# Manage a Cluster

In this solution, MBG clustering is pre-configured during initial deployment. Only Manually Synchronizing the Server Databases must be performed in this environment.

Cluster Management consists of the following:

- Configuring a Cluster
- - Creating the Initial Primary/Auxiliary Pair for a Cluster
  - Adding More Nodes
- Manually Synchronizing the Server Databases
- Changing a Cluster Node's IP Address
- Leaving a Cluster
- Taking Ownership of a Cluster

## Configuring a Cluster

Before you begin, select the server that will be your “primary” server; it holds the authoritative data and is the only server capable of adding peer nodes (“auxiliary”) to the cluster.

To create the cluster, access the primary server, add the primary/auxiliary pair to it and apply a weighting factor for load balancing. Then access the auxiliary server, add the primary/auxiliary pair to it, synchronize the system databases, and apply a weighting factor. If you have another MBG you wish to add to the cluster, follow a similar procedure to add it: First add the peer (auxiliary) to the primary and then add the primary/peer (auxiliary) pair to the peer server.

## Creating the Initial Primary/Auxiliary Pair for a Cluster

To create the cluster and add the primary/auxiliary pair to the primary server:

1. On the MBG main page of the primary server, click the System tab and click Dashboard.
2. In the Clustering status frame, click Create a cluster.
3. In the IP Address of current node list, select the interface or enter the IP address of the server you have selected to be the primary (or accept the default).
   Note: While configuring a cluster between two MBGs in DMZ mode using their public IP addresses, you can choose the drop-down option for Other, and manually enter the public IP address used for the current node and the public IP address used for the peer node. This enables the cluster to synchronize from a public IP address to a public IP address. By choosing the default, the cluster is synchronized from a DMZ private IP address to the peer public IP address.
4. In the IP Address of peer node list, enter the IP address of the server you have selected to be the auxiliary. These entries establish the cluster relationship between the servers.
5. In the Cluster weight of current node field, select the cluster weight factor value to apply to the primary server for load balancing. The default value is 0.
6. Click Save to create the initial primary/auxiliary pair. The two new nodes are added to the Node information list as members of the "Default" cluster zone.
7. Click Save.

To add the primary/auxiliary pair to the auxiliary server and synchronize the system databases:

Note: When you add an MBG as a auxiliary, its current data is lost.

1. On the MBG main page of the auxiliary server, click the System tab and click Dashboard.
2. In the Clustering status frame, click Join a cluster.
3. In the IP Address of current node list, select the interface or IP address of this server.
4. In the IP Address of peer node list, enter the IP address of the primary server.
5. Click Save.

Wait for the primary node to synchronize its database with the auxiliary, which can take five minutes for newly created MBGs and up to 30 minutes for existing MBGs with large databases. When synchronization is complete, the State field on the primary displays, "In sync with peer node" and the State field on the auxiliary displays "In sync with primary node."

1. For the node you have just added, click to Modify node.
2. In the Cluster weight of node field, select a value to apply to the auxiliary server.
3. Click Save.

Note: By default, the auxiliary server has a cluster weight of zero (0). If you fail to update this value, the auxiliary server will not participate in load balancing, even if all other nodes in the cluster fail.

## Adding More Nodes to a Cluster

To add a peer (auxiliary) node to the primary server for an existing cluster:

1. On the MBG main page of the primary server, click the System status tab and then click Dashboard.
2. In the Clustering status frame, click to Add new node.
3. In the IP Address of node list, enter the IP address of the peer server you are adding.
4. (Optional) In the Cluster zone for node list, select a zone for which this node will have affinity.
   Note: Do not set the Cluster weight of node at this time.
5. Click Save.

To add the primary/peer (auxiliary) pair to the peer server for an existing cluster:

1. On the MBG main page of the server you want to add to the cluster, click the System status tab and then click Dashboard.
2. In the Clustering status frame, click Join a cluster.
3. In the IP Address of current node list, select the interface you want to use for this server.
4. In the IP Address of peer node list, enter the IP address of the primary server.
5. Click Save.

Wait for the primary node to synchronize its database with the peer (auxiliary), which can take up to 30 minutes for existing MBGs with large databases. When synchronization is complete, the State field on the primary displays, "In sync with peer node" and the State field on the peer (auxiliary) displays "In sync with primary node."

1. For the node you have just added, click to Modify node.
2. In the Cluster weight of node list, select a value to apply to the peer server.
3. Click Save.
   Note:

   - By default, the new node has a cluster weight of zero. If you fail to update this value, the new node will not participate in load balancing.

   - Failure of the primary server is not service affecting. Any server in the cluster can raise an SNMP alarm to warn of outage or can take ownership of the cluster.

After a cluster is configured, the Clustering status frame provides the following information:

Cluster status
Cluster Status | The status of the local node: whether it belongs to a cluster, and whether it is the primary node or a auxiliary node.
Manage Cluster | Primary: Resync cluster Dissolve cluster
Auxiliary: Resync with primary Take ownership Leave cluster
Zone status
Zone name | The name of this cluster zone. By default, the system has one zone, called "Default", but you can configure other cluster zones and then direct devices to use them. You can also rename the "Default" zone. After configuring a cluster zone, you should select a backup zone to act as a fallback in the event that the MBGs in the cluster zone become unavailable.
Backup | The name of the backup zone for this zone (if any).
Node status
Node ID | The domain name/system name of nodes in the cluster.
Node state | The sync status of this node.
Blade Version | MBG software version installed on this node.
Connected MiNet devices | The number of phones currently configured in the cluster.
Connected devices | The number of phones currently connected to this node.
Address | The IP address FQDN this server uses to communicate cluster events with the cluster.
Weight | The weighting factor applied to this node.
Connected | indicates that node is connected to the cluster.

## Manually Synchronizing the Server Databases

Data is automatically shared between primary and auxiliary servers in the cluster. Use the following procedures to manually synchronize the data.

Synchronizing a Peer with the Primary

To manually re-synchronize a peer node with the primary server in a cluster:

1. On the MBG main page of the peer server, click the System tab and click Dashboard.
2. In the Clustering status frame, click Resync with Primary. A confirmation page appears.
3. Click Initiate Resync. Successful synchronization is confirmed.

Synchronizing all Nodes in a Cluster

To manually re-synchronize all nodes in a cluster:

1. On the MBG main page of the primary server, click the System tab and then click Dashboard.
2. In the Clustering status frame, click Resync cluster. A confirmation page appears.
3. Click Initiate Resync. Successful synchronization is confirmed.

## Changing a Cluster Node's IP Address

MBG clustering uses IP addresses to identify each node and to initiate cluster communications connections.

To change a node's IP address:

1. Ensure that the node to be changed is not the primary node. Take ownership from another node if required.
2. From the auxiliary node to be changed, go to the Clustering tab and click Leave cluster button.
3. Reconfigure the address using the MSL console, and follow the prompts to reboot.
4. Add the node on the primary, and join the server to the cluster.

## Leaving a Cluster

You can remove an individual node from a cluster or completely dissolve a cluster.

## Removing a Peer from a Cluster

To remove a peer node from a cluster:

1. On the MBG main page of the peer server, click the System status tab and then click Dashboard.
2. In the Clustering status frame, click Leave Cluster. A confirmation page appears.
3. When prompted, confirm that you want to leave the cluster.

## Dissolving a Cluster

To completely dissolve a cluster:

1. On the MBG main page of the primary server, click the System status tab and then click Dashboard.
2. In the Clustering status frame, click Dissolve Cluster. A confirmation page appears.
3. When prompted, confirm that you want to dissolve the cluster.

## Taking Ownership of a Cluster

To transform a auxiliary into the primary server of an existing cluster:

1. On the MBG main page of a auxiliary server, click the System tab and then click Dashboard.
2. In the Clustering status frame, click Take Ownership. A confirmation page appears.
3. When prompted, confirm that you want to take ownership of the cluster.

Note: When you upgrade an MBG cluster, you must upgrade the primary node first.
Parent topic: Clustering
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