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# Admin Example

The admin example demonstrates a minimal system that runs the admin component on KOS. The admin
component is an Elixir app that coordinates on-device administration activities, such as system restart and upgrade.
The admin component also acts as a client to a Kry10 Server.

The admin example is entirely implemented by using the KOS Poukai manifest layer, requiring
no further augmentations. In particular, the KOS Poukai apps present in this system are:

- `admin_ex`: an Erlang BEAM VM running an Elixir app that coordinates
  admin activities (such as restart and upgrade) and acts as a client to a
  Kry10 Server.
- `key_store`: server that provides a way to store secrets (e.g private keys) that
  applications can request at runtime.
- `ethernet`: contains an ethernet driver and implements the `ethernet` protocol
  to provide ethernet access to other apps on the device.
- `tunnel`: a secure tunnel to a host machine (typically be managed by the
  Studio or Fleet Server).
- `rng_server`: a CSPRNG server, providing an interface that allows applications to request
arbitrary length streams of random bytes.
- `log_server`: a system-wide logging service. The server provides an interface for
applications to emit semi-structured log strings with an associated log
level i.e. `INFO`, `WARN`, `ERROR` etc.
- `self_test`: an app that performs a series of tests on startup.

This system demonstrates a good project starting point that can then be further modified as needed.

### Build Instructions

Launch a KOS development shell for the target platform:

 ```console
$ kos-tool env -p <am335x|qemu-arm-virt|imx8mm-evk|portenta-x8|rpi4>
 ```

Checkout the admin example sources:

```console
$ mix kos.docs.example admin_example
$ cd admin_example
```

Build the admin example system:

```console
$ mix kos.build
```

Proceed to run the system using the Mix `kos.run` utility:

```console
$ kos-run
```


You will see the admin component start up with output similar to the following:
```
|      0.693| Poukai.admin     | 
|      0.693| Poukai.admin     | ----  Poukai.admin ----
|      0.732| Poukai.admin     | beam tunnel connection established:
|      0.732| Poukai.admin     | IP addr: 192.168.2.6
|      0.733| Poukai.admin     | Netmask: 255.255.255.0
|      0.733| Poukai.admin     | Gateway: 192.168.2.100
|      2.931| Poukai.admin     | 
|      2.931| Poukai.admin     | 08:21:57.837 [info] Starting connection with the Kry10 server on ws://192.168.2.100:4000/cnc
|      2.952| Poukai.admin     | 
|      2.952| Poukai.admin     | 08:21:57.870 [info] starting KosSel4 server
|      2.962| Poukai.admin     | 
|      2.962| Poukai.admin     | 08:21:57.879 [info] starting KosMsg server
|      2.993| Poukai.admin     | 
|      2.993| Poukai.admin     | 08:21:57.909 [warning] Can't start KosTrace. Reason: Tracing Unavailable.
|      2.995| Poukai.admin     | 
|      2.995| Poukai.admin     | 08:21:57.910 [info] Starting KosChannels server
|      3.026| Poukai.admin     | 
|      3.026| Poukai.admin     | 08:21:57.941 [info] admin_ex's public key: 5paBAr9Cv+h6mZxus78c4BxBgIfyFLAdudrPn6xwR+Q=
|      3.033| Poukai.admin     | 
|      3.033| Poukai.admin     | 08:21:57.950 [info] Starting SerialStream server
|      3.033| Poukai.admin     | 08:23:21.065 [info] Connection has been lost. Reason: {:error, :timeout}. Attempting to reconnect
```

Follow the [Connecting a device to a Kry10 Server](server_connect_device) guide to connect it to a server so that you can interact
with the example through your browser.