doc: add how to use the CI containers to build

Extend the README with a section on how to use the existing CI
containers to reproduce build errors on the build servers.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

README.md

@@ -333,3 +333,129 @@ For testing purposes a x86_64 static build from the current HEAD and is
 available here:
 
 https://monom.org/linux-nvme/upload/nvme-cli-latest-x86_64
+
+## Container-Based Debugging and CI Build Reproduction
+
+The nvme-cli project provides prebuilt CI containers that allow you to locally
+reproduce GitHub Actions builds for debugging and development. These containers
+mirror the environments used in the official CI workflows.
+
+CI Containers Repository:
+https://github.com/linux-nvme/ci-containers
+
+CI Build Workflow Reference:
+https://github.com/linux-nvme/nvme-cli/blob/master/.github/workflows/libnvme-build.yml
+
+### 1. Pull a CI Container
+
+All CI containers are published as OCI/Docker images.
+
+Example: Ubuntu latest CI image:
+
+```bash
+docker pull ghcr.io/linux-nvme/debian.python:latest
+```
+
+Or with Podman:
+
+```bash
+podman pull ghcr.io/linux-nvme/debian.python:latest
+```
+
+### 2. Start the Container and Log In
+
+Start an interactive shell inside the container:
+
+```bash
+docker run --rm -it \
+  --name nvme-cli-debug \
+  ghcr.io/linux-nvme/debian.python:latest \
+  bash
+```
+
+Or with Podman:
+
+```bash
+podman run --rm -it \
+  --name nvme-cli-debug \
+  ghcr.io/linux-nvme/debian.python:latest \
+  bash
+```
+
+You are now logged into the same environment used by CI.
+
+### 3. Clone the nvme-cli Repository
+
+Inside the running container:
+
+```bash
+git clone https://github.com/linux-nvme/nvme-cli.git
+cd nvme-cli
+```
+
+(Optional) Checkout a specific branch or pull request:
+
+```bash
+git checkout <branch-or-commit>
+```
+
+### 4. Run the CI Build Script
+
+The GitHub Actions workflow uses `scripts/build.sh`. To reproduce the CI build locally:
+
+```bash
+./scripts/build.sh
+```
+
+Build artifacts remain inside the container unless a host volume is mounted.
+
+### 5. Cross-Build Example
+
+The CI supports cross compilation using a dedicated cross-build container.
+
+#### 5.1 Pull the Cross-Build Container
+
+```bash
+docker pull ghcr.io/linux-nvme/ubuntu-cross-s390x:latest
+```
+
+Or with Podman:
+
+```bash
+podman pull ghcr.io/linux-nvme/ubuntu-cross-s390x:latest
+```
+
+#### 5.2 Start the Cross-Build Container
+
+```bash
+docker run --rm -it \
+  --name nvme-cli-cross \
+  ghcr.io/linux-nvme/ubuntu-cross-s390x:latest \
+  bash
+```
+
+Or with Podman:
+
+```bash
+podman run --rm -it \
+  --name nvme-cli-cross \
+  ghcr.io/linux-nvme/ubuntu-cross-s390x:latest \
+  bash
+```
+
+#### 5.3 Clone the Repository
+
+```bash
+git clone https://github.com/linux-nvme/nvme-cli.git
+cd nvme-cli
+```
+
+#### 5.4 Run a Cross Build
+
+Example: Cross-build for `s390x`:
+
+```bash
+./scripts/build.sh -b release -c gcc -t s390x cross
+```
+
+The exact supported targets depend on the toolchains installed in the container.