 10+ second delay is concerning as well. I’m on a t3.large instance in EC2. Thanks!

e232d6a7-106c-8464-901a-c4976134da62

Hi @jwiener,

It seems there are quite some requests coming from the same IP addresses which usually indicates a bot attack, although they could be from the load balancer, I suggest to check it:

-----------------------------------
Check performance issues: Count number of requests for the 10 most active IP addresses in the last 100.000 requests
-----------------------------------
Running: tail -n 100000 access_log | awk '{print $1}' | sort | uniq -c | sort -nr | head -n 10 | awk '{print $1}'
In: /opt/bitnami/apache2/logs/

Output:

47430
44482
8088

The following guide shows how you can block IP’s:

https://docs.bitnami.com/bch/apps/moodle/troubleshooting/deny-connections-bots-apache/

The php log shows another message:

[16-Nov-2021 23:35:35] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 72 idle, and 97 total children

You could try to decrease the max_children value:

https://docs.bitnami.com/aws/apps/wordpress-pro/configuration/configure-phpfpm-processes/

Best regards,
Michiel

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