chore: optimize docs about LAUNCH instruction

Signed-off-by: yuxing.lyx <[email protected]>

Author: starnop

attachment/images/image-arch.png

@@ -37,9 +37,16 @@ For example , copy directory `apollo` to `rootfs/charts/apollo`
 
 ## CMDS instruction
 
-The format of CMDS instruction will execute any commands in a new layer. The CMDS command will be executed when `sealer run` . it is generally used to start applications or configure
-the cluster. and it is the same with `Dockerfile` CMD , if there are multiple `CMDS` instructions in the `Kubefile`, only the last one takes effect.
-And it conflicts with `LAUNCH`, and only one of the two can exist.
+> NOTE: `LAUNCH` instruction is more recommended than `CMDS`.
+
+The format of CMDS instruction will execute any commands in a new layer. The CMDS command will be executed when `sealer run` .
+It is generally used to start applications or configure the cluster.
+
+And there are some points that require special attention:
+
++ Just like with `Dockerfile` CMD , if there are multiple `CMDS` instructions in the `Kubefile`, only the last one takes effect.
++ The `CMDS` of the parent image will not be inherited, and you need to redefine it in the child image if you need to have it set.
++ The `CMDS` instruction and the `LAUNCH` instruction are in conflict, and only one of them can exist.
 
 > command format：CMD {command args ...}
 
@@ -80,7 +87,12 @@ For example:
 ## LAUNCH instruction
 
 The `LAUNCH` instruction specifies a list of apps to launch when sealer run. Only one `LAUNCH` instruction can be defined in the Kubefile.
-And it conflicts with `CMDS`, and only one of the two can exist.
+
+And there are some points that require special attention:
+
++ The `LAUNCH` of the parent image will not be inherited, and you need to redefine it in the child image if you need to have it set.
++ The `LAUNCH` instruction and the `CMDS` instruction are in conflict, and only one of them can exist.
+
 > command format：LAUNCH {command args ...}
 
 USAGE：

src/docs/concept/kubefile.md

@@ -22,7 +22,7 @@ APP mysql https://charts/mysql.tgz
 APP elasticsearch https://charts/ elasticsearch.tgz
 APP redis local://redis.yaml
 APP businessApp local://install.sh
-LAUNCH [" mysql "," redis "," businessApp]
+LAUNCH ["mysql", "redis", "businessApp"]
 ```
 
 build command:
@@ -39,17 +39,69 @@ An `Sealer Image` that contains Kubernetes or other KxS runtimes.
 
 ![](../../../attachment/images/cluster-kubefile.png)
 
-### How to build an cluster image
+### How to build a custom cluster image
+
+```shell
+# sealer inspect docker.io/sealerio/kubernetes:v1.22.15
+{
+    "id": "bb75382891e7f04f192f1baeab18ef9c9f5503f4de8ac6dfc2a4d94f2164dde6",
+    "name": "docker.io/sealerio/kubernetes:v1.22.15",
+    "digest": "sha256:2f92b0149053ece9de6c683754f76fb9fd023a44540a9e33fc371afb8b76cc1b",
+    "manifestv1": {
+      ......
+    },
+    "ociv1": {
+      ......
+    },
+    "buildClient": {
+        "sealerVersion": "v0.9.0",
+        "buildahVersion": "1.27.1"
+    },
+    "schemaVersion": "v1alpha1",
+    "type": "kube-installer",
+    "applications": [
+        {
+            "name": "calico",
+            "type": "shell",
+            "launchfiles": [
+                "calico.sh"
+            ],
+            "version": "v1"
+        }
+    ],
+    "launch": {
+        "app_names": [
+            "calico"
+        ]
+    }
+}
+```
 
 Kubefile:
 
+> NOTE: When we build an image based on a base image,
+> we need to re-declare the app that needs to be launched in the base image for `LAUNCH` instruction.
+>
+> For more details about `APP` and `LAUNCH`, please refer to [Kubefile](kubefile.md)
+
 ```
 FROM docker.io/sealerio/kubernetes:v1.22.15
 APP mysql https://charts/mysql.tgz
-APP elasticsearch https://charts/ elasticsearch.tgz
+APP elasticsearch https://charts/elasticsearch.tgz
 APP redis local://redis.yaml
 APP businessApp local://install.sh
-LAUNCH [" mysql "," elasticsearch"," redis "," businessApp]
+LAUNCH ["calico", "mysql", "elasticsearch", "redis", "businessApp"]
+```
+
+or
+
+```
+FROM docker.io/sealerio/kubernetes:v1.22.15
+COPY mysql.tgz .
+COPY elasticsearch.tgz .
+COPY redis.yaml .
+COPY install.sh .
+CMDS ["sh application/apps/calico/calico.sh", "helm install mysql.tgz", "helm install elasticsearch.tgz", "kubectl apply -f redis.yaml", "bash install.sh"]
 ```
 
 build command:

src/docs/concept/sealer-image.md

@@ -92,3 +92,9 @@ Some information of the basic settings will be written to the cluster and stored
 ```shell
 sealer delete -a
 ```
+
+## SEE ALSO
+
++ [Kubefile](../concept/kubefile.md)
++ [Sealer Image](../concept/sealer-image.md)
++ [Sealer Cluster Image List](../sealer-images/cluster-images.md)

src/docs/getting-started/quick-start.md

@@ -8,7 +8,7 @@ The Cluster module implements the desired state of cluster through Clusterfile a
 
 ## Image module
 
-![](https://user-images.githubusercontent.com/83740799/210050287-487d3255-96e8-4030-bbff-a0134b1d18bb.png)
+![](../../../attachment/images/image-arch.png)
 
 ### Build Engine
 
@@ -28,4 +28,4 @@ disk and the remote registry hub.
 * common user interface: provides a common user interface to launch Sealer Image through sealer CLI or Clusterfile.
 * image preprocessor: implement content distribution and modification through config or env render for the Sealer Image.
 * cluster runtime: cluster installer implementation, like using kubeadm to install or upgrade k8s cluster.
-* plugin : implements the maintenance of hosts and the modification of the cluster at different process phase.
+* plugin : implements the maintenance of hosts and the modification of the cluster at different process phase.