Open Liberty container images
A container image is a layered executable software package that contains everything you need to build and run a containerized application. You can use an Open Liberty container image to build an application image that meets your development needs.
Open Liberty container images are available from the IBM Container Registry (ICR). You can pull images from ICR without authentication.
Container images on IBM Container Registry
You can append an Open Liberty container image tag to the icr.io/appcafe/open-liberty:
source to specify the details of the container image that you pull from ICR. For more information, see the Build an application image section.
Select from the following container image tags for the latest Open Liberty release from ICR.
kernel-slim-java21-openj9-ubi-minimal
kernel-slim-java17-openj9-ubi
kernel-slim-java11-openj9-ubi
kernel-slim-java8-openj9-ubi
kernel-slim-java8-ibmjava-ubi
full-java21-openj9-ubi-minimal
full-java17-openj9-ubi
full-java11-openj9-ubi
full-java8-openj9-ubi
full-java8-ibmjava-ubi
beta
latest
These tags pull the latest version because they do not specify a version number. You can specify a version other than the latest version in the image tag. If you do not specify a tag value, latest
is used by default. For more information about these tag values, see the Container image tags naming conventions section.
After the initial release of the Liberty container images, they are refreshed regularly (every 1-2 weeks) to include fixes for the operating system (OS) and Java. For more information on the full list of supported Open Liberty container images, see the IBM Container Registry (ICR) page on the Open Liberty GitHub repository.
If you have an IBM Cloud ID, you can generate a list of the currently available images in ICR by using the IBM Cloud CLI with the IBM Cloud Container Registry CLI plug-in installed. Authentication is required only to list the images. You can pull images from ICR without authentication. To list the images, run the following commands.
ibmcloud login ibmcloud cr region-set global ibmcloud cr images --restrict appcafe/open-liberty
Build an application image
You can use an Open Liberty container image tag in a Dockerfile
or Containerfile
file to build an application image that adds a single application and its corresponding configuration. Do not configure the container manually after it is started, except for debugging purposes, because these changes are not reflected in new containers that are created from the image.
Set your image template similar to the following example, which uses the kernel-slim-java21-openj9-ubi-minimal
tag to build an image that uses the latest Open Liberty release with the OpenJ9 distribution of Java 21.
FROM icr.io/appcafe/open-liberty:kernel-slim-java21-openj9-ubi-minimal
# Add a Liberty server configuration including all necessary features
COPY --chown=1001:0 server.xml /config/
# This script adds the requested XML snippets to enable Liberty features and grow the image to be fit-for-purpose.
# This option is available only in the 'kernel-slim' image type. The 'full' and 'beta' tags already include all features.
RUN features.sh
# Add interim fixes (optional)
COPY --chown=1001:0 interim-fixes /opt/ol/fixes/
# Add an application
COPY --chown=1001:0 Sample1.war /config/dropins/
# This script adds the requested server configuration, applies any interim fixes, and populates caches to optimize the runtime.
RUN configure.sh
A template like this example results in a container image that has your application and configuration preinstalled, which means you can create new fully configured containers at any time. For more information about the different arguments and environment variables that you can specify to customize your application image, see the Open Liberty container image GitHub documentation.
You can also use Open Liberty InstantOn to improve the startup time of your application container image.
Container image tags naming conventions
Open Liberty container image tags use the following naming convention.
<optional fix pack version-><liberty image type>-<java version>-<java type>-<base image type>
The following tag values determine the resources that are included in a container image.
- Fix pack version
This value is optional. If you do not specify a fix pack version, your container image includes the latest release of Open Liberty. In addition to the latest release, the two most recent quarterly fix pack releases are always maintained for the
kernel-slim
andfull
image types.Open Liberty quarterly release versions end in
.3
,.6
,.9
, or.12
. For example, if the latest Open Liberty release is24.0.0.1
, then the23.0.0.12
and23.0.0.9
releases are also maintained in ICR. To pull one of these release versions instead of the latest, add your chosen release version to the beginning of any of thekernel-slim
orfull
image tags in the previous list. For example, if23.0.0.12
is a recent quarterly release, you can pull an image that includes the23.0.0.12
release with an OpenJ9 distribution of Java 8 by specifying the23.0.0.12-full-java8-openj9-ubi
tag. Thebeta
image is available only for the latest beta release of Liberty and includes the latest Java JRE.- Liberty image type
Two different image types are available:
kernel-slim
orfull
. Thefull
type provides a server with all Open Liberty features and packages installed.The
kernel-slim
type provides just the bare minimum server, which you can customize by adding only the features that your application needs. This image type supports the best practice for production images because you end up with a more lightweight image that packages only what is essential for your application. For more information, see the Build an application image section.- Java version
This value determines the version of Java SE that the runtime uses. Tags are available for all Java long term support (LTS) releases that are listed on the Java SE Support page.
- Java type
This value determines the type of Java SE distribution that the runtime uses. Current options are IBM Semeru Runtime with Eclipse OpenJ9, named
openj9
and, for Java SE 8 only, the IBM SDK, Java Technology Edition, namedibmjava
.Both the
ibmjava
andopenj9
Java types support the Linux x86_64 (amd64
), Linux on Power (ppc64le
), and Linux on IBM Z (s390x
) architectures. Only images that use theopenj9
Java type support the Linux on ARM (arm64
) architecture.All Java 21 images are based on Universal Base Image (UBI) 9 minimal and include IBM Semeru Runtimes for Java 21 JRE. These images all specify the
openj9
type.Java 8, 11 and 17 images with the
openj9
type are based on Universal Base Image (UBI) 8 standard and include IBM Semeru Runtime for the respective Java version with the JDK. Java 8 images with theibmjava
type are based on Universal Base Image (UBI) 8 standard and include IBM Java 8 JRE.- Base image type
Liberty images are available with two different types of Red Hat Universal Base Image (UBI):
ubi-minimal
orubi
.ubi-minimal
offers a minimized pre-installed content set and the package managermicrodnf
for adding additional packages.ubi
offers the standard images with access toyum
repositories and includes utilities such astar
andgzip
.
In addition to the tags that follow this naming convention, Open Liberty offers the following preformatted tags that pull particular images.
latest
: This tag simplifies pulling the full latest Open Liberty release with the latest Java JRE. It is an alias for thefull-java21-openj9-ubi-minimal
tag. If you do not specify a tag value,latest
is used by default.beta
: This tag is based on Universal Base Image (UBI) 9 minimal and the latest Java JRE and provides the most recent beta release of Liberty, which includes all the features and capabilities from the most recent release, plus new and updated features that are currently in development. The beta image supports only the Linux x86_64 (amd64
) architecture.