Agent Client Collector installation

  • Release version: Australia
  • Updated March 12, 2026
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    Summary of Agent Client Collector installation

    The Agent Client Collector (ACC) can be installed on any supported host machine to enable data collection by connecting to a MID Server over HTTP/S. The connection remains active, with each MID Server capable of managing multiple agents, while each agent connects to a single MID Server at a time and can switch for failover. ACC supports domain separation, assigning the domain of agents and their configuration items based on the MID Server domain. Secure authentication between the agent and MID Web Server is done via manual mTLS.

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    Key Features

    • Scalability: A single MID Server’s agent capacity depends on its memory allocation, with default settings supporting thousands of agents. For example, a 1 GiB MID Server supports 700 agents, and an 8 GiB MID Server supports up to 8,000. Multiple MID Servers can be deployed for scale-out (e.g., 5 MID Servers with 8 GiB each can handle 40,000 agents).
    • Operating system permissions: ACC installs with Ruby 3.3.2 and a local user account "servicenow" with basic permissions. Specific OS permissions are required for advanced features like serial number retrieval, running processes, TCP mapping, and package self-upgrade, varying between Windows, Linux, and macOS.
    • Agent lifecycle management: Reinstalling an agent creates a duplicate record that must be manually deleted. Agents with "Down" or "Disconnected" status are auto-deleted after 30 days by default, configurable via the Autoflush form.
    • Golden image mode: Supports cloning of additional instances, with configuration prerequisites and modular plugin structures by OS.
    • Air-gapped environment support: ACC can be configured for isolated environments, with detailed guidance available in the Now Support Knowledge Base.

    Practical Considerations for ServiceNow Customers

    • Plan MID Server memory allocation according to expected agent volumes to optimize performance and scalability.
    • Ensure appropriate OS permissions are granted to the "servicenow" user to enable all desired agent capabilities.
    • Use manual mTLS for secure communication between agents and MID Web Servers.
    • Manage agent records carefully to avoid duplicates when reinstalling agents, and configure auto-deletion policies as needed.
    • Leverage golden image mode for efficient deployment of multiple agent instances.
    • Refer to platform-specific installation guides for Windows, Linux, and macOS to ensure correct setup and configuration.

    You can install the Agent Client Collector on any supported host machine. The Agent Client Collector connects to a MID Server using the HTTP/S protocol, and the connection remains active after being established. One MID Server may handle several agents simultaneously, while a single agent works with one MID Server at a time and switches to a different MID Server when necessary to provide failover protection.

    When an agent's IP address changes, it selects a MID Server to connect to based on the agent's MID Server list.

    The maximum number of agents that can be connected to a single MID Server is configurable in the sn_agent.mid.max_allowed_agents MID Server property. The default value is 4,000.

    For ACC-VC, a default 1 GiB MID Server can support 700 agents concurrently. An 8 GiB configuration for a MID Server can support 8,000 agents concurrently. You can also scale out. For example, 5 MID Servers with 8 GiB of heap size can handle up to 40k agents.

    Agent Client Collector is installed with ruby version 3.3.2.

    The default user account is a local user called servicenow. This user has basic level permissions.

    The following table describes the permissions required to work with various features associated with the agent, per OS. An asterisk (*) indicates that no special permissions are required.
    Table 1. Agent on Endpoints Deployment
    Feature Windows Linux macOS
    Basic inventory * * *
    Serial number(s) *

    sudo

    dmidecode

    		 *
    Running processes Debug programs * *
    Mapping TCP connections to running processes * sudo ss *
    Storage devices LOCAL SYSTEM * *
    Logged-in users LOCAL SYSTEM * *
    Package self-upgrade LOCAL SYSTEM sudo rpm/dpkg Not supported

    If you completely reinstall the agent on a single host server, a second agent record registers on the instance. Delete the original agent on the Agent Client Collectors page (All > Agent Client Collector > Agents).

    Agents whose Status = Down or Disconnected which haven't been deleted are deleted automatically after 30 days. You can modify this setting on the Autoflush form page (see Autoflush form).

    Use the Manual Transport Layer Security protocol (mTLS) for secure authentication between your MID Web Server and the agent (the client). For details, see Connect the agent to the MID Server using mTLS.

    For details on using Agent Client Collector in an air-gapped environment, see the Agent Client Collector Framework Air Gapped Configuration Item Management Solution [KB1585753] article in the Now Support Knowledge Base.

    Golden image mode enables cloning of additional instances. Setting golden image mode is described in the installation procedure prerequisites for each OS. For information on the structure and modularity of the golden image plugin by operating system, see Golden image structure and modularity.

    Agent Client Collector supports domain separation. The domain of the agent and the CIs it creates is determined by the domain of the MID Server that the agent is connected to. The user's domain must be the lowest domain level (known as a leaf domain) to enable creating a Websocket endpoint extension for the MID Server.