If we use the default atlassian ID, Is there any possiblity that can we login to discourse using it at all?
「いいね!」 2
That might be possible with the Discourse Open ID Connect plugin as this documentation suggests the standard is supported by Atlassian on certain products:
See OpenID Connect for Atlassian Data Center applications | Atlassian Support | Atlassian Documentation
And
「いいね!」 4