Jenkins Slave 403 although Anonymous Slave connect has been enabled

Nothing like an answer 1.5 years later but I just ran across this!

The way I handled this is with the Role-Based Strategy plugin.

Summary

The basics are:

1. Add and enable the Role-Based Strategy plugin
2. Create a global group swarmclient
3. Grant the swarmclient group the slave privileges only
4. I currently allow the Anonymous group to be in the swarmclient group.
   • In the future I will probably deny swarmclient privileges for the Anonymous group and will instead create accounts in the swarmclient group.

Details

In Manage Jenkins > Configure Global Security > Authorization, enable Role-Based strategy.

In Manage Jenkins > Manage Roles > Manage and Define Roles I added "swarmclient" to the global roles. Give this group Create permissions in the slave section of the global settings:

In newer versions of Jenkins the term "Slave" is replaced by "Agents"

Then in Manage Jenkins > Manage Roles > Assign Roles you add the Anonymous group to the swarmclient group:

And finally, as mentioned above, if you want some restrictions on the machines that can connect as a swarm client, just:

1. create user(s) for the swarm
2. add them to the swarmclient group
3. remove swarmclient permissions (on the Assign Roles) page from the Anonymous group.