Marked rebase-snap as deprecated

CHANGELOG.md

@@ -26,6 +26,10 @@
 
 ### Deprecated
 
+- [#4209](https://github.com/firecracker-microvm/firecracker/pull/4209):
+  `rebase-snap` tool is now deprecated. Users should use `snapshot-editor`
+  for rebasing diff snapshots.
+
 ### Fixed
 
 - Fixed a bug that ignored the `--show-log-origin` option, preventing it from

docs/snapshotting/snapshot-editor.md

@@ -20,7 +20,7 @@ This command is used to merge a `diff` snapshot memory file on
 top of a base memory file.
 
 **Note**
-You can also use `rebase-snap` tool for this.
+You can also use `rebase-snap` (deprecated) tool for this.
 
 Arguments:
 

docs/snapshotting/snapshot-support.md

@@ -249,10 +249,10 @@ created by a subsequent `/snapshot/create` API call. The order in which the
 snapshots were created matters and they should be merged in the same order
 in which they were created. To merge a `diff` snapshot memory file on
 top of a base, users should copy its content over the base. This can be done
-using the `rebase-snap` or `snapshot-editor` tools provided with the
+using the `rebase-snap` (deprecated) or `snapshot-editor` tools provided with the
 firecracker release:
 
-`rebase-snap` example:
+`rebase-snap` (deprecated) example:
 
 ```bash
 rebase-snap --base-file path/to/base --diff-file path/to/layer

src/rebase-snap/src/main.rs

@@ -115,6 +115,10 @@ fn rebase(base_file: &mut File, diff_file: &mut File) -> Result<(), FileError> {
 }
 
 fn main() -> Result<(), RebaseSnapError> {
+    println!(
+        "This tool is deprecated and will be removed in the future. Please use 'snapshot-editor' \
+         instead."
+    );
     let result = main_exec();
     if let Err(e) = result {
         eprintln!("{}", e);