红帽全球峰会第 2 章 Building and testing RHEL bootc images
You can build and test RHEL container images using Podman and Containerfiles to create, customize, and share bootable RHEL system images across environments efficiently. You can also use other tools, for example, OpenShift Container Platform. For more examples of configuring RHEL systems by using containers, see the rhel-bootc-examples repository.
You can use a Containerfile to build and customize your own bootc-based image with the tools, configurations, and applications you need. While most standard instructions work, some are ignored when the image is installed on a system.
图 2.1. Building an image by using instructions from a Containerfile, testing the container, pushing an image to a registry, and sharing it with others
A general Containerfile structure is the following:
FROM registry.redhat.io/rhel10/rhel-bootc:latest
RUN dnf -y install [software] [dependencies] && dnf clean all
ADD [application]
ADD [configuration files]
RUN [config scripts]
The available commands that are usable inside a Containerfile and a Dockerfile are equivalent.
However, the following commands in a Containerfile are ignored when the rhel-10-bootc image is installed to a system:
-
ENTRYPOINTandCMD(OCI:Entrypoint/Cmd): you can setCMD /sbin/initinstead. -
ENV(OCI:Env): change thesystemdconfiguration to configure the global system environment. -
EXPOSE(OCI:exposedPorts): it is independent of how the system firewall and network function at runtime. -
USER(OCI:User): configure individual services inside the RHEL bootc to run as unprivileged users instead.
The rhel-10-bootc container image reuses the OCI image format.
-
The
rhel-10-bootccontainer image ignores the container config section (Config) when it is installed to a system. -
The
rhel-10-bootccontainer image does not ignore the container config section (Config) when you run this image by using container runtimes such aspodmanordocker.
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