I have created a new Jenkins agent and the jenkins-deploy user is not in the docker group:
jenkins-deploy@integration-agent-docker-1020:~$ groups wikidev project-bastion project-deployment-prep project-integration project-puppet-diffs $ getent group docker docker:x:498:
Whereas on old agents it is properly setup:
jenkins-deploy@integration-agent-docker-1001:~$ groups wikidev docker project-bastion project-deployment-prep project-integration project-puppet-diffs $ getent group docker docker:x:498:jenkins-deploy