so guys so let's killer load balancing it is a core networking solution used to distribute traffic across multiple servers platform so load balancer is improved application availability and responsiveness to prevent server overload each load balancer site between client device and backend server receiving and distributing incoming request to any available server capable of fulfilling them so in order to understand this I'll go to my whiteboard and I'll explain so consider uh you have the server one and server two so this may be your storefront server or it may be your Exchange Server whatever so by default let's say forget about this you don't have net scalar okay so by default there is no mechanism where you can distribute the traffic for example let's say you have 100 users who are connecting to your exchange server or storefront so the connectivity May land up in either one server or in another server so it may randomly it will go the connection so some out of 180 may go to the first one 30 may go 20 may go to the second one etc etc okay so even if this server is down still your connection will go to the server and you will get a page called cannot you know display the page or all those errors so it won't redirect to the other one okay so there is no mechanism unless and until you bring something called net scalar or any other load balances such as F5 Etc okay so consider the scenario no now you placed your nets killer in between your client and your server okay so now all the connection under connection it will go to the netscaler so netscaler is having a 100 connection so let's killer received this connection through whip okay so netscaler will receive the 100 connection through Whip and now netscaler will check the back end okay so it will check which server is available so in this case let's say both the server is healthy so it will let's scale it will monitor okay it will send constant HTTP request or ping request to make sure that your backend is up and running so now both the server is healthy what it will do out of 100 the first request go to the first second go to the second third go to the first fourth go to the second similarly it will distribute until it reaches 100 so by by the end of 100 packet so 50 may go to the first another 15 will go to the second so this is how it will do the load balancing and this communication it will go over the snip okay so the load distribution will happen between the snip okay so for example due to some reason this server goes down now any new request which is coming to the netscaler netscale will check the health so net schedule will now get to know that this server is not functioning so it won't send any data or any traffic to This Server so everything will so you know send it to another server so that it will avoid issues otherwise user will get the error called page cannot be displayed etc etc okay so you can avoid this so for example let's say if you have multiple servers so it will distribute across other multiple servers instead of sending into this one affected server okay this is the beauty of netscaler so let's see what is the advantage of netskiller or what is the benefit of deploying netscaler in your data center okay so as you can see benefit of let's killer one is redundancy so redundancy means for example let's say if a server goes down the load balancer automatically shifts the traffic to other server therefore load balancer is essential component for your availability architecture for example let's say you have two storefront server so one storefront server goes down means netscaler will automatically route the traffic to the other server so that is why we call it as redundancy second one is flexibility so you can add server remove server or from the form at any time this is often no limit to how many servers you can add to your network okay so the meaning of this is for example you have a server so you have some maintenance right so you need to upgrade your Exchange Server you need to do some maintenance so that case what you can do on the netscaler you can disable traffic for the server one okay so you can only send all the traffic to the other another available servers unless and until you complete your maintenance thing on the server first so and one more thing uh let's say you wanted to add one more Exchange Server to your farmer Farm or one or one more storefront server to your farm for example you have one or two server right you want to add third server so without netscaler that it is quite complicated why because when you are configuring a net scaler uh you know or you need to you know change some configurations for your exchange Etc because your exchange infra should know that there are three servers available now etcetera right so with the help of load balancing uh you know you can avoid such issues okay you have the flexibility to add a number of server to the back end so the third one is scalability when you notice a slow door not performance not uh not only you can add servers on the go but also you can add them without any downtime the meaning of this is for example let's say you have two storage field server so it is capable of to connect to find out users for example let's say and and then you notice that uh connection is coming more than 500 so you need to do scale up of your backend servers so in that case what you can do so simply you can add one more spin up your one more storefront over here and then you can add that you know inside your netscaler so that netscaler will automatically distribute the traffic across the three servers so this we will see in details so in a high level we have the three benefits one is redundancy and another one is flexibility another one is scalability now I'm going to do a load balancing through net scalar okay so to do this lab I'm not going to use this net scalar which I already have another set of Nets killer where I have some license uh you know to do gslb Etc because here I cannot do anything much so I can only do whatever the thing which I you know which is configured over here I cannot do anything much so for that reason I will take another net scaler where everything is sorry where I have I have this license okay which is some demo license I got so I will demonstrate other features using that so for that I am going to turn off this net scalers and let's bring back the other net scaler which I previously configured and kept ready so I'm going to turn off this you can see Lab One I'll shut down this okay lab two also I'm going to shut down okay now I'm going to bring the ns1 which is my uh other net scalar on which I am going to continue my rest of the lab okay okay another one is ns2 as you can see here so let's wait for this to come up so parallelly I have created two servers one is vm1 as you can see here so I have installed is role on this vm1 and uh so IP address of this is 192. 168 181. 140 I have one more VM currently I am facing some issue here but let's see what is is it resolved or not if you config so this is the server IP address of my another server so basically what I did is I have two servers so let's go to the Whiteboard so uh how server one which is a blue server and another one is server 2 which is red so now I am going to create this is configured with HTTP okay back end on Port 80.
so now this is the user so now what I am going to do is I in this is my net scaler so I'm going to create a load balancer virtual IP whip and then I'll have a subnet IP it will communicate with the back end and now I'm going to do a load balancing okay so of these two let's off do these two servers so let's see the behavior so to do the load balancing what all the things we need to know is first one is the backend server details okay so in this case my red server and my blue server IP address I need this is one thing second thing I need to know on which server the backend is listening so in my case the backend is using HTTP okay I need to know these details which is called as services so this is called as service server group and this is called as services and third one is virtual server okay virtual server is nothing but the one which we are going to give it to the user okay the front-end IP address so we need to have our IP address for this so let's take one IP address which is 10. 1 sorry 1 192 Dot 168. 181 Dot or 245 okay so this is the IP we are going to assign it to our Whip and we will give it to the end user so that he will connect then he may get connected to the red server or blue server and automatically netscaler will distribute the load so let's see this is in action okay so if I go to my VM this is my server too right so which is in a red so IP address is 141 and another one is my blue one which is 140.
so now we have the IP address which is 1 which will take a note here uh in the net scalar so 192 168. 181. 140 and 192.
168. 181. 141 so if I go back to my server that is vm1 and if I go to IIs you can see only Port 80 is there not 443 so it means it is only listening on Port 80 in the back end so this is the service we configured on the back end okay so I'll go to my netscaler so let's try to access our netscaler first so NS root so this is the net scalar see I have VPX thousand so this is it is having a license that is why I'm you know I'm using this you know to do all the demonstration because it has got uh uh all the parameters enabled see I can do gslb here I can do SSL sorry certificate Etc okay so that is why I'm using this one so in order to do the load balancing it's very simple we need to go to the traffic management okay so before doing all these things you need to enable the modes okay so we need to enable SSL offloading in this case already enabled other by brand new it won't be enabled so you need to enable see here integrated caching is not enabled so if you wanted to do any caching you need to select this and accordingly it enable so similarly there was Advanced features such as responder gslb Etc so this is also you have to enable it otherwise it will show he or see is not enabled that is why it will show in this so otherwise you can right click here also you can enable it see enable the feature so in my case load balancer it is already enabled so I'll go to the load balancing and uh I will uh first I told you right we need to define the servers okay so let me delete all the things which is already there so let me go to Services okay nothing is there see now nothing is there on my server so on my netscaler it is an empty configuration so now as I told you on the on the what you say on the Whiteboard first we need to define the servers so I have a server which is a green server right so 141 is the red server so I'll name it as red server which is 141 so let me please copy the IP address 141 and I'll click create so now I'm going to Define my blue server okay the IP address is 140.
so now I have defined the IP address of my backend in the netscaler so the next step what I told you is I need to define the services on which service the backend is listening so in my case it is HTTP so I'll click add so I'll click red Service as we see okay I'll select existing server because we already added this service so I'll select red server okay support protocol here we need to select a HTTP because 80 is configured so if you have SSL so you need to use SSL here but since it is HTTP so I'll select HTTP I'll click OK and I'll click on done so similarly for the blue as we see I'll select the blue one and then I'll select protocol HTTP and Port 80 and click ok so click done so now what happened if you go back to my note whiteboard what we have done is on the netscaler this is my blue server this is my red server on the netscaler we defined that there are two backend servers which is listening on Port 80 or HTTP so this we have defined in the netscale now let's scalar what it will do it will communicate through snip to these backends okay now it is initiated a connection through backend that is why you can see this in the green otherwise it will show red if communication is not there then it will show red so now we have the services and servers defined now we need to define the trip which is we told 180 to 168 181. 245 we will take so for that we need to go to the virtual servers click on ADD I'll select server iPhone whip okay I'll give some common name the protocol protocol means the users will listen on which Port this is one okay if this is the user so he will listen on Port 80 or http if it is he is listening on Port SSL then you need to select the protocol SSL but in our case he will listen on Port 80 so I'll keep HTTP IP address I'm going to give 190 168. 181.
245 or let's take 248 okay I'll uh Port is 80 as I mentioned it is HTTP and then click ok so now it will say no load balanced virtual server or service binding so now it is a dummy virtual server it doesn't have anything attached to it so now we need to attach these two backend Services we created right in the netscaler that back-end service we need to attach to our virtual IP so I'll click on load balance service binding I'll click on select so I can see two service so we need to select two service because we need to distribute the load between these two services that is why we are selecting two if you have five service you need to select five service on which you wanted to do the load balancing select click bind continue done colors that's it it's very very simple so now we have done the configuration using our jslb sorry not just sorry load balancing 182 168 181.
