Previously, the Docker image could only be run interactively, which is
not conducive for running clusters. This patch makes the docker image
run in the background (using systemd). This makes the docker workflow
similar to working with virtual machines, i.e. the user launches a
container, and once it is running they can connect to it with
docker exec -it <container_name> bash
and immediately use `cqlsh` to control it.
In addition, the configuration of scylla is done using established
scripts, such as `scylla_dev_mode_setup`, `scylla_cpuset_setup` and
`scylla_io_setup`, whereas previously code from these scripts was
duplicated into the docker startup file.
To specify seeds for making a cluster, use the --seeds command line
argument, e.g.
docker run -d --privileged scylladb/scylla
docker run -d --privileged scylladb/scylla --seeds 172.17.0.2
other options include --developer-mode, --cpuset, --broadcast-address
The --developer-mode option mode is on by default - so that we don't fail users
who just want to play with this.
The Dockerfile entrypoint script was rewritten as a few Python modules.
The move to Python is meritted because:
* Using `sed` to manipulate YAML is fragile
* Lack of proper command line parsing resulted in introducing ad-hoc environment variables
* Shell scripts don't throw exceptions, and it's easy to forget to check exit codes for every single command
I've made an effort to make the entrypoint `go' script very simple and readable.
The goary details are hidden inside the other python modules.
Signed-off-by: Yoav Kleinberger <yoav@scylladb.com>
Message-Id: <1468938693-32168-1-git-send-email-yoav@scylladb.com>
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