Mirrord up init

docs/using-mirrord/multiple-concurrent-sessions.md

@@ -15,7 +15,14 @@ tags: ["open source", "team", "enterprise"]
 `mirrord up` allows creating and running multiple mirrord sessions based on configuration defined in a single file — think `docker compose` but for mirrord. This can be useful for cases when you need to debug multiple related microservices and would like to manage their lifecycle together.
 
 # Getting started
-Start by creating a `mirrord-up.yaml`:
+
+The fastest way to get a valid `mirrord-up.yaml` is the interactive wizard:
+```sh
+$ mirrord up init
+```
+It prompts for common settings and walks you through one or more services, then writes the file (default: `./mirrord-up.yaml`). The generated file contains only the values you set; fields you skip appear as commented-out template lines so you can discover them later. See [`mirrord up init`](#mirrord-up-init) below for details.
+
+To write the file by hand instead, start with:
 ```yaml
 services:
   user-auth-service:
@@ -121,3 +128,17 @@ Allows specifying a different config file, e.g. `mirrord up -f mirrord-up-custom
 
 ### `--key`
 Allows specifying a custom session key. When not supplied, the OS username is used.
+
+## `mirrord up init`
+
+Interactive wizard that generates a skeleton `mirrord-up.yaml`. Targets are entered as freeform strings (e.g. `deployment/foo`) — no cluster lookups are performed.
+
+```sh
+$ mirrord up init [-o path/to/mirrord-up.yaml]
+```
+
+Flow:
+1. **Common settings** — prompts for `operator`, `accept_invalid_certificates`, and `telemetry`. Only values you change from the default are written.
+2. **Services** — loops one service at a time, prompting for name, target, HTTP filter, ignore ports (with presets for Istio/Linkerd sidecars), env overrides, run type (`exec`/`container`), and the local command. Repeats until you answer "no" to *Add another service?*.
+3. **Preview and save** — prints the generated YAML and asks for the output path (confirms before overwriting).
+