Setup of Curator with HADR

For an introduction to Curator and starting the service see the article on Curator Configuration for Zoom versions till 7.2 and Curator Configuration for Zoom 7.3 onwards. This article discusses the initial setup, and, the process for subsequent configuration of the Curator service when Zoom HADR is being used.

Zoom HADR provides High-Availability and Disaster Recovery using multiple Zoom servers. Similarly, multiple instances of the Curator service can be deployed, and, can be on different machines.

Further, different clusters of Zoom servers can use a different Curator service. This is especially useful when the clusters are geographically separated, and any search speed benefits may be overwhelmed by the time taken in network communication. It is also possible to set up some servers to use Curator, while others don’t use any Curator service. Similarly, only some Zoom servers could be set up to provide indexing data to Curator, while others still use Curator for searching.

Due to all this flexibility in setup, more care needs to be taken during configuration, to ensure that the setup design matches the expectation from the system.

 

First Time Setup till Zoom 7.2

  1. Stop the Curator Service that is to be setup.
  2. Select any one Zoom Server for performing the initial setup. This should preferably be the highest-priority server of the cluster designated for that Curator Server.
    • Zoom Servers could be divided into groups or clusters for each Curator Server with some of the following guiding principles:
      • Geographically distant Zoom Servers could be grouped separately.
      • Independently balance the required level of fault-tolerance or availability of the Curator Service, with the number of server machines required for it. The Curator Service could be treated as a less essential service, and hence be deployed on a fewer number of machines.
      • The Curator Service could also be associated one-to-one with every required Zoom Server. This will be similar to a non-HADR Curator setup, thus simplifying management.
  3. On this selected Zoom Server, set up the Curator by directly editing the server.xml in XML format, as described below.
    • Open the <ZOOM_INSTALL_DIR>/conf/server.xml of the Zoom Server in a text editor.
    • In the editor, locate the ftsSpec section. Use the XML field reference for additional details.
    • Set the host tag value to the Curator Service machine’s hostname or IP.
      e.g. <host>zm04.company.local<host>
    • Set the solrDataDir tag value to the Curator Service’s database directory; see the non-HADR configuration post for a detailed description.
    • Set the values of the sub-section hadrServers.
      • List each Zoom Server which can be accessed by the Curator Service for indexing.
      • Typically, every Zoom Server within the cluster for the Curator Server would get listed. Possible reasons for exclusion may be:
        • A Zoom Server dedicated to Zoom users alone; no data requests from Curator.
        • A Zoom Server deployed on a machine with very limited resources, which is designated only as an emergency backup server.
      • It is recommended to list these Zoom Servers in decreasing order of their HADR priority.
    • Set any other fields, as may be required, such as:
    • Save the edited file.
  4. Copy the above configured server.xml‘s ftsSpec section to the Curator Server’s <ZOOM_INSTALL_DIR>/conf/server.xml, in case it is deployed in a different location than the Zoom Server.
    1. Copy just the ftsSpec section of the server.xml to the other Zoom Servers of the same cluster, replacing any pre-existing ftsSpec in their server.xml.
  5. Restart all Zoom Services of that cluster.
  6. Start the Curator Service.
 

First Time Setup from Zoom 7.3 onwards

  1. Start the Curator Service that is to be setup.
  2. Select any one Zoom Server for performing the initial setup. This should preferably be the highest-priority server of the cluster designated for that Curator Server.
    • Zoom Servers could be divided into groups or clusters for each Curator Server with some of the following guiding principles:
      • Geographically distant Zoom Servers could be grouped separately.
      • Independently balance the required level of fault-tolerance or availability of the Curator Service, with the number of server machines required for it. The Curator Service could be treated as a less essential service, and hence be deployed on a fewer number of machines.
      • The Curator Service could also be associated one-to-one with every required Zoom Server. This will be similar to a non-HADR Curator setup, thus simplifying management.
  3. On this selected Zoom Server, set up the Curator by logging into the Web Management Console as shown in Curator Configuration (Zoom 7.3+) .
    • Add the Curator Server by clicking Add New Curator on the Curator Configuration page in the Web Management Console.
    • Set the values for Content Search, Non Content Search, Audit Content Search and choose Curator Servers for Audit and Search.
    • On the Curator Configuration page, choose this Curator Server and set values under the Curator Settings, Auto Restart, Zoom Server, Preview Server, Content Index, Non Content Index, and Audit Settings tab.
      • On the Curator Settings tab, set the Host to Curator Server’s hostname or IP.
      • Set Solr Data Directory to the Curator Server’s database directory.
      • On the Zoom Server tab, make sure that you add all Zoom Servers that this Curator should connect with and leave out those Zoom Servers that are not needed. Possible reasons for exclusion may be:
        • A Zoom Server dedicated to Zoom users alone; no data requests from Curator.
        • A Zoom Server deployed on a machine with very limited resources, which is designated as an emergency backup server only.
      • On the Preview Server tab, specify at least one Preview Server if you want to set up content indexing.
      • Specify values for Content and Non Content Indexes as required.
      • Also, set up other values like for Auto Restart and Audit Settings.
    • Save these values so the changes can take effect.
  4. Restart all Zoom Services of that cluster.
 

Suggested order to start or stop services

For the smooth functioning of the Curator Service, the following order is prescribed for starting and stopping the various Zoom services.

This is not essential for Curator functions.

This is only to prevent receiving warning log messages etc. about the unavailability of Zoom or Preview servers during planned events such as performing maintenance or changing configurations.

Starting order

  1. Start the Zoom service for all the servers of that HADR cluster.
  2. Start the Preview service for all the servers of that HADR cluster.
  3. Start the Curator service for all the servers of that HADR cluster.

Stopping order

  1. Stop the Curator service for all the servers of that HADR cluster.
  2. Stop the Preview service for all the servers of that HADR cluster.
  3. Stop the Zoom service for all the servers of that HADR cluster.
Whenever the Curator service starts, it will try to communicate with the first Zoom server in the list of hadrServers of the Curator config. If for any reason Curator fails to connect with that Zoom server, then similar attempts are made to connect with the other Zoom servers in the listed order; until there is a successful connection, or it fails for all the listed Zoom servers in that Curator’s cluster.