Stepan Mazurov how are you connecting with the swarm plugin? Are you using the GitHub personal access token?
Yes.
Another thing you could try is just setting se-jenkins as an admin.
This indeed did work, but was too permissive for my taste.
Also, contributions are welcome for slave users setting.
I took a look at the code, and to implement it in a way I want (add a field to specify slave users to commiter strategy settings), it appears it would require to modify a lot of code as it would be another discrete permission. I do not feel like the added convince over Matrix strategy is worth the tech debt of adding such functionality.
I can now confirm that, with matrix strategy (or commiter strategy with bot account having admin access), a dedicated github "bot" account with a personal access token allows slaves to correctly connect, register themselves and execute tasks.
I believe this issue can be considered resolved.
The GitHub OAuth plugin release 0.21 supports using personal access tokens as a password. It is now documented in the wiki. Can you test that release?
https://wiki.jenkins-ci.org/display/JENKINS/Github+OAuth+Plugin
http://maven.jenkins-ci.org/content/repositories/releases/org/jenkins-ci/plugins/github-oauth/0.21/