Change Rails session cookie domain without logging users out -

i'm using rails 4.2.2 (with devise 3.4.1) , changing cookie_store domain www.boundless.dev .boundless.dev in order share same session across of our subdomains (single sign-on).

boundless::application.config.session_store :cookie_store, key: '_boundless_session', domain: '.boundless.dev' 

if make change alone. existing logged-in users return site end 2 _boundless_session cookies, 1 domain boundless.dev , other www.boundless.dev. somehow makes logging out impossible.

is possible make change without logging users out of site?

i thought i'd able write method before_filter in applicationcontroller delete session cookie , replace new 1 @ .boundless.dev, doesn't work, , suspect has remember_user_token cookie.

def update_session_cookie_domain   session_cookie = cookies['_boundless_session']   cookies.delete('_boundless_session', domain: 'www.boundless.dev')   cookies['_boundless_session'] = {     value: session_cookie,     domain: '.boundless.dev'   } end 

i able solve problem changing cookie name used session.

so original config was:

boundless::application.config.session_store :cookie_store, key: '_boundless_session', domain: 'www.boundless.dev' 

and changed to:

boundless::application.config.session_store :cookie_store, key: '_boundless_session_new', domain: '.boundless.dev' 

i expected log users out, doesn't reason don't quite understand.

unfortunately, i've yet find way clear old _boundless_session cookie, @ least can log out after having session cookie updated more general domain.