Unable to perform collectstatic

You must have to give path in STATIC_ROOT in settings.py where all your static files are collected as for example:-

STATIC_ROOT = "app-root/repo/wsgi/static"

STATIC_URL = '/static/'

STATICFILES_DIRS = (
    ('assets', 'app-root/repo/wsgi/openshift/static'),

    )

Try this,

PROJECT_DIR = os.path.dirname(os.path.abspath(__file__))
STATIC_ROOT = os.path.join(PROJECT_DIR, 'static')

Look at https://docs.djangoproject.com/en/dev/ref/settings/#std:setting-STATIC_ROOT