What is necessary before someone is considered "saint" in Eastern Orthodox Church? Good life/martyrdom, any miracle/only preservation of the body/some other distinct miracle and cult of the saint? Is there something similar to beatification/canonization process, or is the saintness of certain person just pronounced? Who have the authority to pronounce someone saint?
I can tell you of the
Russian Orthodox Church.
There is a
Synodal Commission which examines the issue and has the authority to glorify the person as a saint.
locally venerated saints, which are venerated in a eparchy, and
commonly venerated saints, which are inserted to the calendar common to all the church.
The eparchial veneration is sanctioned by the Patriarch and common veneration is sanctioned by the Сouncil of Bishops.
The main criteria are:
righteous life irreproachable orthodoxy popular veneration working of miracles imperishable relics martyrdom
After the material confirming a person's sainthood is submitted to the Synodal Commission by the Eparchy or other body, it checks if there are evidences of a righteous life by the contemporaries, documented and verifiable miracles, if relics are present and if the claimed genuinely professed Orthodox Christianity and was in communion with the Patriarchate Church, and it recommends the Patriarch or the Council to affirm the claim.
Also, there are different titles to the saints in Orthodox church, describing their life position - clergymen/laymen/marthyrs etc. See Wikipedia
There is a source in Russian:
What i wrote is from the Internet, I have no personal expertise or experience in canonisation process, so use this info with "limited warranty".