LifeKeeper for Windows imposes certain restrictions on site configurations that can cause an active site to fail over from the primary node to the standby node.
Role and Role Services Required for IIS
For LifeKeeper for Windows to operate with IIS, the following roles and role services must be installed on all nodes:
Roles:
- Web Server (IIS)
Role Services:
- Web server
- FTP Server (when protecting an FTP site)
- Administration tools
IIS Active/Active Configuration
IIS allows multiple sites to run on a single server. Each site can be individually protected and managed by LifeKeeper for Windows.
The following diagram illustrates a standard site configuration.
In this configuration, each node hosts two website instances: one Primary and one Standby. Specifically, Node1 hosts the Primary instance of WebSite1 and the Standby instance of WebSite2, while Node2 is configured oppositely, hosting the Primary instance of WebSite2 and the Standby instance of WebSite1. Only the Primary instance of a website on a given node services user requests.
In addition, Node1 hosts the Primary instance of an FTP site named FTPsite1, while Node2 hosts the Standby instance of that FTP site.
If a Primary website stops servicing user requests, LifeKeeper for Windows activates the corresponding Standby instance on the standby node to take over service. Using the diagram as an example, if WebSite1 on Node1 fails, LifeKeeper for Windows activates the Standby instance of WebSite1 on Node2. After this failover, two website instances are running on Node2.
Once the issue with the failed web server has been resolved, services can be switched back to Node1. With RK for IIS, you can either manually switch the services back or enable the automatic switchback feature provided by LifeKeeper for Windows.
Default Website and New Website
The default website created during the IIS installation process can be protected by LifeKeeper for Windows. To do so, you must reconfigure the default website to use an IP address that is protected by LifeKeeper for Windows.
In addition, newly created websites can also be protected by LifeKeeper for Windows by configuring them to use an IP address protected by LifeKeeper for Windows.
Primary/Standby Roles
The node on which a site’s Primary instance is created serves as the primary node for that site. The node on which the Standby instance is created serves as the standby node for that site.
Note that the assignment of Primary and Standby nodes is determined independently for each configured site.
Naming Conventions
To enable protection with LifeKeeper for Windows, the following site name conventions must be used (enter the name in the Site Name field in the IIS console):
- Use only alphanumeric characters and hyphens.
- Spaces are not allowed.
If you need to change the name of a protected site, first delete the IIS resource, then change the site name, and finally recreate the resource.
Site Configurations
To protect sites using RK for IIS, both nodes must have identical site configurations. When configuring sites in IIS Manager, observe the following guidelines.
When configuring multiple Standby sites for a specific site, the same site ID must be assigned to each corresponding site.
- You must specify the same site name, including letter case, in the Site Name field of the Edit Site dialog.
- In the Site Bindings dialog, configure the settings as follows:
- Type:
Specify the same protocol for both sites. If you configure multiple bindings for a single site, use the same protocol for all bindings. If HTTPS is specified, SSL configuration is required. For details, see Configuring Sites with SSL. - Host name:
Use the same host name for both sites. - Port:
Use the same port number for both sites. - IP Address: Specify the IP address protected by the IP Address resource. If you are protecting a virtual IP address (VIP), the IP address will be the same on both sites. If you are protecting a physical IP address (real IP), the IP addresses will be different.
- Type:
- In Physical Path, specify the directory where the site’s content is stored. This path is typically located on a drive protected by a volume resource. For details, see Specifying a Physical Path.
Configuring SSL-enabled Sites
Websites configured with SSL (Secure Sockets Layer) enhance security by encrypting transmitted data and enabling mutual authentication between the web client and the web server. When configuring site bindings in IIS Manager, note the following:
Website configuration
- Protocol: HTTPS
- Port number: 443 (default when HTTPS is selected)
FTP site configuration (explicit FTP)
- Protocol: FTP
- Port number: 21 (default when FTP is selected)
FTP site configuration (implicit FTP)
- Protocol: FTP
- Port number: 990
RK for IIS protects SSL-enabled websites and non-SSL websites in the same manner. IIS also allows both TCP and SSL bindings to be configured for a single website, and LifeKeeper for Windows enables protection for all configured bindings.
Once the server certificate has been imported into IIS, the SSL port can be configured and used.
Specifying a Physical Path
The physical path must be located on a volume that is accessible from the active node. LifeKeeper for Windows supports the following two options:
- Shared storage
- Local volumes mirrored with DataKeeper for Windows
Using different volumes for multiple IIS sites
When creating an IIS resource hierarchy, RK for IIS creates dependencies for content volumes based on the IP address and physical path of the content directory specified in the IIS site configuration. When protecting multiple sites, assign a unique IP address and volume to each site.
The example below shows IIS-FTP and IIS-Web using the same IP address but different volume resources. In this configuration, maintenance performed on one site affects the other site because both sites share a common IP address resource dependency.
When you start IIS-FTP on the standby node, its dependencies are also moved to the standby node. As a result, IIS-Web is taken out of service on the primary node. In this situation, you must start the IIS-Web service on the standby node.
Assigning different IP addresses and volumes to each protected IIS site allows the sites to be managed independently, providing greater flexibility in resource management. However, as shown in the diagram above, managing the sites as a group may be more appropriate in certain scenarios.
Combining RK for IIS with an IP Address Resource Protecting a Physical (Real) IP Address
When using RK for IIS with an IP Address resource that protects a physical (real) IP address, you must configure different IP addresses for the IIS site on the primary node and the standby node.
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