Your first load balancer-15-minute introductory lesson

"I am a novice in load balancing, the documentation is too complex and needs getting started. ”

"I want to initialize a load balancer for the first time in life and need guidance. ”

If you are a novice, if you first touch the load balancer, if its name is Citrix NetScaler, then congratulations, the previous question is not a problem at all. Turn it on, open the browser, follow the wizard in a few minutes to configure the completion, you have been through the Load Balancer application delivery threshold, a new world suddenly enlightened:

Enter the user name password to configure the management address and you will see this wizard interface

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You see a strange word, Subnet IP address, how to continue? Please do not rush to fill in, to the right to see, 650) this.width=650; "src=" Http://img.baidu.com/hi/jx2/j_0057.gif "alt=" J_0057.gif "/> There is a picture (NetScaler the important teaching materials built-in!!) ）：

Load balancer cheats are opened by you! This picture is the core knowledge you have to master!

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With the load balancer on the front end, the following server groups are virtualized into a VIP. So the upper-left corner of the diagram can be seen when someone accesses your website, the source address is the client IP of the laptop, and the destination address is the VIP.

After the NetScaler receives the request, it carries out various security checks, such as the access of the non-Protocol rule or the SYN Attack of address spoofing, and the SQL injection attack will be prevented from discarding and will not continue to be passed to the rear. There are also a variety of advanced processing, such as allocating traffic according to the equalization algorithm you set, and distributing it to different servers according to the policies you have scheduled.

After processing saw the upper right corner of the diagram, at this time NetScaler actively initiate the connection, the use of the source address is the SNIP we want to configure , the destination address is the real server IP. From the name subnet IP, you can assign an IP from the device's direct subnet, some of which are similar to the interface IP of some network devices, or the IP of the VLAN.

The server's response is also under the same two paragraphs. The server responds to NetScaler SNIP, NetScaler finally uses the VIP response to the client.

So netscaler in the middle, we don't need client-to-server routing, or NAT configuration, just consider the connectivity of both ends and NetScaler. If network planning is relatively straightforward, snip will be on the same subnet as the server address.

Said a lot, actually configured only one step:snip address

Next, let's do a simple load balancer. Click Load Balancing-services-add to add a live Server service

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Why do I want to load a service instead of a server?

Take the Web server, you want to load only this site, this Web service, perhaps just 80 or 443 ports, not the entire server, the server installed a lot of services open a lot of ports, all the ports are published? It's not what you want.

Protocol Select HTTP, the port will automatically fill in 80, if not please change.

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Once you've added one, add another, and you'll see the services you added on the interface.

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See the state status should be green up, netscaler in the process of load, will continue to detect the back-end service, if the service has a problem will not load, the default health detection is TCP. Green stands for two points:

1. Back-end server routing up to

2. Back-end service port Open

This kind of detection avoids the simple ping check, although can ping the server, but in fact the HTTP service is not open at all, no access to the site.

In the future study will encounter more complex problems: such as the normal service but ping is disabled, although the port is open, but the Web page does not exist, or the process is dead, or you want to load the SQL service, to find the corresponding table entries to prove that the service is normal and so on, I hope you in the process of configuration to think how to solve I will continue to discuss the following article.

Everything is ready, only the east wind--Configure VIP, select the Load service

Click-traffic management-load balancing-virtual servers-add

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The protocol here is consistent with our load service selection, and the IP address is the virtual address you want to give the user access to.

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Click After OK, you will be prompted not to connect the service, continue to click

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You will see the real service created before, tick click Select-bind

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At this point, you will see that the virtual IP status becomes green , and you can access the test

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At this time NetScaler according to the default load algorithm evenly to the client's request to your backend servers, disconnect any server, NetScaler will instantly perceive, the new request to the still healthy back end.

In this article we have only made three steps :

1 Configuring Snip

2 Configuring the Service

3 Configuring the VIP and binding the service

Well, after a simple 15-minute configuration, it can be clear that your business will:

"NetScaler, Shou-Fu and Qi"

Well, although I often get feedback that "NetScaler is the most stable load balancer I've ever used", "2001 NetScaler is still in normal service", but I should be responsible for the world peace, it is recommended that you deploy the standby machine.

At this point it may be said: "The standby machine has been idle, bought in most cases just a waste of money." ", this problem is very good, actually used for many years of primary and standby technology in the load balancer early has been outdated, the same two devices, why not all use up, so that performance doubled? See this article for more details true clusters and pseudo-clusters in load balancing technology

@NetScaler_Insight

This article is from the "netscaler_insight" blog, make sure to keep this source http://netscaler.blog.51cto.com/9136680/1692258

Your first load balancer-15-minute introductory lesson