Docker
Apache Karaf provides Docker resources allowing you to easily create your own image and container.
Official Karaf docker image are also available on Docker Hub.
But, Apache Karaf also provides a docker feature that allows you to:
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manipulate Docker containers directly from Apache Karaf
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create a Docker container based on the current running Apache Karaf instance (named provisioning)
Docker images
You can find the docker resource at https://github.com/apache/karaf/tree/master/assemblies/docker.
As prerequisites, you have:
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to install the most recent stable version of docker (https://docs.docker.com/installation/)
-
to install the most recent stable version of docker-compose (https://docs.docker.com/compose/install/)
Official images
The Apache Karaf official images are available on Docker HUB: https://hub.docker.com/r/apache/karaf/tags?page=1&ordering=last_updated
You can directly pull the official image:
docker pull apache/karaf
Build your own
You can create your own docker image. The images are based on the official Java Alpine (OpenJDK 8) image. If you want to build the Karaf image run:
sh build.sh
or
docker build -t karaf .
If you want to build the container for a specific version of Karaf you can configure it with the KARAF_VERSION arg:
docker build --build-arg KARAF_VERSION=4.2.0 -t "karaf:4.2.0" karaf
Run
-
Run Karaf in interactive mode (using Karaf official docker image):
docker run -i -t --name karaf apache/karaf:latest karaf
-
Run Karaf without interaction but log displayed (using Karaf official docker image):
docker run --name karaf apache/karaf:latest
-
Kill Karaf
docker kill karaf
Ports
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The Karaf SSH server is on 8101
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The Karaf WebContainer is on 8888
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The Karaf JMX MBean server is on 1099 (default, not exposed to host) and 44444 (default, not exposed to host)
Edit the docker-compose.yml file to edit port settings.
Docker feature
Docker is an optional feature from the Karaf Enterprise features repository.
It means that you have to install the docker feature first:
karaf@root()> feature:install docker
The Karaf Docker feature uses the Docker HTTP layer to communicate with the Docker backend. It could be on the same local machine where Apache Karaf instance is running or a remote Docker machine.
The location of the Docker backend (URL) can be specified as an option to the docker:* commands. By default, Karaf Docker
feature uses http://localhost:2375. Please, take a look on the Docker documentation how to enable remote API using HTTP
for Docker daemon. In a nutshell, you just have to enable the tcp transport connector for the docker daemon.
You have to do it using the -H option on dockerd:
/usr/bin/dockerd -H fd:// -H tcp://localhost:2375
Apache Karaf Docker feature exposes DockerService OSGi service that you can use programmatically (the docker:* commands
and the DockerMBean use the DockerService service).
System-wide information
The docker:info command provides some details about the docker backend:
karaf@root()> docker:info Containers: 0 Debug: false Driver: overlay2 ExecutionDriver: null IPv4Forwarding: true Images: 1 IndexServerAddress: https://index.docker.io/v1/ InitPath: null InitSha1: null KernelVersion: 4.15.0-29-generic MemoryLimit: true NEventsListener: false NFd: 20 NGoroutines: 34 SwapLimit: false
Show the Docker version information
The docker:version command provides details about the docker version:
karaf@root()> docker:version Version: 17.12.1-ce Os: linux Kernel version: 4.15.0-29-generic Go version: go1.10.1 Git commit: 7390fc6 Arch: amd64 API version: 1.35 Build time: 2018-02-28T17:46:05.000000000+00:00 Experimental: null
Search image
The docker:search command (or search() operation on the DockerMBean) searches for a image on Docker HUB:
karaf@root()> docker:search java Name │ Description │ Automated │ Official │ Star Count ───────────────────────────────────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────┼──────────┼─────────── java │ Java is a concurrent, class-based, and object-oriented programming language. │ false │ true │ 1774 anapsix/alpine-java │ Oracle Java 8 (and 7) with GLIBC 2.23 over AlpineLinux │ true │ false │ 332 node │ Node.js is a JavaScript-based platform for server-side and networking applications. │ false │ true │ 5893 tomcat │ Apache Tomcat is an open source implementation of the Java Servlet and JavaServer Pages technologies │ false │ true │ 1950 openjdk │ OpenJDK is an open-source implementation of the Java Platform, Standard Edition │ false │ true │ 1097 frekele/java │ docker run --rm --name java frekele/java │ true │ false │ 10 ghost │ Ghost is a free and open source blogging platform written in JavaScript │ false │ true │ 799 appuio/s2i-maven-java │ S2I Builder with Maven and Java │ true │ false │ 1 zabbix/zabbix-java-gateway │ Zabbix Java Gateway │ true │ false │ 13 jetty │ Jetty provides a Web server and javax.servlet container. │ false │ true │ 260 fabric8/s2i-java │ S2I Builder Image for plain Java applications │ false │ false │ 5 appuio/s2i-gradle-java │ S2I Builder with Gradle and Java │ true │ false │ 1 cloudbees/jnlp-slave-with-java-build-tools │ Extends cloudbees/java-build-tools docker image to make it a JNLP slave │ true │ false │ 18 blacklabelops/java │ Java Base Images. │ true │ false │ 8 groovy │ Apache Groovy is a multi-faceted language for the Java platform. │ false │ true │ 47 lwieske/java-8 │ Oracle Java 8 Container - Full + Slim - Based off Alpine + CentOS (8u00 - 8u172) │ true │ false │ 39 davidcaste/alpine-java-unlimited-jce │ Oracle Java 8 (and 7) with GLIBC 2.21 over AlpineLinux with unlimited JCE patch applied │ true │ false │ 11 cfje/java-test-applications │ Java Test Applications CI Image │ false │ false │ 0 thingswise/java-docker │ Java + dcd │ true │ false │ 0 rightctrl/java │ Oracle Java │ true │ false │ 2 cfje/java-resource │ Java Concourse Resource │ false │ false │ 0 cfje/java-buildpack │ Java Buildpack CI Image │ false │ false │ 0 tomee │ Apache TomEE is an all-Apache Java EE certified stack where Apache Tomcat is top dog. │ false │ true │ 53 couchdb │ CouchDB is a database that uses JSON for documents, an HTTP API, & JavaScript/declarative indexing. │ false │ true │ 218 dwolla/java │ Dwolla’s custom Java image │ true │ false │ 1
Pull image
The docker:pull command (or pull() operation on the DockerMBean) pull a image from Docker HUB:
karaf@root()> docker:pull -v java:8-jre-alpine
{"status":"Pulling from library/java","id":"latest"}
{"status":"Pulling fs layer","progressDetail":{},"id":"5040bd298390"}
{"status":"Pulling fs layer","progressDetail":{},"id":"fce5728aad85"}
{"status":"Pulling fs layer","progressDetail":{},"id":"76610ec20bf5"}
{"status":"Pulling fs layer","progressDetail":{},"id":"60170fec2151"}
{"status":"Pulling fs layer","progressDetail":{},"id":"e98f73de8f0d"}
{"status":"Pulling fs layer","progressDetail":{},"id":"11f7af24ed9c"}
{"status":"Pulling fs layer","progressDetail":{},"id":"49e2d6393f32"}
{"status":"Pulling fs layer","progressDetail":{},"id":"bb9cdec9c7f3"}
{"status":"Waiting","progressDetail":{},"id":"11f7af24ed9c"}
{"status":"Waiting","progressDetail":{},"id":"49e2d6393f32"}
{"status":"Waiting","progressDetail":{},"id":"bb9cdec9c7f3"}
{"status":"Waiting","progressDetail":{},"id":"60170fec2151"}
{"status":"Waiting","progressDetail":{},"id":"e98f73de8f0d"}
Listing images
The docker:images command (or images() operation on the DockerMBean) lists the available images on docker:
karaf@root()> docker:images
Id │ RepoTags │ Created │ Labels │ Size │ Virtual Size
────────────────────────────────────────────────────────────────────────┼─────────────────────┼────────────┼────────┼───────────┼─────────────
sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ [java:8-jre-alpine] │ 1488578492 │ {} │ 107854045 │ 107854045
sha256:d23bdf5b1b1b1afce5f1d0fd33e7ed8afbc084b594b9ccf742a5b27080d8a4a8 │ [java:latest] │ 1484614374 │ {} │ 643195347 │ 643195347
Remove image
The docker:rmi command (or rmi() operation on the DockerMBean) removes an image from docker:
karaf@root()> docker:rmi --force sha256:d23bdf5b1b1b1afce5f1d0fd33e7ed8afbc084b594b9ccf742a5b27080d8a4a8
Image history
The docker:history command displays the complete history for a given image:
karaf@root()> docker:history sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7
ID │ Created │ Created By │ Tags │ Size
────────────────────────────────────────────────────────────────────────┼────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼──────┼────────────────────
sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ 1488578492 │ /bin/sh -c set -x && apk add --no-cache openjdk8-jre="$JAVA_ALPINE_VERSION" && [ "$JAVA_HOME" = "$(docker-java-home)" ] │ │ [java:8-jre-alpine]
<missing> │ 1488578488 │ /bin/sh -c #(nop) ENV JAVA_ALPINE_VERSION=8.111.14-r0 │ │
<missing> │ 1488578488 │ /bin/sh -c #(nop) ENV JAVA_VERSION=8u111 │ │
<missing> │ 1488578487 │ /bin/sh -c #(nop) ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/lib/jvm/java-1.8-openjdk/jre/bin:/usr/lib/jvm/java-1.8-openjdk/bin │ │
<missing> │ 1488578487 │ /bin/sh -c #(nop) ENV JAVA_HOME=/usr/lib/jvm/java-1.8-openjdk/jre │ │
<missing> │ 1488578458 │ /bin/sh -c { echo '#!/bin/sh'; echo 'set -e'; echo; echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"'; } > /usr/local/bin/docker-java-home && chmod +x /usr/local/bin/docker-java-home │ │
<missing> │ 1488578457 │ /bin/sh -c #(nop) ENV LANG=C.UTF-8 │ │
<missing> │ 1488573141 │ /bin/sh -c #(nop) ADD file:3df55c321c1c8d73f22bc69240c0764290d6cb293da46ba8f94ed25473fb5853 in / │ │
Pushing and tagging image
The docker:push command allows you to push an image on a given repository.
The docker:tag command create a new tag for a given image.
Create container
The Karaf Docker feature can create a Docker container based on a given image.
You can use either the docker:create shell command or the create() operation on the JMX DockerMBean.
For instance, here’s an example of the docker:bootstrap to create a Docker container based on elasticsearch instance:
karaf@root()> docker:create --image fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 --cmd /bin/bash test
Listing containers
You can list the containers:
karaf@root()> docker:ps -a Id │ Names │ Command │ Created │ Image │ Image ID │ Status │ State │ Ports │ Size │ Size Root ─────────────────────────────────────────────────────────────────┼─────────┼───────────┼────────────┼──────────────────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────────────┼─────────┼─────────┼───────┼──────┼────────── 92f8b280a7fa69c9ff673ed9678b7040a56c16c9c4aa403498a538cf0f501e9e │ [/test] │ /bin/bash │ 1532809485 │ fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ sha256:fdc893b19a147681ee764b2edab6c494d60fe99d83b14b8794bbcbc040ec7aa7 │ Created │ created │ │ 0 │ 0
You can also use the containers attribute on the DockerMBean JMX MBean or the containers() method on the DockerService service.
Provision Docker container
Provisioning is a specific way of creating a container based on the current running Karaf instance: it creates a Docker container using the current running Apache Karaf instance karaf.base.
You can then reuse this container to create a Docker image and to duplicate the container on another Docker backend via dockerhub.
karaf@root()> docker:provision my-karaf
You can also use the provision() method on the DockerMBean JMX MBean or the DockerService service.
Start container
You can start a container using the docker:start command:
karaf@root()> docker:start my-container
You can also use the start() method on the DockerMBean JMX MBean or the DockerService service.
Stop container
You can stop a container using the docker:stop command:
karaf@root()> docker:stop my-container
You can also use the stop() method on the DockerMBean JMX MBean or the DockerService service.
Restart container
You can restart a container using the docker:restart command:
karaf@root()> docker:restart my-container
Delete container
You can delete an existing Docker container using the docker:rm commmand:
karaf@root()> docker:rm my-container
You can also use the rm() method on the DockerMBean JMX MBean or the DockerService service.
Pause container
The docker:pause command pauses all processes within one or more containers:
karaf@root()> docker:pause my-container
Unpause container
The docker:unpause command unpauses all processes within one or more containers:
karaf@root()> docker:unpause my-container
Kill container
The docker:kill command kills a running container:
karaf@root()> docker:kill my-container
Rename container
The docker:rename command renames an existing container:
karaf@root()> docker:rename my-container new-container
Logs
The docker:logs command displays the log on an existing container:
karaf@root()> docker:logs --timestamps --details --stdout --stderr my-container
Top
The docker:top command displays the current running processes in an existing container:
karaf@root()> docker:top my-container