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Copy file name to clipboardExpand all lines: content/blog/master-the-redfish-server-states-to-improve-your-monitoring-and-manageme.md
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- ProLiant
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- Synergy
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#### Updated July 25, 2023
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Updated February 26, 2024
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## Introduction
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Server management and monitoring often require the knowledge of the state of the managed servers (On, Off....). The [Redfish®](https://www.dmtf.org/standards/redfish) standard defines the [`PowerState`](https://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_5_0.json)property with 0 (`Off`) and 1 (`On`) as possible values. However, when the system is in the `On` state, we'd like to know in which sub-state the server is: Pre-OS Tasks (POST), UEFI, OS...
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Server management and monitoring often require the knowledge of the state of the managed servers (On, Off....). The [Redfish®](https://www.dmtf.org/standards/redfish) standard defines the <ahref="https://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_5_0.json"target="_blank">PowerState</a> property `Off``On` as possible values. However, when the system is in the `On` state, you may want to know in which sub-state the server is: Pre-OS Tasks (POST), UEFI, OS. You may want to know if the storage controllers or network cards have been discovered properly.
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This blog presents the [`PostState`](https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo6/ilo6_145/ilo6_computersystem_resourcedefns145/#oemhpepoststate)property available in an`Oem.Hpe` Redfish sub-tree of HPE servers (Gen9, Gen10 and Gen11)and providing a fine grained server state.
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This blog presents the <ahref="https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo6/ilo6_156/ilo6_computersystem_resourcedefns156/#oemhpepoststate"target="_blank">PostState</a> property available in the`Oem.Hpe`extension of the `ComputerSystem`Redfish sub-tree of HPE servers (Gen9, Gen10 and Gen11). It presents as well the `DeviceDiscoveryComplete` <ahref="https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo6/ilo6_156/ilo6_computersystem_resourcedefns156/#oemhpedevicediscoverycomplete"target="_blank">property</a>, part of the same OEM extension and extremely important when you want to configure <ahref="https://developer.hpe.com/blog/overview-of-the-platform-level-data-model-for-redfish%C2%AE-device-enablement-standard/"target="_blank">PLDM for RDE</a> devices.
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## HPE PostState
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As mentioned in the [HPE iLO 4](https://hewlettpackard.github.io/ilo-rest-api-docs/ilo4/#poststate) API Reference documents, the `PostState` property can have the following values: `Null`, `Unknown`, `Reset`, `PowerOff`, `InPost`, `InPostDiscoveryComplete` and `FinishedPost`.
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[Following HPE iLO generations ](https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo6/ilo6_145/ilo6_computersystem_resourcedefns145/#oemhpepoststate) have one more value: `InPostDiscoveryStart`.
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<ahref="https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo6/ilo6_156/ilo6_computersystem_resourcedefns156/#oemhpepoststate"target="_blank">Following HPE iLO generations</a> have one more value: `InPostDiscoveryStart`.
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Since the first four values have a straight forward meaning, we will only focus on the other ones.
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Since the first four values have a straight forward meaning, I'll focus only focus on the other ones.
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The `InPost` value means that the server is still performing the Pre-OS Tasks (tests and hardware discovery). With a graphical console opened, when a server is in this state you can see a green progress bar:
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`InPostDiscoveryStart` follows the `InPost` state and then, `InPostDiscoveryComplete`. For the purpose of this blog, we assume that it corresponds to the state in which UEFI is loaded and running:
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`InPostDiscoveryStart` follows the `InPost` state and then, `InPostDiscoveryComplete`. For the purpose of this blog, I'll assume that it corresponds to the state in which UEFI is loaded and running:
Note that when an UEFI executable is running (i.e. UEFI Shell, `grubx64.efi`...) the server stays in the `InPostDiscoveryComplete` state.
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The last possible value for the `PostState` key is `FinishedPost`. In this state, the server is either booting an installed OS or has completely finished its boot process.
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## `PostState` use cases
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## PostState use cases
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The first obvious use case for probing the `PostState` of a server or a set of servers is in a monitoring application. Combined with the health status of the different components of the server, you will be able to draw dashboards or create reports.
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In a server management and configuration context, several properties can only be modified when the server is in a particular state. For example, the boot order can only be modified in the `Off` or in the `FinishedPost` states (OS booted).
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In the following screenshot we use [ilorest](http://hpe.com/info/resttool) to change the next boot entry of a server being in the `InPostDiscoveryComplete` state. In this case, the iLO returns a `[400]` error code with an explicit message.
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In the following screenshot I used <ahref="https://github.com/HewlettPackard/python-redfish-utility/releases/latest"target="_blank">iLOrest</a> to change the next boot entry of a server being in the `InPostDiscoveryComplete` state. In this case, the iLO returns a `[400]` error code with an explicit message.
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## How do I retrieve the Server State
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The easiest way to obtain the `PostState` of a server is to issue the `serverstate` macro command of the [iLOrest](http://hpe.com/info/resttool)utility. ILOrest automatically detects the generation of the server (Gen9, Gen10...) and fetches the `PostState` value from the right Redfish path.
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The easiest way to obtain the `PostState` of a server is to issue the `serverstate` macro command of the <ahref="https://servermanagementportal.ext.hpe.com/docs/redfishclients/ilorest-userguide/ilocommands/#serverstate-command"target="_blank">iLOrest</a> utility. ILOrest automatically detects the generation of the server (Gen9, Gen10...) and fetches the `PostState` value from the right Redfish URI.
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The [Open Source](https://github.com/HewlettPackard/python-redfish-utility)version of iLOrest contains the source of this [`ServerState` macro command](https://github.com/HewlettPackard/python-redfish-utility/blob/master/src/extensions/iLO_COMMANDS/ServerStateCommand.py)in python. Feel free to consult it.
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The <ahref="https://github.com/HewlettPackard/python-redfish-utility"target="_blank">Open Source</a> version of iLOrest contains the source of this <ahref="https://github.com/HewlettPackard/python-redfish-utility/blob/master/src/extensions/iLO_COMMANDS/ServerStateCommand.py"target="_blank">ServerState</a> macro command in Python. Feel free to consult it.
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If you decide to create your own Redfish client, you will have to adapt your code to the potential Redfish [data model changes](https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo5/ilo5_adaptation/#ilo-5-data-model-changes) between the different generations of servers or iLOs.
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If you decide to create your own Redfish client, you will have to adapt your code to the potential Redfish <ahref="https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo5/ilo5_adaptation/#ilo-5-data-model-changes"target="_blank">data model changes</a> between the different generations of servers or iLOs.
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As a concrete example, in an HPE rack mount server the `PostState` property has moved from `/redfish/v1/Systems/1/oem/hp` in Gen9 models to `/redfish/v1/Systems/1/oem/hpe` in Gen10s and Gen11s.
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As a concrete example, in an HPE rack mount server the `PostState` property has moved from `/redfish/v1/Systems/1/Oem/Hp` in Gen9 models to `/redfish/v1/Systems/1/Oem/Hpe` in Gen10s and Gen11s.
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## The HPE Agentless Management Service is your friend
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There are multiples ways to solve this problem, including the use of `ping`, `ssh` or SNMP queries to the host OS. However, this is not always possible or desired.
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An alternative is using the [HPE Agentless Management Service (AMS)](https://www.hpe.com/us/en/product-catalog/detail/pip.5219980.html) combined to Redfish.
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An alternative is using the <ahref="https://www.hpe.com/us/en/product-catalog/detail/pip.5219980.html"target="_blank">HPE Agentless Management Service</a> (AMS) combined to Redfish.
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The AMS is a very high level service running in a bare-metal Operating System and communicating with the iLO through an internal path (CHIF driver over PCIe bus). Among other things, it communicates the OS hostname to the iLO which stores it in the `HostName` property of the `/redfish/v1/Systems/{item}` sub-tree.
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The AMS is a very high level service running in a bare-metal Operating System and communicating with the iLO through an internal path (<ahref="https://developer.hpe.com/blog/chif-driver-not-found/"target="_blank">CHIF driver</a> over PCIe bus). Among other things, it communicates the OS hostname to the iLO which stores it in the `HostName` property of the `/redfish/v1/Systems/{item}` sub-tree.
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By setting this resource to a null or known string when the server is `Off`, and then by polling it regularly during the boot process you can detect its change and conclude with a small risk of error that the OS is running fine.
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In summary, the deployment process of a bare-metal server could be written as:
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```cwl
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```shell
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Set server in`Off` state
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set`HostName` to a null or a well-known string different from the final OS hostname
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Configure other needed parameters including OS deployment bootstraps
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**Restriction**: The configuration of the `HostName` property using Redfish on **Gen9** servers is possible with firmware 2.60 or later.
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## The `DeviceDiscoveryComplete` collection
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## The DeviceDiscoveryComplete collection
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In addition to the `PowerState` and `PostState` properties, the `DeviceDiscoveryComplete` collection returns the discovery state of the AMS, SmartArrays (if any) and a third generic state for all other devices.
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In addition to the `PowerState` and `PostState` properties, the <ahref="https://servermanagementportal.ext.hpe.com/docs/redfishservices/ilos/ilo6/ilo6_156/ilo6_computersystem_resourcedefns156/#oemhpedevicediscoverycomplete"target="_blank">DeviceDiscoveryComplete{} collection</a> returns the states of the AMS, SmartArrays (if any) and a third generic discovery state for all devices.
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It may happen during startup that a system returns `InPostDiscoveryComplete` while not all of its devices have been discovered.
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It may happen during startup that a system returns `InPostDiscoveryComplete` while not all of its devices have been discovered, like <ahref="https://developer.hpe.com/blog/overview-of-the-platform-level-data-model-for-redfish%C2%AE-device-enablement-standard/"target="_blank">PLDM for RDE</a> capable devices.
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The following script polls every other second the `PostState` and the `DeviceDiscoveryComplete` properties:
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done
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```
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The following picture shows three iterations of the the script during the start of a server. In iteration 55 the server is `InPost` while the SmartArray is in a `Cached` state meaning that it will answer queries with cached data.
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The following picture shows three iterations of the above script during the start of a server. In iteration 55 the server is `InPost` while the SmartArray is in a `Cached` state meaning that it will answer queries with cached data.
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Two seconds later the next iteration returns the `InPostDiscoveryComplete` state and shows the SmartArray in `Busy` mode which means that it will return an error if queried during this state.
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Combining the `PowerState` Redfish property with specific HPE features like the `PostState`, `DeviceDiscoveryComplete` and the Agentless Management Service, you will be able to increase the efficiency of your monitoring and management applications.
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HPE provides as well a rich Redfish ecosystem including the free [`ilorest` tool](https://hpe.com/info/resttool), its [Open Source](https://github.com/HewlettPackard/python-redfish-utility)version and a [Python library](https://github.com/HewlettPackard/python-ilorest-library). PowerShell developers have the possibility to use a set of specific Redfish [Cmdlets](https://www.powershellgallery.com/packages/HPRESTCmdlets/)required to run the [GitHub ProLiant SDK](https://github.com/HewlettPackard/PowerShell-ProLiant-SDK).
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HPE provides as well a rich Redfish ecosystem including the free <ahref="https://github.com/HewlettPackard/python-redfish-utility/releases/latest"target="_blank">iLOrest tool</a>, its <ahref="https://github.com/HewlettPackard/python-redfish-utility"target="_blank">Open Source</a> version and a <ahref="https://github.com/HewlettPackard/python-ilorest-library"target="_blank">Python library</a>. PowerShell developers have the possibility to use a set of specific Redfish <ahref="https://www.powershellgallery.com/packages/HPRESTCmdlets/"target="_blank">Cmdlets</a> required to run the <ahref="https://github.com/HewlettPackard/PowerShell-ProLiant-SDK"target="_blank">GitHub ProLiant SDK</a>.
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In addition to the above, technical [Redfish videos](https://www.youtube.com/channel/UCIZhrIYcNh3wHLiY4ola5ew/search?query=redfish) can help you learning more on this new way for managing servers.
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Don't forget to check out some of my other <ahref="https://developer.hpe.com/search/?term=donze"target="_blank">blog posts</a> on the HPE Developer portal to learn more about Redfish tips and tricks.
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