How We Reached A Stable Environment By Using Multiple Instances of the Web Server

[kingcarol]

Attached is our internal PDF document regarding our process for finally having a stable environment and using Multiple Instances of Alpha Anywhere. This may or may not work for someone else, but I've been asked to share how we did it. My server technician wrote this document and I am probably not much help in answering very many questions about it. Since I have gained much valuable help from this forum, I am happy to share this if it will help someone else.

Setting up Multiple Alpha Instances.pdf

[Progytech]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Thanks Carol for sharing this information, I am sure it will be useful for many of us.

[compuaid]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

The one item I would add Carol is that your server technician mentions that when the Alpha Server hangs and fails to respond AlwaysUp does not recognize this and automatically restart the application server. The program I've written and added to the Code Library thread http://www.alphasoftware.com/alphafo...ys-Up-users%29 addresses this by allowing you to create a separate configuration for each instance you want to monitor and then adding a call from the AlwaysUp sanity check to the utility. If the Alpha server is hung and fails to respond the utility returns false to AlwaysUp and triggers a restart of the particular instance that is not responding.

[kingcarol]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Brad, Thanks. I will pass this info along to him.

[kingcarol]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

One thing that I should add is that I created what we call a 'launch' page in Alpha which is the first page our users go to. When a user clicks a button on our launch page to 'open our program' (before ever logging in), the code for that button checks which port has had the least amount of users log onto it in the past 2 hours, and sends them to the login page on that port. This is done using a log in my admin database that records the launch click, AND also records the user login and which port they are on when they log in. That way we don't have to assign our users to different ports. They will simply get rotated to the port with the least logins in the past 2 hours. This is working very well for us, especially because if there is ANY reason the web server is not responding on the port the user is sent to, they can simply go back and launch again and be sent to a different port. Cool, huh?

[imjoken]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Carol, thanks for the info. How many instances of Alpha are you running on the Poweredge server. Also, is your database hosted on the same server?

[compuaid]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Very cool Carol! Nice method of load-balancing without the cost of a dedicated load-balancer.

[kingcarol]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Carol, thanks for the info. How many instances of Alpha are you running on the Poweredge server. Also, is your database hosted on the same server?

We are using 7 instances right now, and yes, all the back end databases for my multi tenants are on the same server. If I were to sum up the reason we had to go through all of this, it would be that Alpha does not make use of multiple cores and everything gets crammed into one core, cause major slowdowns and/or stopping of the web servers.

[Progytech]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Hi Carol,

One question, since you have 7 instances of AWS using different local IP and Ports:

1. Are your users using the port number in the url like www.yoururl:81, www.yoururl:82, etc.
2. If not, how are you managing using a single url and redirect them to each instance?
3. Basically are you doing any load balancing with your instances?

Thanks!!!

[kingcarol]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

1.Are your users using the port number in the url like www.yoururl:81, www.yoururl:82, etc.

Yes to this question. Like I said above, I have a log of which port the user is sent to and I wrote code that sends them to the one with the least records in that log in the past two hours.

[kingcarol]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

The users are tapering off now since it is evening but here is a snapshot of my log this evening. The LAUNCH record means they clicked the button on our Launch page and it stores what port they are sent to. Then when they log in on the page they are sent to, another record is put into the log WITH their user id's (which I have blacked out on the snapshot). Early in our trials, before discovering the Always Up solution, we could look at this log and tell that one of the web app servers had probably stopped responding because we would see the LAUNCH record over and over for one of the ports, but no login record....meaning users probably couldn't get the to the login page on the port they were sent to. There was no indication other than looking at our ports log, (or hearing from a customer), that a web app server had stopped responding. What was good for our users at that time was that they could use the Back button on the browser to return to our Launch page and get directed to a different port.

Now we are very happy that for several weeks, our Ports log shows a launch and then a login and we are not seeing repeated launch logs without logins anymore.

MultiplePortsLog.jpg

[Progytech]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Thanks for the info Carol,

Just to clarify, you have a front end application which they all reach at www.youraddress.com then from here they are assigned a port number and redirected to one of the servers www.youraddress.com:81.
If this is this correct, then what logic are you using to kind of load balancing your WAS instances?

[CharlesParker]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Carol - Thank you so much for sharing this information! Your Awesome.

[kingcarol]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

Our users first go to one address (www.ouraddress.com) and then are redirected to our 'launch' page on Port 81...... http://www.ouraddress.com:81/ourlaunchpage.a5w (this is a fake address I am using to post this)

On our launch page, there is a button to 'Open The Program'. The code I wrote behind that button is:

function OpenProgram as c (e as p)
	
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' 	
dim cn as sql::connection
dim cs as c 

cs = ourConnection

dim flag as l 
flag = cn.open(cs)
if flag = .f. then 
	dim msg as c 
	msg = "Could not connect to database. Error reported was: " + cn.CallResult.text
	msg = js_escape(msg)
	dim jscmd as c 
	jscmd = "alert('" + msg + "');"
	OpenProgram = jscmd
	exit function 
end if	
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'TblPortLog	LOG_DATE   LOG_TIME PORT_NUMBER LOG_HOUR

dim todayDate as D
todayDate = Date()

dim currHour as N
currHour = convert_type(time("h"),"N")

dim thisHourToUse as n
dim lastHourToUse as n

if currHour = 0 then 'it's the middle of the night
	thisHourToUse = currHour
	lastHourToUse = 0
end if

if currHour > 0 then
	thisHourToUse = currHour
	lastHourToUse = currHour - 1
end if

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'check to see if there have been any logins to port 90 in past 2 hours.
'If not, send user to that port
sql5 = "select count(*) from TblPortLog where (LOG_DATE = :whatDate and LOG_HOUR = :whatCurrHour and PORT_NUMBER = 90) or (LOG_DATE = :whatDate and LOG_HOUR = :whatLastHour and PORT_NUMBER = 90)"
dim args5 as sql::Arguments
args5.add("whatDate",todayDate)
args5.add("whatCurrHour",thisHourToUse)
args5.add("whatLastHour",lastHourToUse)

cn.execute(sql5,args5)
dim rs5 as sql::ResultSet
rs5 = cn.ResultSet
dim countPort90 as n
countPort90 = convert_type(rs5.data(1),"N")

if countPort90 = 0 then
	'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
	sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
	dim args55 as sql::Arguments
	args55.add("PORT_NUMBER",90)
	args55.add("LOG_HOUR",currHour)
	args55.add("USER_ID","LAUNCH")
	cn.execute(sql55,args55)
	
	cn.Close()
	OpenProgram = "location.href = 'http://www.ouraddress.com:90/ourloginpage.a5w';"
	exit function
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'check to see if there have been any logins to port 91 in past 2 hours.
'If not, send user to that port
sql4 = "select count(*) from TblPortLog where (LOG_DATE = :whatDate and LOG_HOUR = :whatCurrHour and PORT_NUMBER = 91) or (LOG_DATE = :whatDate and LOG_HOUR = :whatLastHour and PORT_NUMBER = 91)"
dim args4 as sql::Arguments
args4.add("whatDate",todayDate)
args4.add("whatCurrHour",thisHourToUse)
args4.add("whatLastHour",lastHourToUse)

cn.execute(sql4,args4)
dim rs4 as sql::ResultSet
rs4 = cn.ResultSet
dim countPort91 as n
countPort91 = convert_type(rs4.data(1),"N")

if countPort91 = 0 then
	'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
	sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
	dim args55 as sql::Arguments
	args55.add("PORT_NUMBER",91)
	args55.add("LOG_HOUR",currHour)
	args55.add("USER_ID","LAUNCH")
	cn.execute(sql55,args55)
	
	cn.Close()
	OpenProgram = "location.href = 'http://www.ouraddress.com:91/ourloginpage.a5w';"
	exit function
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'check to see if there have been any logins to port 92 in past 2 hours.
'If not, send user to that port
sql2 = "select count(*) from TblPortLog where (LOG_DATE = :whatDate and LOG_HOUR = :whatCurrHour and PORT_NUMBER = 92) or (LOG_DATE = :whatDate and LOG_HOUR = :whatLastHour and PORT_NUMBER = 92)"
dim args2 as sql::Arguments
args2.add("whatDate",todayDate)
args2.add("whatCurrHour",thisHourToUse)
args2.add("whatLastHour",lastHourToUse)

cn.execute(sql2,args2)
dim rs2 as sql::ResultSet
rs2 = cn.ResultSet
dim countPort92 as n
countPort92 = convert_type(rs2.data(1),"N")

if countPort92 = 0 then
	'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
	sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
	dim args55 as sql::Arguments
	args55.add("PORT_NUMBER",92)
	args55.add("LOG_HOUR",currHour)
	args55.add("USER_ID","LAUNCH")
	cn.execute(sql55,args55)
	
	cn.Close()
	OpenProgram = "location.href = 'http://www.ouraddress.com:92/ourloginpage.a5w';"
	exit function
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'check to see if there have been any logins to port 93 in past 2 hours.
'If not, send user to that port
sql1 = "select count(*) from TblPortLog where (LOG_DATE = :whatDate and LOG_HOUR = :whatCurrHour and PORT_NUMBER = 93) or (LOG_DATE = :whatDate and LOG_HOUR = :whatLastHour and PORT_NUMBER = 93)"
dim args1 as sql::Arguments
args1.add("whatDate",todayDate)
args1.add("whatCurrHour",thisHourToUse)
args1.add("whatLastHour",lastHourToUse)

cn.execute(sql1,args1)
dim rs1 as sql::ResultSet
rs1 = cn.ResultSet
dim countPort93 as n
countPort93 = convert_type(rs1.data(1),"N")

if countPort93 = 0 then
	'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
	sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
	dim args55 as sql::Arguments
	args55.add("PORT_NUMBER",93)
	args55.add("LOG_HOUR",currHour)
	args55.add("USER_ID","LAUNCH")
	cn.execute(sql55,args55)
	
	cn.Close()
	OpenProgram = "location.href = 'http://www.ouraddress.com:93/ourloginpage.a5w';"
	exit function
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'check to see if there have been any logins to port 86 in past 2 hours.
'If not, send user to that port
sql7 = "select count(*) from TblPortLog where (LOG_DATE = :whatDate and LOG_HOUR = :whatCurrHour and PORT_NUMBER = 86) or (LOG_DATE = :whatDate and LOG_HOUR = :whatLastHour and PORT_NUMBER = 86)"
dim args7 as sql::Arguments
args7.add("whatDate",todayDate)
args7.add("whatCurrHour",thisHourToUse)
args7.add("whatLastHour",lastHourToUse)

cn.execute(sql7,args7)
dim rs7 as sql::ResultSet
rs7 = cn.ResultSet
dim countPort86 as n
countPort86 = convert_type(rs7.data(1),"N")

if countPort86 = 0 then
	'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
	sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
	dim args55 as sql::Arguments
	args55.add("PORT_NUMBER",86)
	args55.add("LOG_HOUR",currHour)
	args55.add("USER_ID","LAUNCH")
	cn.execute(sql55,args55)
	
	cn.Close()
	OpenProgram = "location.href = 'http://www.ouraddress.com:86/ourloginpage.a5w';"
	exit function
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'NOTE THAT PORTS 87 and 88 cannot be used because they appear to be reserved for most browsers
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'check to see if there have been any logins to port 89 in past 2 hours.
'If not, send user to that port
sql9 = "select count(*) from TblPortLog where (LOG_DATE = :whatDate and LOG_HOUR = :whatCurrHour and PORT_NUMBER = 89) or (LOG_DATE = :whatDate and LOG_HOUR = :whatLastHour and PORT_NUMBER = 89)"
dim args9 as sql::Arguments
args9.add("whatDate",todayDate)
args9.add("whatCurrHour",thisHourToUse)
args9.add("whatLastHour",lastHourToUse)

cn.execute(sql9,args9)
dim rs9 as sql::ResultSet
rs9 = cn.ResultSet
dim countPort89 as n
countPort89 = convert_type(rs9.data(1),"N")

if countPort89 = 0 then
	'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
	sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
	dim args55 as sql::Arguments
	args55.add("PORT_NUMBER",89)
	args55.add("LOG_HOUR",currHour)
	args55.add("USER_ID","LAUNCH")
	cn.execute(sql55,args55)
	
	cn.Close()
	OpenProgram = "location.href = 'http://www.ouraddress.com:89/ourloginpage.a5w';"
	exit function
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'IF we get to here then all ports have been accessed within the past 2 hours
'So.. find which port has had the least access in the past 2 hours

if countPort90 <= countPort91 then
	if countPort90 <= countPort92 then
		if countPort90 <= countPort93 then
			if countPort90 <= countPort86 then
				if countPort90 <= countPort89 then
					'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
					sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
					dim args55 as sql::Arguments
					args55.add("PORT_NUMBER",90)
					args55.add("LOG_HOUR",currHour)
					args55.add("USER_ID","LAUNCH")
					cn.execute(sql55,args55)
					
					cn.Close()
					OpenProgram = "location.href = 'http://www.ouraddress.com:90/ourloginpage.a5w';"
					exit function	
				end if
			end if
		end if
	end if
end if

if countPort91 <= countPort90 then
	if countPort91 <= countPort92 then
		if countPort91 <= countPort93 then
			if countPort91 <= countPort86 then
				if countPort91 <= countPort89 then
					'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
					sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
					dim args55 as sql::Arguments
					args55.add("PORT_NUMBER",91)
					args55.add("LOG_HOUR",currHour)
					args55.add("USER_ID","LAUNCH")
					cn.execute(sql55,args55)
					
					cn.Close()
					OpenProgram = "location.href = 'http://www.ouraddress.com:91/ourloginpage.a5w';"
					exit function	
				end if
			end if
		end if
	end if
end if

if countPort92 <= countPort90 then
	if countPort92 <= countPort91 then
		if countPort92 <= countPort93 then
			if countPort92 <= countPort86 then
				if countPort92 <= countPort89 then
					'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
					sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
					dim args55 as sql::Arguments
					args55.add("PORT_NUMBER",92)
					args55.add("LOG_HOUR",currHour)
					args55.add("USER_ID","LAUNCH")
					cn.execute(sql55,args55)
					
					cn.Close()
					OpenProgram = "location.href = 'http://www.ouraddress.com:92/ourloginpage.a5w';"
					exit function	
				end if
			end if
		end if
	end if
end if

if countPort93 <= countPort90 then
	if countPort93 <= countPort91 then
		if countPort93 <= countPort92 then
			if countPort93 <= countPort86 then
				if countPort93 <= countPort89 then
					'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
					sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
					dim args55 as sql::Arguments
					args55.add("PORT_NUMBER",93)
					args55.add("LOG_HOUR",currHour)
					args55.add("USER_ID","LAUNCH")
					cn.execute(sql55,args55)
					
					cn.Close()
					OpenProgram = "location.href = 'http://www.ouraddress.com:93/ourloginpage.a5w';"
					exit function	
				end if
			end if
		end if
	end if
end if

if countPort86 <= countPort90 then
	if countPort86 <= countPort91 then
		if countPort86 <= countPort92 then
			if countPort86 <= countPort93 then
				if countPort86 <= countPort89 then
					'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
					sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
					dim args55 as sql::Arguments
					args55.add("PORT_NUMBER",86)
					args55.add("LOG_HOUR",currHour)
					args55.add("USER_ID","LAUNCH")
					cn.execute(sql55,args55)
					
					cn.Close()
					OpenProgram = "location.href = 'http://www.ouraddress.com:86/ourloginpage.a5w';"
					exit function	
				end if
			end if
		end if
	end if
end if

if countPort89 <= countPort90 then
	if countPort89 <= countPort91 then
		if countPort89 <= countPort92 then
			if countPort89 <= countPort93 then
				if countPort89 <= countPort86 then
					'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
					sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
					dim args55 as sql::Arguments
					args55.add("PORT_NUMBER",89)
					args55.add("LOG_HOUR",currHour)
					args55.add("USER_ID","LAUNCH")
					cn.execute(sql55,args55)
					
					cn.Close()
					OpenProgram = "location.href = 'http://www.ouraddress.com:89/ourloginpage.a5w';"
					exit function	
				end if
			end if
		end if
	end if
end if
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'IF WE GET TO HERE FOR SOME REASON, THEN JUST PUT THEM ON PORT 91
'NOTE that the TblPortLog supplies date and time via the defaults for LOG_DATE and LOG_TIME
sql55 = "INSERT INTO TblPortLog (PORT_NUMBER, LOG_HOUR, USER_ID) Values (:PORT_NUMBER, :LOG_HOUR, :USER_ID)"
dim args55 as sql::Arguments
args55.add("PORT_NUMBER",91)
args55.add("LOG_HOUR",currHour)
args55.add("USER_ID","LAUNCH")
cn.execute(sql55,args55)

cn.Close()

OpenProgram = "location.href = 'http://www.ouraddress.com:91/ourloginpage.a5w';"
	
end function
'_____________________________________________________

[Mkpatil]

Re: How We Reached A Stable Environment By Using Multiple Instances of the Web Server

The home grown Load Balancer looks awesome. Thanks for sharing it.
Question: When an user gets redirected to say http://www.ouraddress.com:93/ourloginpage.a5w, does the url show that particular port number (here 93) for the rest of the session for that session in the url?

Regards!