Getting Started with Fedora CoreOS
There are three Fedora CoreOS (FCOS) update streams available: `stable`, `testing`, and `next`. In general, you will want to use `stable`, but it is recommended to run some machines on `testing` and `next` as well and provide feedback.
Each stream has a canonical URL representing its current state in JSON format, known as "stream metadata". For example, the stream metadata URL for `stable` is: https://builds.coreos.fedoraproject.org/streams/stable.json
For automating Fedora CoreOS installations, it is expected that you will interact with stream metadata. While Fedora CoreOS does automatic in-place updates, it is generally a good practice to start provisioning new machines from the latest images.
For more information on using stream metadata, see xref:stream-metadata.adoc[Stream Metadata]. For more about the available streams, see xref:update-streams.adoc[Update Streams].
Provisioning Philosophy
Fedora CoreOS does not have a separate install disk. Instead, every instance starts from a generic disk image which is customized on first boot via https://github.com/coreos/ignition[Ignition].
Each platform has specific logic to retrieve and apply the first boot configuration. For cloud deployments, Ignition gathers the configuration via user-data mechanisms. In the case of bare metal, Ignition can fetch its configuration from the disk or from a remote source.
For more information on configuration, refer to the documentation for xref:producing-ign.adoc[Producing an Ignition File].
Booting on a cloud VM (AWS example)
Booting on a local hypervisor (libvirt example)
Exploring the OS
Once the VM has finished booting, its IP addresses will appear on the serial console. By design, there are no hard-coded default credentials.
If you set up an xref:authentication.adoc[SSH key] for the default `core` user, you can SSH into the VM and explore the OS:
ssh core@<ip address>
Getting in touch
We recommend that all users subscribe to the low-volume https://lists.fedoraproject.org/archives/list/coreos-status@lists.fedoraproject.org/[coreos-status mailing list] for operational notices related to Fedora CoreOS.