added 1st version of a section for sap cube replication setup

wiki/server-replication.md

@@ -90,4 +90,74 @@ Fortunately, the dangerous-to-parallelize operations seem to be the ones that oc
 These encompass leaderboard and leaderboard group creation and manipulation, including score corrections. In a replica these operations must be executed in the same sequence they were executed in on the master. It probably encompasses the creation of a tracked race and its course, we well as the updates to a race course with waypoint additions and mark passings because mark passing events relate to the waypoints. 
 Paralllel operations
 
-These encompass the receiving of raw sensor data. The order in which this data is re-played doesn't matter. The data is time-stamped, and its history is not rewritten (as maybe the case for the mark passings or for the race tracking start/finish times). Applying these operations to a replica is idempotent, so serializing an initial state doesn't need to be synchronized with the receiving of such data. Duplicate application of these operations to a server doesn't do any harm.
+These encompass the receiving of raw sensor data. The order in which this data is re-played doesn't matter. The data is time-stamped, and its history is not rewritten (as maybe the case for the mark passings or for the race tracking start/finish times). Applying these operations to a replica is idempotent, so serializing an initial state doesn't need to be synchronized with the receiving of such data. Duplicate application of these operations to a server doesn't do any harm.
+
+### Replication in SAP Cube
+This section will describe, how a working local replica can be set up at the SAP Cube.
+The setup at the Travemünder Woche 2014 was done by Steffen Wagner as it follows:
+
+LTE router --> gigabit switch --> cube computers (dhcp) && local replica machine (with e.g. Ubuntu 14.04 LTS & a version of the analytics suite installed)
+
+Steps to get everything working:
+* The LTE router (192.168.1.1) should have DHCP and NS activated. Dhcp was within range XXX.XXX.1.2 - XXX.XXX.1.49 and our local replica machine had a static ip address of XXX.XXX.1.50. Please make sure, that the ip address is outside of the dhcp range. For a better setup we should think of using the local replica server for dhcp and ns services.
+* Setup networking (to your needs) on the local replica machine as follows:
+/etc/networking/interfaces
+<pre>
+auto eth0
+iface eth0 inet static
+	address 192.168.1.50
+	netmask 255.255.255.0
+	gateway 192.168.1.1
+</pre>
+/etc/hosts
+<pre>
+127.0.0.1		localhost
+127.0.0.1		tw2014 tw2014.sapsailing.com
+192.168.1.50	tw2014 tw2014.sapsailing.com
+</pre>
+* For rewriting the URLs and Ports to the fitting Spectator URL when entering the URL we need a Apache installed (apt-get install apache2) and set up like on our sapsailing.com server. Please check 000-macros.conf, 001-events.conf and 000-main.conf and set it up as you need for the event. They need to be in the config dir of apache (/etc/apache2/mods-enabled and /etc/apache2/sites-enabled)
+* For better remote administration of the local replica, set up and autossh tunnel to trac@sapsailing.com and put it into rc.local for autostarting, e.g. as the following:
+<pre>
+autossh -M 20009 -f -N -L 1337:127.0.0.1:22 -i SSHKEY trac@sapsailing.com
+</pre>
+* Set up automatic replication in env.sh of the analystics server and start the server (not with root!) with startscript ~/servers/server/start
+* On all Cube computers add the folling batch file to the windows task scheduling for a check every minute. The script switches hosts to local replica if available. Before the script can work, you have to edit host file manully and add the required hostnames: e.g. 192.168.1.50	tw2014.sapsailing.com. You also need to replace find and replace to the required ip addresses.
+<pre>
+@echo off
+@setlocal enableextensions enabledelayedexpansion
+
+REM Set a variable for the Windows hosts file location
+set "hostpath=%systemroot%\system32\drivers\etc"
+set "hostfile=hosts"
+
+REM Make the hosts file writable
+attrib -r -s -h "%hostpath%\%hostfile%"
+
+ping -n 1 -w 1000 -l 2000 192.168.1.50
+REM if local replica is available
+IF %ERRORLEVEL% == 0 (
+	REM set the string you wish to find
+	set find=54.229.94.254
+	REM set the string you wish to replace with
+	set replace=192.168.1.50
+
+REM if local replica is not available
+) ELSE (
+	REM set ring you wish to find
+	set find=192.168.1.50
+	REM set the string you wish to replace with
+	set replace=54.229.94.254
+)	
+
+for /f "delims=" %%a in ('type "%hostpath%\%hostfile%"') do (
+set "string=%%a"
+set "string=!string:%find%=%replace%!"
+>> "newfile.txt" echo !string!
+)
+
+move /y "newfile.txt" "%hostpath%\%hostfile%"
+REM Make the hosts file un-writable - not necessary.
+REM attrib +r "%hostpath%\%hostfile%"
+echo hostfile done.
+</pre>
+* If server should be shutted down, then first stop replication manually in the backend and then call ~/servers/server/stop. If everything works fine, then the Cube computers should recognize, that the replica machine is not available anymore and then switch to the real sapsailing host.