add how to for using intellij (#305)

Author: vlogic

site/docs/getting-started/3-whats-next.md

@@ -9,3 +9,4 @@ Congratulations! You have just learned how to design and experiment with a (virt
 - Follow one of the [tutorials](/docs/category/tutorials) using OpenDC.
 - Read about [existing work using OpenDC](/community/research).
 - Get involved in the [OpenDC Community](/community/support).
+- If you are interested in contributing to OpenDC you can find a How-To here [4-start-using-intellij](4-start-using-intellij.md), please also read https://github.com/atlarge-research/opendc/blob/master/CONTRIBUTING.md.

site/docs/getting-started/4-start-using-intellij.md

@@ -0,0 +1,172 @@
+
+
+# In this How-To we explain how you setup IntelliJ IDEA
+
+First of all you can download IntelliJ here: https://lp.jetbrains.com/intellij-idea-promo/
+
+# Basic steps
+
+```
+git clone git@github.com:atlarge-research/opendc
+```
+
+Check if you have a compatible java version available. Make sure to have one of these versions available: [19, 20, 21]
+
+If not install a supported version!
+
+On a MAC
+
+```
+/usr/libexec/java_home -V
+```
+
+On Debian
+
+```
+update-alternatives --list java
+```
+
+On Redhat/Centos
+
+```
+yum list installed | grep java
+```
+
+
+Open the project in IntelliJ
+
+![Intellij Open Project](img/intellij_open_project.png)
+
+Now fix the settings so that you use the correct java version. (In the example the java version is set to "21")
+Navigation path in the settings pannel: "Build, Execution, Deployment" -> "Build Tools" -> "Gradle"
+
+![Intellij Settings](img/intellij_settings.png)
+
+Now navigate in the file menu to and open the file: "gradle"/"libs.versions.toml"
+
+Make sure the java version is set to the same version as previously cofigured in the settings.
+
+![Intellij Libs Versions Toml](img/intellij_libs_versions_toml.png)
+
+
+Now open the Gradle panel on the right-hand side of the editor (1) and hit the refresh button at the top of the panel (2).
+
+![Intellij Gradle Panel](img/intellij_gradle_panel.png)
+
+
+# Setup your first experiment and run it from source
+
+
+Create a directory where you are going to put the files for your first experiment.
+
+File structure:
+
+![Experiment File Structure](img/experiment_file_structure.png)
+
+You can download the example workload trace (bitbrains-small-9d2e576e6684ddc57c767a6161e66963.zip) [here](https://atlarge-research.github.io/opendc/assets/files/bitbrains-small-9d2e576e6684ddc57c767a6161e66963.zip)
+
+Now unzip the trace.
+
+The content of "topology.json"
+
+```
+{
+    "clusters":
+    [
+        {
+            "name": "C01",
+            "hosts" :
+            [
+                {
+                    "name": "H01",
+                    "cpu":
+                    {
+                        "coreCount": 32,
+                        "coreSpeed": 3200
+                    },
+                    "memory": {
+                        "memorySize": 256000
+                    }
+                }
+            ]
+        },
+        {
+            "name": "C02",
+            "hosts" :
+            [
+                {
+                    "name": "H02",
+                    "count": 6,
+                    "cpu":
+                    {
+                        "coreCount": 8,
+                        "coreSpeed": 2930
+                    },
+                    "memory": {
+                        "memorySize": 64000
+                    }
+                }
+            ]
+        },
+        {
+            "name": "C03",
+            "hosts" :
+            [
+                {
+                    "name": "H03",
+                    "count": 2,
+                    "cpu":
+                    {
+                        "coreCount": 16,
+                        "coreSpeed": 3200
+                    },
+                    "memory": {
+                        "memorySize": 128000
+                    }
+                }
+            ]
+        }
+    ]
+}
+```
+
+The content of "experiment.json"
+
+The paths in the "experiment.json" file are relative to the "working directory" which is configured next.
+
+
+```
+{
+    "name": "simple",
+    "topologies": [{
+        "pathToFile": "topology.json"
+	}],
+    "workloads": [{
+        "pathToFile": "bitbrains-small",
+        "type": "ComputeWorkload"
+    }]
+}
+```
+
+In the project file structure on the left open the following file:
+
+"opendc-experiments"/"opendc-experiments-base"/"src"/"main"/"kotlin"/"org.opendc.experiment.base"/"runner"/"ExperimentCLi.kt"
+
+![Intellij Experimentcli](img/Intellij_experimentcli.png)
+
+Now open the "Run/Debug" configuration (top right).
+
+![Intellij Open Run Config](img/intellij_open_run_config.png)
+
+We need to edit two settings:
+
+"Program arguments": --experiment-path experiment.json
+
+"Working Directory": a path where you have put the experiment files
+
+![Intellij Edit The Run Config](img/intellij_edit_the_run_config.png)
+
+Now you can click "Run" and start your first experiment.
+
+In the working directory a "output" direcotry is created with the results of the experiment.
+