5 September 2015 Culrur-exp project CULTURe EXchange Platform (CULTUR-EXP) project kick-off meeting, 26-27 August 2013, Tbilisi, Georgia Joint Operational

April 19, 2023 Culrur-exp project

CULTURe EXchange Platform (CULTUR-EXP) project

kick-off meeting, 26-27 August 2013, Tbilisi, Georgia

Joint Operational Programme - BLACK SEA BASIN 2007-2013

April 19, 2023 culrur-exp project

GA5. Platform operation and maintenance – overview


GA5: Introduction, good experiences and real life


GA5: Introduction, good experiences and real life

The above scheme represents one of the good solutions for Load Balance, High Availability and security of web service. At every layer of the topology there are some devices and software that organize availability of the service.But this topology is expensive and in real life there are some limitations – network topology, capacity, funding and others. And as a result more often we can’t install firewall in front of web servers, we can’t install needed number of web servers and so on…


GA5: CULTUR-EXP Topology Scheme


GA5: CULTUR-EXP - Topology TasksWe propose reliable topology that will contain two sites (Moldova and Georgia). The main task is to organize High Availability (HA) between these two sites. To implement HA we have to have minimum two web servers in every location and specify software/hardware solutions to organize operational processes:• Balancer – Machine + Software that receive client’s requests for web server and send these requests to one of the web servers based on some criteria (Web Server Load or Availability) or just send one client’s request to first server and another client’s request to second server (Balancing).• Data replicator – Software that synchronize server’s file system in real time.


GA5: CULTUR-EXP - Topology Tasks (part 2)The main problem is that the both sites are placed in two different geo locations and different networks. The speed of the link between these sites can slow down or can not be stable. We’ve analyzed some open source software that can run as Balancer or Data replicator and these are our conclusions:• Network topology of the sites (Moldova, Georgia) using known open source Balancer doesn’t make sense for a few reasons. Therefore we will not describe technical details of this solution.• Like Data Replicator we have analyzed “DRDB as dual primary” as one of the top open source solutions for this task. But for our topology using DRDB and other software like this can slow down HDD performance. And there are many software dependencies on web server and in case of one software failure entire system will be down. And using DRDB as dual primary in our topology can create more problems than resolve them.


GA5: CULTUR-EXP - Proposed Solutions• As a solution for Balancer can be round-robin DNS although. It is not very effective solution and has some technical limitations. In case of using round-robin DNS we have to have DRDB dual primary, so the site contents have to be synchronized in real time, but it was mentioned that in our case “DRDB dual primary” is not a good idea.• As a solution for Data synchronization we can use an scheduled script that synchronize web site’s content between the two Web servers and MySQL master to master replication over SSL for web sites database. In this case we can use DNS without round-robin but with slow TTL (for ex: 15 min) and monitor web server: if the primary Server will be down for a long time we will change DNS record for web site to point to secondary server. In this case all the clients that doesn’t have registration for the web site in their DNS cache will be redirected to secondary server. The clients that were visited web site and have in their DNS cache registration for it will be able to access the site after DNS TTL will expire.


GA5: CULTUR-EXP – Proposed Topology and Basic Software Requirements

So, in our topology we can use Secondary Web Server as a backup if the primary server will be down for a long time with possible partial data loss (depends of scheduled data synchronization script)Also we have to have an backup server for backing up website’s content and database with possibility to make incremental / differential backups.

As basic software we consider to use:• OS – Linux CentOS• Web Server – Nginx + PHP-FPM• Database Server – MySQL• FTP Server• CMS - Wordpress


GA5: CULTUR-EXP – Basic (initial) Hardware Allocation for the Platform Hosting

• CPU – 2 x Quad-Core Intel Xeon• RAM – 8GB DDR3 ECC FB• HDD – 8 x 300GB SAS 15krpm (depends how much

information will be stored)• Raid – PCI Raid Controller with support of Raid 1,0,10,5• LAN – 2 x 1Gbps LAN controller with 802.1Q

encapsulation support• Form factor – rack mountable• Module for remote management like KVM, ILO, ILOM• PSU – two PSU

Scenarios for the basic hosting hardware upgrading

The project budget for RENAM contains the sum for the hosting equipment upgrade. We are considering two approaches for extending hosting hardware capabilities: • To use planned sum for the existing servers’ equipment upgrading (increasing storage element capacity and upgrading RAM of exsting servers) or• To purchase new server that will be dedicated to the elaborated platform hosting and use existing storage facilities. Other existing servers will be used for the platform informational DB backup.



Thank you for attention!

http://www.renam.md

RENAM Association, Chisinau, Moldova

RENAM team members involved in GA5 activities: - Peter Bogatencov;- Alexandru Cacean;- Pavel Vaseanovici.

http://www.renam.md/

Documents

5 September 2015 Culrur-exp project CULTURe EXchange Platform (CULTUR-EXP) project kick-off meeting, 26-27 August 2013, Tbilisi, Georgia Joint Operational