Quick Reference Handbook: Notes on Metadash Development Server

Metadash is powered by Node.js and Flask. Simliar projects could be brought up with tiny adjustment.

Quick Reference Handbook: Notes on Metadash Development Server

Metadash is powered by Node.js and Flask. Simliar projects could be brought up with tiny adjustment.

ryncsn/metadash
A full stack boilerplate for building metadata manager and dashboard - ryncsn/metadash
Metadash repository on GitHub

Install and Build Dependencies

# Install EPEL for Python 3 and Node.js packages
$ sudo yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
# Dependencies for building python packages
$ sudo yum install -y git python3 python3-devel python3-pip @c-development postgresql-devel
$ sudo pip install pipenv
# Dependencies for building npm packages
$ sudo yum install -y npm bzip2

Then build dependencies for both Python and Node.js.

$ [metadash] pipenv install
$ [metadash] pipenv run bin/md-manager setup --dev

Prepare Database and Redis

We will use container to run both PostgresQL and Redis service.

Install podman and podman-compose. To keep things simple, we will not arrange containers by Kubernetes resources description but instead by podman-compose. Create a docker-compose like YAML file.

version: 3
services:
    db:
        image: postgres:9.6
        restart: always
        volumes:
            - '/var/lib/metadash-db:/var/lib/postgresql/data'
            - './metadash-backups:/var/backups'
        ports:
            - '5432:5432'
        environment:
            'POSTGRES_USER': 'metadash'
            'POSTGRES_PASSWORD': 'metadash'
    cache:
        image: redis
        volumes:
            - '/var/lib/metadash-redis:/data'
        ports:
            - '6379:6379' 

docker-compose.yml

Install podman and podman-compose.

$ sudo yum install -y podman
$ sudo pip install podman-compose

Then create data directories and grant SELinux permission to container role.

$ sudo mkdir /var/lib/metadash-db /var/lib/metadash-redis
$ sudo chcon -Rt svirt_sandbox_file_t /var/lib/metadash-db /var/lib/metadash-redis

Use podman-compose to create and run the containers.

$ sudo podman-compose -f docker-compose.yml pull
$ sudo podman-compose -f docker-compose.yml up -d

Configure Kerberos Authentication [Optional]

Metadash backend will need to know  keytab file and principle for Kerberos authentication. They could be configured via environment variables.

KERBEROS_KEYTAB_FILE=/path/to/key_table_file
KERBEROS_PRINCIPLE=name.principle.example.com

In case of a self-signed or custom certificates, REQUESTS_CA_BUNDLE needs to be specified for python-requests library.

REQUESTS_CA_BUNDLE=/etc/pki/tls/certs/ca-bundle.crt

Save the content to metadash.env for later sourcing.

Bring Up Metadash Backend and Frontend

Metadash backend need a database and a message queue to work. By default, it will use postgres://postgres:5432 and redis://redis:6379. Since the database and message queue is running on localhost, we need to add a line to /etc/hosts.

$ sudo echo "127.0.0.1 postgres redis" >> /etc/hosts

If a brand new instance is setup without any test data, a bootstrap to database and an administrator account are needed

$ [metadash] pipenv run bin/md-manager create_database
$ [metadash] pipenv run bin/md-manager create_user --username admin --password passw0rd

Then we can bring up Metadash backend and frontend respectively.

$ [metadash] source metadash.env
$ [metadash] pipenv run bin/md-manager runserver -h 127.0.0.1
$ [metadash] npm run ui-dev

For running in background and other convenience, running these commands within tmux is recommended.

Nginx Reverse Proxy

Install nginx.

$ sudo yum -y install nginx

Create a simple configuration file at /etc/nginx/conf.d/metadash.conf.

server {
    listen 80;
    server_name _;

    location / {
        proxy_pass http://localhost:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Port $server_port;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
    }
}

Reverse proxy configuration for Metadash

The default UI server is running on port 8080. SELinux policy should be adjusted with a single command without compiling a policy.

$ sudo setsebool httpd_can_network_connect 1 -P

Start nginx and you will enjoy a Metadash development server with hot reload.

$ sudo systemctl start nginx
$ sudo systemctl enable nginx
Landing (loading) page of Metadash

Running Celery Worker [Optional]

Metadash implements a task wrapper mechanism that if no celery worker is online. However, a worker and a beat worker can prevent Metadash from returning timeout error and help with routine jobs.

$ pipenv run celery worker -A metadash.worker.task.celery -l info -n [email protected]%h
$ pipenv run celery worker -B -A metadash.worker.task.celery -l info -n [email protected]%h

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