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This is a start at an install document that will, once complete, supercede some of the sections of the README.

etcd-compute composes several different pieces of functionality to result in a relatively simple tool for booting virtual machines. Getting those several pieces installed and functioning can be somewhat complex. This document describes how to get things working on a collection of one or more Ubuntu bionic (18.04) hosts.

Host Types

Three different types of services need to be hosted. These can all be on the same machine, or spread around.

  1. One host running docker on which etcd and placement containers will be run.

  2. One or more hosts running ecompute. This host needs to have working Python 3 and libvirtd installations. This host must be able to reach the etcd container over the network.

  3. At least one host where eschedule can run. This does not need to be a Linux machine. Anywhere that can run Python 3 and talk to the placement and etcd container over the network will work.

Each host that runs ecompute becomes one potential hypervisor when placing workloads.

Docker Host

To install docker, run the following as root:

apt install -y docker.io

By default, you have to run all docker commands as root. To avoid this, add your user to the docker group:

sudo usermod -a -G docker <your username>

You will have to exit your current session and re-connect for that to take effect.

Once docker is running, the database used by the placement service must be set up and configured. You can use MySQL or PostgreSQL. Whatever you use it needs to be reachable from the docker host.

Create a database named placement. If you're not familiar with how to do this, the quick-dev docs from the Placement project may help. Choose a username and password of your own when granting permissions.

Get a copy of the etcd-compute code:

git clone https://github.com/cdent/etcd-compute.git
cd etcd-compute

Edit dockerenv to change the value of OS_PLACEMENT_DATABASE__CONNECTION to a database URL that matches the database you configured above. If you're using MySQL it should look something like:

OS_PLACEMENT_DATABASE__CONNECTION=mysql+pymysql://cow:[email protected]/placement?charset=utf8

If PostgreSQL, this:

OS_PLACEMENT_DATABASE__CONNECTION=postgresql+psycopg2://cow:[email protected]/placement?client_encoding=utf8

Start the containers:

./docker.sh

Running docker ps will list the resulting containers. Running docker logs -f placement will tail the logs of the placement container, and docker logs -f etcd will tail the etcd container logs.

Hypervisor Host

One the docker host is set up and the placement and etcd containers are running, hypervisors hosts can be configured. If you are using the same host as the docker host, some of the following steps will duplicate earlier work.

As root, install the necessary packages using apt:

apt update
apt install -y git libvirt-dev virtinst libguestfs-tools python3-dev \
    libvirt-daemon libvirt-daemon-system python3-venv

libvirtd and dnsmasq should now be running. A virbr0 device should be present in the output of ip a.

Create a non-root user. Add them to the libvirt group by running:

sudo usermod -a -G libvirt <your username>

As that user, install and run the necessary Python code in a virtual environment:

git clone https://github.com/cdent/etcd-compute.git
cd etcd-compute
python3 -m venv .venv
. .venv/bin/activate
pip install -r requirements.txt && python setup.py develop

Note: python setup.py develop alone ought to install the requirements properly, but libvirt-python gets confused so pip is used first to work around that issue. Also note that you can name your virtual environment whatever you like; it doesn't have to be named .venv.

Edit compute.yaml. Set uuid to uniquely identify this node in a persistent way. Change the host to point to the host on which the etcd service is running. Change the endpoint to point to the URL at which the placement service can be found. This will be the same host as etcd, with a port of 8080. For now, comment out the bridge line. Later, read BRIDGE.md to use that.

ecompute is now ready to run and listen for boot requests:

ecompute

It will print debugging output to the console. When it starts up it will report resource inventory to the placement service. When it is interrupted, it will reserve that inventory to prevent workloads being scheduled to this node.

You may have as many hypervisor hosts as you like.

Schedule Host

The schedule host is any host which has been configured to run the eschedule command. If you are using the same host as one of your hypervisor hosts, you can skip forward to the Edit paragraph.

As an unprivileged user install the necessary Python code in virtual environment:

git clone https://github.com/cdent/etcd-compute.git
cd etcd-compute
python3 -m venv .venv
. .venv/bin/activate
pip install -r requirements.txt && python setup.py develop

Edit schedule.yaml. Change the host to point to the host on which the etcd service is running. Change the endpoint to point to the URL at which the placement service can be found. This will be the same host as etcd, with a port of 8080.

To ask to schedule a VM run the eschedule command:

eschedule resources=VCPU:1,DISK_GB:1,MEMORY_MB:256

If you deactivate the virtual environment you can schedule without re-activating with:

.venv/bin/eschedule resources=VCPU:1,DISK_GB:1,MEMORY_MB:256

For more information on what to try go back to the README.