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Mistral
Workflow Service for OpenStack cloud. This project aims to provide a mechanism to define tasks and workflows without writing code, manage and execute them in the cloud environment.
Installation
The following are the steps to install Mistral on debian-based systems.
To install Mistral, you have to install the following prerequisites:
$ apt-get install python-dev python-setuptools libffi-dev libxslt1-dev libxml2-dev libyaml-dev libssl-dev
Mistral can be used without authentication at all or it can work with OpenStack.
In case of OpenStack, it works only with Keystone v3, make sure Keystone v3 is installed.
Install Mistral
First of all, clone the repo and go to the repo directory:
$ git clone https://git.openstack.org/openstack/mistral.git
$ cd mistral
Devstack installation
Information about how to install Mistral with devstack can be found here.
Configuring Mistral
Mistral configuration is needed for getting it work correctly with and without an OpenStack environment.
Install and configure a database which can be MySQL or PostgreSQL (SQLite can't be used in production.). Here are the steps to connect Mistral to a MySQL database.
Make sure you have installed
mysql-server
package on your Mistral machine.Install MySQL driver for python:
$ pip install mysql-python
or, if you work in virtualenv, run:
$ tox -evenv -- pip install mysql-python
NOTE: If you're using Python 3 then you need to install
mysqlclient
instead ofmysql-python
.Create the database and grant privileges:
$ mysql -u root -p
CREATE DATABASE mistral; USE mistral GRANT ALL ON mistral.* TO 'root'@'localhost';
Generate
mistral.conf
file:$ oslo-config-generator \ --config-file tools/config/config-generator.mistral.conf \ --output-file etc/mistral.conf.sample
Copy service configuration files:
$ sudo mkdir /etc/mistral $ sudo chown `whoami` /etc/mistral $ cp etc/event_definitionas.yml.sample /etc/mistral/event_definitions.yml $ cp etc/logging.conf.sample /etc/mistral/logging.conf $ cp etc/policy.json /etc/mistral/policy.json $ cp etc/wf_trace_logging.conf.sample /etc/mistral/wf_trace_logging.conf $ cp etc/mistral.conf.sample /etc/mistral/mistral.conf
Edit file
/etc/mistral/mistral.conf
according to your setup. Pay attention to the following sections and options:[oslo_messaging_rabbit] rabbit_host = <RABBIT_HOST> rabbit_userid = <RABBIT_USERID> rabbit_password = <RABBIT_PASSWORD> [database] # Use the following line if *PostgreSQL* is used # connection = postgresql://<DB_USER>:<DB_PASSWORD>@localhost:5432/mistral connection = mysql://<DB_USER>:<DB_PASSWORD>@localhost:3306/mistral
If you are not using OpenStack, add the following entry to the
/etc/mistral/mistral.conf
file and skip the following steps:[pecan] auth_enable = False
Provide valid keystone auth properties:
[keystone_authtoken] auth_uri = http://<Keystone-host>/identity_v2_admin/v3 identity_uri = http://<Keystone-host/identity_v2_admin auth_version = v3 admin_user = <user> admin_password = <password> admin_tenant_name = <tenant>
Register Mistral service and Mistral endpoints on Keystone:
$ MISTRAL_URL="http://[host]:[port]/v2" $ openstack service create --name mistral workflowv2 $ openstack endpoint create mistral public $MISTRAL_URL $ openstack endpoint create mistral internal $MISTRAL_URL $ openstack endpoint create mistral admin $MISTRAL_URL
Update the
mistral/actions/openstack/mapping.json
file which contains all available OpenStack actions, according to the specific client versions of OpenStack projects in your deployment. Please find more detailed information in thetools/get_action_list.py
script.
Before the First Run
After local installation you will find the commands
mistral-server
and mistral-db-manage
available
in your environment. The mistral-db-manage
command can be
used for migrating database schema versions. If Mistral is not installed
in system then this script can be found at
mistral/db/sqlalchemy/migration/cli.py
, it can be executed
using Python command line.
To update the database schema to the latest revision, type:
$ mistral-db-manage --config-file <path_to_config> upgrade head
- To populate the database with standard actions and workflows, type::
-
$ mistral-db-manage --config-file <path_to_config> populate
For more detailed information about mistral-db-manage
script please check file
mistral/db/sqlalchemy/migration/alembic_migrations/README.md
.
Running Mistral API server
To run Mistral API server:
$ tox -evenv -- python mistral/cmd/launch.py \
--server api --config-file <path_to_config>
Running Mistral Engines
To run Mistral Engine:
$ tox -evenv -- python mistral/cmd/launch.py \
--server engine --config-file <path_to_config>
Running Mistral Task Executors
To run Mistral Task Executor instance:
$ tox -evenv -- python mistral/cmd/launch.py \
--server executor --config-file <path_to_config>
Note that at least one Engine instance and one Executor instance should be running in order for workflow tasks to be processed by Mistral.
If you want to run some tasks on specific executor, the task affinity feature can be used to send these tasks directly to a specific executor. You can edit the following property in your mistral configuration file for this purpose:
[executor]
host = my_favorite_executor
After changing this option, you will need to start (restart) the
executor. Use the target
property of a task to specify the
executor:
... Workflow YAML ...
task1:
...
target: my_favorite_executor
... Workflow YAML ...
Running Multiple Mistral Servers Under the Same Process
To run more than one server (API, Engine, or Task Executor) on the same process:
$ tox -evenv -- python mistral/cmd/launch.py \
--server api,engine --config-file <path_to_config>
The value for the --server
option can be a
comma-delimited list. The valid options are all
(which is
the default if not specified) or any combination of api
,
engine
, and executor
.
It's important to note that the fake
transport for the
rpc_backend
defined in the configuration file should only
be used if all
Mistral servers are launched on the same
process. Otherwise, messages do not get delivered because the
fake
transport is using an in-process queue.
Project Goals 2017
Complete Mistral documentation.
Mistral documentation should be more usable. It requires focused work to make it well structured, eliminate gaps in API/DSL specifications, add more examples and tutorials.
Definition of done: All capabilities are covered, all documentation topics are written using the same style and structure principles. The obvious sub-goal of this goal is to establish these principles.
Complete Mistral Custom Actions API.
There has been the initiative in Mistral team since April of 2016 to refactor Mistral actions subsystem in order to make the process of developing Mistral actions easier and clearer. In 2017 we need to complete this effort and make sure that all APIs are stable and it’s well-documented.
Definition of done: All API interfaces are stable, existing actions are rewritten using this new API, OpenStack actions are also rewritten based on the new API and moved to mistral-extra repo. Everything is well documented and the doc has enough examples.
Finish Mistral multi-node mode.
Mistral needs to be proven to work reliably in multi-node mode. In order to achieve it we need to make a number of engine, executor and RPC changes and configure a CI gate to run stress tests on multi-node Mistral.
Definition of done: CI gate supports MySQL, all critically important functionality (join, with-items, parallel workflows, sequential workflows) is covered by tests.
Reduce workflow execution time.
Definition of done: Average workflow execution time reduced by 30%.
Project Resources
- Mistral Official Documentation
- Project status, bugs, and blueprints are tracked on Launchpad
- Additional resources are linked from the project Wiki page
- Apache License Version 2.0 http://www.apache.org/licenses/LICENSE-2.0