Adding upstream version 1.44.3.upstream/1.44.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/health/guides/haproxy/haproxy_backend_status.md b/health/guides/haproxy/haproxy_backend_status.md
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+### 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)
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