Available Control Center Information

The pages of the HiveMQ Control Center have a consistent look and feel. The top of each page provides the title of the page, the username of the person who is currently logged in, and a Log out option.

Starting with HiveMQ 4.32, you can access an open beta version of the newly designed HiveMQ Control Center v2 from the current Control Center main navigation or with the URL http://<host>:8080/v2/.
During the beta phase, you can explore and test Control Center v2 alongside the current Control Center version (v1).
However, although the new interface introduces many great features, v2 is not yet intended for use in production environments.
In the coming months, we will continue to enhance the functionality and usability of the interface with new features and eagerly encourage your feedback.

The version number of the HiveMQ version that you are currently running appears below the side navigation. Please keep the version information on hand when you contact our support.

To view more information about an item in the control center, select the question mark (?) next to the desired item.

By default, the control center contains the following views:

Page Description

Dashboard

Shows the current status of HiveMQ and each node in the HiveMQ cluster (including notifications, license information, and key metrics)

Clients

Overview of all available clients with links to further client details

Shared Subscriptions

Overview of all available shared subscriptions with links to further shared subscription details

Extension Consumers

Overview of all extension consumers with current queue level per topic for each.

Retained Messages

Overview of all available retained messages with links to further retained message details

Data Hub

Overview of all available modules and policies with visualizations of current data pipeline quality and an interactive user interface for management of your Data Hub deployment

License

Overview of all active and inactive HiveMQ licenses that are associated with the HiveMQ installation with links to further active license details

Trace Recordings

Overview of all current trace recordings, with links to create and manage trace recordings

Dropped Messages

Detailed information on dropped messages

Backup

Overview of all stored backups with actions to create a backup or restore from an existing backup.

Support

Opens a page where you can generate a diagnostic archive that collects all relevant information about the current state of your HiveMQ cluster.

HiveMQ Enterprise Extensions add additional pages and features to your control center. For more information, see HiveMQ Enterprise Extensions.

Dashboard

The dashboard of the control center provides a clear overview of the current state of HiveMQ and your entire cluster. This information gives you immediate insights on key issues and allows you to quickly check the state of each available cluster node.

Overview of the Dashboard page

At the top of the dashboard, an overview bar shows you key metrics such as the current usage and throughput of the cluster at a glance. For more information on a specific metric, select the metric in the overview bar to open a detail view.

Notifications

The Notifications area of your dashboard displays useful information and alerts. For example, information if a client drops a message. An alert does not necessarily mean that something is wrong. However, an alert can indicate that an unwanted behaviour has occurred.

Example notification area with connection-limit alert:

Dropped message notifiaction

Example notification area with no connected clients that displays useful links:

No client connected

Active License Information

The Active License Information card on your control center dashboard displays key information about the HiveMQ license that is currently in use.

For detailed information on all licenses associated with your HiveMQ installation and the features your active license enables, open the License view from the main navigation. For more information, see Licenses.
License information
Item Description

Connections

The number of client connections currently in use and the maximum number of concurrent connections the active license allows.

CPU Cores

The number of CPU cores currently in use and the maximum number of cores the active license supports.

License Type

The validity status and the type of license (for example, Trial License or valid, commercial license).

Edition

The variant for which the license is valid. HiveMQ. For more information, see HiveMQ Editions.

Filename

The filename of the license that is currently in use.

License Expiration Date

Expiration date of the license that is currently in use.

Based on the maximum number CPU cores the active licence allows, the cores status bar shows the current CPU capacity of the selected node:

A green bar indicates that less than 75% of the CPU cores that the active license allows are in use.

Green bar

A yellow bar indicates that more than 75% of the CPU cores that the active license allows are in use.

Yellow bar

A red bar indicates that more than 90% of the CPU cores that the active license allows are in use.

Red bar
If no valid license is available in the licence folder of your HiveMQ installation, a trial license is used automatically. Trial licenses are limited to 25 concurrent connections and not intended for production use. For more information, see Trial license.
Trial license information

Cluster Node Statistics

The statistics area of your control center dashboard shows information for each individual node in your cluster. Nodes are identified with a randomly-generated cluster node ID. An asterisk (*) after the cluster node ID indicates the node that is used for the HiveMQ control-center connection.

To view statistics for a node, select the node ID.

Cluster node status of the first node

The following metrics are available for each node in the cluster:

Metric Description

JVM Memory

The amount of the JVM-memory heap space that is in use and the total amount that is available

Disk Space

The amount of disk space where the HiveMQ data folder is located that is in use and the total amount that is available

Running Since

The startup time of the selected node

Total Inbound Publish Messages

The total number of inbound publish messages

Total Outbound Publish Messages

The total number of outbound publish messages

HiveMQ Version

The HiveMQ version the selected node runs

Hostname

The network hostname of the selected node

Total Inbound Volume

The total volume of inbound MQTT messages in bytes

Total Outbound Volume

The total volume of outbound MQTT messages in bytes

Inbound Network Traffic

The amount of inbound MQTT messages per second

Outbound Network Traffic

The amount of outbound MQTT messages per second

Clients

With millions of connected clients, keeping track of specific clients can become a challenge. The HiveMQ Control Center provides tools to list, view, and manage all the MQTT clients known to HiveMQ. Information about subscriptions, connection status, TLS, and more offer detailed insights into every client.

Clients Overview

HiveMQ uses cluster-wide snapshots to display all available MQTT sessions. To view information for the MQTT sessions that are currently available, you need to create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all available MQTT sessions.

To create a snapshot, select Refresh Snapshot. Based on the number of MQTT sessions on your cluster, the refresh process can take a few moments. When the process finishes, an overview table of the current clients displays.

To change the order in which clients are sorted on the overview, click the column header.

To filter clients by client ID, username, or IP address, select the desired option from the drop-down menus in the Clean Session and Connected columns.

The sorting options and filters that you apply to the Clients overview table are stored until you log out.
If you leave the Clients overview and return later, the filters and sorting options that you applied to the overview table remain active.

Snapshots do not update automatically. To manually refresh the data that is shown in the Clients overview, select Refresh Snapshot.
Clients Overview
Column Description

Client ID

The unique identifier of the client.

Connected

Shows whether a client is currently connected.

  • All: Displays connected and disconnected clients.

  • Yes: Displays only connected clients.

  • No: Displays only disconnected clients.

Queue Size

The current and maximum number of messages in the message queue of the client.

  • Current: Shows the number of messages in the message queue of the client at the time that the snapshot is taken.

  • Maximum: Shows the queue size limit that is set for the client.

Username

The username of the client. When blank, no username was set.

IP Address

The IP address of the client.

To open the Client Detail page of a client and access additional client actions, select the identifier of the client on the overview.

Client Details

This page displays when you select a client identifier in the Clients overview.
The client identifier and the connection status of the client for which details are shown appears at the top of the page.

The Prev and Next options on your client detail pages allow you to easily navigate through the clients on your Clients overview.

Prev displays information for the client one row before the currently selected entry in the overview table.
Next displays information for the client one row after the currently selected entry in the overview table.

If you change the sorting order or filters of your Clients overview table, the changes that you make are immediately reflected in the Prev and Next information.

Session information

To view more information about each item that is shown on the details page, select the question mark next to the desired column.

For example, more information on sessions:

Help session

Session

When a client connects to an MQTT broker, the client subscribes to each topic for which it wants to receive messages from the broker. If the client connects to the MQTT broker with a non-persistent session, the broker does not save any subscription information when the client disconnects. In a non-persistent session, each time the client reconnects to the MQTT broker, the client must resubscribe to each topic of interest.

In a persistent session, the MQTT broker saves all relevant client information. The session is identified by the client ID that the client provides during connection establishment.

The following information is stored in the session:

Item Description

Client ID

Identifies the MQTT client within an MQTT broker or MQTT broker cluster.

Clean Session

If set to true, sessions are stateless. Information such as unfinished message flows and subscriptions is lost on disconnect.

Connected/Disconnected Since

Date and time when the client last established or lost connection with the broker.

Offline Session TTL

Shows the Time to live (TTL) limit that is set for the client. The TTL timer starts when the client disconnects. If the client does not reconnect within the predefined period, the session is invalidated and the broker deletes all client information (including subscriptions and queued messages). The TTL does not apply while the client is connected

Offline Message Queue Size

When a client with a persistent session is offline (session-expiry-interval > 0), this entry shows the current number of QoS 1 and 2 messages that are queued for the client.

Connection

A central principle of MQTT is the decoupling of communication partners. Decoupling means that the clients that send and receive the MQTT messages only connect to the MQTT broker. One MQTT client never connects directly to another MQTT client.
To establish an MQTT connection, the client sends a CONNECT message to the HiveMQ broker and the HiveMQ broker replies to the client with a CONNACK message. The protocol the HiveMQ broker uses for the connection is TCP.

The Client Detail page provides the following connection information for the client that is currently selected on the overview:

Item Description

Client IP

The network IP address of the client. The address can be IPv4 or IPv6.

Username

Username of the selected client.

Password

The password of the selected connected client, if present. By default, the password is not stored in memory and this value is set to Was Present.

MQTT Version

The version number of the MQTT protocol that is used for the connection.

Keep-Alive

Interval during which the client is required to send control packets. If the client fails to send a packet within the defined interval, the broker disconnects the client.

Listener

The type of listener and the address the client uses to connect to the broker.

Connected Node

The unique identifier of the cluster node to which the client is connected.

TLS

Transport Layer Security (TLS) is a cryptographic protocol that allows secure and encrypted communication between a client application and a server at the transport layer. If a TLS listener is enabled in HiveMQ, each client connection for that listener is encrypted and secured by TLS. It is also possible to use an X.509 certificate to authenticate the client. Authentication with an X.509 certificate is an alternative to the username/password authentication.
The TLS column of the Client Details page shows the most important aspects of the TLS that the selected client uses.

For more information, see Transport Layer Security (TLS).

Item Description

TLS Version

The version of the TLS protocol that is used.

Cipher Suite

The cipher suite that is used for the encryption of the connection. The cipher suite is a combination of authentication, encryption, message authentication code (MAC), and key exchange algorithms.
To view more information for the cipher suite that the TLS of the selected client uses, select show more.

X.509 client certificate

The X.509 certificate of the client.
To view more information for the X.509 certificate of the selected client, select show certificate.

Information from the X.509 certificate of the client is grouped into two sections:

General
Item Description

Common Name

Common name of the owner of the certificate

Organization

Organization of the subject

Organizational Unit

Organizational unit of the subject

Serial

Serial number of the certificate

x.509 Version

Version of the certificate

Valid From

Timestamp from which the certificate is valid

Valid Until

Timestamp until which the certificate is valid

Country

Country of the subject

State

State of the subject

Extensions
Item Description

Subject Key Identifier

Fingerprint of the key

Last Will

Last will is a feature that is used when a client disconnects ungracefully. The last will of a client publishes a last-will message to a specific topic with a specified Quality of Service upon an ungraceful disconnection.

For more information, see MQTT Essentials: Last Will and Testament.

When a client connects to the broker, the client can specify a last will message. The will message is a normal MQTT message with a topic, QoS, retained flag, and payload.

Item Description

Will Topic

The topic on which the last will payload is published.

Will QoS

The Quality of Service level with which the last will message is published.

Will Retained

Indicates whether the last will message is a retained message.

Will Payload

The payload that is published when the last will is triggered.

To view or download the payload of the last will message, select the show payload next to the Will Payload size of the desired payload. The LWT Payload window for the selected last will message opens:

In the LWT Payload window, you can select how the payload is presented. It is possible to show the payload as a UTF-8 string, hexadecimal value, or binary value. The Content area of the window shows a preview of the payload in the selected format. If desired, you can copy the payload content to your clipboard or download the content as a .dat file.

Restrictions

To ensure a trouble-free communication process, some restrictions have to be observed.

Item Description

Maximum Bytes per Second Inbound

The maximum bytes per second this client can receive from the broker.

Maximum Bytes per Second Outbound

The maximum bytes per second this client can send to the broker.

Maximum Message Size

The maximum payload size in bytes that MQTT PUBLISH messages sent by this client.

Maximum Message Queue Size

The maximum number of messages that the client can store in its message queue on the broker.

Drop Strategy for Queued Messages

Defines how the broker manages messages when the message queue limit is reached.

  • Discard: Once the queue size limit is reached, new messages that arrive are dropped.

  • Discard Oldest: Once the queue size limit is reached, the oldest message in the queue is dropped when a new message arrives.

Proxy Protocol

HiveMQ supports the PROXY protocol for all listener types. The PROXY protocol is a TCP-based protocol that provides a convenient way to transport client details such as the IP address and port over multiple proxies. If you run your HiveMQ brokers behind a load balancer that proxies the TCP connection, PROXY protocol is helpful. Otherwise, useful client information such as the IP address, port, and SSL information is lost since the broker only recognizes the TCP connection of the load balancer (not of the original client).

For more information, see PROXY protocol.

Item Description

Source IP/Port

The source (origin) IP address and port of the proxy.

Destination IP/Port

The destination IP address and port of the proxy.

Additional TLVs

The type-length values (TLVs) are key-value pairs that provide optional information such as the SSL X.509 client certificate common names or the TLS version the client used to connect to the proxy.

Subscriptions

The Client Detail page provides information on the subscriptions and shared subscriptions of each client. On the detail page, you can add and remove subscription and shared subscription topics for the selected client.

The Subscriptions area shows all topics to which the selected client subscribes. Each subscription consists of a topic and the Quality of Service (QoS) level for the subscription. There are three QoS levels:

  • 0 - At Most Once: Messages are delivered one time or not at all.

  • 1 - At Least Once: Messages are delivered at least once and can be delivered multiple times.

  • 2 - Exactly Once: Message delivery is guaranteed with no duplicates.

Subscription information

Shared Subscriptions

The ability to use shared subscriptions with all versions of MQTT is a unique feature of HiveMQ. Shared subscriptions allow MQTT clients to share a subscription to the same topic on the broker. In a "standard" MQTT subscription, each client receives a copy of the message. Shared subscriptions distribute the message load of the subscribed topic equally among each client in the shared group. HiveMQ delivers the message to only one subscriber in the group that share the subscription. This mechanism is sometimes called client load balancing.

Shared-subscription information

The shared subscription area shows the topic, shared group name, and QoS level of all shared subscriptions of the selected client.

  • To view the shared subscriptions details of a specific shared subscription, select the subscription topic.

  • To unsubscribe the client from a shared subscription, select the x symbol next to the subscription you wish to end.

  • To add new shared subscriptions to the client, enter the topic, shared group, and quality of service level for the desired subscription.

Session Attributes

Session attributes are a convenient way to add additional key-value data to the session of an MQTT client. The Session Attributes area of the Client Detail lists all available session attributes for the selected client. Use the concise control center view to easily review and verify the session attributes of your clients.

Each session attribute contains a key and a value. The Sessions Attributes area can display a maximum of 100 entries.

Session Attributes
Item Description

key

The key of the session attribute. To view, download, or copy the information stored in the key, select show key. In the information dialog that opens you can select how the information is shown.

value

The value of the session attribute. If the value contains only ASCII characters, an ASCII string displays. If the value contains non-ASCII characters, the size of the value in bytes is shown. To view, download, or copy the information stored in the value, select show value. In the information dialog that opens you can select how the information is shown.

When you select show key or show value for the key or value of a session attribute, you can select how the data is presented. It is possible to show the data as a UTF-8 string, hexadecimal value, or binary value. The Content area of the information dialog shows a preview of the payload in the selected format. If desired, you can copy the session attribute content to your clipboard or download the content as a .dat file.

Show Value
Figure 1. Example Show Value information dialog

Event History

HiveMQ deployments are built to handle millions of clients and massive amounts of data. The Event History area gives you access to all previous events associated with the selected client. The historical view of client events makes it easier to monitor and analyze the behavior of a specific client over time and diagnose problems.

You can use the event history integration in the HiveMQ enterprise extension SDK to trigger actions that are based on the event history of a client or to export historical data for further analysis in a third-party tool.
Client Event History
Item Description

Timestamp

The UTC timestamp when the event occurred.

Event

Shows the type of event that was captured. The following options are available:

  • Successful Connection: Client connected successfully.

  • Failed Connection: Client did not connect successfully.

  • Graceful Disconnection: Client sent a DISCONNECT package.

  • Ungraceful Disconnection: Client did not send a DISCONNECT package.

  • Server Disconnection: HiveMQ disconnected the client.

  • Session Removed: HiveMQ ended the client session.

  • Overload Protection On: Activation of client overload protection.

  • Overload Protection Off: Deactivation of client overload protection.

Details

Shows additional information for the event:

  • Successful connection details: Node ID, clean start flag, and session present flag.

  • Failed connection details: Node ID and optional reason code.

  • Graceful disconnection details: Node ID, session expiry interval, and reason code.

  • Ungraceful disconnection details: Node ID and session expiry interval.

  • Server disconnection details: Node ID, session expiry interval, and optional reason code.

  • Session removal details: UNIX timestamp of disconnect and session expiry interval in seconds.
    NOTE: No additional information is listed for the activation and deactivation of overload protection.

Events can be sorted and filtered by time interval, event type, and event details.

To change the order in which events are sorted, click the column header.

To filter events by type or details, enter your filter criteria in the Event and Details columns. To filter for events in a specific timeframe, use the calendar option in the Timestamp column to define your desired time period.

The Event History area can display a maximum of 100,000 entries. If the number of events exceeds the display limit, reduce the selected time interval.

Shared Subscriptions

Shared subscriptions are an effective way to distribute messages across different MQTT subscribers with standard MQTT mechanisms. This type of subscription lets you add MQTT-client load balancing without any proprietary additions to your MQTT clients. For more information, see Shared Subscriptions.
The HiveMQ Control Center provides all the information you need to efficiently manage all your shared subscriptions.

Shared subscriptions can dramatically alleviate cluster traffic and latency for high-scalability deployments. The load-balancing abilities of shared subscriptions are especially useful for backend systems or high-traffic topics that can quickly overwhelm a single MQTT client. Shared subscriptions are the recommended way to connect horizontally scaling backend systems with HiveMQ. For more information see, MQTT Client Load Balancing with Shared Subscriptions.

Shared Subscription Overview

The Shared Subscriptions overview provides basic information for each shared subscription on your HiveMQ cluster.

HiveMQ uses cluster-wide snapshots to display all available shared subscriptions. To view information for the shared subscriptions that are currently available, you need to create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all of the available MQTT sessions.

To create a snapshot, select Refresh Snapshot. Based on the number of shared subscriptions on your cluster, the refresh process can take a few moments. When the process finishes, an overview table of your current shared subscriptions displays.

To change the order in which the data is sorted on the overview, click the column header. To filter for a specific shared subscription, enter the desired topic in the Topic field.

The sorting options and filters that you apply to the overview table are stored until you log out. If you leave the overview and return later, the filters and sorting options that you applied remain active.

Snapshots do not update automatically. To manually refresh the data that is shown in the Shared Subscriptions overview, select Refresh Snapshot.
Shared Subscription Overview
Column Description

Topic

The complete topic of the shared subscription including the shared name.

Queue Size

The current number of messages that are queued for the shared subscription.

Shared Subscriptions Details

This page displays when you select a topic in the Shared Subscriptions overview.
The shared subscription topic for which details are shown appears at the top of the page.

To view more information about an item on the details page, click the question mark next to the desired column.

For example, more information about shared subscription client details:

Help Clients

The Prev and Next options on your detail pages allow you to easily navigate through entries and respect the filters and sorting options that you apply to the overview table.

Prev: Displays information for the subscription one row before the currently selected entry in the overview table.
Next: Displays information for the subscription one row after the currently selected entry in the overview table.

When you change the sorting order or filters of your Shared Subscription overview, your changes are immediately reflected in the Prev and Next information of your detailed view.

Shared Subscription Details
Column Description

General

Provides basic information on the selected shared subscription:

  • Topic: The specific topic subscriptions of the shared subscription (can include wildcards).

  • Shared Name: The shared name of the shared subscription group.

Queue

The number of messages that are currently in the queue of the shared subscription.

Restrictions

Shows the limits that apply to the shared subscription:

  • Maximum Message Queue Size: The maximum number of messages the shared subscription can store in its message queue.

  • Drop Strategy for Queued Messages: Defines how the broker manages messages when the limit for the message queue is reached, There are two options:

    • Discard: The broker drops new messages that arrive after the queue is full.

    • Discard Oldest: When the queue is full, the broker removes the oldest message in the queue and adds the new message.

Clients

Lists information for each client that shares the subscription. The Clients area can display a maximum of 100 entries:

  • Client ID: The unique identifier of the MQTT client within the MQTT broker or MQTT broker cluster.

  • QoS: The quality of service level of the shared subscription. Two levels are supported:

    • 0 - At Most Once: Messages are delivered one time or not at all.

    • 1 - At Least Once: Messages are delivered at least once and can be delivered multiple times.

In the Clients area, a green icon indicates that the client is currently connected. A red icon indicates that the client is disconnected. Connected clients are listed first in the table.

Extension Consumers

The Consumer Service of the HiveMQ Enterprise Extension SDK allows you to register and unregister message consumers. Message consumers can be used to react quickly to incoming publishes on a specific set of topics and further process the consumed messages to meet your business needs. For example, the HiveMQ Enterprise Extension for Kafka uses the Consumer Service to transform MQTT publish messages into Kafka records and then write the records into a Kafka system. For more information, see Consumer Service.

The Extension Consumers overview gives you all the information you need to analyze and adjust the behavior of the extension consumers in your HiveMQ cluster.

HiveMQ uses cluster-wide snapshots to display all available extension consumers. To access up-to-date information on the extension consumers that are currently active, you need to create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all available MQTT sessions.

To create a snapshot, select Refresh Snapshot. Depending on the number of extension consumers in your cluster, the refresh process can take a few moments to complete. When the process finishes, an overview table of your current extension consumers displays.

Snapshots do not update automatically. To manually refresh the data that is shown in the Extension Consumers overview, select Refresh Snapshot.
Extension Consumers Overview
Column Description

Consumer ID

The unique ID of the consumer.

Topic Filter

The topic filter from which the selected extension consumer consumes messages.

Extension

The name of the extension for which the selected consumer is registered.

Queue Size

The current and maximum number of messages in the message queue of the extension consumer.

  • Current: Shows the number of messages in the message queue of the extension consumer at the time that the snapshot is taken.

  • Maximum: Shows the queue size limit that is set for the extension consumer per topic filter. The default value is 500,000.

To change the order in which the data is sorted on the overview, click the column header. To filter for a specific extension consumer, enter your search criteria in the input field at the top of the column.

The sorting options and filters you apply to the overview table are stored until you log out. If you leave the overview and return later, the filters and sorting options you applied remain active.

Filter the Extension Consumers Entries

Retained Messages

Keeping track of the millions of retained messages that your HiveMQ cluster processes can be a challenge. The HiveMQ Control Center provides the tools you need to manage all the retained messages in your HiveMQ cluster.

Retained Messages Overview

HiveMQ uses cluster-wide snapshots to display all available retained messages. To view information for the retained messages that are currently available, you need to create a fresh snapshot. The HiveMQ snapshot gives you a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all retained messages that are available on your cluster.

To create a snapshot, select Refresh Snapshot. Based on the number of retained messages that are available in your cluster, the refresh process can take a few moments. When the process finishes, an overview table of the retained messages displays.

To change the order in which the data is sorted on the overview, click the column header. To filter the messages that are displayed by topic, enter the desired topic in the input field of the Topic column.

The sorting options and filters that you apply to the retained messages overview table are stored until you log out. If you leave the retained messages overview and return later, the filters and sorting options that you applied to the overview table remain active.

Snapshots do not update automatically. To manually refresh the data that is shown in the retained messages overview, select Refresh Snapshot.
Retained Messages Overview
Column Description

Topic

The topic of the retained message.

Payload Size

The size of the payload of the retained message.

Creation Date

The date and time when the retained message was created.

Retained Message Details

This page displays when you select the topic of a retained message in the Retained Messages overview. The topic of the retained message for which details are shown appears at the top of the page.

Prev and Next options on each detail page allow you to easily navigate through the retained messages that are listed on your retained messages overview table.

Prev displays detailed information for the message one row before the currently selected entry in the overview table.
Next displays detailed information for the message one row after the currently selected entry in the overview table.

If you change the sorting order or filters on the Retained Messages overview table, the changes are immediately reflected in the Prev and Next information.

Retained Message Detail

The Retained Message Detail page provides message information and user property information for the retained message that is currently selected.

To view more information for items shown on the details page, select the question mark next to the desired column.

Message Information

General

Shows basic information about the retained message that is currently selected.

Item Description

Topic

The topic of the retained message.

QoS

The Quality of Service (QoS) level of the retained message. There are three QoS levels:

  • 0 - At Most Once: Messages are delivered one time or not at all.

  • 1 - At Least Once: Messages are delivered at least once and can be delivered multiple times.

  • 2 - Exactly Once: Message delivery is guaranteed with no duplicates.

Payload Size

The amount of data that the payload of the retained message contains in bytes.

NOTE: The payload size does not reflect other data such as user properties or correlation data that the retained message can transmit.

Expiry

Shows when the retained message was created and how long the message is valid.

Item Description

Creation Date

The date and time the retained message was published.

Message Expiry

The message-expiry interval that is set for the retained message. The expiry timer starts at the moment that the retained message is published.

Remaining Time

The time in seconds until the message expires and is deleted from HiveMQ. The time is calculated in seconds at the moment the detail page loads. To recalculate the time until the message expiration, select Refresh Snapshot.

Message Metadata

Shows information that is used in a request/response pattern for the retained message. This information is only available for MQTT 5.

Item Description

Response Topic (optional)

The identifier used to implement a request/response pattern between clients.

Correlation Data (optional)

The data used to match response requests to the correct response messages.

Payload Metadata

Shows information about the type and format of the data in the payload of the retained message. This information is only available in MQTT 5.

Item Description

Content Type (optional)

The UTF-8 encoded strings that describe the content of the retained message payload. For example, text/plain.

Payload Format Indicator (optional)

A value that shows whether the message payload contains UTF-8 encoded character data or unspecified bytes.
Only two values are possible:
- 0 - The payload of the retained message is unspecified bytes.
- 1 - The payload of the retained message is well-formed UTF-8 data.

To view more information on the payload of the retained message, select Show Payload.

User Properties

The User Properties area of the details page shows the name and value of all user properties for the retained message. User properties are defined as part of the sender implementation. The meaning of the user properties is not defined by MQTT.
User properties are only available for MQTT 5.

The User Properties area shows a maximum of 500 properties.

Data Hub in the HiveMQ Control Center

In modern business initiatives, data provides the foundation for making informed and strategic decisions. Data-driven insights can lead to improved products and services, better customer experiences, and more efficient operations. HiveMQ Data Hub gives you the ability to ensure that the data you accept from your data sources has the quality you expect. Data Hub also makes it possible to model how your MQTT clients work with your broker. You can manage Data Hub from the HiveMQ Control Center or with the HiveMQ REST API.

HiveMQ Control Center support for Data Hub simplifies usage for users who prefer graphical user interfaces over command line tools. Our policy creation wizards provide an intuitive way to create new policies with context help and immediate feedback on policy validity. Our well-organized overviews help you efficiently manage your schemas and policies:

Data Hub Views in the HiveMQ Control Center

Dashboard

The Data Hub dashboard provides a clear overview of the current quality of your data pipelines.

Data Hub Dashboard

The visualizations and client list on the dashboard can help you quickly understand the state of your data pipelines and act to resolve issues with problematic clients efficiently:

  • Data Quality Policies: The recent aggregated quality of all data policies on your HiveMQ deployment as indicated by the percentage of successful policies cluster-wide.

  • Data Policies Success / Failed: The current cluster-wide percentages of failed policies and successful policies.

  • Clients with failed policies: A snapshot of all clients that have failed policies with basic information to identify the client and links to the associated policy details.

Table 1. Client list available information and actions
Column Description

Client ID

Displays the client ID of the client that failed the policy.

Failed Policy IDs

Lists all policies that the client failed. To view the details of a policy, select the policy ID. If the policy has been deleted, the ID is not clickable.

First Failed Policy Timestamp

Displays the timestamp when the client sent the first payload that violated a policy.

Last Failed Policy Timestamp

Displays the timestamp when the client sent the latest payload that violated a policy.

Failed Policies

Displays the aggregated number of all failed policies for the client.

Successful Policies

Displays the aggregated number of all successful policies for the client.

The charts on the dashboard automatically update every 10 seconds. To manually refresh the data shown in the list of failed clients, select Refresh Data. By default, the client list is sorted with the most recent entries at the top. To clear the data that is shown in the list, select Delete Data.

For detailed information on Data Hub features and configuration options, see HiveMQ Data Hub.

Modules Overview

HiveMQ Modules for Data Hub offer easy-to-use functionality that can be quickly accessed from the HiveMQ Control Center. Modules can be used to define fine-grained and fully flexible Data Hub policies or to utilize pre-defined modules that implement pre-defined functionality.

The HiveMQ Modules for Data Hub feature utilizes transformation scripts that are not yet fully supported for Linux Arm64.
As a result, you cannot use the Data Hub Modules feature on Linux Arm64.

The Modules overview provides basic information for each module on your HiveMQ cluster.

To update information on the overview to the most current stand, select Refresh Modules.
When you filter or sort information on the overview, the overview automatically refreshes.

Modules Overview
Since Data Hub supports module versioning, each module can have multiple versions.
To enhance readability, the Modules overview displays only the latest version of the module.
Use the Select Version option to switch to a different version of the module.

For more information on the use of modules in HiveMQ Data Hub, see HiveMQ Modules for Data Hub.

Modules Tab

The Modules tab lists all modules that are available on your system.

Currently, three HiveMQ Modules for Data Hub are provided by default:

  • hivemq-duplicate-message

  • hivemq-sparkplug

  • hivemq-validate-simple-jason

Table 2. Available module information and actions
Entry Description

Module

The name of the module.

Latest Version

The version number of the most recent update of the module. To facilitate module management, HiveMQ automatically increments the module version each time a module updated is posted.

Maintainer

The entity responsible for the management of the module.

Description

A brief summary of the capabilities and purpose of the module.

Selected Version

The available versions to select from to create a new instance of a module. Expand the list to view all versions of the module. By default, the latest module version is selected.

Create Instance

Opens a page on which you can configure and add a new instance of the selected module. You can create as many instances of a module as your use case requires.

Instances Tab

The Instances tab lists all the module instances created on the system and provides access to further actions.

Table 3. Available instance information and actions
Entry Description

Module

The name of the module from which th instantiated module was created.

ID

The unique identifier of the instance. You can use the automatically generated ID or enter a custom identifier of your choice. The ID must begin with a letter and can only contain lowercase letters, uppercase letters, numbers, periods, hyphens, and underscores.

Version

The version of the module from which the instance is created.

Created At

The ISO 8601 format timestamp when the instance is created.

Actions

Provides options to view configuration details or disable the selected module instance.

Schemas Overview

Schemas are an essential part of data policies. Your Data Hub schemas define the rules and constraints that MQTT payload data must adhere to. These constraints help to ensure data quality and to maintain the integrity of your HiveMQ deployment.
Data Hub currently supports JSON Schemas and Protobuf.
For more information on the use of schemas in HiveMQ Data Hub, see Schemas.

The Schemas overview provides basic information for each schema on your HiveMQ cluster.

HiveMQ uses cluster-wide snapshots to display all available schemas. To view information for the schemas that are currently available, you need to create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all available schemas.

To take a new snapshot, select Refresh Snapshot.
When you filter or sort the information on the overview, the snapshot automatically updates.

Schemas Overview
Since Data Hub supports schema versioning, each schema can have multiple versions.
To enhance readability, the Schemas overview displays only the latest version of the schema.
Table 4. Schemas overview available information and actions
Column Description

Schema ID

Shows the schema identifier. To view the schema details, select the desired schema in the table.

Version

The latest version number of the schema.

Type

Filters for JSON Schema or Protobuf.

Last Updated

The time when the schema has been updated latest

Action

Depending on your permissions, icons are shown to view, edit, or download the data policy.

To create a new schema, select Add New Schema. For more information see, Schema Detail - Create Schema.

To view and manage an existing schema, select the name of the schema in the Schemas overview. For more information, see Schema Detail -View Schema Details

Schema Detail - Create Schema

The Schema Detail - Create Schema page displays when you select the Add New Schema option on the Schemas overview. Here, you can create and save new schemas:

Schema Detail - Create
All Data Hub detail pages include extensive context-sensitive help. To open additional information for a particular item, click the ? icon.
Schema Detail - Create Schema - JSON:

Schema Detail - Create JSON Schema

The options and help text automatically adjust based on your configuration choices. For example, the creation of a JSON Schema requires a Schema ID and a Schema Definition and the creation of a Protobuf schema requires a Schema ID, Schema Definition, and a Message Type.

Schema Detail - Create Schema - Protobuf :

Data Hub Schemas Protobuf

For detailed information on the configuration and use of schemas in Data Hub, see Data Hub Schemas.

Schema Detail -View Schema Details

The Schema Detail - for Schema ID page displays when you select an existing schema on the Schemas overview. Here, you can add new schema versions, download schema versions, or delete all versions of the selected schema:

Schema Detail -View
It is only possible to delete schemas and schema versions that are not referenced in a policy. If an existing policy references the schema, you must delete the policy before you delete the schema.

Scripts Overview

IoT devices can send a wide range of data sets. As a result, the MQTT data you receive often contains diverse data points, formats, and units. Data transformation scripting with JavaScript can help you bring diverse data into a common format that an application can understand and process.

The HiveMQ 4.23 platform release introduced the Early Access Preview (EAP) version of the new Data Hub data transformation functionality. Our transformations feature gives you the ability to add custom JavaScript-based transformation functions to Data Hub data policies. For more information on the use of JavaScript scripting in Data Hub see, Transformations.

HiveMQ uses cluster-wide snapshots to display all available scripts. To view information for the scripts that are currently available, create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all scripts in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all available scripts.

To take a new snapshot, select Refresh Snapshot.
When you filter or sort the information on the overview, the snapshot automatically updates.

Data Hub Scripts Overview
Table 5. Scripts overview available information and actions
Column Description

Script ID

Shows the script identifier. To view the script details, select the desired script in the table.

Version

The latest version number of the script.

Description

Information about the purpose of the script.

Last Updated

The time when the script was most recently updated.

Action

Depending on your permissions, icons are shown to view, edit, or download the script.

To create a new script, select Add New Script. For more information see, Script Detail - Create Script.

To view and manage an existing schema, select the name of the schema in the Script overview. For more information, see Script Detail -View Script Details

Script Detail - Create Script

The Script Detail - Create Script page displays when you select the Add New Script option on the Script overview. Here, you can create and save new scripts:

Script Detail - Create
All Data Hub detail pages include extensive context-sensitive help. To open additional information for a particular item, click the ? icon. Required fields are marked with an asterisk (*).

To save your script, select Save Script.

Script Detail -View Script Details

The Script Detail - for Script ID page displays when you select an existing script on the Script overview. Here, you can add new script versions, download script versions, or delete all versions of the selected script:

Script Detail -View

The Referencing Data Polices area of the detail lists and links to all data policies that use the script.

It is only possible to delete scripts that are not referenced in a policy. To delete the script, you must first delete all policies that reference the script. After you delete the policies listed, wait at least 30 seconds before deleting the script. The delay ensures that all pipelines that currently execute the script can finish.

Data Policies Overview

You can create and manage two types of policies on the control center: data policies and behavior policies.

Data Hub data policies ensure that the payload data in MQTT messages has the structure and format you expect. Data Policies use schema-based data validation to verify that MQTT data meets your requirements.

The Data Policies overview provides basic information for each data policy on your HiveMQ cluster.

Data Policies Overview
Table 6. Data Policies available information and actions
Column Description

Policy ID

Displays the unique identifier of the policy on the HiveMQ cluster. Select the policy ID, to open a summary of the data policy to access details and editing options.

Topic Filter

The defined topic filter of the data policy.

Created At

The time when the data policy was initially created.

Last Updated

The time when the data policy was last updated.

Actions

Depending on your permissions, icons are shown to view, edit, or download the data policy.

HiveMQ uses cluster-wide snapshots to display all available data policies. To view information for the data policies that are currently available, you need to create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all available data policies.

To take a new snapshot, select Refresh Snapshot.
Based on the number of data policies on your cluster, the refresh process can take a few moments.
When you filter or sort the information on the overview, the snapshot automatically updates.

To create a new data policy, select Add New Policy.

Data Policy Detail

The Data Policy Detail page displays when you select the Add New Data Policy option on the Data Policies overview.

The tabs of the Data Policy Detail guide you through the policy creation process from the selection of validators to the configuration of actions the validation outcomes can trigger.

All Data Hub detail pages include extensive context-sensitive help. To open additional information for a particular item, click the ? icon.

Policies Detail

For detailed configuration information and examples, see Data Hub Data Policies

Required fields are marked with an *. To save the policy, all required fields must be completed. You can save your policy at any time or switch to the Summary tab to review the policy before you save.

The Summary page of the Data Policy Detail allows you to review, edit, save, or delete your data policy. The summary information includes links to all schemas and scripts that are associated with the selected policy.

Data Policy Detail - Summary

To close the Summary and return to the Data Policies overview, select Cancel.

Behavior Policies Overview

You can create and manage two types of policies on the control center: data policies and behavior policies.

Data Hub behavior policies give you the ability to model the behavior of your MQTT clients throughout the entire lifecycle of the client.
Client behavior is checked against your defined behavior model to determine whether the client is acting in the expected manner. The behavior model builds a level of control on top of the MQTT protocol with a state machine that checks how the client works with the HiveMQ broker.

For more information on the use of behavior policies in HiveMQ Data Hub, see Behavior Policies.

The Behavior Policies overview provides basic information for each behavior policy on your HiveMQ cluster.

Behavior Policies Overview
Column Description

Client ID Regex

Displays regular expression matching the client ID. For more information, see Behavior Policy Matching

Created At

The time when the behavior policy was initially created.

Last Updated

The time when the behavior policy was last updated.

Action

Depending on your permissions, icons are shown to view, edit, or download the data policy.

HiveMQ uses cluster-wide snapshots to display all available behavior policies. To view information for the behavior policies that are currently available, you need to create a fresh snapshot. The HiveMQ snapshot offers a consolidated view of all nodes in your cluster at a particular point in time. This unified snapshot provides an efficient way to sort, filter, and navigate through all available behavior policies.

To take a new snapshot, select Refresh Snapshot.
When you filter or sort the information on the overview, the snapshot automatically updates. Based on the number of behavior policies on your cluster, the refresh process can take a few moments.

To create a new behavior policy, select Add New Policy.

Behavior Policy Detail

The Behavior Policy Detail displays when you select the Add New Policy option on the Behavior Policies overview.

The tabs of the Behavior Policy Detail guide you through the policy creation process from defining for which clients the policy applies to defining actions that the transitions in the state of the client trigger.

All Data Hub detail pages include extensive context-sensitive help. To open additional information for a particular item, click the ? icon.
Behavior policy Detail

For detailed configuration information and examples, see Data Hub Behavior Policies

Required fields are marked with an *. To save the policy, all required fields must be completed. You can save your policy at any time or switch to the Summary tab to review the policy before you save.

The Summary page of the Data Policy Detail allows you to review, edit, save, or delete your data policy at any time. To close the Summary and return to the Behavior Policies overview, select Cancel.

Licenses

Your HiveMQ instance can contain more than one license. The control center License view provides information on all active and inactive HiveMQ licenses that are available for the HiveMQ installation.

Control Center Licenses Overview
Figure 2. License overview
Only licenses that are installed on the currently selected node are shown.

Active License

The Active License area of the control center Licenses view provides detailed information on the HiveMQ license that is currently in use. Only one license can be active at a time.

The Active License overview provides detailed information on the license that is in use.

license_table
A brief summary of key information for the active license is also shown on the Active License Information card of the control center dashboard.
Table 7. Available active license information
Item Description

Connections

The number of concurrent client connections currently in use and the maximum number of connections the active license allows.

CPU Cores

The number of CPU cores currently in use and the maximum number of cores the active license supports.

Cluster Nodes

The number of cluster nodes currently in use and the maximum number of cluster nodes the active license supports.

Cluster License

Indicates whether the license enables the use of HiveMQ clusters.

Edition

The type of HiveMQ edition the license enables. For more information, see Editions.

Filename

The filename of the current license.

Start Date

The date on which the license was activated.

License Expiration Date

The expiration date of the license that is currently in use.

License Owner

The owner of this license.

Contact

Contact information for the owner of the license.

Email

Email address of the owner of the license.

Show Features for Active License

To view a list of all the features the selected active license includes, expand the Show Features option.

Show Features Option

When selected, the Show Features option in the Active License area indicates all the HiveMQ features that your active HiveMQ license enables and provides links to further information.

Expanded Features List
Table 8. Available features
Feature Description

Backup and Restore

Provides mechanisms to ensure minimum loss and quick recovery from potentially disastrous situations. For more information, see Backup and Restore.

Client Event History

Adds fine-grained per-client observability to the HiveMQ Control Center and provides a historical view of client events. For more information, see Client Event History.

Configurable Connect Overload Protection

Allows you to enable, disable, and configure your connect overload protection to control the rate of MQTT CONNECT packets your HiveMQ broker allows per second. For more information, see Configurable Connect Overload Protection.

Control Center Audit Log

Adds a record of all administrative actions that occur in your HiveMQ Control Center to provide a single, unified log for tracking auditing-relevant data. For more information, Audit Log.

Control Center Clients View

Provides information on subscriptions, connection status, TLS, and more to give you detailed insights into every client on your HiveMQ installation. For more information, see Control Center Client View.

Control Center Dropped Messages View

Provides the tools to track all dropped messages in your HiveMQ cluster. For more information, see Control Center Dropped Messages View.

Control Center Retained Messages View

Provides the tools to track and manage all the retained messages in your HiveMQ cluster including detailed information on each retained message. For more information, see Control Center Retained Message View.

Control Center Shared Subscriptions View

Provides a snapshot of all shared subscriptions on your HiveMQ cluster. Control Center Shared Subscriptions View.

Data Hub Data Validation (Beta version)

Adds the ability to validate messages based on the structure of the message content and control the flow of messages through your HiveMQ broker accordingly.
NOTE: To test the beta version of this feature, contact sales@hivemq.com for a trial license.

Encrypted Cluster Communication

Enables the use of a secure TLS connection to provide encrypted communication between the nodes of your HiveMQ cluster. For more information, see TLS.

Fine-grained Control Center Permissions

Adds the ability to define access to all pages of your control center and to all control center functionality. For more information, see Control Center Access Control.

Fine-grained REST API Permissions

Allows you to implement fine-grained access control for the HiveMQ REST API. For more information, see REST API Permissions.

MQTT Add-on Dead Topic

Adds a special analytical MQTT topic that you can use to automatically collect detailed information for all dead MQTT messages on your HiveMQ system. For more information, see MQTT Add-on Dead Message Topic.

MQTT Add-on Dropped Topic

Adds a special analytical MQTT topic that you can use to automatically collect detailed information for all dropped MQTT messages on your HiveMQ system. For more information, see MQTT Add-on Dropped Message Topic.

MQTT Add-on Expired Topic

Adds a special analytical MQTT topic that you can use to automatically collect detailed information for all expired MQTT messages on your HiveMQ system. For more information, see MQTT Add-on Expired Message Topic.

Native SSL

Enables the use of the HiveMQ native SSL implementation. For more information, see Native SSL.

OCSP Stapling

Allows the HiveMQ broker, rather than the client, to make status requests to the OCSP responder. For more information, see OCSP.

PROXY Protocol

Allows the transportation of client details such as the IP address and port over multiple proxies. For more information, see Proxy Protocol.

REST API

Provides an interface for applications to interact programmatically with the HiveMQ Enterprise MQTT broker. For more information, see REST API.

SSL Handshake Throttling

Allows you to limit the number of SSL handshake operations the HiveMQ broker allows per listener. For more information, see Restrictions.

Trace Recordings

Allows you to track the messages of specific clients or topics and review the information in a human-readable format. For more information, see Trace Recordings.

A warning notification displays at the top of the Active License area when your license is about to expire. The default setting is 30 days before the license expiration date. This time period can be adjusted individually for each license.
License expiration warning

Trial license

If no license is installed in the license folder of your HiveMQ installation, HiveMQ automatically uses a free trial license. Trial licenses are limited to 25 concurrent connections:

Trial license information

To view a list of the features the trial license includes, expand the Show Features area:

Trial license features

If your license expires, a trial license is used automatically. Information on the expired license appears in the Inactive Licenses area.

License expiration