Configure a MID Server cluster

  • Release version: Washingtondc
  • Updated February 1, 2024
  • 4 minutes to read

    • Group multiple MID Servers to form clusters, then configure clusters for fail-over protection or load balancing. Load-balancing clusters automatically balance work between each MID Server to improve stability and performance, as well as handle fail-over. Fail-over clusters have a configured order used to determine which MID Server to use next if a failure occurs.

    Before you begin

    Ensure that all MID Servers in the cluster have the same capabilities (Supported Applications, IP Ranges, and Capabilities). A MID Server should not belong to more than one cluster.

    Role required: admin

    Setup indicator for configuration phaseEnsure that the MID Server can connect to elements inside and outside your networkDownload and install the MID Server on a Linux or Windows hostConfigure your MID ServerConfigure MID Server securityEnsure that the MID Server can connect to elements inside and outside your networkDownload and install the MID Server on a Linux or Windows hostConfigure your MID ServerConfigure MID Server security

    About this task

    Create a new cluster or edit an existing cluster.

    Procedure

    1. Navigate to All > MID Server > Clusters.
    2. Click New to create a new cluster, or open an existing cluster's record to edit.
    3. Name the cluster and select the cluster type: Failover or Load Balance.
    4. Right click in the header bar and select Save from the context menu.
    5. Click Edit in the Includes MID Servers Related List.
    6. Select appropriate MID Servers for this cluster from the slushbucket.

    MID Server clusters

    MID Server clusters enable multiple MID Servers with the appropriate capabilities to be grouped together for load balancing and fail-over protection.

    External data sources

    For performance and reliability reasons, these data sources should not be used with MID Server clusters. These external data sources should only be used with dedicated MID Servers.
    • LDAP
    • Export sets
    • JDBC data sources
    Note:
    If a MID Server in a cluster fails, the fail-over MID Server starts over at the beginning of the ECC queue task even if much of the information from the JDBC data source was already returned. This can result in duplicate data. For more details, see the Using MID Server clusters for JDBC data sources can cause duplicate and out-of-date data [KB0727739] article in the HI Knowledge Base.

    How clusters work

    MID Servers in clusters must be able to connect to the instance and to all the devices with which they are expected to communicate. If all MID Servers in a cluster are down, the discovery is canceled. Make sure all the MID Servers are added to any Access Control List (ACL) in use. MID Server clusters are managed by a business rule called MID Server Cluster Management, which checks to see if the MID Server assigned to a job in the ECC Queue belongs to a cluster.

    Load balancing

    If the cluster business rule determines that a MID Server is part of a load balancing cluster, the application using the MID Server automatically balances the work between the MID Servers in that cluster. It is good practice to put MID Servers with the same capabilities in a load balancing cluster.

    Fail-over protection

    MID Servers in a fail-over cluster each have a configured order that the platform uses to determine which MID Server to use next in case of failure. MID Servers in a fail-over cluster work independently and do not load balance with other MID Servers in that cluster (although they might also be members of load balancing clusters). When a MID Server fails, the MID Server Cluster Management business rule selects the highest available MID Server in the order to take over the work. The selected MID Server checks the ECC Queue and starts with jobs that are either Processing or Ready.

    Note:
    MID Server clustering does not support the ECC queue topics Command or SystemCommand. If these commands are received, the clustered MID Servers do not redirect the ECC queue to another MID Server. The ECC queue records stay on the ECC queue without being processed.
    Configure a fail-over MID Server with at least the same capabilities as the MID Server it is intended to relieve.
    Note:
    If a MID Server fails while the Shazzam probe is running and auto-selection is configured, failover is not available. The Shazzam discovery stops. Discovery does not automatically choose another MID Server.

    MID Server cluster event

    The following event is triggered when the platform cannot find a MID Server with the appropriate capabilities to replace a MID Server in a fail-over cluster. Use this event to create an email to notify appropriate users that the cluster has failed.

    Table 1. MID Server cluster event
    Event Table Description Business Rule
    mid_server.cluster.down MID Server Cluster [ecc_agent_cluster] A MID Server cluster has failed MID Server Cluster Management

    Combining clusters

    A MID Server can be added to both types of clusters at the same time. This diagram shows a scenario in which a MID Server from a load balancing cluster (MID Server D) is also present in a fail-over cluster. If MID Server D fails, MID Server E in the failover cluster is available to the load balancing cluster to perform the tasks previously assigned to MID Server D.

    MID Server failover example

    Specifying a specific MID Server cluster

    You can specify a specific MID Server cluster for a Discovery schedule. The discovery process uses that cluster only. You cannot chain clusters or specify a single MID Server that belongs to multiple clusters.

    Distributed MID Server clusters for Operational Intelligence

    The distributed MID Server cluster type is used exclusively in Operational Intelligence, which analyzes Event Management events and generates anomaly alerts. These MID Servers communicate with one another to distribute and balance the workload. For details, see MID Server distributed clusters for Operational Intelligence