Ironic Python Agent (IPA)
IPA is a service written in python that runs within a ramdisk. It provides remote access for Ironic to perform various operations on the managed server. It also sends information about the server to Ironic.
By default, we pull IPA images from Ironic upstream archive where an image is built on every commit to the master git branch.
However, another remote registry or a local IPA archive can be specified. ipa-downloader is responsible for downloading the IPA ramdisk image to a shared volume from where the nodes are able to retrieve it.
Data flow
IPA interacts with other components. The information exchanged and the component to which it is sent to or received from are described below. The communication between IPA and these components can be encrypted in-transit with SSL/TLS.
- Inspection: data about hardware details, such as CPU, disk, RAM and network interfaces.
- Heartbeat: periodic message informing Ironic that the node is still running.
- Lookup: data sent to Ironic that helps it determine Ironic’s node UUID for the node.
The above data is sent/received as follows.
- Inspection result is sent to Ironic
- Lookup/heartbeats data is sent to Ironic.
- User supplied boot image that will be written to the node’s disk is retrieved from HTTPD server