Azure上七层负载均衡APP Gateway

时间:2023-01-22 05:52:35

Azure的SLB和ILB是最常用的4层负载均衡工具。但有些场景是7层的负载均衡,SLB和ILB就无能为力了。

Azure上已经推出了APP Gateway的服务,就是7层负载均衡的负载均衡器。

Azure上七层负载均衡APP Gateway

如上图,APP Gateway实现用户HTTPS网站的SSL Offload,还可以实现多个VM的负载均衡。而且可以实现Cookie Affinity功能,这也是7层负载均衡的一种功能。

通过App Gateway、SLB、Traffic Manager综合使用,可以实现对应用系统的高扩展性:

Azure上七层负载均衡APP Gateway

可以通过智能DNS选择北部的Azure的数据中心还是东部的Azure的数据中心,再通过4层的SLB把流量分担到多个Application Gateway上,Application Gateway再根据策略,把流量分担到各个虚拟机上。

Application Gateway的部署基于VNet,但其负载均衡的节点可以是非本VNet的虚拟机。如下图:

Azure上七层负载均衡APP Gateway

其负载均衡的节点除本VNet的虚拟机外,可以是其他的Cloud Service,其他VNet内的虚拟机(需要VPN打通),甚至外部的虚拟机都可以成为Application Gateway的负载均衡节点。

App Gateway一共有3中型号:

  1. Small – Dev/Test使用,不建议部署在生产环境
  2. Medium – 可以支持150Mbps的SSL流量
  3. Large – 可以支持200Mbps的SSL流量

具体配置命令:

  1. 创建Application Gateway

    New-AzureApplicationGateway -Name hwappgw -VnetName hwvnet -Subnets Subnet-1 -InstanceCount 2 -GatewaySize Medium

    New-AzureApplicationGateway -Name hwappgw02 -VnetName hwvnet -Subnets Subnet-1 -InstanceCount 2 -GatewaySize Medium

    上面的配置中配置了两个APP Gateway。

    第一个会把其对外的地址设定为Subnet-1的地址,将采用ILB的四层负载均衡;第二个会让其自动获得公网的VIP地址,将采用SLB的四层负载均衡。

  2. 设置Application Gateway的配置文件

    首先编辑Application Gateway的配置文件,a.xml将采用ILB的方式实现负载均衡,c.xml将采用SLB的方式实现负载均衡:

a.xml

<?xml version="1.0" encoding="utf-8"?>

<ApplicationGatewayConfiguration xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/windowsazure">

<FrontendIPConfigurations>

<FrontendIPConfiguration>

<Name>fip1</Name>

<Type>Private</Type>

<StaticIPAddress>10.1.1.140</StaticIPAddress>

</FrontendIPConfiguration>

</FrontendIPConfigurations>

<FrontendPorts>

<FrontendPort>

<Name>FrontendPort1</Name>

<Port>80</Port>

</FrontendPort>

</FrontendPorts>

<BackendAddressPools>

<BackendAddressPool>

<Name>BackendPool1</Name>

<IPAddresses>

<IPAddress>10.1.1.151</IPAddress>

<IPAddress>10.1.1.152</IPAddress>

</IPAddresses>

</BackendAddressPool>

</BackendAddressPools>

<BackendHttpSettingsList>

<BackendHttpSettings>

<Name>BackendSetting1</Name>

<Port>80</Port>

<Protocol>Http</Protocol>

<CookieBasedAffinity>Enabled</CookieBasedAffinity>

</BackendHttpSettings>

</BackendHttpSettingsList>

<HttpListeners>

<HttpListener>

<Name>HTTPListener1</Name>

<FrontendIP>fip1</FrontendIP>

<FrontendPort>FrontendPort1</FrontendPort>

<Protocol>Http</Protocol>

</HttpListener>

</HttpListeners>

<HttpLoadBalancingRules>

<HttpLoadBalancingRule>

<Name>HttpLBRule1</Name>

<Type>basic</Type>

<BackendHttpSettings>BackendSetting1</BackendHttpSettings>

<Listener>HTTPListener1</Listener>

<BackendAddressPool>BackendPool1</BackendAddressPool>

</HttpLoadBalancingRule>

</HttpLoadBalancingRules>

</ApplicationGatewayConfiguration>

 

可以注意到其前端的IP地址是10.1.1.140。

 

c.xml

<?xml version="1.0" encoding="utf-8"?>

<ApplicationGatewayConfiguration xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/windowsazure">

<FrontendPorts>

<FrontendPort>

<Name>FrontendPort1</Name>

<Port>80</Port>

</FrontendPort>

</FrontendPorts>

<BackendAddressPools>

<BackendAddressPool>

<Name>BackendPool1</Name>

<IPAddresses>

<IPAddress>10.1.1.151</IPAddress>

<IPAddress>10.1.1.152</IPAddress>

</IPAddresses>

</BackendAddressPool>

</BackendAddressPools>

<BackendHttpSettingsList>

<BackendHttpSettings>

<Name>BackendSetting1</Name>

<Port>80</Port>

<Protocol>Http</Protocol>

<CookieBasedAffinity>Enabled</CookieBasedAffinity>

</BackendHttpSettings>

</BackendHttpSettingsList>

<HttpListeners>

<HttpListener>

<Name>HTTPListener1</Name>

<FrontendPort>FrontendPort1</FrontendPort>

<Protocol>Http</Protocol>

</HttpListener>

</HttpListeners>

<HttpLoadBalancingRules>

<HttpLoadBalancingRule>

<Name>HttpLBRule1</Name>

<Type>basic</Type>

<BackendHttpSettings>BackendSetting1</BackendHttpSettings>

<Listener>HTTPListener1</Listener>

<BackendAddressPool>BackendPool1</BackendAddressPool>

</HttpLoadBalancingRule>

</HttpLoadBalancingRules>

</ApplicationGatewayConfiguration>

 

这个配置中的前端IP不进行设置,讲自动获得VIP地址。

  1. 设置Application Gateway的配置

    Set-AzureApplicationGatewayConfig -Name hwappgw -ConfigFile D:\a.xml

    Set-AzureApplicationGatewayConfig -Name hwappgw02 -ConfigFile D:\c.xml

  2. 启动Application Gateway

    Start-AzureApplicationGateway -Name hwappgw

    Start-AzureApplicationGateway -Name hwappgw02

    这个过程将比较耗时,这一步需要大约20分钟的时间创建。这个过程中,Azure会在后台创建多台Application Gateway的VM,实现HA的配置。

  3. 获得Application Gateway的状态

    Get-AzureApplicationGateway

Name

hwappgw

Description

 

VnetName

hwvnet

Subnets

{Subnet-1}

InstanceCount

2

GatewaySize

Medium

State

Running

VirtualIPs

{10.1.1.140}

DnsName

 

 

 

 

 

 

 

 

 

Name

hwappgw02

Description

 

VnetName

hwvnet

Subnets

{Subnet-1}

InstanceCount

2

GatewaySize

Medium

State

Running

VirtualIPs

{42.159.241.87}

DnsName

70da9ed4-cf13-45a9-9fa3-c44f7e98e73a.chinacloudapp.cn

 

 

 

 

 

 

 

可以观察到,hwappgw的地址是一个内部地址,而hwappgw02的地址是一个公网地址,并有DNS的域名。

这时已经可以通过这个两个负载均衡的地址访问后台的服务了。Application Gateway会根据10.1.1.151和10.1.1.152两台虚拟机的状态进行负载均衡的流量转发。

  1. 上传SSL证书

    Add-AzureApplicationGatewaySslCertificate -Name hwappgw02 -CertificateName hengweicert -Password xxxx -CertificateFile D:\HengweiCert.pfx

    Name HTTP Status Code Operation ID Error

    ---- ---------------- ------------ -----

    Successful OK ae3d3289-618f-4da0-bf45-56ed2542d098

  2. 确认证书状态

    Get-AzureApplicationGatewaySslCertificate -Name hwappgw02

    Name     : hengweicert

    SubjectName     : CN=ClientCertificateHengwei

    Thumbprint     : 1336E8F9BB18A947AD79F0A2939411B0BC3D893B

    ThumbprintAlgo     : sha1RSA

    State         : Provisioned

  3. 更改hwappgw02的配置文件

    修改c.xml配置文件,修改协议为https、443端口,以及添加证书配置:

    <?xml version="1.0" encoding="utf-8"?>

    <ApplicationGatewayConfiguration xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/windowsazure">

    <FrontendPorts>

    <FrontendPort>

    <Name>FrontendPort1</Name>

    <Port>443</Port>

    </FrontendPort>

    </FrontendPorts>

    <BackendAddressPools>

    <BackendAddressPool>

    <Name>BackendPool1</Name>

    <IPAddresses>

    <IPAddress>10.1.1.151</IPAddress>

    <IPAddress>10.1.1.152</IPAddress>

    </IPAddresses>

    </BackendAddressPool>

    </BackendAddressPools>

    <BackendHttpSettingsList>

    <BackendHttpSettings>

    <Name>BackendSetting1</Name>

    <Port>80</Port>

    <Protocol>Http</Protocol>

    <CookieBasedAffinity>Enabled</CookieBasedAffinity>

    </BackendHttpSettings>

    </BackendHttpSettingsList>

    <HttpListeners>

    <HttpListener>

    <Name>HTTPListener1</Name>

    <FrontendPort>FrontendPort1</FrontendPort>

    <Protocol>Https</Protocol>

         <SslCert>hengweicert</SslCert>

    </HttpListener>

    </HttpListeners>

    <HttpLoadBalancingRules>

    <HttpLoadBalancingRule>

    <Name>HttpLBRule1</Name>

    <Type>basic</Type>

    <BackendHttpSettings>BackendSetting1</BackendHttpSettings>

    <Listener>HTTPListener1</Listener>

    <BackendAddressPool>BackendPool1</BackendAddressPool>

    </HttpLoadBalancingRule>

    </HttpLoadBalancingRules>

    </ApplicationGatewayConfiguration>

  4. 上传APP Gateway的设置

    Set-AzureApplicationGatewayConfig -Name hwappgw02 -ConfigFile D:\c.xml

    此时通过https访问这个网站,会提示证书不受信任(自签名证书)

    Azure上七层负载均衡APP Gateway

点击继续后,出现网站主页面:

Azure上七层负载均衡APP Gateway

 

而此时虚拟机提供的只是HTTP服务,由application gateway做了SSL的加密发送给用户。

 

目前Application Gateway可以实现的功能主要是基于CookieAffinity的负载均衡和SSL的Offload。

将来还会出基于URL的HTTP路由策略。新功能出来后,再做更新!