Morning quick question does prefect have to be installed whe

Question

Morning quick question does prefect have to be installed where the agent is running from If so does it not create 2 database instances When prefect is installed on host running the webservice the prefect directory and orion db instance gets created And then when installing prefect again on the host from where the flows are being run then another prefect directory and orion db instance gets created

Bianca Hoch · Answer

Hello Byron in short yes Prefect must be installed in any environment in which you intend to run the agent or <https docs prefect io concepts work queues h=agent|execute a flow run>

Bianca Hoch · Answer

In regard to whether or not it creates a new instance let me consult with the team and we ll get back to you here

Byron Kilian · Answer

Hi Bianca thanks for the reply I hope you dont mind but I think this thread might get a bit lengthy as I have lots of confusion around the setup and documentation I don t know if there are concepts introduced in Prefect V1 but I m starting from the documentation on Prefect V2 The context I have are just based on what I m reading within this documentation Example for work queue setup it speaks to agent configuration but its not clear how the agent is configured The backend seems to expect certain fields that describes the concept of an agent but I cannot seem to find what that is from the PrefectV2 documentation From my screenshot it looks like prefect work queue CLI command has to run first in order to create the entry on table work queue which is then a key into the agent table work queue id but I can run prefect agent start command even though the agent on table agent does not exist yet I need to understand how to configure the agent first and only then it should allow me to start the agent schedule The command prefect agent start lt queue id gt is also confusing When the agent is created it should already be associated with a queue and the command prefect agent start lt agent id gt make more sense Please let me know your thoughts

Byron Kilian · Answer

this is something in addition to the multiple environments that require prefect to be installed There is the agent process that could run on hostA There is the execution environment where the agent deploys the flow run which also requires prefect to be installed lets say on hostB then there is the orion service webservice that runs on a hostC that also requires prefect to be installed In each of these cases the prefect project directory gets created and I m confused as to why and what prefect environment variables to set for each of these hosts Will continue to discover in the meantime while I await feedback

Byron Kilian · Answer

Hi Bianca some feedback on the definitions used The term concurrency limit is used in two different configurations It refers to both queue concurrency and task concurrency limits which is confusing My suggestion here is to use task concurrency limits for tasks and also rename the database tbl and prefect CLI command accordingly + doc update and the concurrency limit field on the work queue table to remain as is since it is an attribute of the work queue object and makes sense when configuring it

Byron Kilian · Answer

Hi Bianca I notice when a flow is configured within your code base and then run the flow manually with python my flow py it will automatically populate the table flow on the backend However the DB model object does not align with what can be configured from the documentation explaining the flow concept image below shows the configuration vs the backend

Byron Kilian · Answer

From the documentation these configurations can be set but where does it persist