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CLOUDSTACK-893 conceptual info around gslb

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Radhika PC 2013-05-10 10:03:11 +05:30
parent 75a2457af6
commit 7fea21e31f
2 changed files with 118 additions and 35 deletions
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33
docs/en-US/added-API-commands-4.2.xml
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@ -91,20 +91,31 @@
</listitem>
<listitem>
<para>listGlobalLoadBalancerRule</para>
<para>Lists load balancer rules. account (lists resources by account. Use with the domainId
parameter); domainid (lists only resources belonging to the domain specified) id (the unique
ID of the global load balancer rule) isrecursive (defaults to false, but if true, lists all
resources from the parent specified by the domainId till leaves); keyword (List by keyword);
listall (if set to false, list only resources belonging to the command's caller; if set to
true - list resources that the caller is authorized to see. Default value is false); page;
pagesize; projectid (lists objects by project); regionid (region ID); tags (lists resources
by tags: key/value pairs). </para>
<para>Lists load balancer rules.</para>
<para>The request parameters are: account (lists resources by account. Use with the domainid
parameter); domainid (lists only resources belonging to the domain specified); id (the
unique ID of the global load balancer rule); isrecursive (defaults to false; but if true,
lists all the resources from the parent specified by the domainid); keyword (lists by
keyword); listall (if set to false, lists only resources belonging to the command's caller;
if set to true, lists resources that the caller is authorized to see. Default value is
false); page; pagesize; projectid (lists objects by project); regionid ; tags (lists
resources by tags: key/value pairs). </para>
</listitem>
<listitem>
<para>updateGlobalLoadBalancerRule</para>
<para>Archives the specified events. The request parameters are: ids (allowed to pass one or
more IDs separated by comma); type (string); olderthan (yyyy-mm-dd format).</para>
<para>The response parameters are: true, false </para>
<para>Updates global load balancer rules.</para>
<para>The request parameters are: id (the unique ID of the global load balancer rule); account
(lists resources by account. Use with the domainid parameter); description (the description
of the load balancer rule); domainid (lists only resources belonging to the domain
specified); gslblbmethod (the load balancer algorithm that is used to distributed traffic
across the zones participating in global server load balancing, if not specified defaults to
round robin); gslbstickysessionmethodname (the session sticky method; if not specified
defaults to sourceip); isrecursive (defaults to false, but if true, lists all resources from
the parent specified by the domainid till leaves); keyword (lists by keyword); listall (if
set to false, list only those resources belonging to the command's caller; if set to true,
lists resources that the caller is authorized to see. Default value is false); page;
pagesize; projectid (lists objects by project); regionid; tags (lists resources by tags:
key/value pairs)</para>
</listitem>
</itemizedlist>
</section>

120
docs/en-US/gslb.xml
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@ -41,6 +41,60 @@
alternate location for accessing a resource in the event of a failure, or to provide a means
of shifting traffic easily to simplify maintenance, or both.</para>
</section>
<section id="gslb-comp">
<title>Components of GSLB</title>
<para>A typical GSLB environment is comprised of the following components:</para>
<itemizedlist>
<listitem>
<para><emphasis role="bold">GSLB Site</emphasis>: In &PRODUCT;terminology, GSLB sites are
represented by zones that are mapped to data centers, each of which has various network
appliances. Each GSLB site is managed by a NetScaler appliance that is local to that site.
Each of these appliances treats its own site as the local site and all other sites,
managed by other appliances, as remote sites.</para>
</listitem>
<listitem>
<para><emphasis role="bold">GSLB Services</emphasis>: A GSLB service is typically
represented by a load balancing or content switching virtual server. In a GSLB
environment, you can have a local as well as remote GSLB services. A local GSLB service
represents a local load balancing or content switching virtual server. A remote GSLB
service is the one configured at one of the other sites in the GSLB setup. At each site in
the GSLB setup, you can create one local GSLB service and any number of remote GSLB
services.</para>
</listitem>
<listitem>
<para><emphasis role="bold">GSLB Virtual Servers</emphasis>: A GSLB virtual server refers to
one or more GSLB services and balances traffic between traffic across the VMs in multiple
zones by using the &PRODUCT; functionality. It evaluates the configured GSLB methods or
algorithms to select a GSLB service to which to send the client requests. One or more
virtual servers from different zones are bound to the GSLB virtual server. GSLB virtual
server does not have a public IP associated with it, instead it will have a FQDN DNS
name.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Load Balancing or Content Switching Virtual Servers</emphasis>:
According to Citrix NetScaler terminology, a load balancing or content switching virtual
server represents one or many servers on the local network. Clients send their requests to
the load balancing or content switching virtual server’s virtual IP (VIP) address, and the
virtual server balances the load across the local servers. After a GSLB virtual server
selects a GSLB service representing either a local or a remote load balancing or content
switching virtual server, the client sends the request to that virtual server’s VIP
address.</para>
</listitem>
<listitem>
<para><emphasis role="bold">DNS VIPs</emphasis>: DNS virtual IP represents a load balancing
DNS virtual server on the GSLB service provider. The DNS requests for domains for which
the GSLB service provider is authoritative can be sent to a DNS VIP.</para>
</listitem>
<listitem>
<para><emphasis role="bold">ADNS</emphasis>: ADNS (Authoritative Domain Name Server) is a
service that provides actual answer to DNS queries, such as web site IP address. In a GSLB
environment, an ADNS service responds only to DNS requests for domains for which the GSLB
service provider is authoritative. When an ADNS service is configured, the service
provider owns that IP address and advertises it. When you create an ADNS service, the
NetScaler responds to DNS queries on the configured ADNS service IP and port.</para>
</listitem>
</itemizedlist>
</section>
<section id="prereq-gslb">
<title>Prerequisites and Guidelines</title>
<itemizedlist>
@ -63,23 +117,23 @@
</listitem>
<listitem>
<para>When users have VMs deployed in multiple availability zones which are GSLB enabled,
user is allowed to use the GSLB functionality to load balance traffic across the VMs in
multiple zones.</para>
they can use the GSLB functionality to load balance traffic across the VMs in multiple
zones.</para>
</listitem>
<listitem>
<para>The users are allowed to use GSLB to load balance across the VMs across zones in a
region only if the admin has enabled GSLB in that region. </para>
<para>The users can use GSLB to load balance across the VMs across zones in a region only if
the admin has enabled GSLB in that region. </para>
</listitem>
<listitem>
<para>The users are allowed to load balance traffic across the availability zones in the
same region or different regions.</para>
<para>The users can load balance traffic across the availability zones in the same region or
different regions.</para>
</listitem>
<listitem>
<para>The admin is allowed to configure DNS name for the entire cloud.</para>
<para>The admin can configure DNS name for the entire cloud.</para>
</listitem>
<listitem>
<para>The users can specify an unique name, across the cloud, for a globally load balanced
service. The provided name will be used as the domain under the DNS name associated with
<para>The users can specify an unique name across the cloud for a globally load balanced
service. The provided name is used as the domain name under the DNS name associated with
the cloud.</para>
<para>The user-provided name along with the admin-provided DNS name is used to produce a
globally resolvable FQDN for the globally load balanced service of the user. For example,
@ -88,13 +142,12 @@
foo.xyztelco.com.</para>
</listitem>
<listitem>
<para>While setting up GSLB, users can select a load balancing method, such as round robin
or least RTT, that would be the load balance traffic used across the zones that are part
of GSLB.</para>
<para>While setting up GSLB, users can select a load balancing method, such as round robin,
for using across the zones that are part of GSLB.</para>
</listitem>
<listitem>
<para>The user shall be able to set weight to zone-level virtual server. Weight shall be
considered by the load balancing method is distributing the traffic.</para>
considered by the load balancing method for distributing the traffic.</para>
</listitem>
<listitem>
<para>The GSLB functionality shall support session persistence, where series of client
@ -103,6 +156,24 @@
</listitem>
</itemizedlist>
</section>
<section id="gslb-workflow">
<title>Configuring GSLB</title>
<para>To configure GSLB in your cloud environment, as a cloud administrator you must perform the
following.</para>
<para>To configure such a GSLB setup, you must first configure a standard load balancing setup
for each server farm or data center. This enables you to balance load across the different
servers in each server farm. Then, configure both NetScaler appliances as authoritative DNS
(ADNS) servers. Next, create a GSLB site for each server farm, configure GSLB virtual servers
for each site, create GLSB services, and bind the GSLB services to the GSLB virtual servers.
Finally, bind the domain to the GSLB virtual servers. The GSLB configurations on the two
appliances at the two different sites are identical, although each sites load-balancing
configuration is specific to that site.</para>
<orderedlist>
<listitem>
<para/>
</listitem>
</orderedlist>
</section>
<section id="gslb-add">
<title>Adding a GSLB Rule</title>
<orderedlist>
@ -174,17 +245,18 @@
</section>
<section id="concept-gslb">
<title>How Does GSLB Works in &PRODUCT;?</title>
<para>The following is an illustrated conceptual model of how GLSB functionality is provided in
&PRODUCT;: An organization, xyztelco, has set up a public cloud that spans two zones, Zone-1
and Zone-2, across geographically separated data centers that are managed by &PRODUCT;.
Tenant-A of the cloud launches a highly available solution by using xyztelco cloud. For that
purpose, they launch two instances each in both the zones: VM1 and VM2 in Zone-1 and VM5 and
VM6 in Zone-2. Tenant-A acquires a public IP, IP-1 in Zone-1, and configures a load balancer
rule to load balance the traffic between VM1 and VM2 instances. &PRODUCT; orchestrates setting
up a virtual server on the LB service provider in Zone-1. Virtual server 1 that is set up on
the LB service provider in Zone-1 represents a publicly accessible virtual server that client
reaches at IP-1. The client traffic to virtual server 1 at IP-1 will be load balanced across
VM1 and VM2 instances. </para>
<para>Global server load balancing is used to manage traffic flow to a web site hosted on two
separate zones that ideally are in different geographic locations. The following is an
illustration of how GLSB functionality is provided in &PRODUCT;: An organization, xyztelco,
has set up a public cloud that spans two zones, Zone-1 and Zone-2, across geographically
separated data centers that are managed by &PRODUCT;. Tenant-A of the cloud launches a highly
available solution by using xyztelco cloud. For that purpose, they launch two instances each
in both the zones: VM1 and VM2 in Zone-1 and VM5 and VM6 in Zone-2. Tenant-A acquires a public
IP, IP-1 in Zone-1, and configures a load balancer rule to load balance the traffic between
VM1 and VM2 instances. &PRODUCT; orchestrates setting up a virtual server on the LB service
provider in Zone-1. Virtual server 1 that is set up on the LB service provider in Zone-1
represents a publicly accessible virtual server that client reaches at IP-1. The client
traffic to virtual server 1 at IP-1 will be load balanced across VM1 and VM2 instances. </para>
<para>Tenant-A acquires another public IP, IP-2 in Zone-2 and sets up a load balancer rule to
load balance the traffic between VM5 and VM6 instances. Similarly in Zone-2, &PRODUCT;
orchestrates setting up a virtual server on the LB service provider. Virtual server 2 that is