From b485aab7e71c1625cfc27e0f92c9509f42378458 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 5 May 2024 13:19:16 +0200 Subject: Adding upstream version 1.45.3+dfsg. Signed-off-by: Daniel Baumann --- .../guides/haproxy/haproxy_backend_status.md | 49 ++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 src/health/guides/haproxy/haproxy_backend_status.md (limited to 'src/health/guides/haproxy/haproxy_backend_status.md') diff --git a/src/health/guides/haproxy/haproxy_backend_status.md b/src/health/guides/haproxy/haproxy_backend_status.md new file mode 100644 index 000000000..47be09c73 --- /dev/null +++ b/src/health/guides/haproxy/haproxy_backend_status.md @@ -0,0 +1,49 @@ +### Understand the alert + +This alert monitors the average number of failed HAProxy backends over the last 10 seconds. If you receive this alert in a critical state, it means that one or more HAProxy backends are inaccessible or offline. + +HAProxy is a reverse-proxy that provides high availability, load balancing, and proxying for TCP and HTTP-based applications. A backend in HAProxy is a set of servers that receive forwarded requests and are defined in the backend section of the configuration. + +### Troubleshoot the alert + +- Check the HAProxy configuration file for errors + + Making changes in the configuration file may introduce errors. Always validate the correctness of the configuration file. In most Linux distros, you can run the following check: + + ``` + haproxy -c -f /etc/haproxy/haproxy.cfg + ``` + +- Check the HAProxy service for errors + + 1. Use `journalctl` and inspect the log: + + ``` + journalctl -u haproxy.service --reverse + ``` + +- Check the HAProxy log + + 1. By default, HAProxy logs under `/var/log/haproxy.log`: + + ``` + cat /var/log/haproxy.log | grep 'emerg\|alert\|crit\|err\|warning\|notice' + ``` + + You can also search for log messages with `info` and `debug` tags. + +- Investigate the backend servers + + 1. Verify that the backend servers are online and accepting connections. + 2. Check the backend server logs for any errors or issues. + 3. Ensure that firewall rules or security groups are not blocking traffic from HAProxy to the backend servers. + +- Review the HAProxy load balancing algorithm and configuration + + 1. Analyze the load balancing algorithm used in the configuration to ensure it is suitable for your setup. + 2. Check for any misconfigurations, such as incorrect server addresses, ports, or weights. + +### Useful resources + +1. [The Four Essential Sections of an HAProxy Configuration](https://www.haproxy.com/blog/the-four-essential-sections-of-an-haproxy-configuration/) +2. [HAProxy Explained in DigitalOcean](https://www.digitalocean.com/community/tutorials/an-introduction-to-haproxy-and-load-balancing-concepts) \ No newline at end of file -- cgit v1.2.3