# Configuring Failover for Windows App Console in DDI Central ![Failover cycle diagram](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/windows_ddi_central_console_failover_cycle.png) DDI Central supports failover for the Management UI console, helping ensure service continuity during console server downtime. The application console can be installed on both primary and secondary servers to enable a complete failover mechanism. If the primary server goes down, the secondary server takes over and assumes full control of all managed DNS and DHCP servers in the network. To configure failover in the DDI Central application: - Two installations are required. The DDI Central app console must be installed on both primary and secondary servers. - The primary and secondary servers can be in different time zones. However, ensure that both servers are configured to run on the correct local time. - Both primary and secondary servers should run on the same **HTTPS** port. - Both servers should be in sync and have consistent connectivity. - Both servers should run on the same version of the app console. Initially, before setting up Console Failover, you can see the **NOT CONFIGURED** status in the top right corner, clearly indicating there is no console failover configuration in place. ![Not configured status](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/not_configured.png) To start, go to **Settings → System → Console Failover**. Enter the Primary Server details such as Server IP, HTTPS Port, and DB Port. ![Primary server details](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-2.png) Similarly, enter the same details for the secondary server. When entering the secondary server details, users need to provide the secondary server's client ID and client secret in the respective fields. ![Secondary server details](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-3_11zon.png) To get the client ID and client secret, log in to the secondary server. Click on the **Profile**, where you can find the **Client credentials** section. Selecting the **View** option will display the client ID and client secret. ![Client credentials](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/appfailover_4_11zon.png) ## Database Replication In this section, users need to provide the password for the replication process, as the username field will be auto-filled with a constant username called **"replicator"** and cannot be changed. You can provide any secure password, or you can generate a random one using DDI Central's suggestion by clicking on the **Suggest button**. **Note:** The replication password must be alphanumerical. ![Replication password setup](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-4.png) Once the password is added, admins cannot edit or change it, as doing so would cut down the connectivity between the servers. **Note:** In case you forget the password, please contact DDI Central support. The main purpose of the data replication section is to keep both database servers in sync and enable data redundancy, i.e., changes made on the primary server are also updated on the secondary server. Under the High Availability section, enable the **Enable Web Interface HA** toggle and click **Save**. ![Enable Web Interface HA](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/appfailover_12_11zon.png) Before failover occurs, web login for the secondary server will be restricted when the primary is up. The secondary server will be available only in a "read only" mode, and no configurations or data changes can be implemented through the secondary server. Once the failover configuration is saved successfully, you can see the **CONFIGURED** status in the top right corner. The failover setup is initiated in the background and may take some time to complete. The duration depends on factors such as database volume and network latency. During this period, the console failover status appears with a **Not Synced** status on both the main dashboard and under **Settings → System → App Failover** as shown below. ![Not synced status](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console_failover_11zon.png) ![Dashboard failover status](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/dashboard_failover_11zon.png) Once the sync is complete, the secondary server begins sending health-monitoring heartbeats every 30 seconds to check the status of the primary server. ![Heartbeat monitoring](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-1.png) When the failover setup is live, the secondary server continuously monitors the primary server through heartbeat health checks (sent every 30 seconds). If the secondary server does not receive heartbeats from the primary server continuously for 10 minutes, it treats this 10-minute period as the deciding window and determines that the primary server has failed. After this 10-minute time window, the secondary server is automatically promoted as the primary server. DDI Central does not promote the secondary server immediately after one missed heartbeat. The secondary server waits and checks whether the primary server continues to miss heartbeats for a full 10 minutes. ## Maintenance mode ![Maintenance mode](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-5.png) While upgrading a service pack or PPM, or starting a service, network admins must enable **maintenance mode** on the primary server. Maintenance mode pauses the data replication process between primary and secondary servers, which allows admins to perform configurations and changes such as upgrading PPM. Enabling maintenance mode on the primary server will reflect on the secondary server. **Note:** Maintenance mode needs to be manually enabled on the primary server. ![Maintenance mode enabled](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-6.png) During maintenance mode, service takeover will not occur, but data syncing continues. As a result, the sync status will display **"synced"** and also show the **"last synced time."** ### Promoting servers ![Promote server](https://cdn.manageengine.com/sites/meweb/images/dns-dhcp-ipam/console-failover-7.png) When the current secondary server is up and ready, if the admin wants to promote it as the primary for handling the service, it can be promoted by clicking on the **Promote** button. Once you click **Yes** in the promotion confirmation dialog box, it will trigger a log-out, and you will have to wait for some time. The waiting time depends on the size of your database.