DaCHS on Docker

This repository contains the files for encapsulating GAVO DaCHS in Docker containers. You'll find the corresponding images in 'chbrandt/dachs' DockerHub repository.

ToC

• Getting started
  • Test migration
    • DaCHS 2

Check the documents directory (docs/) for (practical) notes on

• versioning your resources,
• persisting data,
• upgrading DaCHS,
• running dachs and postgresql individually.

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DaCHS -- the service -- is composed by two daemons: PostgreSQL and the DaCHS server itself. Postgres stores the data, whereas DaCHS-server interfaces the data-store and the user and everything related to Virtual Observatory.

If you dig into the files and dockerfiles of this repo you'll find out three Docker containers being defined out this repo, which ultimately are defining the containers chbrandt/dachs, chbrandt/dachs:server, chbrandt/dachs:postgres.

If you're new to DaCHS and Docker don't worry too much and focus on chbrandt/dachs container. Or all you want is to have a DaCHS instance running in no time, quick and easy, you too just focus on chbrandt/dachs container.

The dockerfiles in here will setup image families (with their respective tags):

• chbrandt/dachs: DaCHS server + Postgres db -- the quickest way to action
  • can be called the recommended container
• chbrandt/dachs:server: the DaCHS data-manager/server suite
• chbrandt/dachs:postgres: the Postgres db used by DaCHS

In this document we'll see how to run Dachs-on-Docker.

For detailed information on DaCHS itself or Docker, please visit their official documentation, DaCHS/docs or Docker/docs.

Command-lines running from the host system are prefixed by (host); And (dock) are run from inside the container.

Getting started

chbrandt/dachs

The latest (Docker) image provides the (DaCHS) service as a whole, encapsulating dachs-server and postgresql dbms in the same container.

By default, DaCHS provides an HTML/GUI interface at port 8080, on running the container you want to map the container's port (8080) to some on the host:

(host)$ docker run -it --name dachs -p 8080:8080 chbrandt/dachs

, where we made an identity map (host's 8080 to container's 8080).

Inside the container, to start the services work like in a normal machine:

(dock)$ service postgresql start
(dock)$ service dachs start

. You can also use a convenience dachs.sh script to start everything for you:

(dock)$ /dachs.sh start

Go to your host's 'http://localhost:8080' to check DaCHS front-page.

To make a directory from the host system available from the container one can use the option argument '-v' to mount a volume at given location inside the container:

(host)$ docker run -it --name dachs -p 80:8080 \
                   -v /data/inputs/resourceX:/var/gavo/inputs/resourceX \
                   chbrandt/dachs

You can mount as many volumes (directories) as you want.

Inside the container, you can use dachs as you would on an usual machine. For instance, run DaCHS and load/pub "resourceX":

(dock)$ service postgresql start
(dock)$ service dachs start
(dock)$
(dock)$ cd /var/gavo/inputs
(dock)$ gavo imp resourceX/q.rd
(dock)$ gavo pub resourceX/q.rd
(dock)$
(dock)$ service dachs reload

Test migration

If you're using the container to test a new version to eventually migrate your datasets to, you'll likely want to mount your VO/DaCHS resources as in the example above. To add security to your data -- if they are being shared with the data resource live in production -- you may want to use 'ro' (read-only) as an option for mounting points:

(host)$ docker run -v /data/rd/input:/var/gavo/inputs/input:ro \
                   -it --name dachs -p 80:8080 \
                   chbrandt/dachs

And then do the imports, publications, data access tests necessary to check for compatibility; and eventually migrate to the new version if/when everything is fine.

DaCHS 2

• Docker image tags: latest, 2.1 (previously, beta)

DaCHS' version 2 is available as a beta version, which runs on Python-3. Because it is a major upgrade dachs has gone through, it is a good idea to test your data and services as extensively as possible.

To use the new version, just have to use the beta image:

(host)$ docker run -v /data/rd/input:/var/gavo/inputs/input:ro \
                   -it --name dachs -p 80:8080 \
                   chbrandt/dachs:beta

Everything should feel the same. Start docker (here through the convenience script left in your container's '/'), and use/test it as usual:

(dock)$ /dachs.sh start
9.6/main (port 5432): down
[ ok ] Starting PostgreSQL 9.6 database server: main.
[ ok ] Starting VO server: dachs.
(dock)$
(dock)$ dachs --version
Software (2.0.4) Schema (23/23)

/.\