Volunteering benefits recipients, volunteers, communities, and society, while digital technologies establish new opportunities for virtual volunteering. We describe how volunteers transitioned the UK's long-established Oxjam grassroots music festival online in response to the COVID pandemic, delivering a local pilot before scaling up nationwide. We adopt an infrastructural perspective to reveal how two teams of volunteers defined a flexible festival format, knitted together diverse technologies into a technical platform, and operated this to deliver the festival. We highlight the need for teams of volunteers to orchestrate both audience and performer trajectories through festivals. We argue for deliberately designing in volunteer labour rather than automating it out by translating traditional roles online while defining new digital ones. We propose to make these roles rewarding through a more social volunteer experience, including privileged backstage access. We highlight the challenges of using social media for such events, including complying with algorithmic policing of rights.