16.5. Virtual Router

The virtual router is a type of System Virtual Machine. The virtual router is one of the most frequently used service providers in CloudStack. The end user has no direct access to the virtual router. Users can ping the virtual router and take actions that affect it (such as setting up port forwarding), but users do not have SSH access into the virtual router.

There is no mechanism for the administrator to log in to the virtual router. Virtual routers can be restarted by administrators, but this will interrupt public network access and other services for end users. A basic test in debugging networking issues is to attempt to ping the virtual router from a guest VM. Some of the characteristics of the virtual router are determined by its associated system service offering..

16.5.1. Configuring the Virtual Router

You can set the following:

IP range
Supported network services
Default domain name for the network serviced by the virtual router
Gateway IP address
How often CloudStack fetches network usage statistics from CloudStack virtual routers. If you want to collect traffic metering data from the virtual router, set the global configuration parameter router.stats.interval. If you are not using the virtual router to gather network usage statistics, set it to 0.

16.5.2. Upgrading a Virtual Router with System Service Offerings

When CloudStack creates a virtual router, it uses default settings which are defined in a default system service offering. See Section 8.2, “System Service Offerings”. All the virtual routers in a single guest network use the same system service offering. You can upgrade the capabilities of the virtual router by creating and applying a custom system service offering.

Define your custom system service offering. See Section 8.2.1, “Creating a New System Service Offering”. In System VM Type, choose Domain Router.
Associate the system service offering with a network offering. See Section 9.4.1, “Creating a New Network Offering”.
Apply the network offering to the network where you want the virtual routers to use the new system service offering. If this is a new network, follow the steps in Adding an Additional Guest Network on page 66. To change the service offering for existing virtual routers, follow the steps in Section 15.6.3, “Changing the Network Offering on a Guest Network”.

16.5.3. Best Practices for Virtual Routers

WARNING: Restarting a virtual router from a hypervisor console deletes all the iptables rules. To work around this issue, stop the virtual router and start it from the CloudStack UI.
WARNING: Do not use the destroyRouter API when only one router is available in the network, because restartNetwork API with the cleanup=false parameter can't recreate it later. If you want to destroy and recreate the single router available in the network, use the restartNetwork API with the cleanup=true parameter.