Global load Balancing GSLB "Deployment Chapter"

http://virtualadc.blog.51cto.com/3027116/875622

Objective

With the continuous development of Web applications, customers also put forward higher requirements for the stability and reliability of the business, which is no longer limited to the server virtualization within IDC. Many people know that the effect of data exchange between the major domestic operators is not satisfactory, and as a user, especially the business users who require timely response, on the one hand to consider the data disaster of IDC, on the other hand to achieve near-sex access, improve customer access experience, at this time, Global load Balancing GSLB is a good solution.

GSLB the implementation principle

Most people only know that the role of DNS is to help the client to "remember" every service IP published on the internet, after all, there are related words than 32 digits more convenient memory. The role of GSLB is similar to DNS, where the GSLB device can be treated as a DNS server, and all domain names set on this device can parse a record (service IP). But a more important function than the normal server, is "smart". Before parsing, the GSLB device will be based on the "source" of the request package, the response efficiency of each a record, the availability of the backend server and so on to analyze and judge, so in many cases, people will gslb also known as "IDNS", that is, intelligent DNS.

About the parsing process of GSLB, you can go to search for a while there are articles mentioned, here no longer repeat.

GSLB the deployment

Need to implement intelligent parsing, you need to transfer the resolution of the domain name to the GSLB device, more DNS recursive query principle, as long as the domain name of the resolution request can eventually reach the GSLB device, GSLB device can make appropriate response. Here's a look at the resolution configuration on the DNS server:

A10test.com NS dns1.chinadns.com

A10test.com NS dns2.chinadns.com

Www.a10test.com A 222.222.222.222

There are two common ways to delegate authorization resolution to accommodate different DNS servers

1) NS Direct delegation

Erase the original a record

A10test.com NS dns1.chinadns.com

A10test.com NS dns2.chinadns.com

dns1.chinadns.com A GSLB Device ISP1 interface DNS listening address

dns2.chinadns.com A GSLB Device ISP2 interface DNS listening address

2) Alias Method delegation

A10test.com NS dns1.chinadns.com

A10test.com NS dns2.chinadns.com

Www. A10test.com CNAME www.ax. A10test.com.

Ax. A10test.com NS dns1. Ax. A10test.com

Ax. A10test.com NS dns2. Ax. A10test.com m

Dns1. Ax. a10test.com A GSLB Device ISP1 interface DNS listening address

Dns2. Ax. a10test.com A GSLB Device ISP2 interface DNS listening address

The following is a legend on the internet

NS Direct Delegation is the most convenient way, but the entire authorization domain will be forwarded to the GSLB device, if the GSLB device does not fully support all DNS server records, such as Mx/soa, and so on, there will be problems, and the DNS switchover takes about a day to basic completion, The disconnection time of a business must be taken into account. While the alias mode affects a single domain name, the impact is small, but also requires the original domain name maintainer can provide the alias change permissions (some domain name maintainers only provide a record and NS record changes).

After completing the domain name resolution delegation, do the corresponding domain name resolution configuration on the GSLB device. It is important to note that if you are delegating directly, the domain name is the same as the domain name accessed on the Internet:

GSLB Zone a10test.com

Service HTTP www

In the case of aliases, the domain name is the subdomain name after the alias.

GSLB Zone ax.a10test.com

Service HTTP www

To verify that the GSLB device can be resolved, first set the client's Nslookup server to the DNS listening address of gslb, as long as a record return indicates that the device's parsing function is normal. Then is waiting for the internet on all levels of DNS server record updates, this process is relatively lengthy, need to do is to wait patiently ...

Nginx+web servers can be load balanced, but an nginx is also limited, if not high, how to achieve load balancing on his upper level.       If it is a DNS or CDN, building a number of rooms, there is bound to be a number of computer room data synchronization problem.       is there any good information on this?

2013-12-28 10:57# Insider High-quality smooth answer race hot start! Super Hao Li, wait for you to ~#.The questioner is adopted by

The information in this regard is basically a piece of incomplete. I'll probably tell you a basic architecture:
1, DNS server, if the funds are sufficient, it is recommended to use the BGP room, 2-3 DNS server equalization, usually using bind software. If the funds are tight, you can buy professional DNS services, such as domestic dnspod.
2, CDN Server, a start if you want to save money, you can buy professional services, such as ChinaCache, but with the development costs will be higher. Self-built, may be set up separately, the telecommunications, Unicom, mobile and other computer room server, through the DNS to do dynamic analysis. Super Big website, can use squid, ordinary medium to large with nginx, inside play with varnish.
3, the front-end equalization, sufficient funds, you can use hardware equipment, hundreds of thousands of a. If you have a technical team, you can use nginx/haproxy+keepalived to build your own front end. The balance of the way are more flexible, random, weight, IP, URL has.
4, synchronization of the problem to see the synchronization of what things, the ordinary can be real-time file synchronization. But the database, to see the specific type of synchronization mode.
5, the backend application server and the database cluster, depends on the traffic planning.

Ask:

There seems to be no specific way to say, if more than one nginx how to achieve load balancing.  See what you mean, is not the use of DNS and CDN set up a number of programs each program using Nginx to    do reverse proxy.   if consider the cost and other reasons, do not want to set up a number of systems, is a computer room or private cloud inside, the establishment of this system, to achieve a number of nginx load balance, what is the best way?

Chase Answer:

More than one nginx to achieve equalization, there are several methods:
1, each nginx has a public address, in the domain name set up the same domain name multiple points, the simplest realization of wheel xun. But failure to cut the negative will be a little slower.
2, a public network nginx through the upstream function, wheel Xun, IP, URL multi-mode distribution to the intranet more than Nginx. But the public network nginx if down machine, intranet whole paragraph.
3, a pair of public network Nginx plus three public network IP, through the keepalive to achieve high availability, and then upstream to the intranet.
4, a hardware balance server in the front-end, and then through the hardware equalization to the content of other servers.

You say that if, can be achieved by 2, 3, 4 method.

Deployment chapter of Global load Balancing GSLB