Editing Category:YOUSECURE (section)

==Training on YOUSECURE Project KT PART 1. Dated 19 April 2024 - Tetra Support Staff - Alok Singh==

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'''Video summary:''' "YOUSECURE Project KT PART 1" -- a Hindi-language architecture walkthrough of the YouSecure hosting environment, drawn on a whiteboard/diagram live during the call. YouSecure runs two parallel environments -- "eSign Production" and "Traditional Production" -- both LAMP-based (Linux/Apache/PHP) with separate MySQL database servers, and every server is deployed as an HA pair (e.g. a primary and an "A" duplicate with adjacent IPs, each with its own paired database). The network is split into a DMZ zone (a 192.168.1.x segment, holding the WAF and external HAProxy) and an MZ/internal zone (a 192.168.2.x segment, holding the internal HAProxy, the four LAMP web servers -- each serving a different client domain in the Traditional environment -- and the database servers), with NAT rules on the firewall exposing the private DMZ IPs to the internet. Request flow: internet -> WAF -> external HAProxy -> internal HAProxy -> the correct backend LAMP server per the HAProxy config's per-domain routing rules -> its paired database. HAProxy is configured for priority/failover order rather than even round-robin -- it sends all traffic to the primary backend and only fails over to the secondary if the primary goes down -- and the two MySQL databases behind each pair stay in sync via master-to-master replication so no data is lost on failover. A separate problem is also covered: because uploaded files (PDFs etc.) land only on whichever LAMP server actually handled the request, and the paired servers aren't otherwise replicated, a failover could leave the secondary server missing files the primary had received. This was solved with a shared NFS server -- both paired LAMP servers mount the same NFS-backed directory (e.g. the upload folder), so either server can read files regardless of which one originally wrote them. The eSign environment mirrors this exact design but with a smaller footprint (essentially one web server instead of four).