### Wrapped dnf install Command Output

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/cliwrap.md

Example output when attempting to use dnf install on an image-based system.

```text
[root@cosa-devsh ~]# dnf install foo
Note: This system is image (rpm-ostree) based.
Before installing packages to the host root filesystem, consider other options:
 - `toolbox`: For command-line development and debugging tools in a privileged container
 - `podman`: General purpose containers
 - `docker`: General purpose containers
 - `rpm-ostree install`: Install RPM packages layered on the host root filesystem.
   Consider these "operating system extensions".
   Add `--apply-live` to immediately start using the layered packages.
error: not implemented
```

--------------------------------

### Start Fedora CoreOS VM with Ignition

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Use virt-install to launch a Fedora CoreOS VM with a specified Ignition configuration for automatic setup. Ensure the Ignition config file and disk image are accessible.

```bash
$ virt-install --name=fcos --vcpus=2 --ram=2048 --os-variant=fedora-coreos-stable \
    --import --network=bridge=virbr0 --graphics=none \
    --qemu-commandline="-fw_cfg name=opt.com.coreos/config,file=${PWD}/autologin.ign" \
    --disk=size=20,backing_store=${PWD}/fedora-coreos.qcow2
```

--------------------------------

### Install packages with rpm

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

You can also use the `rpm` command directly to install packages, for example, by providing a URL to an RPM file.

```bash
rpm -Uvh https://mirror.example.com/iptables-1.2.3.rpm
```

--------------------------------

### Install and run composecheck tests

Source: https://github.com/coreos/rpm-ostree/blob/main/tests/README.md

Builds and installs the project before invoking the compose test script.

```bash
make && sudo make install
```

```bash
./tests/compose
```

--------------------------------

### Sync with custom installation tree

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

Use the SKIP_INSTALL flag to sync binaries from a previously prepared installation tree.

```sh
$ make vmsync SKIP_INSTALL=1
$ make vmoverlay SKIP_INSTALL=1
```

--------------------------------

### Verify installed packages and configuration

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Check package installation details and verify configuration file integrity.

```bash
[core@tutorial ~]$ rpm -qi cachefilesd
```

```bash
[core@tutorial ~]$ cat /etc/cachefilesd.conf
```

--------------------------------

### Clone and Navigate to Example Repository

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Clone the `fcos-derivation-example` repository and change into its directory to prepare for building a custom image.

```bash
$ git clone git@github.com:coreos/fcos-derivation-example.git && cd fcos-derivation-example
```

--------------------------------

### Install RPMs and run post-processing scripts

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/compose-server.md

Use `rpm-ostree compose install` for a granular approach to image composition. This command installs RPMs, executes specified post-processing scripts from the treefile, and places the result in a target directory. A cache directory and repository should also be specified.

```bash
# rpm-ostree compose install --unified-core --cachedir=cache --repo=./build-repo /path/to/manifest.yaml ./sysroot
```

--------------------------------

### Install custom ostree version

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

Build and install a custom version of ostree into a local installation tree for testing.

```sh
$ # from the rpm-ostree build dir
$ INSTTREE=$PWD/insttree
$ rm -rf $INSTTREE
$ # from the ostree build dir
$ make
$ make install DESTDIR=$INSTTREE
$ # from the rpm-ostree build dir
$ make
$ make install DESTDIR=$INSTTREE
```

--------------------------------

### Wrapped grubby Command Output

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/cliwrap.md

Example output when executing the wrapped grubby command.

```text
[root@cosa-devsh ~]# grubby
This system is rpm-ostree based; grubby is not used.
Use `rpm-ostree kargs` instead.
```

--------------------------------

### Example Treefile with Packages

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Demonstrates the structure of a treefile including package specifications, with support for version constraints and whitespace splitting.

```yaml
packages:
  - ca-certificates
  - efitools pesign sbsigntools
  - "'podman >= 4.1'"
  - kernel-6.9.11-100.fc39
```

--------------------------------

### Build a container image

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Example Dockerfile and build command to create a container image for later import into an ostree repository.

```bash
$ cat Dockerfile
FROM quay.io/fedora/fedora-bootc:41
RUN <<EORUN
set -xeuo pipefail
dnf -y install cowsay
dnf clean all
rm /var/{log,lib,cache}/* -rf
bootc container lint
EORUN
$ podman build -t quay.io/exampleos/exampleos:latest && podman push quay.io/exampleos/exampleos:latest
```

--------------------------------

### Define Repository Configuration

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/ex-replace.md

Example configuration for a disabled repository file.

```ini
[updates-testing]
name=Fedora $releasever - $basearch - Test Updates
#baseurl=http://download.example/pub/fedora/linux/updates/testing/$releasever/Everything/$basearch/
metalink=https://mirrors.fedoraproject.org/metalink?repo=updates-testing-f$releasever&arch=$basearch
enabled=0
countme=1
repo_gpgcheck=0
type=rpm
gpgcheck=1
```

--------------------------------

### Install layered packages with rpm-ostree

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Downloads and installs a specified package and its dependencies, creating a new deployment. Can also install local package files.

```bash
# rpm-ostree install <pkg>
```

--------------------------------

### Declarative package management with treefiles

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/ex-rebuild.md

Create a YAML configuration file in the origin.d directory to define packages to install and remove, then trigger a system rebuild.

```bash
$ mkdir -p /etc/rpm-ostree/origin.d
$ cat > /etc/rpm-ostree/origin.d/mycustom.yaml <<EOF
packages:
  - vim
  - NetworkManager-wifi
override-remove:
  - moby-engine
EOF
$ rpm-ostree ex rebuild
```

--------------------------------

### Install packages with rpm-ostree

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Use `rpm-ostree install` to add packages to your system. This functions similarly to package managers like `dnf` or `microdnf`.

```bash
rpm-ostree install
```

--------------------------------

### Run Container and Check strace Version

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Launch an interactive container from the custom image and execute `strace --version` to confirm its successful installation.

```bash
$ podman run -it localhost/my-custom-fcos /bin/bash
```

```bash
$ strace --version
strace -- version 5.15
Copyright (c) 1991-2021 The strace developers <https://strace.io>.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Optional features enabled: stack-trace=libdw stack-demangle m32-mpers mx32-mpers secontext
```

--------------------------------

### Download Fedora CoreOS next stream image

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Fetches the latest 'next' stream QEMU image for Fedora CoreOS. Ensure `jq` is installed for JSON parsing.

```bash
# This is the 'next' image we will be using.
# Anything newer than this should work too.
$ RELEASE_URL=$(curl https://builds.coreos.fedoraproject.org/streams/next.json | jq -r '.architectures.x86_64.artifacts.qemu.formats."qcow2.xz".disk.location')

# Download the image.
$ curl -o fedora-coreos.qcow2.xz "$RELEASE_URL"

# Uncompress the qemu image.
$ unxz fedora-coreos.qcow2.xz
```

--------------------------------

### Verify cachefilesd Package Installation

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Use `rpm -qi` to confirm that the `cachefilesd` package is not installed on the system.

```bash
[core@tutorial ~]$ rpm -qi cachefilesd
package cachefilesd is not installed
```

--------------------------------

### Configure Custom RPM Repository

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/ex-replace.md

Download and install a repository configuration file into the system's yum directory.

```bash
$ curl -s https://copr.fedorainfracloud.org/coprs/g/kernel-vanilla/mainline-wo-mergew/repo/fedora-rawhide/group_kernel-vanilla-mainline-wo-mergew-fedora-rawhide.repo | sudo tee /etc/yum.repos.d/kernel-vanilla-mainline-wo-mergew.repo
```

--------------------------------

### Install package with forced file replacement

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Installs a package, allowing it to overwrite files from other packages. Useful for specific scenarios like kernel module updates without rebuilding.

```bash
# rpm-ostree install --force-replacefiles <pkg>
```

--------------------------------

### Wrapped rpm Command Output

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/cliwrap.md

Example output when executing the wrapped rpm command on an image-based system.

```text
[root@cosa-devsh ~]# rpm -e toolbox
rpm-ostree: Note: This system is image (rpm-ostree) based.
rpm-ostree: Dropping privileges as `rpm` was executed with not "known safe" arguments.
rpm-ostree: You may invoke the real `rpm` binary in `/usr/libexec/rpm-ostree/wrapped/rpm`.
rpm-ostree: Continuing execution in 5 seconds.

error: can't create transaction lock on /usr/share/rpm/.rpm.lock (Read-only file system)
[root@cosa-devsh ~]# 
```

--------------------------------

### Wrapped dracut Command Output

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/cliwrap.md

Example output when executing the wrapped dracut command.

```text
[root@cosa-devsh ~]# dracut
This system is rpm-ostree based; initramfs handling is
integrated with the underlying ostree transaction mechanism.
Use `rpm-ostree initramfs` to control client-side initramfs generation.
```

--------------------------------

### Arch-Include Example

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Includes base architectures with specific treefiles. Each member maps a base architecture to a single string or array of strings for inclusion. Processed after general 'include'.

```yaml
arch-include:
  x86_64: bootloader-x86_64.yaml
  s390x:
    - bootloader-s390x.yaml
    - tweaks-s390x.yaml
```

--------------------------------

### Containerfile for rpm-ostree Build Environment

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Sets up a CentOS Stream 9 environment with necessary tools and repositories for building rpm-ostree. Includes updating packages, enabling CRB, adding custom repositories, installing rpm-build, and setting up the rustup toolchain.

```bash
FROM centos:stream9

RUN dnf update -y
RUN dnf install -y 'dnf-command(config-manager)' epel-release
RUN dnf config-manager --set-enabled crb
RUN dnf config-manager --add-repo https://buildlogs.centos.org/9-stream/automotive/aarch64/packages-main/
RUN dnf config-manager --add-repo https://buildlogs.centos.org/9-stream/autosd/aarch64/packages-main/

# Install rpm-build and create empty dir structure.
RUN dnf install -y rpm-build
RUN mkdir -p $HOME/rpmbuild/{BUILD,RPMS,SOURCES,SPECS,SRPMS}

# Install deps required for recent rpm-ostree
RUN cd $HOME/rpmbuild/SPECS/ && curl -OL https://gitlab.com/redhat/centos-stream/rpms/rpm-ostree/-/raw/c9s/rpm-ostree.spec

RUN cd $HOME/rpmbuild/SPECS && dnf builddep -y rpm-ostree.spec
RUN cargo install cargo-vendor-filterer --version ^0.5

# Lets use the latest from community (see next curl rustup step).
# Also avoids "cargo metadata: error: failed to run rustc to learn about target-specific information"
RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
```

--------------------------------

### Build and Test rpm-ostree with Kola

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

This sequence demonstrates the workflow for iterating on kola external tests. It includes building the project, generating a local FCOS VM, installing test suite components, and running a specific kola test.

```bash
make                                 # To build
cosa build-fast                      # Generate a local FCOS VM
sudo make -C tests/kolainst install  # Run this only when you change the test suite
kola run ext.rpm-ostree.destructive.container-image  # Or any other test you want
```

--------------------------------

### Replace RPM with local file

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Downloads a package locally and replaces the installed version with the local file.

```bash
$ curl https://rpmfind.net/linux/fedora/linux/updates/testing/38/Everything/x86_64/Packages/p/podman-4.5.1-1.fc38.x86_64.rpm --output podman.rpm
$ sudo rpm-ostree override replace ./podman.rpm
```

--------------------------------

### Postprocess Script Example

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Specifies a script to be executed within the target tree context. The script is copied, run in a restricted chroot, and then deleted. Avoid unless necessary, as it bypasses RPM versioning.

```shell
#!/bin/bash
# Example postprocess script
echo "Running postprocess script..."
# Add your commands here
```

--------------------------------

### Include Example

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Specifies paths to other treefiles for inheritance. Non-array values override parent values, while array values are concatenated. Supports single string or array of strings.

```yaml
include:
  - manifests/kernel.yaml
  - manifests/bootupd.yaml
```

--------------------------------

### Postprocess Inline Script Example

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

An inline variant of postprocess-script, defined as an array of strings. Useful for inheritance and ordering. Scripts in included manifests are executed before those in the main manifest.

```yaml
postprocess:
  - echo foo
```

--------------------------------

### Check cachefilesd Version Inside Container

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Execute `cachefilesd --version` within the running container to verify that `cachefilesd` has been correctly installed.

```bash
$ cachefilesd --version
```

```text
cachefilesd version 0.10.10
```

--------------------------------

### Conditional Include Example

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Includes treefiles based on conditions involving variables. Supports multiple conditions that must all be met for inclusion. Operators include ==, !=, <, <=, >, >=.

```yaml
conditional-include:
  - if:
    - "os.version == 22"
    - "arch == x86_64"
    include: "base-x86_64.yaml"
```

--------------------------------

### Add Commit Metadata Example

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Inject custom metadata into composed commits. Keys can be overridden via the command line. Supports variable substitution for string values.

```yaml
add-commit-metadata:
  cool-os.is-production: false
  cool-os.git-snapshot: "${git_snapshot}"
```

--------------------------------

### Set automatic version prefix with date and variable substitution

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Use `automatic-version-prefix` with a date format and variable substitution to dynamically set commit versions. This example uses the `${releasever}` variable and a daily date format.

```yaml
automatic-version-prefix: "${releasever}.<date:%Y%m%d>.dev"
```

--------------------------------

### Spawn VM and sync build

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

Use the helper script to spawn a QEMU image and sync the current build into the VM.

```sh
export COSA_DIR=/path/to/cosa/workdir
tests/vm.sh spawn
make vmsync
```

--------------------------------

### Replace kernel packages

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Overrides the kernel by replacing the entire set of installed kernel-related RPMs.

```bash
$ ls -al kernel*.rpm
-rw-r--r--. 1 root root  8085596 Jan 27 22:02 kernel-4.18.0-123.el8.x86_64.rpm
-rw-r--r--. 1 root root 40709632 Jan 27 22:02 kernel-core-4.18.0-123.el8.x86_64.rpm
-rw-r--r--. 1 root root 32533504 Jan 27 22:02 kernel-modules-4.18.0-123.el8.x86_64.rpm
-rw-r--r--. 1 root root  8790996 Jan 27 22:02 kernel-modules-extra-4.18.0-123.el8.x86_64.rpm
$ rpm-ostree override replace ./kernel*.rpm
```

--------------------------------

### Verify Automatic Login and Hostname

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

After the VM boots, observe the console output to confirm automatic login and check the hostname, which should reflect the applied configuration.

```text
[  OK  ] Started rpm-ostree System Management Daemon.

Fedora CoreOS 32.20200715.3.0
Kernel 5.7.8-200.fc32.x86_64 on an x86_64 (ttyS0)

SSH host key: SHA256:XlbayjbgDKNoAAHQxsEL5Q7BdwLxxWSw4NXN9SALLmo (ED25519)
SSH host key: SHA256:3sx5jseteO4BvdOMWIi0J4koQL015mLonnD0UPTtnZk (ECDSA)
SSH host key: SHA256:K0fn5/TMJOoMs7Fu7RRkE7IBEf2t8OYCfVaVc+GJWGs (RSA)
ens2: 192.168.122.127 fe80::5054:ff:feb9:3d97
Ignition: user provided config was applied
No ssh authorized keys provided by Ignition or Afterburn
tutorial login: core (automatic login)

[core@tutorial ~]$

```

--------------------------------

### Clone the autosd repository

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Initializes the project environment by cloning the sample-images repository.

```bash
git clone https://gitlab.com/CentOS/automotive/sample-images && cd sample-images
```

--------------------------------

### Add cachefilesd to Dockerfile

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Modify the `Dockerfile` to include `cachefilesd` in the `rpm-ostree install` command, alongside `strace`.

```dockerfile
RUN rpm-ostree install strace cachefilesd && rpm-ostree cleanup -m
```

--------------------------------

### Rebase to a container image

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Use this command to switch your system to boot from a container image. This operation rebases the system to the specified container image from a registry.

```bash
$ rpm-ostree rebase ostree-unverified-registry:quay.io/fedora/fedora-coreos:stable
```

--------------------------------

### Replace RPM with remote URL

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Replaces an installed RPM package with a specific version from a remote HTTP URL.

```bash
$ sudo rpm-ostree override replace https://kojipkgs.fedoraproject.org//packages/podman/3.3.1/1.fc34/x86_64/podman-3.3.1-1.fc34.x86_64.rpm
```

--------------------------------

### Initialize Git Submodules and Build rpm-ostree

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

This sequence of commands initializes git submodules, configures the build using autotools, and then compiles the rpm-ostree project. Ensure the repository is cloned before running.

```bash
$ git submodule update --init
$ ./autogen.sh --prefix=/usr --libdir=/usr/lib64 --sysconfdir=/etc
$ make
```

--------------------------------

### Run rpm-ostree Unit Tests

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

Execute the project's unit tests using the 'make check' command. This is a standard way to verify the correctness of the code.

```bash
$ make check
```

--------------------------------

### Generate the autosd image

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Executes the build process for the qcow2 image using the initoverlayfs target.

```bash
pushd osbuild-manifests
     sudo make cs9-qemu-initoverlayfs-ostree.x86_64.qcow2
popd
```

--------------------------------

### Set automatic version prefix

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Use `automatic-version-prefix` to set a static prefix for commit versions. This example sets the prefix to "22.0".

```yaml
automatic-version-prefix: "22.0"
```

--------------------------------

### Create a local RPM repository

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Generates repository metadata for the local RPM build directory.

```bash
pushd ~/rpmbuild/RPMS
    createrepo .
popd
```

--------------------------------

### Live-apply package additions with rpm-ostree

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Applies package additions to the running system immediately, provided there are no other pending changes. Use with caution.

```bash
# rpm-ostree install -yA <pkg>
```

--------------------------------

### Apply image configuration

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Use the --image-config flag to apply a JSON configuration file during image composition.

```bash
rpm-ostree compose image --initialize --format=ociarchive --image-config=config.json manifest.yaml image.ociarchive
```

--------------------------------

### Build OCI image from root filesystem tree

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/build-chunked-oci.md

This command builds a chunked OCI image from a source root filesystem tree. First, create the rootfs using `rpm-ostree compose rootfs`, then use `build-chunked-oci` with the `--rootfs` option. The output can be directed to `containers-storage` or `oci`.

```bash
# assumes package system configuration in /repos
rpm-ostree compose rootfs --source-root=/repos /path/to/input_manifest.yml /path/to/target_rootfs
rpm-ostree compose build-chunked-oci --bootc --format-version=1 --rootfs=/path/to/target_rootfs \
           --output containers-storage:quay.io/exampleos/exampleos:latest
podman push quay.io/exampleos/exampleos:latest
```

--------------------------------

### Perform an offline rpm-ostree system upgrade

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Prepares a system upgrade by creating a new deployment, which is finalized at shutdown. A reboot is required to apply the update.

```bash
# rpm-ostree upgrade
```

--------------------------------

### Run additional post-processing on sysroot

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/compose-server.md

After `rpm-ostree compose install`, you can manually modify files under the sysroot's rootfs. Then, run `rpm-ostree compose postprocess` to apply any remaining post-processing steps defined in the manifest.

```bash
# rpm-ostree compose postprocess ./sysroot/rootfs /path/to/manifest.yaml
```

--------------------------------

### Enable Testing Repository with sed

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/ex-replace.md

Use this command to enable a testing repository by modifying the repository configuration file. It targets the first occurrence of 'enabled=0' and replaces it with 'enabled=1'.

```bash
sudo sed -i '0,/enabled=0/s//enabled=1/' /etc/yum.repos.d/fedora-updates-testing.repo
```

--------------------------------

### Build Custom FCOS Image with Podman

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Use Podman to build an OCI image from the modified `Dockerfile`. The image will be tagged as `localhost/my-custom-fcos`.

```bash
$ podman build -t localhost/my-custom-fcos .
```

--------------------------------

### Build OCI image from container image

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/build-chunked-oci.md

Use this command to build a chunked OCI image from an existing container image. Ensure the input image is already fetched into a `containers-storage` instance. The output can be directed to `containers-storage` or `oci`.

```bash
podman build -t quay.io/exampleos/exampleos:build ...
... 
rpm-ostree compose build-chunked-oci --bootc --format-version=1 \
           --from=quay.io/exampleos/exampleos:build --output containers-storage:quay.io/exampleos/exampleos:latest
podman push quay.io/exampleos/exampleos:latest
```

--------------------------------

### Push OCI image to registry

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Authenticate with the container registry and push the local image.

```bash
$ podman login quay.io
```

```bash
$ podman push localhost/my-custom-fcos quay.io/<YOURUSER>/my-custom-fcos
```

--------------------------------

### Rebase Fedora CoreOS to custom image

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Stop the Zincati service to prevent auto-updates and perform the system rebase.

```bash
[core@tutorial ~]$ sudo systemctl stop zincati.service
```

```bash
[core@tutorial ~]$ sudo rpm-ostree rebase \
    ostree-unverified-registry:quay.io/<YOURUSER>/my-custom-fcos
```

--------------------------------

### Run fcos-buildroot Container Interactively

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

Use this command to work interactively inside the fcos-buildroot container. Ensure you run it from the project's root directory. This mounts your current directory into the container.

```bash
# IMPORTANT: Run this command from the projects root directory!
$ podman run --rm -it -v "$PWD:$PWD:z" -w "$PWD" \
    quay.io/coreos-assembler/fcos-buildroot:testing-devel
```

--------------------------------

### Check rpm-ostree system status

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Displays current deployments and the default boot entry. The '●' indicates the currently booted deployment.

```bash
# rpm-ostree status
```

--------------------------------

### Apply overrides live

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/administrator-handbook.md

Applies staged override changes to the live system or reverts to the booted tree.

```bash
$ rpm-ostree apply-live --allow-replacement
```

--------------------------------

### Set SELinux label for Ignition config

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Applies the correct SELinux label (`svirt_home_t`) to the Ignition configuration file to ensure it can be accessed by the virtual machine. This is necessary when using `virt-install` with libvirt.

```bash
# Setup the correct SELinux label to allow access to the config
$ chcon --verbose --type svirt_home_t autologin.ign
```

--------------------------------

### Check cachefilesd Configuration

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/layering.md

Inspect the contents of the `/etc/cachefilesd.conf` file to verify the cache configuration settings have been applied.

```bash
[core@tutorial ~]$ cat /etc/cachefilesd.conf
dir /var/cache/fscache
tag mycache
brun  8%
bcull 6%
bstop 2%
frun  9%
fcull 5%
fstop 4%
secctx system_u:system_r:cachefiles_kernel_t:s0
```

--------------------------------

### View manifest configuration changes

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Displays the required diff for adding the extra repository to the manifest.

```diff
diff --git a/osbuild-manifests/distro/cs9.ipp.yml b/osbuild-manifests/distro/cs9.ipp.yml
index c2e3abc..1564c9d 100644
--- a/osbuild-manifests/distro/cs9.ipp.yml
+++ b/osbuild-manifests/distro/cs9.ipp.yml
@@ -15,6 +15,8 @@ mpp-vars:
     baseurl: https://mirror.stream.centos.org/SIGs/9-stream/autosd/$arch/packages-main/
   - id: next
     baseurl: https://download.copr.fedorainfracloud.org/results/@centos-automotive-sig/next/epel-9-$arch/
+  - id: extra
+    baseurl: file:///root/rpmbuild/RPMS/
   distro_devel_repos:
   - id: crb
     baseurl: $distro_baseurl/CRB/$arch/os/
```

--------------------------------

### rpm-ostree Configuration Schema

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Configuration parameters for defining the build manifest in rpm-ostree.

```APIDOC
## Configuration Schema

### Description
Defines the structure and options for the rpm-ostree build manifest.

### Parameters
- **repo-packages** (Array of objects) - Optional - Set of packages to install from specific repos.
  - **packages** (Array of strings) - Required - List of packages to install.
  - **repo** (String) - Required - Name of the repo.
- **ostree-layers** (Array of strings) - Optional - OSTree refs to check out after package installation.
- **ostree-override-layers** (Array of strings) - Optional - OSTree refs that override files in packages and prior layers.
- **container-cmd** (Array of strings) - Optional - Maps to the CMD Dockerfile instruction.
- **recommends** (Boolean) - Optional - Install Recommends, defaults to true.
- **units** (Array of strings) - Optional - Systemd units to enable.
- **default-target** (String) - Optional - Set the default systemd target.
- **rpmdb** (String) - Optional - RPM database backend (target or host).
- **rpmdb-normalize** (Boolean) - Optional - Deterministic RPM database result.
- **selinux-label-version** (Integer) - Optional - Set to 1 to label /usr/etc as /etc.
- **readonly-executables** (Boolean) - Optional - Remove write bit from all executables.
- **remove-files** (Array of strings) - Optional - Files to delete from the generated tree.
- **remove-from-packages** (Array) - Optional - Delete files matching regex from specified packages.

### Request Example
{
  "repo-packages": [{"packages": ["vim"], "repo": "fedora"}],
  "recommends": false,
  "units": ["sshd.service"],
  "remove-from-packages": [["cpio", "/usr/share/.*"]]
}
```

--------------------------------

### Move /opt files during build

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Use this pattern in a Dockerfile to relocate files from /opt to /var/opt and create a symlink for compatibility.

```dockerfile
FROM quay.io/fedora/fedora-coreos:testing-devel
RUN mkdir /var/opt && \
    rpm -Uvh https://downloads.linux.hpe.com/repo/stk/rhel/7/x86_64/current/hp-scripting-tools-11.60-20.rhel7.x86_64.rpm && \
    mv /var/opt/hp/ /usr/lib/hp && \
    echo 'L /opt/hp - - - - ../../usr/lib/hp' > /usr/lib/tmpfiles.d/hp.conf && \
    ostree container commit
```

--------------------------------

### Enable cliwrap at Build Time

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/cliwrap.md

Set this configuration in the treefile to enable cliwrap during the build process.

```yaml
cliwrap: true
```

--------------------------------

### Run rpm-ostree Development Container

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Executes the built container, mounting the host's rpmbuild directory to persist generated RPMs. This allows interactive access to the build environment.

```bash
sudo podman run --rm --security-opt label=disable -v /home/$USER/rpmbuild/:/home/$USER/rpmbuild/ -ti rpmostreedevel /bin/bash
```

--------------------------------

### Create buildroot Alias for Container Usage

Source: https://github.com/coreos/rpm-ostree/blob/main/HACKING.md

Create a 'buildroot' alias to use the fcos-buildroot container for commands like 'make'. This simplifies running build commands within the container environment. Remember to run this from the project's root directory.

```bash
# IMPORTANT: Run this command from the projects root directory!
$ alias buildroot="podman run --rm -it -v \"$PWD:$PWD:z\" -w \"$PWD\" \
    quay.io/coreos-assembler/fcos-buildroot:testing-devel"
# These commands run in the container now
$ buildroot make ...
```

--------------------------------

### Import container image to ostree repository

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Commands to pull a container image into a bare-user ostree repository and identify the resulting commit.

```bash
$ ostree container image pull /path/to/repo ostree-unverified-registry:quay.io/exampleos/exampleos:latest
# Find the branch/ref for the container
$ imgref=$(ostree --repo=/path/to/repo refs ostree/container/image)
# Find its commit
$ commit=$(ostree --repo=/path/to/repo rev-parse ostree/container/image/$imgref)
```

--------------------------------

### Define extensions in extensions.yaml

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/extensions.md

Configuration file format for specifying OS extensions and development packages to be downloaded during the compose process.

```yaml
# Any additional repos to enable on top of treefile repos
repos:
  - myrepo

# The top-level object is a dict. The only supported key
# right now is `extensions`, which is a dict of extension
# names to extension objects.
extensions:
  # This can be whatever name you'd like. The name itself
  # isn't used by rpm-ostree.
  sooper-dooper-tracers:
    # Optional; defaults to `os-extension`. An OS extension
    # is an extension intended to be `rpm-ostree install`ed.
    kind: os-extension
    # List of packages for this extension
    packages:
        - strace
        - ltrace
    # Optional additional repos (still added globally).
    # The reason use per-extension `repos` and `modules`
    # is that it more closely groups them (where relevant)
    # and further these are only added after architecture conditionals
    # apply, so one can use repositories that only exist
    # on a particular architecture.
    repos:
      - sooper-repo
    # Optional list of architectures on which this extension
    # is valid. These are RPM basearches. If omitted,
    # defaults to all architectures.
    architectures:
        - x86_64
        - aarch64
  kernel-dev:
    # A development extension lists packages useful for
    # developing for the target OSTree, but won't be layered
    # on top. A common example is kernel modules. No
    # depsolving happens, packages listed are downloaded.
    kind: development
    packages:
      - kernel-devel
      - kernel-headers
    # Optional name of a base package used to constrain the
    # EVR of all the packages in this extension.
    match-base-evr: kernel
```

--------------------------------

### Compose base images

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Generate base images from treefiles using different formats.

```bash
$ rpm-ostree compose image --initialize-mode=if-not-exists --format=ociarchive \
             workstation-ostree-config/fedora-silverblue.yaml fedora-silverblue.ociarchive
```

```bash
$ rpm-ostree compose image  --initialize-mode=if-not-exists --format=registry \
             workstation-ostree-config/fedora-silverblue.yaml quay.io/example/exampleos:latest
```

--------------------------------

### Clone and Prepare rpm-ostree Fork

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/building-rpm-ostree-and-autosd.md

Clones a forked rpm-ostree repository and checks out a specific branch for development. Initializes necessary submodules required for the build process.

```bash
cd /tmp
git clone https://github.com/dougsland/rpm-ostree.git && cd rpm-ostree
git checkout remotes/origin/initoverlayfs -b initoverlayfs
```

```bash
git submodule update --init
```

--------------------------------

### Variable Substitution in Mutate OS Release

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/treefile.md

Illustrates variable substitution for the 'mutate-os-release' field to customize OS release information.

```yaml
mutate-os-release: "${releasever}"
```

--------------------------------

### Enable or Disable cliwrap on a Client System

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/cliwrap.md

Use these commands to toggle the cliwrap feature on an existing system.

```bash
$ rpm-ostree deploy --ex-cliwrap=true
```

```bash
$ rpm-ostree deploy --ex-cliwrap=false
```

--------------------------------

### Configure OCI image metadata

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Define environment variables, commands, and labels for OCI images using a JSON configuration file.

```json
{
    "Env": [
        "FOO=BAR"
    ],
    "Cmd": [
        "/bin/bash"
    ],
    "Labels": {
        "license": "MIT"
    }
}
```

--------------------------------

### Polkit Policy for rpm-ostree

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/architecture-daemon.md

This is a base Polkit policy file for rpm-ostree. It defines the actions that can be authorized, allowing unprivileged users to perform system mutations when properly configured.

```polkit
polkit.addRule(function(action, subject) {
    if (action.id.indexOf("org.projectatomic.rpmostree1.") == 0 &&
        subject.isInGroup("wheel")) {
        return polkit.Result.YES;
    }
});

```

--------------------------------

### Generate chunked images

Source: https://github.com/coreos/rpm-ostree/blob/main/docs/container.md

Create efficient, multi-layer container images to optimize download sizes.

```bash
$ rpm-ostree compose container-encapsulate --repo=/path/to/repo fedora/35/x86_64/silverblue \
             docker://quay.io/myuser/fedora-silverblue:35
```