docs: update README.md

This commit updates the README file to include detailed steps for installing and
using criu-coordinator.

Signed-off-by: Kouame Behouba Manasse <[email protected]>

Author: behouba

README.md

@@ -3,29 +3,116 @@ CRIU Coordinator
 
 _criu-coordinator_ enables checkpoint coordination among multiple processes, containers, or Kubernetes Pods.
 
-Usage Example
+
+Installation
+------------
+
+To install _criu-coordinator_, follow these steps:
+
+1. Clone the repository
+```console
+git clone https://github.com/checkpoint-restore/criu-coordinator.git
+cd criu-coordinator
+```
+
+2. Build the project
+```console
+make
+```
+
+3. Install the binary
+```console
+make install
+```
+
+Usage
 -------------
 
+__criu-coordinator__ operates in a client-server model. The server manages the coordination of checkpoints, while clients are invoked as CRIU action scripts that communicate with the server during checkpoint and restore operations.
+
 1. Start coordinator server
 
 ```console
 criu-coordinator server --address 127.0.0.1 --port 8080
 ```
 
-2. Create directory for CRIU image files and copy `criu-coordinator.json`
+2. Create a configuration
 
-```console
-mkdir /tmp/test
-cp example-config/criu-coordinator.json /tmp/test/
+Create a global configuration file at /etc/criu/criu-coordinator.json. For example:
+
+```json
+{
+  "address": "127.0.0.1",
+  "port": "8080",
+  "dependencies": {
+    "A": ["B"],
+    "B": ["A"]
+  }
+}
 ```
+A and B could be process names, process IDs, or container IDs. The dependencies define which processes must be checkpointed together.
 
-3. Configure CRIU to use criu-coordinator
+
+Alternatively, for simple processes, you can create a per process configuration file `criu-coordinator.json` and place it in the directory where CRIU images will be stored. For example:
+
+For process A:
+```json
+{
+	"id": "A",
+	"dependencies": ["B"],
+	"address": "127.0.0.1",
+	"port": "8080",
+	"log-file": "coordinator.log"
+}
+
+```
+
+For process B:
+```json
+{
+    "id": "B",
+    "dependencies": ["A"],
+    "address": "127.0.0.1",
+    "port": "8080",
+    "log-file": "coordinator.log"
+}
+```
+
+3. Configure CRIU to use criu-coordinator as the action script
 
 ```console
 mkdir -p /etc/criu/
 echo action-script="$(which criu-coordinator)" | sudo tee /etc/criu/default.conf
 ```
 
+4. Coordinated Checkpoint/Restore
+
+You can now perform coordinated checkpoint and restore operations. For example, to checkpoint process A and B:
+
+In terminal 1 (for process A):
+
+```console
+sudo criu dump -t <PID_A> -D /tmp/images-a -j
+```
+
+In terminal 2 (for process B):
+
+```console
+sudo criu dump -t <PID_B> -D /tmp/images-b -j
+```
+
+To restore the processes, use the following commands:
+
+In terminal 1 (for process A):
+```console
+sudo criu restore -D /tmp/images-a
+```
+
+In terminal 2 (for process B):
+```console
+sudo criu restore -D /tmp/images-b
+```
+
 License
 -------