Configuring Management Servers for Failover

When you set up a management server failover configuration if one of the management servers fails or is offline, another management server in the cluster can provide services. Failover configuration provides fault tolerance for production environments.

Configuring Failover

You establish failover support by installing multiple management servers, adding them to a single management cluster, and configuring your DNS (Domain Name System) server to associate all management servers in the cluster with one symbolic name.

Things to remember

How does it work?

If you have 3 different management servers installed on 3 different machines called machine1, machine2, and machine3 and have added them to a single cluster, then you can setup a DNS entry with the symbolic name my-management-cluster and in that DNS entry you can add machine1, machine2, and machine3.

When a client wants to connect to the management cluster, instead of providing the address of a management server in the cluster (for example, machine1), the client provides the DNS symbolic name, my-management-cluster. Because the DNS entry contains more than one machine, the DNS service provides the list addresses configured for the entry. If a management server is not running, then the client can connect to another server configured for the DNS entry, and failover support is achieved.

You can also configure the DNS service to achieve load balancing support. Since data replication automatically occurs between all servers in a management cluster the client will have the same experience regardless of the management service to which they are connected.

Demonstration Video

This video, which takes about 7 minutes, shows configuration steps and a runtime demonstration of load distribution and failover.

Play video

Setting Up Management Servers for Failover Support

Management server clusters can be set up during installation or anytime using the Administrative Console Management Server Explorer.

  1. During installation, after you install Host Integrator and the management server component on the first server, select Join an existing installation and use the host name or IP address of the first server when installing on subsequent servers.

  2. Create a single DNS alias (common name) for all the IP addresses of management servers in the installation environment. Each management server IP address must be assigned to the same common name.

  3. In Administrative Console, it is a good idea to change the name of the management cluster (Perspective > Management > Servers > Management Cluster > Properties). The default cluster name is the system host name where management server was first installed, but you can change it to the cluster DNS alias for your installation environment. The cluster name displays in the Administrative Console status bar (lower right) when connected.

  4. To achieve failover capability, enter the cluster DNS alias name whenever you are required to provide a management server address:

What happens at runtime?

When establishing a connection to the management server alias name, IP name resolution returns the list of IP addresses. An attempt is made to contact the first address in the list. If no response is received, the next address is tried, and so forth.

When deploying models, the session server contacts the management server for authentication and authorization. If you see the following errors when deploying a model, you may have an incorrect configuration in step 2 above.

[VHI 3852] Deployment of model failed: Cannot establish management session
[VHI 3852] Deployment of model failed: Token binding is invalid

 

Related Topics
Bullet Adding a Management Server to a Cluster
Bullet About Management Servers
Bullet Adding Management Servers