Prior to the release of Device42 18.07.00, an unrestricted number of remote agents could request binary update files from the main Device42 appliance. However, this could lead to performance issues on the main appliance, especially if many agents requested updates concurrently.
In the latest version of Device42, agents will only receive an update if the allowed number of concurrent updates has not been reached yet. If the application is currently busy updating the maximum number of requests that have been configured, Device42 will reject any further update requests from agents, and the agent will continue running with its current version.
- Local Agent
- Remote Agent
- Packet Capture
- Ping Sweep
Applying The Limit
To apply the limit you need to access the Appliance Manager then navigate to
Global Settings -> API Limits
In the above configuration, we are setting a default limit of 16 concurrent connections to the binary agent update endpoint. We are also creating a shared memory pool that is used to track the number of active connections to the binary agent update endpoint.
When a client attempts to make a request to the binary agent update endpoint and the maximum number of concurrent connections has already been reached, NGINX will return an error message to the client. This will prevent the endpoint from becoming overwhelmed with requests and allow continued access to the system.
A new configuration option has been added to limit the number of remote agents that can concurrently initiate updates, thereby preventing a surge of agents from overloading Device42. The default setting allows 16 concurrent updates, but can be adjusted to any value between 8 and 128, although it requires restarting the application after modification.