Docker is a simple container runtime and standard. Every day, the egeria build processing creates a docker image of egeria and pushes it to the docker catalog on the Docker website.
This docker image provides a simple way to bring a runnable version of Egeria onto your machine. It also provides the basis for a Kubernetes deployment of Egeria.
The docker catalog page for egeria is at https://hub.docker.com/r/odpi/egeria. The Overview tab describes the docker container.
The Tags tab shows the different releases that are available.
Getting the docker runtime¶
The docker image needs a runtime to execute. It can run in the cloud using Docker Hub or on your machine using the Docker Desktop. The description below describes how to use the docker desktop.
Docker Desktop supports running a docker image as a standalone container, or as part of group of containers started with docker-compose.
Go to the Docker website and select the Download Docker Desktop.
Follow the instructions for you operating system. For macOS, the docker desktop is installed like a standard application.
Once it is installed, it can be launched like any application, such as through the launchpad/start menu.
This tutorial explains how to use the Egeria Docker Image published to the docker catalog at https://hub.docker.com/r/odpi/egeria.
Egeria's docker image includes the Egeria install image. When the image is started using docker, a new egeria docker container is created. As it starts up, an instance of the Egeria runtime - that is the OMAG Server Platform - is started at port https 9443.
This container can be incorporated into larger container orchestration environments or used standalone.
This tutorial describes how to use it standalone. The Open Metadata Labs
use this container with
container services to create a complete open metadata solution.
Link to Open Metadata Labs to learn more.
Working with Egeria's docker image¶
Once the docker desktop is installed, start the docker desktop application. It may take a little while to complete its start up so check it is running before continuing.
For example, on macOS, the docker desktop can be found on the Launchpad. Once it is running, the docker whale icon appears on the top menu bar. Clicking on the docker whale icon reveals a menu and the status of the desk top is visible. This menu is used to shutdown docker at the end of the dojo.
Downloading the egeria docker image¶
The command to download Egeria's docker image is
docker pull odpi/egeria.
This is issued from a command/terminal window in the directory where you want the
container to be copied to.
If you see the following response, then the docker runtime is not installed properly on your machine.
$ docker pull odpi/egeria -bash: docker: command not found
If all is well, the image downloads. Notice it is pulling the latest master build by default.
$ docker pull odpi/egeria Using default tag: latest latest: Pulling from odpi/egeria e7c96db7181b: Pull complete f910a506b6cb: Pull complete b6abafe80f63: Pull complete a83b87485b54: Pull complete 10d9ee7d5688: Pull complete 9558171b7a95: Pull complete Digest: sha256:18451a4676a6688e03f284f887ba5be7026c17805ee0b919ed02cb131621d45b Status: Downloaded newer image for odpi/egeria:latest docker.io/odpi/egeria:latest $
docker run --publish 19443:9443 odpi/egeria. This will start the image as a new docker container. As the container initializes it starts a single copy of the OMAG Server Platform. The OMAG Server Platform is the Egeria runtime platform where the Egeria REST services run.
--publish 19443:9443 parameter maps the 9443 port inside the docker that the OMAG Server Platform
has registered with to port 19443
You should see the server logo come up and finally a message
OMAG server platform ready for more configuration. This message means it has successfully started.
Once you can see that it has started, use
Control-C to stop it.
$ docker run --publish 19443:9443 odpi/egeria Picked up JAVA_TOOL_OPTIONS: ODPi Egeria ____ __ ___ ___ ______ _____ ____ _ _ ___ / __ \ / |/ // | / ____/ / ___/ ___ ____ _ __ ___ ____ / _ \ / / __ / / / _ /__ ____ _ _ / / / // /|_/ // /| | / / __ \__ \ / _ \ / __/| | / // _ \ / __/ / /_/ // // | / _\ / /_ / | / _// || | / /_/ // / / // ___ |/ /_/ / ___/ // __// / | |/ // __// / / __ // // / \ / /_ / _// / // / / / / / \____//_/ /_//_/ |_|\____/ /____/ \___//_/ |___/ \___//_/ /_/ /_/ \__/\//___//_/ \__//_/ /_/ /_/ :: Powered by Spring Boot (v2.3.0.RELEASE) :: 10:12:28.047 [main] INFO o.s.b.w.e.tomcat.TomcatWebServer - Tomcat initialized with port(s): 9443 (https) 10:12:41.688 [main] INFO o.s.b.w.e.tomcat.TomcatWebServer - Tomcat started on port(s): 9443 (https) with context path '' Thu Jun 04 10:12:32 BST 2020 No OMAG servers listed in startup configuration Thu Jun 04 10:12:41 BST 2020 OMAG server platform ready for more configuration ^C $
Working with the Docker Desktop Dashboard¶
The docker desktop dashboard makes it easy to control your docker containers.
It is started from the docker desktop menu. Select the
You will see something like this:
Each time a new docker container is created, it is given a generated name.
In the example above the name is
gifted-lovelace which is a great tribute to
You can see that the container is not running (
EXITED) because you stopped it earlier with
Hover your mouse pointer over the container entry and some options appear.
The triangular "START" button is to start the container running again and the Bin/Trash can is to delete your container. Press the "START" button to start your container again.
When the container is running, more options are available to you when you hover the mouse over the container entry.
The first symbol is the "OPEN IN BROWSER" option. Click on it and your browser opens. You should see an error displayed:
Update the URL as follows:
and press enter. After a few moments, Egeria's Swagger page should open. This is an automatically generated page that describes the REST APIs of Egeria's OMAG Server Platform. There is more information on swagger in the Swagger Tutorial.
Page down until you see the "Platform Services". The platform services provide support for administrators running Egeria.
Click on the angle bracket on the right hand end of the entry and the list of REST API operations is displayed.
Now click on the first blue entry for platform origin. Then press the
Try it Out button.
garygeeke in the
userId field and then the
You can see that through the Swagger UI it is possible to try out different REST requests and make sure the platform is operating correctly. The platform origin request is particularly useful for verifying what version of the OMAG Server Platform is running.
The Swagger UI is useful for ad hoc testing. However, later in the Dojo we will cover a tool called Postman that provides a more powerful testing experience.
So back to the Docker Desktop. The second option on the docker desktop is "CLI".
This opens the Terminal/Command
window inside the docker container. You are in the home directory of the OMAG Server Platform.
This contains the contents of the egeria install image. It is also the home directory of
the OMAG Server Platform which is where it will write its files. Type
ls to list the files.
$ ls LICENSE clients server utilities NOTICE conformance-suite user-interface $
(If you want to know more about the egeria install image, see the Installing Egeria Tutorial.)
The third button on the docker desktop is the "STOP" button and the fourth button is "RESTART". If you just need to test these buttons, remember to ensure that the docker container is running when you have finished because it is needed for the rest of the session.
The final button is "DELETE". As described above, it deletes the container and uoi need to start again with
docker run --publish 19443:9443 odpi/egeria.
If you now click on the whitespace of the container's entry, a new section opens up with 3 tabs.
"Logs" shows the console logs. Each new run of the container appends new log information to the end of this console.
"Inspect" shows the settings for the container.
"Stats" shows the resource usage of the container.
... and that is all you need to know about docker.