open-liberty

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Official Open Liberty image.

GitHub repo: https://github.com/OpenLiberty/ci.docker

Library reference

This content is imported from the official Docker Library docs, and is provided by the original uploader. You can view the Docker Store page for this image at https://store.docker.com/images/open-liberty

Supported tags and respective Dockerfile links

Quick reference

Overview

The images in this repository contain Open Liberty. For more information about Open Liberty, see the Open Liberty Website site.

Images

There are multiple images available in this repository.

The kernel image contains the Liberty kernel and can be used as the basis for custom built images that contain only the features required for a specific application. For example, the following Dockerfile starts with this image, copies in the server.xml that lists the features required by the application.

FROM open-liberty:kernel
COPY server.xml /config/

The microProfile1 image contains the features required to implement Eclipse MicroProfile 1.3. The webProfile8 image contains the features required for Java EE8 Web Profile compliance. The javaee8 image adds the features required for Java EE8 Full Platform compliance. The javaee8 image is also tagged with latest. The webProfile7 image contains the features required for Java EE7 Web Profile compliance. The javaee7 image adds the features required for Java EE7 Full Platform compliance. The springBoot1 and springBoot2 images contain the features required for running Spring Boot 1.5 and 2.0 applications.

There are also additional images for different JVM combinations. Currently there are tags for java8 only, but there are two variants one based on IBM Java and Ubuntu and the other based on the IBM small footprint Java which is based on alpine linux. The naming structure for the variants is tag-javaversion-vandor/variant. This leads to webProfile8-java8-ibmsfj as one. At this time the full list of images are:

kernel
kernel-java8-ibm
kernel-java8-ibmsfj
microProfile1
microProfile1-java8-ibm
microProfile1-java8-ibmsfj
springBoot1
springBoot1-java8-ibm
springBoot1-java8-ibmsfj
springBoot2
springBoot2-java8-ibm
springBoot2-java8-ibmsfj
webProfile8
webProfile8-java8-ibm
webProfile8-java8-ibmsfj
javaee8
javaee8-java8-ibm
javaee8-java8-ibmsfj
webProfile7
webProfile7-java8-ibm
webProfile7-java8-ibmsfj
javaee7
javaee7-java8-ibm
javaee7-java8-ibmsfj

Usage

The images are designed to support a number of different usage patterns. The following examples assume that DefaultServletEngine.zip has been extracted to /tmp.

  1. Each image contains a default server configuration that specifies the corresponding features and exposes ports 9080 and 9443 for HTTP and HTTPS respectively. A .WAR file can therefore be mounted in the dropins directory of this server and run. The following example starts a container in the background running a .WAR file from the host file system with the HTTP and HTTPS ports mapped to 80 and 443 respectively.

    $ docker run -d -p 80:9080 -p 443:9443 \
        -v /tmp/DefaultServletEngine/dropins/Sample1.war:/config/dropins/Sample1.war \
        open-liberty:webProfile8
    

    When the server is started, you can browse to http://localhost/Sample1/SimpleServlet on the Docker host.

  2. For greater flexibility over configuration, it is possible to mount an entire server configuration directory from the host and then specify the server name as a parameter to the run command. Note: This particular example server configuration provides only HTTP access.

    $ docker run -d -p 80:9080 \
      -v /tmp/DefaultServletEngine:/config \
      open-liberty:webProfile8-sfj
    
  3. You can also build an application layer on top of this image by using either the default server configuration or a new server configuration. In this example, we have copied the Sample1.war from /tmp/DefaultServletEngine/dropins to the same directory as the following Dockerfile.

    FROM open-liberty:webProfile8
    COPY Sample1.war /config/dropins/
    

    This can then be built and run as follows:

    $ docker build -t app .
    $ docker run -d -p 80:9080 -p 443:9443 app
    
  4. You can mount a data volume container that contains the application and the server configuration on to the image. This has the benefit that it has no dependency on files from the host but still allows the application container to be easily re-mounted on a newer version of the application server image. This example assumes that you have copied the /tmp/DefaultServletEngine directory in to the same directory as the Dockerfile.

    Build and run the data volume container:

    FROM open-liberty:webProfile8
    COPY DefaultServletEngine /config
    
    $ docker build -t app-image .
    $ docker run -d -v /config \
        --name app app-image true
    

    Run the Open Liberty image with the volumes from the data volume container mounted:

    $ docker run -d -p 80:9080 \
      --volumes-from app open-liberty:webProfile8
    

Using springBoot images

The springBoot images introduce capabilities specific to the support of Spring Boot applications, including the springBootUtility used to separate Spring Boot applications into thin applications and dependency library caches. To elaborate these capabilities this section assumes the standalone Spring Boot 2.0.x application hellospringboot.jar exists in the /tmp directory.

  1. A Spring Boot application JAR deploys to the dropins/spring directory within the default server configuration, not the dropins directory. Liberty allows one Spring Boot application per server configuration. The following example starts a container running a Spring Boot application.

    $ docker run -d -p 8080:9080 \
        -v /tmp/hellospringboot.jar:/config/dropins/spring/hellospringboot.jar \
        open-liberty:springBoot2
    

    Similarly, you can create a Spring Boot application layer over this image by adding the application JAR to the dropins/spring directory. In this example we copied hellospringboot.jar from /tmp to the same directory containing the following Dockerfile.

    FROM open-liberty:springBoot2
    COPY hellospringboot.jar /config/dropins/spring/
    

    The custom image can be built and run as follows.

    $ docker build -t app .
    $ docker run -d -p 8080:9080 app
    
  2. The springBoot images provide the library cache directory, lib.index.cache, which contains an indexed library cache created by the springBootUtility command. Use lib.index.cache to provide the library cache for a thin application.

    For example, run the following command to thin the hellospringboot.jar application.

    $ <wlp>/bin/springBootUtility thin \
       --sourceAppPath=/tmp/hellospringboot.jar \
       --targetLibCachePath=/tmp/lib.index.cache \
       --targetThinAppPath=/tmp/thinhellospringboot.jar
    

    You can run the thin application by mounting both the target application JAR and library cache when starting the container.

    $ docker run -d -p 8080:9080 \
        -v /tmp/thinhellospringboot.jar:/config/dropins/spring/thinhellospringboot.jar \
        -v /tmp/lib.index.cache:/lib.index.cache \
        open-liberty:springBoot2
    

    Similarly, you can use the springBootUtility command to create thin application and library cache layers over a springBoot image. The following example uses docker staging to efficiently build an image that deploys a fat Spring Boot application as two layers containing a thin application and a library cache.

    FROM open-liberty:springBoot2 as staging
    COPY hellospringboot.jar /staging/myFatApp.jar
    RUN springBootUtility thin \
       --sourceAppPath=/staging/myFatApp.jar \
       --targetThinAppPath=/staging/myThinApp.jar \
       --targetLibCachePath=/staging/lib.index.cache
    FROM open-liberty:springBoot2
    COPY --from=staging /staging/lib.index.cache /lib.index.cache
    COPY --from=staging /staging/myThinApp.jar /config/dropins/spring/myThinApp.jar
    

    For Spring Boot applications packaged with library dependencies that rarely change across continuous application updates, you can use the capabilities mentioned above to to share library caches across containers and to create even more efficient docker layers that leverage the docker build cache.

Providing your own keystore/truststore

When an open-liberty image starts, it can generate a Liberty server XML snippet in /config/configDropins/defaults/keystore.xml that specifies a keyStore stanza with a generated password. This causes Open Liberty to generate a default keystore and truststore with a self-signed certificate when it starts. Images can request this by setting:

ENV KEYSTORE_REQUIRED "true"

When providing your own keystore/truststore, this default behavior can be disabled by adding:

ENV KEYSTORE_REQUIRED "false"

It is good practice to place the keystore customization in /config/configDropins/defaults/keystore.xml even when not generated since this makes it easier to find and makes moving to the websphere-liberty docker image simpler.

Using IBM JRE Class data sharing

The IBM JRE provides a feature Class data sharing which offers transparent and dynamic sharing of data between multiple Java Virtual Machines running on the same host by using shared memory backed by a file. When running the Liberty Docker image, it looks for the file at /opt/ol/wlp//output/.classCache. To benefit from Class data sharing, this location needs to be shared between containers either through the host or a data volume container.

Taking the application image from example 3 above, containers can share the host file location (containing the shared cache) /tmp/open-liberty/classCache as follows:

docker run -d -p 80:9080 -p 443:9443 \
    -v /tmp/open-liberty/classCache:/opt/ol/wlp/output/.classCache app

Or, create a named data volume container that exposes a volume at the location of the shared file:

docker run -v /opt/ol/wlp//output/.classCache \
    --name classcache open-liberty true

Then, run the Open Liberty image with the volumes from the data volume container classcache mounted as follows:

docker run -d -p 80:9080 -p 443:9443 --volumes-from classcache app

Running Open Liberty in read-only mode

Liberty writes to two different directories when running: /opt/ol/wlp//output and /logs. In order to run the Liberty image in read-only mode these may be mounted as temporary file systems. If using the provided image, the keystore will be generated on initial start up in the server configuration. This means that the server configuration directory either needs to be read-write or the keystore will need to be built into the image. In the example command /config is mounted as a read-write volume.

docker run -d -p 80:9080 -p 443:9443 \
    --tmpfs /opt/ol/wlp//output --tmpfs /logs -v /config --read-only \
    open-liberty:webProfile8

Relationship between Open Liberty and WebSphere Liberty

WebSphere Liberty is a commercial distribution of Open Liberty. There is an official docker image for websphere-liberty. The websphere-liberty docker image predates the open-liberty one, so to make it simpler to move from open-liberty to websphere-liberty (or vice versa) the images are broadly compatible. It should be possible to move from one to the other with a simple FROM clause change. Some considerations for moving between them:

Open Liberty installs into `/opt/ol` rather than `/opt/ibm`.
Use the `/config` folder for accessing the server configuration.
Use the `/output` folder for accessing the server output.
When adding your own SSL configuration use the `/config/configDropins/defaults/keystore.xml`.

License

View license information for the software contained in this image.

As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).

Some additional license information which was able to be auto-detected might be found in the repo-info repository’s open-liberty/ directory.

As for any pre-built image usage, it is the image user’s responsibility to ensure that any use of this image complies with any relevant licenses for all software contained within.

library, sample, open-liberty